I just rewatched this video after finishing an autocad class last semester. CAD has quickly become one of my most valuable tools. I don't know how I've gotten this far without it. Thanks again for showing your thought process and taking the time to make these videos.
Tom, you are amazing. I cannot thank you enough for these videos. It would take me somewhere between a very long time and never to figure out the procedures you teach us to get things right. Your explanations of why the designer of a mechanism included certain features, like relieving the center of the clamp, are also extremely helpful. You are giving me exactly the information I need to design and build first class projects. Anything you can add about the physical properties of materials and why you might select them and any details on heat treating would be appreciated.
Not a "CAD people", but absolutely NOT boring or unfathomable. Whether an avid machinist, or not, always learn something (or more accurately MANY THINGS) interesting in your vids. Sure appreciate your channel, Tom. 👍👍 Mark (in the UK)
The Soviets once made a Mikrokator with an optical readout- they called it an Optikator. It used a mirror to project a line across what was basically the larger version of a Mikrokator scale.
The CAD explanation was a really good primer on why I would WANT spend the time, effort and money to learn to use a CAD program. Thanks for that. It's kind of like trying to explain to someone why they should learn calculus before they have any understanding of what calculus is.
27:52 - no this not boring, I always wondered how to solve problems like these when making or designing parts and how I should go about it. really helpful.
About the 12' mark in the vid, I really thought you said, "125 plus 14, that's 134." Hmm? Should be 139, I said to myself. Maybe I heard it wrong. So I turned on the closed captioning and it picked up "25 plus 14 that's 134." (it missed the "1" in 125) That could have been one reason the .250 pin wasn't working in your CAD simulation. Great video. Late on the comment...
Great video, especially the CAD segment. I do a-lot of work with Autodesk Inventor and as I am self taught found that segment very informative. If possible I would like to see more videos on the use of CAD programs. Thanks again for all your great videos, I truly enjoy watching and learning from them.
Let me say this, I’m not a machinist. But I do know and understand the tools. Also I know and understand CAD. Everything Tom said and showed on the mill and on the computer screen was easy to fallow. To the tool room experts You have to know where Tom works everyday. I don’t think Tom makes measurements over burrs. Thanks Tom it was another peach of a video.
Hi Tom Very nice job like all your projects. One other important on the stand construction, I have found that when the gage holding clamp and the measuring platen are supported off the same column deflection is vastly improved. I noted this when experimenting with stands some 25 years ago. Large steel mass is great but not a replacement for good Design. Really enjoy all of your videos. PS the undercut in the clamp center, now I know why. Best Bill B
I keep thinking if I was let loose with that part and the surface grinder it would not end well for the part wheel or me. Respect for your knowledge, skill and sharing Mr Ox.
Holy Cow Tom, watching that CAD work, never have I been so happy to be born in a country that converted to metric :P It must be a sense of relief when you get to work! Rob Renz would be having a fit that you didn't use any precision ground stones on that chuck, and lift the work with a spatula! You both do fantastic work and are an inspiration for us mere mortals. Keep up the amazing efforts.
Pete F I have CAD drawings with some measurements in inches and others in metric, and I switch the document units depending on which feature I’m working on. My point? It doesn’t matter what the units are when you’re using CAD, Tom could have been using attoparsecs or standardized left toenails. As far as the computer is concerned they’re just arbitrary floating point numbers. Metric would have made not a fart of difference.
You're entitled to your opinion and I respect that, but let me put this to you, I have seen SOOO many mistakes from people with the attitude you have that if I counted every one I wouldn't need to work for a living ;) NASA has lost missions and had some other serious cockups because of mixing units and not being familiar with what would be obvious errors to those more familiar with the standard. A CAD program doesn't "give a fart" what unit you use, nor does it give a fart if the operator makes an error. A computer is only as good as the information it receives, and BS in BS out. I have absolutely no idea how long a "left toenail" is, nor does anyone else, therefore there is no possibility for anyone to think to themselves "that doesn't sound right" and catch mistakes. A good machinist and tradesman will "see" units without having to measure them every time and can spot cockups through the familiarity with the units. I'm not interested in a metric/imperial argument, I've heard them all before and even most major manufacturers in the US have switched ... as we all did almost 50 years ago. If someone wants to work in some archaic "left toenail" standard they can knock themselves out. What can't be denied however is that when working in metric the units tend to provide sensible numbers, and for most applications are rarely more than one decimal point. It makes mentally keeping track of what is going on much easier and because the mental image makes more sense, mistakes are more easily avoided.
