I have to say I've never built a Bike Frame before, but as a TIG Welder of over 20 years whenever doing Structural Assembly (round or square tubing) we provided maximum support with Jigs and/or Fixtures minimising distortion. I've seen other Videos of Frame-builders do the same - Tacking all the Joints in the Jig, but doing the Full Welds out of the Jig? For myself personally, I found it hard enough keeping things square, even with max support of Jigs and Fixtures, than just Welding without them.. regardless of welding sequences! Just to mention, whenever the call on welding Tubing, or materials of 18 gage or thinner, we always used a .040" Tungsten, minimising the HAZ, in the parts!
Problem is that it becomes very difficult to reach certain spots while the frame is in the jig. So it becomes a tradeoff between minmizing distortion and potentially getting bad welds due to awkward positioning/visibility. Since you want the welds on a frame to be as nice as possible most people choose to weld in a position that is as comfortable as possible. Also cold setting is very common in framebuilding since it always distorts a little anyway. Ideally you'd have an alignment table or surface plate to mount the frame after welding and then align it.
kbex I’m ok with organic channel growth. And glad to have viewers who actually care about what I’m doing. 👍 thanks for the kind words none the less. And thanks for watching!
@Pithy Bikes when you are welding metals, some metals more and some less, but all have same characteristic to bend during welding. That is why you measure precisely before welding then after welding there is different angle. This effect you need to take on account when you are welding thin metals.
16:20 A way of stopping the bridge pulling the dropouts together is to spread them with the dummy axle before fitting the bridge. That way when welded it will pull them into the correct position and you wont have to cold set them afterwards. HTH
Really enjoyed seeing what it takes to build a frame set. I’m an old USCF Cat 2 roadie that used to race for Raleigh many years ago. Been thinking of building a frame between welding jobs. I’m a new Sub as well. Cheers!
I usually never expect the frame to be in the same spot after welding it fully. And end up bending it after. If using the welding to try to straighten the frame, need to see it move while welding with pointers extended from the pieces being welded. Weld a spot then watch the pointer till it cools then weld a different spot to bring it back, sort a thing.
This whole experience has made me really miss the aluminum jig that I own. The wood jig was a good experiment and experience but it does add a significant amount of "off the jig" alignment work. I had nearly no alignment issues with the aluminum jig and have built 2 frames on it so far.
Nice fabrication , wondering about mig welding rather than the tig , .6 wire pulsed on a multi roller wire feed unit I would think would give a better result , than the tig , which I've noticed even on high end bikes often show slight undercutting ,
Paul Schmidtke never tried mig so have no idea. For this particular application, TIG is what pros use. But would be interested to know if anyone has had success with mig.
Question: can't you cold set the stays once both sets are welded? Or would that be too rigid a structure. Finally, isn't a bit dangerous to take these measurements off the tyre and not the rim? Tyres can be a little off-centre in places even when mounted carefully? Looks like you got a good result in the end though!
Richard H yep cold setting before the SS works well. In the end that’s basically what I did. And yes the tire is not the most accurate gauge! Some builders make an actual gauge for that purpose. In my case, I built the wheel and know it’s within 2 mm.
Twisting the rear axle (as Steve was doing) when the SS are in there is next to impossible but bending the left or right sides in or out a bit to correct spacing or left/right centering is quite easy. If you do need a twist it works to just file the dropout a bit. If the wheel is 5mm too far to one side at the top that's only about 1mm at the dropout (for a 700c wheel, Steve's are quite a bit smaller). If you're building something with a thru axle then this isn't an option and you have to get it perfect first time. I suspect the reason old British bikes used to have those sort of diagonal horizontal dropouts was so you could get away with a fairly misaligned frame and just correct it every time you put the wheel in :)
@@PithyBikes That's not what he's trying to say. You built the wheel & trued the Rim to +/-2mm but the tyre (tire in USA) is not that accurate and very rarely sits perfectly centered on the Rim. Even if you get the bead seated perfectly the tyre's tread can still be way off to one side or snake side to side.
Ben C great question and I was waiting for someone to ask! So I’ve been learning a lot about the downside of the low cost jig. No surprise that rigidity is an issue. The other problems are more with my design of BB shell fixture and dummy axle fixture. I have a solution that I’ll talk about in next video. Long story short, main frame could be stiffer and fixtures need better tolerance.
