After having your videos and alignment methods pointed out to me...by one of my students...I switched to your method! I was aware of using the head tube as the datum, by Jamie Swan and others, but no one ever would show how they would cold set it and that always baffled me...you have to cold set and using the bottom bracket whipping post was the only way I knew or was taught. And yes we [at the factories where I worked] always had the problem of not being able to flip the frame and we had very nice flat surface plates. I think it has to do with squeezing the bottom bracket shell and that gives you a different reading every time you smash it in the BB post. So thank you very much!
@@paulbrodie I have read all these and took a machinist class and run CNC and am fascinated with metal and making thing. Your knowledge of lining things up is good. I think of it all like my tire changer and balancer little weight here spins around so pay attention. Thanks for the info.
Could it also be because of the offset while trying to screw in the center of the bottom bracket? By not having cones to precisely index the center of the bottom bracket clamping, even if it's on a outside flat/machine surface plate, that offset could cause the problem when you flip the bike.
I'm not a frame builder, but a hobby machinist. This just show how much can be done with simple home made tools, instead of running off to buy the most expensive and fancy equipment. Very interesting video, and alignment is useful in many ways. Totally agree on the symmetrical test, by flipping the frame over. It should be the same. Thanks.
Old school frame building, I learnt in the 1970's at the Holdsworth cycle, from British old school frame builders same way you do now, thanks for sharing from the UK
Another good show about frames Paul, nice. When I bought my first MTB I could not ride and take off my hand it as no balance at all but six months later I saw a TV documentary about different professions that was about a couple of brothers who built bikes and they had done for 70 years the oldest was 92 years old when they did the program and it was 26 years ago, they showed how they built their bikes including how to align their frames. It was easy, they used the window frame and then aimed and bend with an iron bar, they then told that if you did not do it, you could not cycle without hands on the handlebars. When I had seen the documentary, I tore down my mtb and bent it as they had done, it turned out that the frame was anything but straight but 30 minutes later it was and I still have the bike and ride it.
I saw that documentary on YT the other day! th-cam.com/video/g0QjhGr73Ns/w-d-xo.html. I think I probably saw it in 1989 as well. They had an Italian framebuilder with some fancy machined tools and then cut to Ken, Jack and Norman Taylor in Yorkshire who used the window. They didn't mention whether the window frame itself had been Blanchard ground. I think they also said they'd made 6000 frames. So Paul has to do another 2000 to catch up.
@@benc8386 I have seen this documentary too but but what I am thinking of was made in the mid 90's and was just about these two brothers and maybe only 30 minutes long. They were like Paul told about every step and why they did so, but everything about bicycles is interesting.
I had a machinist teach me that, you never take your hand off the chuck key when it is in the chuck. NEVER. That is best lesson ever when using any machine that uses a Chuck Key. Thanks for the Video. 😎👍
I remember that lesson in school many moons ago! Alas, I managed to switch it on with my hand still holding the key pinning my fingers against the bed. Fortunately, the key shaft left enough gap between it and the handles and at 14 years old, I was still "rubbery" enough to prevent any broken fingers but I had deep wedges in the back of my fingers for a couple of hours. I can be a touch sloppy with safety but 40 years later, I am still very strict in my Chuck/ Chuck-Key discipline!
I'd love that also. Especially as it is harder to find industrial stuff up here in Canada. Did you get it ground flat? Did you do it in the Lower Mainland or cross the border? I got my (used) Tig machine in Ferndale WA because it was about 60% of the cost of a Vancouver one, even with the hassle of driving down to get it.
@paul brodie Hi Paul, a long time ago, I remember watching a motorcycle frame repairer aligning frames virtually exactly the way you do, except that he had a very solidly anchored fixture to attach the bottom bracket to. He aligned by hand, but used much longer bars than you do to give him the leverage to create the force needed. I also saw him demonstrate how much stiffer you can make a frame with the addition of some very simple relatively small gussets. The difference in resistance to twisting force is astonishing. I have another engineering friend here in Melbourne who currently makes motorbike frames, and if they're not aligned when they come off the jig, he either does them by hand with long levers, or uses a very simple hydraulic jack set up to align them. It's great watching you demonstrating these techniques, my oldest son is doing a welding apprenticeship, and wants to start a shop building custom bicycle frames. This will be the first clip I forward to him. I think your channel will be enormously helpful, and of course it's always easier for someone other than 'dad' to teach them.
Andrew thanks for your great comment. Yes, motorcycles can be viewed as very heavy duty bicycles in some ways. I was always reading motorcycle magazines when I was a kid and became quite aware of gussets and how they could increase strength. Thanks for watching!
Over engineered solution vs old school, tried and true machinist practices based on basic geometric principles. Simpler is always better. Thanks for taking the time to show this.
As stated in the comments, the surface table should be very accurate for flatness, I would suspect the subtle amount that the downtube is off-centre to the BB is the reason for the discrepancy and perhaps the clamp that holds the seat tube doesn't do enough to isolate movement in that area. the theory behind the expensive surface table is sound, what it doesn't allow for is making a "best case" alignment for a frame when there are discrepancies present (which would almost always be the case). Paul's familiarity with his own method and the way it isolates the different steps are what give him confidence in the result.
That was g'damn awesome. I am getting a 73 Atala back from the sandblaster this week. I have a Home Cheapo straightedge, a c- clamp and a tape measure. I will do what I can.
Really interesting video. My thought after watching it was how well does the alignment hold with use? There wasn't a tremendous amount of force needed to tweak things. I saw you answer to a similar question below, and it sounds like alignments hold well with regular use. I like the examples using homemade alignment tools. Thanks for that. Very useful, and shows what a little creativity and knowledge can do.
When I was a student in the machine shop the way the chuck key being left in the chuck was handled was a demonstration by the teacher. Everyone stood to one side. He put the key in and punched the start button with a bit of tubing. The chuck key fetched up in the wall that was some decent distance away with almighty bang. Yes the wall had numerous holes in it! Then we were taken to the office and shown his 'archive' of accidents involving Lathes that he had attended as an OHS inspector over the years. What was seen cannot be unseen. Over the next two years nobody in the class left the chuck in that I ever saw.
Yes, that is certainly one way of leaving an impression. You can also damage the lathe and the chuck key, so that would not be my first choice. But thanks :)
A drill press I have came with a chuck key with a spring centre bit so it will pop out if you aren't holding it in. Might be a good idea for a student use lathe in a school.