Incidentally, I see many products where the manufacturer has hit the unit button on the CAD program, just as you suggested, and the results are often ridiculous. Try going in to a Subway store and asking for a 304.8 mm sandwich and see how you get on! Yet I've seen countless products from the US where the engineers have evidently been told to work in metric, and have just hit the units button. Instead of designing something to be truly metric (eg a 300 mm long subway, they will specify it as 304 mm). Whatever units you decide to work in, know them and stick with them if you're able, but for goodness sake don't try to fudge it by flicking between the two and finishing up in a complete no-man's land.
There was no metric/imperial argument there, it was about idiots thinking the answer is to hit the CAD units button. feel free to substitute any unit you use on your planet.
Awesome content, as usual! I especially enjoyed the CAD, as any complex project that I'm working on gets drafted. I also really liked the blade tip depth mic, but could see error potentially in it not contacting the pin tangentially. Burrs would have to be very carefully removed or that too would have an effect on your measurements. Thanks again!
You could locate the grooves on the side by putting a large gauge pin in the v-block and finding the center of the v-block and tool height, then calculating the x and z values for the groove. You would be locating off the opposite side, so any problems in squareness or size would be multiplied.
Thank you as always sir!!! Btw thanks for sharing the .035” slot cutting. I know have an alternative way to finish a job for a customer other than using the waterjet.
Tom, I use cad in that way too, it's a great tool. For the guys without CAD, a "wee-block" or vee-block sitting on the corner of the part (vee down) can get you very close with an edge finder.
So how did you know I was planning to figure out how to position a v-grove this afternoon... thanks for the lesson... it will save me more times for making little clips out of big chips
Wow ..never seen a slot cut with a slitting wheel. You're bang on about the coolant though with it...cos when they grab...bang !! Goes the wheel especially .5mm
My Machine Shop instructor over 40 years ago pronounced Johansson as yo-han-sun...so did an oldster toolroom workmate say his father did also. Don't know if they were correct though they did have some Swede in them? We had a huge Johansson hydraulic shaper in our HS machine shop.
AWDJR, Your shop instructor was correct. When J is pronounced Y: Jaeger: Sum versions the name use Y instead of J in order to elicit correct pronunciation buy English speakers; James Yeager th-cam.com/channels/h6iq_mOy33ZPp2EMhqQOeA.htmlvideos Jorgensen: th-cam.com/video/h9WpqYVd1yE/w-d-xo.html Johann: (Serbastian Bark) th-cam.com/video/abBbG39BNeE/w-d-xo.html Johannes: Huss aka jan hus en.wikipedia.org/wiki/File:Cs-Jan_Hus.ogg
My very old AEG drill press has the same kind of locking mechanism (2 rings and a single screw) for the column connecting to the stand...just much bigger.
If you watch closely 11:52 the 0.250 pin rotates out of the grove when the depth mic touches it due to the soft pads of the clamp. It seems to me it should have worked and not to big, agree Tom?
like the theoretical optical comparator function of cad... like a crystal ball. just a thought but if you had to be off in either direction i'd bring the lower flat up so the set screw bears on it and "locks" it down love that blade depth mic all good tom
ya I kinda got you had a target CL your looking for accounting for a little surface grinding of the wear surfaces of the top and bottom and the set screw grooves that cut off wheel slotting was really cool
Is the dressing stick Borazon? Or is Borazon a trade name? When I worked at Hardinge in the late '70's in the collet dept. we had Norton wheels that were rubber composition.......down to .002 thick. Used for 'webbing' the slots in collets with really small 'order holes'. I think the smallest Order Holes were .005 for a 5C collet. Some other collets, possibly 1C, went down to .003 on Order Hole size.