@@PithyBikes Looking forward to the next video. My homemade jig is very untrustworthy. I found a good way to measure what was going on with the rear end was to use a bit of string around the dropouts and the bottom of the ST and then to repeat with the string around the top of the ST (i.e. over the TT) in both cases comparing left and right distances between the rim and the string. Provided you are sure that the dropouts are evenly spaced from the centreline left and right this can help you fix the two kinds of twist you might have (I guess "yaw" and "roll") without muddling them up.
Would be nice if the bender was designed with drop in the arm to align the start of the bend on a visible edge rather than in the middle. Would really take that thing to the next level.
What did you do to match the 'clocking' of the sliding dropouts relative to one another? I would assume if the "rails" of the dropouts are not parallel in all three axis, you will have binding as you slide the dropouts forward/backward to adjust chain tension.
Matthew Menze correct. Before I tightened the dummy axle, I aligned the SS and cs ends of the drop outs on a flat surface. If I welded these all the time I would machine a dedicated dummy axle that fits directly into the sliding dropout slots.
@@PithyBikes awesome! That is the same process I did when I welded up new dropouts onto my ~50s Monark Klunker rebuild. It worked surprisingly well, though it left me worried about alignment through the whole process, haha!
Ryann Galea yes absolutely. Someday I’ll make a wheel gauge for this application. Not an excuse but I built the wheel so I know it’s pretty true. But another way without a gauge is to take note of a section on the wheel. Say the valve area. Then flip the wheel back and forth and putting on frame each time. Measuring only one sides distance of course. Thanks for watching!
@@kevinhornbuckle not yet nope. thanks for the offer (if it was to me). looks like you might be in the US tho and I don't suppose you fancy posting a frame to the UK. Theres plenty options on the old fleabay.
I have to say I've never built a Bike Frame before, but as a TIG Welder of over 20 years whenever doing Structural Assembly (round or square tubing) we provided maximum support with Jigs and/or Fixtures minimising distortion.
I've seen other Videos of Frame-builders do the same - Tacking all the Joints in the Jig, but doing the Full Welds out of the Jig? For myself personally, I found it hard enough keeping things square, even with max support of Jigs and Fixtures, than just Welding without them.. regardless of welding sequences!
Just to mention, whenever the call on welding Tubing, or materials of 18 gage or thinner, we always used a .040" Tungsten, minimising the HAZ, in the parts!
Problem is that it becomes very difficult to reach certain spots while the frame is in the jig. So it becomes a tradeoff between minmizing distortion and potentially getting bad welds due to awkward positioning/visibility. Since you want the welds on a frame to be as nice as possible most people choose to weld in a position that is as comfortable as possible. Also cold setting is very common in framebuilding since it always distorts a little anyway. Ideally you'd have an alignment table or surface plate to mount the frame after welding and then align it.
it's a crime you don't have 100k subs.
kbex I’m ok with organic channel growth. And glad to have viewers who actually care about what I’m doing. 👍 thanks for the kind words none the less. And thanks for watching!
@@PithyBikes high quality content :D
@Pithy Bikes
when you are welding metals, some metals more and some less, but all have same characteristic to bend during welding. That is why you measure precisely before welding then after welding there is different angle. This effect you need to take on account when you are welding thin metals.
16:20 A way of stopping the bridge pulling the dropouts together is to spread them with the dummy axle before fitting the bridge.
That way when welded it will pull them into the correct position and you wont have to cold set them afterwards.
HTH
Great job on the frame. Really enjoy watching your channel.
Really enjoyed seeing what it takes to build a frame set. I’m an old USCF Cat 2 roadie that used to race for Raleigh many years ago. Been thinking of building a frame between welding jobs. I’m a new Sub as well. Cheers!
I usually never expect the frame to be in the same spot after welding it fully. And end up bending it after. If using the welding to try to straighten the frame, need to see it move while welding with pointers extended from the pieces being welded. Weld a spot then watch the pointer till it cools then weld a different spot to bring it back, sort a thing.
This whole experience has made me really miss the aluminum jig that I own. The wood jig was a good experiment and experience but it does add a significant amount of "off the jig" alignment work. I had nearly no alignment issues with the aluminum jig and have built 2 frames on it so far.
Regarding the blow-throughs: a less experienced welder could braze the holes closed. Your repair looks good.
Nice fabrication , wondering about mig welding rather than the tig , .6 wire pulsed on a multi roller wire feed unit I would think would give a better result , than the tig , which I've noticed even on high end bikes often show slight undercutting ,
Paul Schmidtke never tried mig so have no idea. For this particular application, TIG is what pros use. But would be interested to know if anyone has had success with mig.
Some more great problem solving.
Have you ever thought of getting a scotch brite wheel for your bench grinder for polishing your tubes instead of your bench sander?