I am glad I found your videos as a craftsman is always a joy to watch, Watching your other videos it is easy to you have refined your metal working skills to a very high standard. I came up in auto racing and we straightened race car frames with the same principles as you use. Tie one corner down , support it at the point to bend and as many people as needed on the opposite corner to apply the bending force. Multiple tie downs also help if the supply of human counter weight is low
Thanks so much for making your channel Paul. I've built two fillet brazed frames and I'm soaking up your content like a sponge. Seeing you jump on the front triangle while it's bolted to your jig/plate brings back memories!
thank you for sharing this! i dont have the space for an alignmet table as a hobbyist, but your method should work fine in the tight space i have. and its very impressive how far you have to move a frame to get it to bend permanently
I got here one year later, but it was still a very impressive video! I don't build bike frames (or repair them), but I have 3 bikes and I'm pretty sure they are not aligned - now I have some input on how to check them. Thanks!
👏👏👏 i agree 100% with your allignment process. The reason when you clamp the bike to the surface table your assuming that the face of the bottom bracket it in line with the bikes centre line, when in fact most bottom brackets are a pile of cough! So when you flip it over the errors are seen.
You said it well. The BB starts off a nice cylinder but after adding heat and welds or brass etc it is anything but perfect. Facing each side only makes them flat...not parallel. The best we can do is what Brodie does...take an average of the two (thats what your spindle and crank will end up doing anyway) and align everything to that average. I think what Brodie was showing was not tht the blanchard ground plate was off...its that the BB is no longer straight and square...So you end up aligning the frame to two different reference points. This is a fine method but you must again, take an average of the two...very time consuming.
I once injured myself trying to align a frame for a NOLA local frame builder, when I worked at the Bikesmith in NOLA way back in the mid '80s.(my brain forgets his name, he did consultation for NASA in welding technology) Our table used the Campy bb facing inserts to center the bb on the shaft. It had a very stout and heavy picklefork looking tool for prying, but his frames were so stout, I pulled muscles in the ribs, cracked a braze joint, and the stays barely moved. It was a prototype time trial frame with 3 rear stays a side. First thing we did for aligning was chase the bb threads and then face the bb as little as possible to get a full flat surface yet keep the faces where they were supposed to be. When I flipped frames to check, if it wasn't right both sides, the measurements were wrong at the start. I forget the brand table it was, but it was just a small cast iron one that used a machinist indicators. I rarely had issues with it being right when aligned crank side down vs checking it crank side up. That said, road frames were notorious for moving any how . . . try keeping an old Columbus tubed, Motobecane flexi-flyer aligned. Get the head and seat tube at ∟ to the bb and get the axles in place, and first ride, it moves.
You're 100% classy Paul. Thanks again... I always look forward to your videos. How many Campagnolo tools do you have? You should do a video on those tools only! I have a full boxed set of Campy tools that I bought back in the late 90s. I still use them when servicing bicycles today.
@@paulbrodie I've heard a very skilled mechanic refer to those Campy dropout alignment tools as 'coconuts'. The (probably older) model he had used rounded half-spheres that were almost the size of said nuts!
Awesome videos, I'm learning a lot. I'm looking to get a 1987 gt performer with the rear tripod bent and a small dent in the down tube. So this is a great help. Thank you.
Thank you a lot Paul! Your videos are a real pleasure in those strange times.I'm learning some nice tricks, thank you again. If you would make a video on checking a motorcycle frame it would be amazing. Ciao from Filandro!
To align a motorcycle frame you need a heavy duty "alignment cage" to push and pull the frame with hydraulics. I do not have one of those, sorry. Thanks for watching!
Thank you for this. Tons of great information. I wish I had got out there for a tour when you were running the school. One question: why are you measuring the centre on the downtube? does it not make more sense to just do head tube and seat tube? To me a downtube theoretically could be any weird shape, like a chain or seat stay can be, as long as it holds the head tube it the right place. But maybe I am missing something? Thanks
Yes, you can measure off the head tube. My alignment fixture is the right length to do the seat tube and down tube. To do the head tube I would need a much longer fixture, especially with modern geometries. I don't use down tubes with "weird shapes". They are very straight. Thanks for watching and commenting.
My cro-mo frame need a going over to spread the rear drops. Your method # 2 looks just like the equipment I'd be rigging up. Thanks for a perfect demo.
Beautiful well documented , well filmed and great value for the mind and skill . Just mind blowing how clearly and easily you explaind techniques and how easy it looks in your hands. Just wow ,exelent tutorials. that's why I really, really appreciate your videos and advices in them . Please have a huge aplouse from me and I hope you will continue to make me be amassed and overvelmed by your videos. Huge fan. Sincerely from across the ocean. Cheers
@@paulbrodie I found it very interesting. One thing I found interesting that caught my attention when you talked about how some bikes you can ride with no hands and some you cannot. I have one bicycle aluminum frame that I’ve recently converted to a bottom bracket E-bike. I used to be able to ride it easily with no hands , Not anymore ,?,I now can feel the rear triangle torque while powering it,.I can no longer ride without hands. I’m thinking the rear portion of the frame is tweaked.? I need to find a stronger frame..
Wow ,,, I never knew that this is where Mighty Mitch made his debut . Ive never seen a surface table like that , is it a special one for bike frame building .? good grief , now Im half way through , and have serious doubts that the surface table is even flat , it would do for making gates on or rough welding jobs ,,,, but thats it. made it to the end , your simple hand tools work the best and follow total logic , the only other thing I would have done was put the frame back on the surface table as a known , and see how far out the table actually is. great video , totally enjoyed it , I will never true a bike frame , but so much of this translates into so many other engineering problems ,.. many thanks for showing us this.
I enjoyed watching the process and wish some of LBS in my area would adopt a similar process in frame alignment. Very educational, thank-you. On another note, in your opinion would you attempt to straighten out a wrinkle in a steel top tube and down tube due to a head on collision or replace both tubes? This is a vintage bike and would prefer to keep as much original as possible.
A head on collision usually produces more than just a "wrinkle". Replacing both tubes is quite a bit of work and is not cheap. You will have to figure out if your Vintage bike bike is worth the cost, time, energy, and paint job to make it a worthwhile and viable project. Good luck 😉
Very helpful video, Paul. I’ve got a 105 year old motorcycle with a bent frame and I’m trying to work out a method for straightening it. Those old motorcycles are a lot like bicycles, so a lot of your tools and methods will be applicable, at least in principle. Thanks. 😎
The motorcycle tubing will be much thicker and stronger. You probably need an "alignment cage" where the frame is held rigidly and force applied (usually hydraulics..) in the right spot to get it back into suitable alignment. Thanks for watching.
I personally use a combination of a faceplate, gauges (some similar to yours), and a known true and dished rear wheel. The trick with a surface plate is not to use the bottom bracket faces as your datum point but to align your tubes to be parellel to the surface plate. This involves checking your tubing and finding the flattest side which, you can use as your reference point. However that goes out the window a bit if the tubing diameter and profile is not the same along its length. But then all my frames are traditional lugged road frames.