Years ago I read something about making collets, it may have been a PDF scan from google books. It said how on the smallest collets the final cut was done with paper disks, I am guessing there was some abrasive mixed in the slurry when the paper was made. But it may have been just a paper with a high percentage of clay in it. There was a picture of a room with long benches with these machines, looked like 50 or 100 of them and a few people going from one machine to the next changing in disks and indexing and changing collets. I think the machines were powered by a small line shaft down the center of each bench with machines on each side.
I believe it is silicon carbide. Borazon is an old tradename for cubic boron nitride, and you sometimes find the name being used to describe old Soviet tooling which is coated with the same.
Hmmm… knowledge acquired with years of study… adroit skill, acquired with endless practice… driven by curiosity and discipline… results in, consummate mastery of leading edge technology. Or, a good grasp of old technology that few appreciate or even recognize. Still remember you talking about prime numbers when working out a solution to a machining problem in a past TH-cam vid. Nice one! Brad
Thanks, Tom Very informative as to CAD. Real world, the smaller pin was the obvious solution. Getting the exact alignment from the fixture (i.e. angle of points) more difficult. Being that it's desirable to have the pins align with the sides and not the point. Norbide = Hot Pressed Boron Carbide (B4C) As used in armour plate. Not as hard as Boron Nitride, or diamond.
Hi Tom, thank you for putting together such fantastic videos. They are incredibly informative and interesting. I noticed your comments about losing diameter on the cutting wheel. I was wondering exactly the same thing, but in relation to the grinding wheel when doing precision grinds. Obviously there are many factors, but how much can you expect to lose on a grinding wheel? Also, what CAD program was that? Cheers, Al
Hi Al. There is a formula out there somewhere but I don't think it applies to cutting discs. There were quite a few grooves and I was pushing it a bit so the wear factor was oxified somewhat. The CAD program was old reliable AutoCAD LT.
Hey Tom! Great video. CEJ also made a very similar comparator stand but instead of the adjustment screw on the bottom they used a flexture in the arm of the comparator holder. And we all love flextures isn't that right Tom!? :) Mr Trendzetter (Renzetti) has helped make sure of that :)
Question - I noticed the, what appears to be, abrasive material on the back rail of the surface grinder. What's up with that, never heard you talk about that before. Nice video, including the cad.... Thanks
I think it's a big deal for any machine shop to get a cloud based(online) drafting solution capable of running on tablets or smartphones. I tried Autocad 360 just for giggles but it ended up saving my ass on a irregular bolt pattern. You just open the sketch and you can measure things in every imaginable way and some more too!
"We got a groove on the other side". Was that groove actually small enough to let the micrometer base hit both sides ? If not you are measuring for the CAD comparison/correction in an not straight line, which you should base your CAD correction on. One thing I didn't understand though. Why wasn't the piece clamped using the v-grooves as a reference to surface grind the top and notches, since it will zeroed in on these when mounted.
Tom, two quick questions, first I see the thermometer tape stuck to the front of your magnetic chuck, can you explain what you use that for in a video sometime or let me know if you talked about it in the past and I just missed it. I understand the need to keep track of thermal growth, and I found that to be an interesting place to keep track of. Second, I really like the cutoff wheel in the grinder, is there a down side to using that compared to a slitting saw when making grind reliefs in tools etc.? It always seems like slitting saws are very finicky and can be slow and that cutoff wheel looks like a good alternative. Thanks for the CAD geekness. R.J.
The cutoff wheel is a lot less fussy than an .035 slitting saw. Also I wanted a rounded bottom to the groove which the cutting disc produces all on its own. The thermometer tape just allows me to monitor changes in temperature as I work. Depending on what I might be doing I might take a break to let things cool off.
Why would you choose to creep feed a part like this for the grooves rather than traverse like you typically would on a grinder and bring the Z down? Also, I know of some tweezers that might help you keep hold of that pin hehehe.
Since the block is held at a 45° angle, wouldn’t it be possible to indicate both sides/flats at each side of the upwards facing corner (at the same height of course) to find the exact Center line of the corner to use as a datum? Best regards from Mr. Johansson ✌🏻 in Sweden.