Pudster that’s a really good idea. I have a coarse wheel on right side I never use.
Question: can't you cold set the stays once both sets are welded? Or would that be too rigid a structure. Finally, isn't a bit dangerous to take these measurements off the tyre and not the rim? Tyres can be a little off-centre in places even when mounted carefully? Looks like you got a good result in the end though!
Richard H yep cold setting before the SS works well. In the end that’s basically what I did. And yes the tire is not the most accurate gauge! Some builders make an actual gauge for that purpose. In my case, I built the wheel and know it’s within 2 mm.
Twisting the rear axle (as Steve was doing) when the SS are in there is next to impossible but bending the left or right sides in or out a bit to correct spacing or left/right centering is quite easy. If you do need a twist it works to just file the dropout a bit. If the wheel is 5mm too far to one side at the top that's only about 1mm at the dropout (for a 700c wheel, Steve's are quite a bit smaller). If you're building something with a thru axle then this isn't an option and you have to get it perfect first time. I suspect the reason old British bikes used to have those sort of diagonal horizontal dropouts was so you could get away with a fairly misaligned frame and just correct it every time you put the wheel in :)
@@PithyBikes That's not what he's trying to say.
You built the wheel & trued the Rim to +/-2mm but the tyre (tire in USA) is not that accurate and very rarely sits perfectly centered on the Rim.
Even if you get the bead seated perfectly the tyre's tread can still be way off to one side or snake side to side.
Great video! So do you think things moved a bit as you tacked them or the jig wasn't quite holding things in exactly the right place?
Ben C great question and I was waiting for someone to ask! So I’ve been learning a lot about the downside of the low cost jig. No surprise that rigidity is an issue. The other problems are more with my design of BB shell fixture and dummy axle fixture. I have a solution that I’ll talk about in next video. Long story short, main frame could be stiffer and fixtures need better tolerance.
@@PithyBikes Looking forward to the next video. My homemade jig is very untrustworthy. I found a good way to measure what was going on with the rear end was to use a bit of string around the dropouts and the bottom of the ST and then to repeat with the string around the top of the ST (i.e. over the TT) in both cases comparing left and right distances between the rim and the string. Provided you are sure that the dropouts are evenly spaced from the centreline left and right this can help you fix the two kinds of twist you might have (I guess "yaw" and "roll") without muddling them up.
Maybe back to 8020 jig?
Pushyhog oh yeah if this has taught me anything it is that a good solid jig is worth every penny.
Would be nice if the bender was designed with drop in the arm to align the start of the bend on a visible edge rather than in the middle. Would really take that thing to the next level.
Bradley Weingartner that would be. But imagine it would increase the price to manufacture.
What kid of software do you use to design this bicycle?
What did you do to match the 'clocking' of the sliding dropouts relative to one another? I would assume if the "rails" of the dropouts are not parallel in all three axis, you will have binding as you slide the dropouts forward/backward to adjust chain tension.
Matthew Menze correct. Before I tightened the dummy axle, I aligned the SS and cs ends of the drop outs on a flat surface. If I welded these all the time I would machine a dedicated dummy axle that fits directly into the sliding dropout slots.
@@PithyBikes awesome! That is the same process I did when I welded up new dropouts onto my ~50s Monark Klunker rebuild. It worked surprisingly well, though it left me worried about alignment through the whole process, haha!
Hi there! If I may ask, what type and size of tires are you using for this build? thanks! Keep up sir!
20” kenda I think 1.5” wide.
Put's a lot of trust in that wheel being trued to center properly, wouldn't it be best to used some sort of known accurate wheel fixture?
Ryann Galea yes absolutely. Someday I’ll make a wheel gauge for this application. Not an excuse but I built the wheel so I know it’s pretty true. But another way without a gauge is to take note of a section on the wheel. Say the valve area. Then flip the wheel back and forth and putting on frame each time. Measuring only one sides distance of course. Thanks for watching!
@@PithyBikes copy, makes sense 😊
can u make BMX frame for flatland design
hype. ever weld any aluminium?
Wezly only scrap aluminum. Nothing serious.
Pithy Bikes nice, I’m new to welding but planning to build a cargo bike, potentially using the rear end of an aluminium MTB frame.
@@Wezly It really should be heat treated after welding unless you use thick 1/8 wall.
Pithy Bikes Do you have one (an alum rear frame)? I have one which I'd give you.
@@kevinhornbuckle not yet nope. thanks for the offer (if it was to me). looks like you might be in the US tho and I don't suppose you fancy posting a frame to the UK. Theres plenty options on the old fleabay.