@@paulbrodie the bottom bracket faces are parallel to the centre line of the frame but they are not used to as a datum. Personally I would argue that both wheels running in line is more important than a slight discrepancy at the bottom bracket, however the bottom bracket faces are parallel to the surface plate. It is the surface plate that should be the reference as you can check how flat it is. A slight discrepancy at the head tube for example is amplified by the length of the fork. If you use the bottom bracket face as your main reference and then use a tool which then measure the distance from the side of the tube on both sides, how do you know that tube is not bowed? And also how do you know it's perfectly round at that point? When you roll a tube on the surface plate you find that it is not perfectly straight but deviates across its length. Then after that the bottom bracket is abandoned as a reference point and the headtube becomes the reference?
The reason that the surface table doesn't produce more accurate results than it does is because using the surface table introduces a change in the frame of reference, thereby introducing error. You base everything on the bottom bracket - as you should - to align all the other parts. But if you bolt a surface table to the underside of a bike frame, you are making the new frame of reference the surface of the table. So now, instead of aligning everything to the bottom bracket, you are now aligning everything to the surface of the table. No matter how perfect the fixture is and the surface of the table is, the act of bolting the bottom bracket to the table will introduce errors between the bottom bracket and the table's surface, and even more error will be introduced by the height measuring tool that sits on the table surface. A surface table is great for jigging together parts into a unique frame so you can initially weld/braze them together, but anything that is as sensitive as a bike frame apparently is to small changes should use the bottom bracket as it's final all-encompassing frame of reference to bend parts to their final shapes/angles, exactly as you have done.
Enjoyed your video, thanks! I suspect that all the square/rectangular holes in the commercial plate have, by introducing bending forces, deformed the plate to the point where it has lost some accuracy. The forces introduced by the tapered pattern hold down nut-block has not helped that situation either. A master plate of granite or cast iron which has been scraped to a known standard and some Prussian blue will reveal the anomalies in the commercial plate. Likewise it can prove the homemade plate. The homemade plate should have been stress relieved by heat treatment (for mild steels gentle to 1150 F plus or minus 20 degrees soaked for 1 hour of thickness and then gentle cool to ambient). Welding after stress relief will introduce new stresses into the plate, so mechanical fastening is recommended. A reference datum that is truly perpendicular to the axis of the bottom bracket should yield very accurate results.
Thank you Rick. A frame (or fork..) has to be quite far out of alignment before you notice it and can't ride no hands. Maybe you need a better quality bicycle?
Always informative with with amazing snippets... I made my 2 of my frame alignment tools eg: "Brodie Sticks".... simple and effective tools.....a good solid bench and vice needed......now to make a fork stay jig.....and..... ....Hummmm how to do the final head tube seat stay alignment without a flat solid table? Thanks again!
Ok, you usually show us tools that most can access or afford, that table, amazing and out of reach. This needs to be a resource at every community college, available by the hour for jobs like this!
@@paulbrodie yeah, I was drooling over the spendy cast table....then I finished the video and wiped my face. My attitude shifted and I reverted to supporting the manual methods I knew. I no longer have a "need" for that bigol table.
Thank you for the teaching and SHARING! I imported topline Brit bikes from Mercian, Hetchin, Bob Jackson and a few Italian framesets, DaRosa etc when I owned a shop. It was normal to find the alignment off on the well packed frames when they would arrive stateside. Cold setting was D'rigeur. I know your viewers are sharp enough to realize you do NOT use cold setting techniques the same way on aluminum frames. Just on good, faithful steel, Chro-Mo etc.
Paul, simple cure for leaving the key in the chuck; add a spring to the end of the key. By doing so you have to push the key in the square hole and if you release it, it pops out. Safety third ;-) Best, Job
@@paulbrodie I don't use it on my lathes for exactly the same reason. But it's a solution for students. I worked at a factory during my school years. They had quite a firm policy on leaving your chuck key in the chuck. If it happened twice in a two week period you where sacked. Next to this I saw one flying during my education and it made quite an impression. So I don't need a spring too. Thank you Paul. Best! Job
The method that you went through double checks everything. I am not a frame builder but I have straightened a good number of frames. The only frame table that I had available to me warped over time so I would have to flip the frame for each measurement. That is what is going on with the frame table that the University purchased. He is having the table cast and then grinding it without any time to let it settle. It was really suprising to me that the seller of the table didn't understand what you were talking about by flipping the frame. The last frame that I aligned I did on my milling machine.
You might be right about not letting the new casting age. Years ago I heard that the Mercedes factory had engine blocks cast, then left them outside in the elements for several years before bringing them back inside for machining.
And... in the "bicycle co-op" end of town, I teach people how to test and correct frame alignment using a string, a pencil and a 5ft x 2in x 4in (1.75m x 50mm x 100mm) board. As accurate as a rider needs, using less floor space.
It's great how you're sharing your knowledge and passing on great skills. Could it be that the dropouts were so far off because you lowered the alignment tool to the headset bar and I didn't see you move it back to frame height (unless done off camera) to line up the dropouts. It's really late here in England, I should get some sleep. Thanks again.
Years ago I considered buying that alignment table, after this glad I didn’t! I suspect the problem is that the table isn’t flat enough and that the bb post isn’t sufficiently tight fitting in the bb or square with the world. I have a similar setup on a huge granite surface plate that I bought used from a leading Californian bike builder. He had made a beautiful Bb post and I have had no problems with flipping the bike when and aligning it. I do not however gronk on the bike while it is on the stone. I think that surface plate is around 1 thousands within flat across the entire surface. I have also used a Build pro welding table with Bringheli alignment tools, never had any problems with flipping on that either. I think that table was within 3 thou of flat.
@@paulbrodie I suspect it was the design of the cast iron surface plate stand that cause it to go out of flat. With that much material removed from the plate from those holes, that table will sag like a fish net. If you look at other Surface Plate design its always support at 4 corners plus crossbeams in the middle. The table might be surface grounded but i highly doubt they ground it as a whole unit, so when installed on that center post the outer edge will sag under its own weights.
@@kingwu9613 It's a high grade of cast iron, so is very rigid. Highly doubtful it would sag under its' own weight, but it's a great theory. Thanks for watching!
I have a new mountain bike and I can ride with no hands very Easily without problem. I recently restored my father's road bike that has a frame "equal" to this and I cant ride it without hands, it seems that is always tilting to one side and is difficult to control, can be the frame out of alignment then? I think he had a crash on it many years ago idk. Anyway amazing video, thank you!
Some bikes are just hard to ride no hands, like a track bike with a 75 degree head angle. If you can't ride your father's road bike no hands, it is likely the frame is out of alignment. You could do a simple check using some string. Not a perfect system, but it will give you an idea...
The purpose of a bicycle frame (motor or pedal) is that it holds the front and rear wheels in line. So the position of the in-between tubes is not critical so long as 1) the rear wheel centre-line is in-line with the frame centre line . 2) the rear wheel is parallel to the frame centre line . 3) the rear wheel axle is perpendicular to the steering head axis. How does your method cover the above 3 points?