The reason you have a error with the larger pin, is because the offset isn't exactly .125". The corner of the groove is keeping the pin from being measured accurately. The bottom is inside the radius and the side is outside the radius making your center line off and introducing your error. Moral of the story, if your groove is not symmetrical, make sure your pin is inside the radius on both sides of your grove to get a accurate center line :)
Tom, Wouldn't you need to finish grinding and lapping the top and bottom surfaces first before adding the side grooves if using them for references? Enjoyed the video.
When using the regular micrometer you had it resting on the flat, not straight across the block, right? Doesn't that cause a cosine error? You're measuring the hypotenuse but wanting the adjacent side length. It will be a small error, but it will cause an error.
Not following you here. It was measuring from the opposite side of the block bridging the groove on the opposite side. It was a small spot and took a second to find the true position.
I just stumbled on your channel and its very nice. I'm wondering, since you do many different work in your shop, some quite dirty and some requiring extremely clean environment, if you ever condsidered using a laminar fux with some very fine filter. Its a bit areospace and all but it may save you some time.
I'm curious Tom, you moved the .250 pin relative to the slot, but your dimensions were taken from the pin, so you know where it sits relative to the block. What I'm thinking is you can still use that pin to determine the current slot position by moving the slot instead of the pin, it wouldn't be sitting on the flat, but it would still be bearing on the two corners. It would be interesting to check the intersection between the two "slots" as they are indicated by the two pins. TL;DR, the big pin is where you measured it, the slot therefore isn't where you drew it
Agreed! The measurements you are taking with the pin is to determine (mill) offset in X and Z to achieve the final location from the measured location. You have drawn the pin location correctly using .145 depth mic and 1.582 thickness gauge. My suggestion is that instead of moving the pin, or drawing tangents off the pin to establish where the slot is currently, instead use the intersection of the pin circumference and the un-machined face of the block, then draw two 45 degree extensions to intersection. As this is the physical, measured location of the pin, that is where the block must be machined to. Measuring the perpendicular distance between that and the desired end location will then give you your X and Z offsets to machine to the correct depth. The difference I believe is that instead of drawing tangents from the pin, (wrong location due to the pin size as you suggest) draw from the intersection of the circumference to the block face.
It’s early in the morning, so maybe I’m missing something, but: why are the scribe lines unequally spaced at the start of milling? The two interior surfaces should intersect the outside face at equal spaces from the centerline, because both are 45°, I think. The “center” line might bound roughly equal volumes when milling, but I would be surprised if that was a concern for a notch this small. Or maybe it’ll all be clear once I’ve had caffeine…
Hi Josh. I moved the layout off camera and increased the vertical position of the groove. I didn't bother to redo the centerline since it gets blown away instantly.
oxtoolco Ah, that makes more sense, thanks! As the softest of soft hands (I got a math degree), everything else here made perfect sense and was great. Thanks for doing the thorough CAD demo: hopefully more folks will see the beauty and power of mathematics and geometry. Or at least that it’s not (all) voodoo and has not-so-expected practical applications.
I have a stupid question. if someone wants to buy or build a lathe. is it necessary that the floor (location) on which the lathe will sit should be perfectly leveled ?
Thanks Tom. I though plastic was chosen for thermal conductivity/expansion reasons, but the fine adjust knob at the bottom is made of metal... so that can't be the reason. Plus, I imagine it costs more to make those 2 parts out of plastic than to make them out of metal. Anyone care to venture a reason as to why the company made the 2 bottom knobs in metal but the 2 top ones in plastic?
Hey Tom -- around 13:45, I noticed that the screw in the rotating handle of your micrometer was rotating as you were rotating the handle itself. I'm not a machinist/engineer/toolmaker, so I'm not sure if this is anything that'd throw off your measurements, but just wanted to mention it jic. Does that guy need to be tightened for the mic to be as precise as it can be?
It's part of the friction drive thimble. It moves with the adjusting screw but once the dial hits a certain torque, it stops and lets the thimble slip. It keeps you from over tightening the anvil and getting erroneous readings.
Ever considered doing a few video tutorials on how to use CAD? I know I'd be infinitely grateful if you did. Perhaps using Sketchup as it's a freely distributed CAD program and easily relatable to many other programs such a Fusion, CorelCAD, etc.