Yes, the purpose of a frame is to hold the wheels inline, but also to provide flex for rider comfort, and assist road holding ability. You've seen the video, when you align a frame this way and your wheels are in dish, then all of your 3 points are covered.
@@paulbrodie A frame cant hold the wheels in line and provide sprung suspension (flex). Further more if there is flex in a structure it becomes a spring. Any spring requires a damper to control the oscillations otherwise the structure system could be come subjected to resonance. I don't see any dampers on that frame.
@@nortoncommandoupgradestrav2474 I think you should go to TH-cam and study up on MotoGP frame design and technology. They are designed to flex a certain amount, in a certain direction. This, in conjunction with the flex of the tires, is what allows those incredible lean angles with out the tires sliding out.
@@paulbrodie Incorrect. Ducati designed a flexible frame to compensate for front suspension stiction between the sliders and stanchions caused by the bending force at large lean angles. A motorcycle frame is designed to keep the front and rear wheels in-line with the frame. The suspension keeps the tyres in contact with the road. The tyres and road surface provide the grip. I think you should read Tony Foale's book, "Motorcycle Chassis Design: The Theory and Practice".
So appreciate these videos, this one especially really demystified something that’d been weighing one me as i gear up to build my first steel frame. Cheers!
OMG that looks like my dream shop... I really need to find a place in South Central PA that can help me learn a few things and maybe I can build a frame and make my own electric bike. Edit: I remember as a kid helping my friends straighten their bmx frames and used a piece of square tube w/ a threaded hole on all sides on the ends and in the middle so I could use a bolt as the fine adjust... I'd just bolt it to whatever I was trying to straighten and use it as leverage, it also worked like an alignment tool because I could use a bolt as my fine adjustment.
I hope you do find a suitable shop, and gain more frame building knowledge. It's a great hobby because your brain will be working hard too, and the end result (hopefully..) will give you many years of riding pleasure. Thanks for watching and commenting.
What truly becomes the zero alignment reference is the crank itself. Any tiny misalignment variables in the bottom bracket shell faces may slightly affect the bearing race parallelism but once the bottom bracket is assembled the crank assumes an averaged position that's becomes predictably consistent. Bottom bracket cups with their bore turned to precisely fit the heavy table's shaft might offer an improvement to the most expensive alignment method in the room. Your bottom bracket face reference alignment tool is packing enough cool tool to leave any table flat on it's floor. Just thinking in a line meant.
I have read a lot of comments from other framebuilders, and it seems they are most concerned with the headtube as a reference point, then aligning the seattube, and finally the dropouts so the wheel will be centred and true to the frame centreline. If the BB faces are close to being parallel with the frame centreline, that's great! Every framebuilder has their own philosophy and way.
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Now this is what you call learning..
The best few minutes spend on TH-cam ever..
Respect
Thank you very much. Appreciate you comments 😄
After having your videos and alignment methods pointed out to me...by one of my students...I switched to your method! I was aware of using the head tube as the datum, by Jamie Swan and others, but no one ever would show how they would cold set it and that always baffled me...you have to cold set and using the bottom bracket whipping post was the only way I knew or was taught. And yes we [at the factories where I worked] always had the problem of not being able to flip the frame and we had very nice flat surface plates. I think it has to do with squeezing the bottom bracket shell and that gives you a different reading every time you smash it in the BB post. So thank you very much!
Thank you Mike!
@@paulbrodie I have read all these and took a machinist class and run CNC and am fascinated with metal and making thing. Your knowledge of lining things up is good. I think of it all like my tire changer and balancer little weight here spins around so pay attention. Thanks for the info.
@@Todd936 Thank you Todd 😉
Could it also be because of the offset while trying to screw in the center of the bottom bracket? By not having cones to precisely index the center of the bottom bracket clamping, even if it's on a outside flat/machine surface plate, that offset could cause the problem when you flip the bike.
@@serdiefgotreb I was at NTC a college and they had one of them tables and he isn’t the only one to have this problem.
I looked into it.
Good day guys
Thank you so much. This will help preserve the tiny precious bit of sanity I still have.
Thanks for watching!
I'm not a frame builder, but a hobby machinist. This just show how much can be done with simple home made tools, instead of running off to buy the most expensive and fancy equipment. Very interesting video, and alignment is useful in many ways. Totally agree on the symmetrical test, by flipping the frame over. It should be the same.
Thanks.
Thanks for watching!
This is the best and easy to find cheap tools to use in alignment
I agree. Thanks for watching!
Old school frame building, I learnt in the 1970's at the Holdsworth cycle, from British old school frame builders same way you do now, thanks for sharing from the UK
Any one want to buy a tracking table, Ha Ha
Paul should have at least 100k subscribers.
Slowly getting there!
Another good show about frames Paul, nice.
When I bought my first MTB I could not ride and take off my hand it as no balance at all but six months later I saw a TV documentary about different professions that was about a couple of brothers who built bikes and they had done for 70 years the oldest was 92 years old when they did the program and it was 26 years ago, they showed how they built their bikes including how to align their frames. It was easy, they used the window frame and then aimed and bend with an iron bar, they then told that if you did not do it, you could not cycle without hands on the handlebars. When I had seen the documentary, I tore down my mtb and bent it as they had done, it turned out that the frame was anything but straight but 30 minutes later it was and I still have the bike and ride it.
Good on you to straighten your own frame. Thanks for watching!
I saw that documentary on YT the other day! th-cam.com/video/g0QjhGr73Ns/w-d-xo.html. I think I probably saw it in 1989 as well. They had an Italian framebuilder with some fancy machined tools and then cut to Ken, Jack and Norman Taylor in Yorkshire who used the window. They didn't mention whether the window frame itself had been Blanchard ground. I think they also said they'd made 6000 frames. So Paul has to do another 2000 to catch up.
@@benc8386 I have seen this documentary too but but what I am thinking of was made in the mid 90's and was just about these two brothers and maybe only 30 minutes long. They were like Paul told about every step and why they did so, but everything about bicycles is interesting.
Great masterclass Mr. Brodie!
I had a machinist teach me that,
you never take your hand off the chuck key when it is in the chuck.
NEVER. That is best lesson ever when using any machine that uses a Chuck Key.
Thanks for the Video. 😎👍
That's a good lesson. Thanks for watching!
I remember that lesson in school many moons ago!
Alas, I managed to switch it on with my hand still holding the key pinning my fingers against the bed.
Fortunately, the key shaft left enough gap between it and the handles and at 14 years old, I was still "rubbery" enough to prevent any broken fingers but I had deep wedges in the back of my fingers for a couple of hours.
I can be a touch sloppy with safety but 40 years later, I am still very strict in my Chuck/ Chuck-Key discipline!
Thanks for your videos
Ken, thanks for liking our videos 😉
I like starting with bottom bracket seems logical
Yes, that's where most frame builders start. There are a few exceptions... 😉
I'd love to see a video about building that mini alignment table!
Might be able to do an overview. Will add that to the list. Thanks for watching!
@@paulbrodie actually the little bit you did in the shop tour was pretty helpful!
I'd love that also. Especially as it is harder to find industrial stuff up here in Canada. Did you get it ground flat? Did you do it in the Lower Mainland or cross the border? I got my (used) Tig machine in Ferndale WA because it was about 60% of the cost of a Vancouver one, even with the hassle of driving down to get it.
@paul brodie Hi Paul, a long time ago, I remember watching a motorcycle frame repairer aligning frames virtually exactly the way you do, except that he had a very solidly anchored fixture to attach the bottom bracket to. He aligned by hand, but used much longer bars than you do to give him the leverage to create the force needed. I also saw him demonstrate how much stiffer you can make a frame with the addition of some very simple relatively small gussets. The difference in resistance to twisting force is astonishing. I have another engineering friend here in Melbourne who currently makes motorbike frames, and if they're not aligned when they come off the jig, he either does them by hand with long levers, or uses a very simple hydraulic jack set up to align them. It's great watching you demonstrating these techniques, my oldest son is doing a welding apprenticeship, and wants to start a shop building custom bicycle frames. This will be the first clip I forward to him. I think your channel will be enormously helpful, and of course it's always easier for someone other than 'dad' to teach them.
Andrew thanks for your great comment. Yes, motorcycles can be viewed as very heavy duty bicycles in some ways. I was always reading motorcycle magazines when I was a kid and became quite aware of gussets and how they could increase strength. Thanks for watching!
Over engineered solution vs old school, tried and true machinist practices based on basic geometric principles. Simpler is always better. Thanks for taking the time to show this.
I agree. Simpler is always better. Thanks for watching.
Yes yes yes! Great topic. Fork alignment would make just as interesting viewing. Thanks again for these amazing videos
If you check the Unicrown video fork alignment is covered there.
Hello Paul your a good man, you answered almost all the comments in this channel, God bless you Paul! Take care!
Thank you Shem. Yes, so far I can keep up with the comments. Not sure what happens as the channel grows!
Even better on the second viewing. Thanks again Paul.
I love the Eyecrometer. Hopefully one day mine will be as accurate as Paul's.
You will have to practice a lot!
What an awesome space to take a class. Thanks for the alignment tips. Very helpful.
Very good tips. Thanks🚲🚲🚲
Thank you Mark.
As stated in the comments, the surface table should be very accurate for flatness, I would suspect the subtle amount that the downtube is off-centre to the BB is the reason for the discrepancy and perhaps the clamp that holds the seat tube doesn't do enough to isolate movement in that area. the theory behind the expensive surface table is sound, what it doesn't allow for is making a "best case" alignment for a frame when there are discrepancies present (which would almost always be the case). Paul's familiarity with his own method and the way it isolates the different steps are what give him confidence in the result.
Gregory, thanks for watching and commenting.
Thanks Paul for sharing your methods. You are like a Shaolin Monk sharing the sacred art with the outside world...Watch your back!
Makes me think of pancakes for some reason. Thanks for watching!
Thanks Mr. Brodie. You are a true Master Builder.
That was g'damn awesome. I am getting a 73 Atala back from the sandblaster this week. I have a Home Cheapo straightedge, a c- clamp and a tape measure. I will do what I can.
Interesting, mesmerizing, and relaxing.
Thanks Jo!
Usted es un gran maestro. Ahora toca conseguir esas herramientas o hacerlas.
Gracias por compartir sus conocimientos.
Thanks for watching..
Really interesting video. My thought after watching it was how well does the alignment hold with use? There wasn't a tremendous amount of force needed to tweak things. I saw you answer to a similar question below, and it sounds like alignments hold well with regular use. I like the examples using homemade alignment tools. Thanks for that. Very useful, and shows what a little creativity and knowledge can do.
Thank you Chuck!
Once it has yielded, it won't return. That's the fundamental difference between elastic and plastic deformation.
Love seeing the Campy dropout tools in use. Reminds me of my bike shop days 🤠🔥🔨
Great work
Thank you Shakeel.
When I was a student in the machine shop the way the chuck key being left in the chuck was handled was a demonstration by the teacher. Everyone stood to one side. He put the key in and punched the start button with a bit of tubing. The chuck key fetched up in the wall that was some decent distance away with almighty bang. Yes the wall had numerous holes in it! Then we were taken to the office and shown his 'archive' of accidents involving Lathes that he had attended as an OHS inspector over the years. What was seen cannot be unseen. Over the next two years nobody in the class left the chuck in that I ever saw.
Yes, that is certainly one way of leaving an impression. You can also damage the lathe and the chuck key, so that would not be my first choice. But thanks :)
A drill press I have came with a chuck key with a spring centre bit so it will pop out if you aren't holding it in. Might be a good idea for a student use lathe in a school.
I am glad I found your videos as a craftsman is always a joy to watch, Watching your other videos it is easy to you have refined your metal working skills to a very high standard. I came up in auto racing and we straightened race car frames with the same principles as you use. Tie one corner down , support it at the point to bend and as many people as needed on the opposite corner to apply the bending force. Multiple tie downs also help if the supply of human counter weight is low
That's cool! Now I know how to straighten a race car frame. I like being a part of those kind of things. Thanks for watching!
Amazing Sir
Semesta, thank you.
Thanks so much for making your channel Paul. I've built two fillet brazed frames and I'm soaking up your content like a sponge. Seeing you jump on the front triangle while it's bolted to your jig/plate brings back memories!
Thanks for watching!
wow Paul, thank you!!!!!
You're welcome. Thanks for watching!
thank you for sharing this! i dont have the space for an alignmet table as a hobbyist, but your method should work fine in the tight space i have.
and its very impressive how far you have to move a frame to get it to bend permanently
Yes, some frames are pretty tough and have a lot of "spring". Thanks for watching!
A super lesson for aligning a crooked bicycle frame.
Thanks!!!
I got here one year later, but it was still a very impressive video! I don't build bike frames (or repair them), but I have 3 bikes and I'm pretty sure they are not aligned - now I have some input on how to check them. Thanks!
Thanks for watching!
@@paulbrodie My pleasure 🙂
love your videos Paul and this has to be my favorite one yet. I hope you're healing up ok!
Thanks Eric. Yes, I am spending more time in my shop so I must be getting better! 😉
👏👏👏 i agree 100% with your allignment process. The reason when you clamp the bike to the surface table your assuming that the face of the bottom bracket it in line with the bikes centre line, when in fact most bottom brackets are a pile of cough! So when you flip it over the errors are seen.