See me I am lazy. I would center punch thru the bolt holes to mark 4 points then drill at 90deg with a 90deg spotting drill to the desired depth then put it in the v blocks and come in with the end mill till I cleaned the hole edges up and run it. No math or computers to hurt my head that way. :-)
bcblock........... LOL .... Just have to comment LOL I had a similar reaction but I took Tom's demonstration as an exploration in metrology and good measurement techniques as opposed to the Keith Fenner "get her done" approach. There's definitely room for both but how much room depends on how much time, talent and money is available for the given project.
Interesting but the location of those V grooves do not need to be so accurate. It is actually a + ~.010 - 0.0 tolerance. Those cone screws are designed to pull the block down on the carrier, not to hold it in a position so all the V grooves have to do is be high enough that they are above the screw cones so the cones bear only on the lower surface of the V.
I just rewatched this video after finishing an autocad class last semester. CAD has quickly become one of my most valuable tools. I don't know how I've gotten this far without it. Thanks again for showing your thought process and taking the time to make these videos.
Tom, you are amazing. I cannot thank you enough for these videos. It would take me somewhere between a very long time and never to figure out the procedures you teach us to get things right. Your explanations of why the designer of a mechanism included certain features, like relieving the center of the clamp, are also extremely helpful. You are giving me exactly the information I need to design and build first class projects. Anything you can add about the physical properties of materials and why you might select them and any details on heat treating would be appreciated.
It's great that you showed the CAD info. I always learn something from your videos. Thanks for sharing.
Not a "CAD people", but absolutely NOT boring or unfathomable. Whether an avid machinist, or not, always learn something (or more accurately MANY THINGS) interesting in your vids. Sure appreciate your channel, Tom. 👍👍
Mark (in the UK)
Mark Pearce the second-best time to learn a new skill is now!
The Soviets once made a Mikrokator with an optical readout- they called it an Optikator. It used a mirror to project a line across what was basically the larger version of a Mikrokator scale.
I absolutely love how thorough and in depth your videos are. Thanks for the amazing content.
The CAD explanation was a really good primer on why I would WANT spend the time, effort and money to learn to use a CAD program. Thanks for that. It's kind of like trying to explain to someone why they should learn calculus before they have any understanding of what calculus is.
I like it when you show your thought process, Thanks
Enjoyed and FAR from boring...great discussion/demonstrations
Absolutely brilliant. I love your workmanship and attention to detail. Thanks for the heads up on the pin diameter.
I thought this was an absolutely excellent video, I liked it from beginning to end. Thanks so much for your time and energy to make it.
27:52 - no this not boring, I always wondered how to solve problems like these when making or designing parts and how I should go about it. really helpful.
Cool CAD work Tom, keeps me thinking.
Nice! I really like the detail that you give us
Very interesting. I like the idea that every time I watch one of your video's I learn another nuance of good work.
Wow, the shank on that indicator!! Great video as always, Tom!
Beautiful job! You are a master. Thanks for the video.
Fantastic Tom. Always enjoy your vids
Thanks Professor Lipton! That was an awesome lesson!
Great work. I didn’t know your grinder could do that. Thanks for sharing.
The relieving of the clamp centre of the bore was a new trick I've just learned....total logical but not apparent if you didn't know about it and why.
About the 12' mark in the vid, I really thought you said, "125 plus 14, that's 134." Hmm? Should be 139, I said to myself. Maybe I heard it wrong. So I turned on the closed captioning and it picked up "25 plus 14 that's 134." (it missed the "1" in 125) That could have been one reason the .250 pin wasn't working in your CAD simulation. Great video. Late on the comment...
Thanks for the explanation, great work as always.
Great video, especially the CAD segment. I do a-lot of work with Autodesk Inventor and as I am self taught found that segment very informative. If possible I would like to see more videos on the use of CAD programs. Thanks again for all your great videos, I truly enjoy watching and learning from them.
Excellent lesson in using cad to minimize trig perception errors. Nicely done Tom!
ATB, Robin
Not so sure I did anything special here. Now I'm thinking I fooled myself into the correct groove position.
oxtoolco even a broken clock makes a nice lamp when it is heated to incandescence.
Wait, no that’s not how the saying goes...