You said it well. The BB starts off a nice cylinder but after adding heat and welds or brass etc it is anything but perfect. Facing each side only makes them flat...not parallel. The best we can do is what Brodie does...take an average of the two (thats what your spindle and crank will end up doing anyway) and align everything to that average. I think what Brodie was showing was not tht the blanchard ground plate was off...its that the BB is no longer straight and square...So you end up aligning the frame to two different reference points. This is a fine method but you must again, take an average of the two...very time consuming.
I know I'm a #fussyframebuilder when it comes to alignment, and that makes me wonder just how fussy other framebuilders are.
@@paulbrodie im no frame builder but i would have done it your way. As i was taught " if a jobs worth doing its worth doing well"
Following from Germany
Your Channel is fantastic.
I learned so much. 😀
Thanks for watching!
I once injured myself trying to align a frame for a NOLA local frame builder, when I worked at the Bikesmith in NOLA way back in the mid '80s.(my brain forgets his name, he did consultation for NASA in welding technology)
Our table used the Campy bb facing inserts to center the bb on the shaft. It had a very stout and heavy picklefork looking tool for prying, but his frames were so stout, I pulled muscles in the ribs, cracked a braze joint, and the stays barely moved. It was a prototype time trial frame with 3 rear stays a side.
First thing we did for aligning was chase the bb threads and then face the bb as little as possible to get a full flat surface yet keep the faces where they were supposed to be. When I flipped frames to check, if it wasn't right both sides, the measurements were wrong at the start. I forget the brand table it was, but it was just a small cast iron one that used a machinist indicators. I rarely had issues with it being right when aligned crank side down vs checking it crank side up.
That said, road frames were notorious for moving any how . . . try keeping an old Columbus tubed, Motobecane flexi-flyer aligned. Get the head and seat tube at ∟ to the bb and get the axles in place, and first ride, it moves.
Thanks for your stories. Hope the rib muscles fully healed!
@@paulbrodie back then, I was young and healed fast (~_^)
The way you explain and transfer knowledge is absolutely great. Thanks
Thank you Abraham.
"Alignment" has some good music.
Thanks for sharing so much of your experience! This is of incredible value.
You're 100% classy Paul. Thanks again... I always look forward to your videos.
How many Campagnolo tools do you have? You should do a video on those tools only!
I have a full boxed set of Campy tools that I bought back in the late 90s. I still use them when servicing bicycles today.
I have the Campy dropout alignment tools, one insert for facing the BB, and a pair of Campy 1" headset wrenches. That's it. Thanks for watching!
@@paulbrodie I've heard a very skilled mechanic refer to those Campy dropout alignment tools as 'coconuts'. The (probably older) model he had used rounded half-spheres that were almost the size of said nuts!
@@sampowrie6381 I have not heard that...
Thank you Sir...more of your expertise to share
Thanks for your video.. im planning to build my own frame,😊
Very good. I hope it works out well for you.
This was simply delightful to watch! thanks for sharing all that knowledge and experience Paul. It's priceless, really :)
Thank you Martin.
Awesome videos, I'm learning a lot. I'm looking to get a 1987 gt performer with the rear tripod bent and a small dent in the down tube. So this is a great help. Thank you.
Thank you a lot Paul! Your videos are a real pleasure in those strange times.I'm learning some nice tricks, thank you again. If you would make a video on checking a motorcycle frame it would be amazing. Ciao from Filandro!
To align a motorcycle frame you need a heavy duty "alignment cage" to push and pull the frame with hydraulics. I do not have one of those, sorry. Thanks for watching!
This was great! thank you, would love to see a fork alignment too
The Unicrown video has fork alignment, and so does the Gatorblade video, which also happens to be our very first video.
Thank you for this. Tons of great information. I wish I had got out there for a tour when you were running the school.
One question: why are you measuring the centre on the downtube? does it not make more sense to just do head tube and seat tube? To me a downtube theoretically could be any weird shape, like a chain or seat stay can be, as long as it holds the head tube it the right place. But maybe I am missing something?
Thanks
Yes, you can measure off the head tube. My alignment fixture is the right length to do the seat tube and down tube. To do the head tube I would need a much longer fixture, especially with modern geometries. I don't use down tubes with "weird shapes". They are very straight. Thanks for watching and commenting.
Brilliant amount of information thanks again you’re saving me a lot of money and allowed me to go in a different direction 😊👍
Right on.
My cro-mo frame need a going over to spread the rear drops. Your method # 2 looks just like the equipment I'd be rigging up. Thanks for a perfect demo.
Thank you Paul for your awesome sharing of knowledge !
Nicholas you are welcome!
Excelente adiestramiento. Es un genio!!
Thanks for watching!
Podrías hacer un vídeo igual pero alineando horquillas
Excellent video! Thank you for showing both options! Really educational!
Thank you David!
Excellent video Paul! Thanks for your time, cheers, Doug
Thank you Doug.
Beautiful well documented , well filmed and great value for the mind and skill . Just mind blowing how clearly and easily you explaind techniques and how easy it looks in your hands. Just wow ,exelent tutorials. that's why I really, really appreciate your videos and advices in them . Please have a huge aplouse from me and I hope you will continue to make me be amassed and overvelmed by your videos. Huge fan. Sincerely from across the ocean. Cheers
Thank you Darko. Yes, Mitch and I were just filming another episode today. After a month holiday it was good to be back!
@@headcrusher1966 Thank you Gabagool. You are figuring it out with common sense and logic, and your explanations are easy to follow too.
Fantastic video 😊
Thank you very much...
@@paulbrodie I found it very interesting. One thing I found interesting that caught my attention when you talked about how some bikes you can ride with no hands and some you cannot. I have one bicycle aluminum frame that I’ve recently converted to a bottom bracket E-bike. I used to be able to ride it easily with no hands , Not anymore ,?,I now can feel the rear triangle torque while powering it,.I can no longer ride without hands. I’m thinking the rear portion of the frame is tweaked.? I need to find a stronger frame..
Wow ,,, I never knew that this is where Mighty Mitch made his debut .
Ive never seen a surface table like that , is it a special one for bike frame building .?
good grief , now Im half way through , and have serious doubts that the surface table is even flat , it would do for making gates on or rough welding jobs ,,,, but thats it.
made it to the end , your simple hand tools work the best and follow total logic , the only other thing I would have done was put the frame back on the surface table as a known , and see how far out the table actually is.
great video , totally enjoyed it , I will never true a bike frame , but so much of this translates into so many other engineering problems ,.. many thanks for showing us this.
Thank you ,, you have educated me . I'm really surprised that the "expensive" table is out of wack ,
Thank you for your experience ;)
And thank you for watching.
I enjoyed watching the process and wish some of LBS in my area would adopt a similar process in frame alignment. Very educational, thank-you. On another note, in your opinion would you attempt to straighten out a wrinkle in a steel top tube and down tube due to a head on collision or replace both tubes? This is a vintage bike and would prefer to keep as much original as possible.
A head on collision usually produces more than just a "wrinkle". Replacing both tubes is quite a bit of work and is not cheap. You will have to figure out if your Vintage bike bike is worth the cost, time, energy, and paint job to make it a worthwhile and viable project. Good luck 😉
Very helpful video, Paul. I’ve got a 105 year old motorcycle with a bent frame and I’m trying to work out a method for straightening it. Those old motorcycles are a lot like bicycles, so a lot of your tools and methods will be applicable, at least in principle. Thanks. 😎
The motorcycle tubing will be much thicker and stronger. You probably need an "alignment cage" where the frame is held rigidly and force applied (usually hydraulics..) in the right spot to get it back into suitable alignment. Thanks for watching.
@@paulbrodie agreed. I have some thoughts on how I might do this, but I’ll be “winging it.” Thanks for the response. 😎
using a cast bb shell, if the faces are not equal to the centerline of the bores . the frame will be out, when you fill it. i was by tot by D.S.
What a lesson!. Great method, simple and with common tools, great. I will take note
Thank you Jorge!
I personally use a combination of a faceplate, gauges (some similar to yours), and a known true and dished rear wheel.
The trick with a surface plate is not to use the bottom bracket faces as your datum point but to align your tubes to be parellel to the surface plate. This involves checking your tubing and finding the flattest side which, you can use as your reference point.
However that goes out the window a bit if the tubing diameter and profile is not the same along its length. But then all my frames are traditional lugged road frames.
So if the bottom bracket faces are not parallel with the centre line of the frame, you're ok with that...
@@paulbrodie the bottom bracket faces are parallel to the centre line of the frame but they are not used to as a datum. Personally I would argue that both wheels running in line is more important than a slight discrepancy at the bottom bracket, however the bottom bracket faces are parallel to the surface plate. It is the surface plate that should be the reference as you can check how flat it is.
A slight discrepancy at the head tube for example is amplified by the length of the fork.
If you use the bottom bracket face as your main reference and then use a tool which then measure the distance from the side of the tube on both sides, how do you know that tube is not bowed? And also how do you know it's perfectly round at that point? When you roll a tube on the surface plate you find that it is not perfectly straight but deviates across its length.
Then after that the bottom bracket is abandoned as a reference point and the headtube becomes the reference?
@@paulgibson9006 Good comment, thank you.
Thank you so much for sharing!
Thanks for watching!
The reason that the surface table doesn't produce more accurate results than it does is because using the surface table introduces a change in the frame of reference, thereby introducing error. You base everything on the bottom bracket - as you should - to align all the other parts. But if you bolt a surface table to the underside of a bike frame, you are making the new frame of reference the surface of the table. So now, instead of aligning everything to the bottom bracket, you are now aligning everything to the surface of the table. No matter how perfect the fixture is and the surface of the table is, the act of bolting the bottom bracket to the table will introduce errors between the bottom bracket and the table's surface, and even more error will be introduced by the height measuring tool that sits on the table surface. A surface table is great for jigging together parts into a unique frame so you can initially weld/braze them together, but anything that is as sensitive as a bike frame apparently is to small changes should use the bottom bracket as it's final all-encompassing frame of reference to bend parts to their final shapes/angles, exactly as you have done.
Yes, I am not a fan of surface tables, for the reasons you gave. Thanks for watching and commenting.
Enjoyed your video, thanks! I suspect that all the square/rectangular holes in the commercial plate have, by introducing bending forces, deformed the plate to the point where it has lost some accuracy. The forces introduced by the tapered pattern hold down nut-block has not helped that situation either. A master plate of granite or cast iron which has been scraped to a known standard and some Prussian blue will reveal the anomalies in the commercial plate. Likewise it can prove the homemade plate. The homemade plate should have been stress relieved by heat treatment (for mild steels gentle to 1150 F plus or minus 20 degrees soaked for 1 hour of thickness and then gentle cool to ambient). Welding after stress relief will introduce new stresses into the plate, so mechanical fastening is recommended. A reference datum that is truly perpendicular to the axis of the bottom bracket should yield very accurate results.
Love your videos.
I've never built a frame, but do sometimes wonder why some bikes I ride won't go straight with hands off the bars. Awesome
Thank you Rick. A frame (or fork..) has to be quite far out of alignment before you notice it and can't ride no hands. Maybe you need a better quality bicycle?
Wow thanks a lot Paul for this video!
You sir is a very good mecanical teatcher☺️☺️☺️👌
Thank you Robert.
Always informative with with amazing snippets... I made my 2 of my frame alignment tools eg: "Brodie Sticks".... simple and effective tools.....a good solid bench and vice needed......now to make a fork stay jig.....and.....
....Hummmm how to do the final head tube seat stay alignment without a flat solid table? Thanks again!
Ok, you usually show us tools that most can access or afford, that table, amazing and out of reach. This needs to be a resource at every community college, available by the hour for jobs like this!
If you are talking about the large surface table, I do not believe it is necessary.
@@paulbrodie yeah, I was drooling over the spendy cast table....then I finished the video and wiped my face. My attitude shifted and I reverted to supporting the manual methods I knew. I no longer have a "need" for that bigol table.
@@patrickhayes3099 And you'll have extra room in your shop :)
Thank you for the teaching and SHARING! I imported topline Brit bikes from Mercian, Hetchin, Bob Jackson and a few Italian framesets, DaRosa etc when I owned a shop. It was normal to find the alignment off on the well packed frames when they would arrive stateside. Cold setting was D'rigeur. I know your viewers are sharp enough to realize you do NOT use cold setting techniques the same way on aluminum frames. Just on good, faithful steel, Chro-Mo etc.
Bud, good stories. Thanks for watching and commenting.
Paul, simple cure for leaving the key in the chuck; add a spring to the end of the key. By doing so you have to push the key in the square hole and if you release it, it pops out. Safety third ;-) Best, Job
Yes, I have seen that method. I'm sure it works but I would hate it and wouldn't want it on my chuck key. But thanks for mentioning it :)
@@paulbrodie I don't use it on my lathes for exactly the same reason. But it's a solution for students. I worked at a factory during my school years. They had quite a firm policy on leaving your chuck key in the chuck. If it happened twice in a two week period you where sacked. Next to this I saw one flying during my education and it made quite an impression. So I don't need a spring too. Thank you Paul. Best! Job
The method that you went through double checks everything. I am not a frame builder but I have straightened a good number of frames. The only frame table that I had available to me warped over time so I would have to flip the frame for each measurement. That is what is going on with the frame table that the University purchased. He is having the table cast and then grinding it without any time to let it settle. It was really suprising to me that the seller of the table didn't understand what you were talking about by flipping the frame. The last frame that I aligned I did on my milling machine.
You might be right about not letting the new casting age. Years ago I heard that the Mercedes factory had engine blocks cast, then left them outside in the elements for several years before bringing them back inside for machining.
Amazing there are no weld burns on the straightening plate.
Yes, totally amazing! 😉
And... in the "bicycle co-op" end of town, I teach people how to test and correct frame alignment using a string, a pencil and a 5ft x 2in x 4in (1.75m x 50mm x 100mm) board. As accurate as a rider needs, using less floor space.
Years ago I used the string method. It's good if that's all you have.
It's great how you're sharing your knowledge and passing on great skills.
Could it be that the dropouts were so far off because you lowered the alignment tool to the headset bar and I didn't see you move it back to frame height (unless done off camera) to line up the dropouts.
It's really late here in England, I should get some sleep. Thanks again.
It is possible. On the video we only usually do one take, so it's basically "live", and mistakes can happen. I can't remember. Thanks for watching!
I really really really thank you for your knowledge giving!
You are an amazing guy!!!
Thanks again!!
Stylianos, thanks for watching. It is the right time in my life to be sharing my knowledge.
Years ago I considered buying that alignment table, after this glad I didn’t! I suspect the problem is that the table isn’t flat enough and that the bb post isn’t sufficiently tight fitting in the bb or square with the world. I have a similar setup on a huge granite surface plate that I bought used from a leading Californian bike builder. He had made a beautiful Bb post and I have had no problems with flipping the bike when and aligning it. I do not however gronk on the bike while it is on the stone. I think that surface plate is around 1 thousands within flat across the entire surface. I have also used a Build pro welding table with Bringheli alignment tools, never had any problems with flipping on that either. I think that table was within 3 thou of flat.
The table was surface ground, so it can't be out that much...
Id like a demmeler table .......expensive though
@@paulbrodie I suspect it was the design of the cast iron surface plate stand that cause it to go out of flat. With that much material removed from the plate from those holes, that table will sag like a fish net. If you look at other Surface Plate design its always support at 4 corners plus crossbeams in the middle. The table might be surface grounded but i highly doubt they ground it as a whole unit, so when installed on that center post the outer edge will sag under its own weights.
@@kingwu9613 It's a high grade of cast iron, so is very rigid. Highly doubtful it would sag under its' own weight, but it's a great theory. Thanks for watching!
@@paulbrodie If it was surface ground under different enough ambient temperatures vs your shop maybe?
I have a new mountain bike and I can ride with no hands very Easily without problem. I recently restored my father's road bike that has a frame "equal" to this and I cant ride it without hands, it seems that is always tilting to one side and is difficult to control, can be the frame out of alignment then? I think he had a crash on it many years ago idk.
Anyway amazing video, thank you!
Some bikes are just hard to ride no hands, like a track bike with a 75 degree head angle. If you can't ride your father's road bike no hands, it is likely the frame is out of alignment. You could do a simple check using some string. Not a perfect system, but it will give you an idea...
amazing job i have one ,crashed frame and now i know how to fix it, tnx from brazil,
although dont have those tools
Hey Brazil, thanks for watching!
Master Class Frame Tweaking!
You know it! Thanks Sean.
Realigned a car frame with a telephone pole a torch, I beam, and come along. SPOT ON !
Excellent!
A truly realigned car is straighter (in most cases) then it sold new as !
The purpose of a bicycle frame (motor or pedal) is that it holds the front and rear wheels in line. So the position of the in-between tubes is not critical so long as 1) the rear wheel centre-line is in-line with the frame centre line . 2) the rear wheel is parallel to the frame centre line . 3) the rear wheel axle is perpendicular to the steering head axis. How does your method cover the above 3 points?
Yes, the purpose of a frame is to hold the wheels inline, but also to provide flex for rider comfort, and assist road holding ability. You've seen the video, when you align a frame this way and your wheels are in dish, then all of your 3 points are covered.
@@paulbrodie A frame cant hold the wheels in line and provide sprung suspension (flex). Further more if there is flex in a structure it becomes a spring. Any spring requires a damper to control the oscillations otherwise the structure system could be come subjected to resonance. I don't see any dampers on that frame.
@@nortoncommandoupgradestrav2474 I think you should go to TH-cam and study up on MotoGP frame design and technology. They are designed to flex a certain amount, in a certain direction. This, in conjunction with the flex of the tires, is what allows those incredible lean angles with out the tires sliding out.
@@paulbrodie Incorrect. Ducati designed a flexible frame to compensate for front suspension stiction between the sliders and stanchions caused by the bending force at large lean angles. A motorcycle frame is designed to keep the front and rear wheels in-line with the frame. The suspension keeps the tyres in contact with the road. The tyres and road surface provide the grip. I think you should read Tony Foale's book, "Motorcycle Chassis Design: The Theory and Practice".
@@nortoncommandoupgradestrav2474 You are correct. I have no clue. You are indeed the expert.
excellent ! very well explained.
That's great! What about thru axles?
I have thru axles on my MTB. What about them?
Paul Brodie Bike whisperer thanks
Nice job! 👏👏👏👏👏
Thank you!
So appreciate these videos, this one especially really demystified something that’d been weighing one me as i gear up to build my first steel frame. Cheers!
OMG that looks like my dream shop... I really need to find a place in South Central PA that can help me learn a few things and maybe I can build a frame and make my own electric bike.
Edit: I remember as a kid helping my friends straighten their bmx frames and used a piece of square tube w/ a threaded hole on all sides on the ends and in the middle so I could use a bolt as the fine adjust... I'd just bolt it to whatever I was trying to straighten and use it as leverage, it also worked like an alignment tool because I could use a bolt as my fine adjustment.
I hope you do find a suitable shop, and gain more frame building knowledge. It's a great hobby because your brain will be working hard too, and the end result (hopefully..) will give you many years of riding pleasure. Thanks for watching and commenting.
I got a question, doesnt the oversized parts of the tubing influence the part where the tube is bending?
It could, yes.
Awesome video !!! This just goes to show you don’t have to spend a lot of money to do a better tune !!
Thank you Timothy. You are correct. You don't have to spend a lot of money if you are resourceful and creative...
I really like the shop made tools. Not everyone starting out has the tools. Keep the hacks coming,
You know you are set when the tool to make the US$50 tool cost US$50,000.
What truly becomes the zero alignment reference is the crank itself. Any tiny misalignment variables in the bottom bracket shell faces may slightly affect the bearing race parallelism but once the bottom bracket is assembled the crank assumes an averaged position that's becomes predictably consistent.
Bottom bracket cups with their bore turned to precisely fit the heavy table's shaft might offer an improvement to the most expensive alignment method in the room.
Your bottom bracket face reference alignment tool is packing enough cool tool to leave any table flat on it's floor.
Just thinking in a line meant.
I have read a lot of comments from other framebuilders, and it seems they are most concerned with the headtube as a reference point, then aligning the seattube, and finally the dropouts so the wheel will be centred and true to the frame centreline. If the BB faces are close to being parallel with the frame centreline, that's great! Every framebuilder has their own philosophy and way.