Thanks Tom for showing this - I had a similar V channel to machine recently and this technique would have been very helpful.
Hey Tom
Very informative as always
Thanks for sharing
Pat
Thanks for showing the cad stuff with the machining!
Nice project and excellent schooling, Tom!
first class Tomas always, keep 'em coming.
Let me say this, I’m not a machinist. But I do know and understand the tools. Also I know and understand CAD.
Everything Tom said and showed on the mill and on the computer screen was easy to fallow. To the tool room experts
You have to know where Tom works everyday. I don’t think Tom makes measurements over burrs. Thanks Tom it was another peach of a video.
Hi Tom Very nice job like all your projects. One other important on the stand construction, I have found that when the gage holding clamp and the measuring platen are supported off the same column deflection is vastly improved. I noted this when experimenting with stands some 25 years ago. Large steel mass is great but not a replacement for good Design. Really enjoy all of your videos. PS the undercut in the clamp center, now I know why. Best Bill B
Awesome vid !
Good reminder to reference surfaces to locate an edge.
Enjoyed the video, thanks.
I keep thinking if I was let loose with that part and the surface grinder it would not end well for the part wheel or me. Respect for your knowledge, skill and sharing Mr Ox.
That was one of the best Tom.
Holy Cow Tom, watching that CAD work, never have I been so happy to be born in a country that converted to metric :P It must be a sense of relief when you get to work!
Rob Renz would be having a fit that you didn't use any precision ground stones on that chuck, and lift the work with a spatula! You both do fantastic work and are an inspiration for us mere mortals. Keep up the amazing efforts.
Pete F I have CAD drawings with some measurements in inches and others in metric, and I switch the document units depending on which feature I’m working on. My point? It doesn’t matter what the units are when you’re using CAD, Tom could have been using attoparsecs or standardized left toenails. As far as the computer is concerned they’re just arbitrary floating point numbers. Metric would have made not a fart of difference.
You're entitled to your opinion and I respect that, but let me put this to you, I have seen SOOO many mistakes from people with the attitude you have that if I counted every one I wouldn't need to work for a living ;) NASA has lost missions and had some other serious cockups because of mixing units and not being familiar with what would be obvious errors to those more familiar with the standard. A CAD program doesn't "give a fart" what unit you use, nor does it give a fart if the operator makes an error.
A computer is only as good as the information it receives, and BS in BS out. I have absolutely no idea how long a "left toenail" is, nor does anyone else, therefore there is no possibility for anyone to think to themselves "that doesn't sound right" and catch mistakes. A good machinist and tradesman will "see" units without having to measure them every time and can spot cockups through the familiarity with the units.
I'm not interested in a metric/imperial argument, I've heard them all before and even most major manufacturers in the US have switched ... as we all did almost 50 years ago. If someone wants to work in some archaic "left toenail" standard they can knock themselves out. What can't be denied however is that when working in metric the units tend to provide sensible numbers, and for most applications are rarely more than one decimal point. It makes mentally keeping track of what is going on much easier and because the mental image makes more sense, mistakes are more easily avoided.
Incidentally, I see many products where the manufacturer has hit the unit button on the CAD program, just as you suggested, and the results are often ridiculous. Try going in to a Subway store and asking for a 304.8 mm sandwich and see how you get on! Yet I've seen countless products from the US where the engineers have evidently been told to work in metric, and have just hit the units button. Instead of designing something to be truly metric (eg a 300 mm long subway, they will specify it as 304 mm). Whatever units you decide to work in, know them and stick with them if you're able, but for goodness sake don't try to fudge it by flicking between the two and finishing up in a complete no-man's land.
If you're not interested in the metric/imperial argument, then why did you write a 400 word essay spread over two posts about it?
There was no metric/imperial argument there, it was about idiots thinking the answer is to hit the CAD units button. feel free to substitute any unit you use on your planet.
GREAT VIDEO !!
Wow. This video has it all. I really like the drafting program.
Awesome content, as usual! I especially enjoyed the CAD, as any complex project that I'm working on gets drafted. I also really liked the blade tip depth mic, but could see error potentially in it not contacting the pin tangentially. Burrs would have to be very carefully removed or that too would have an effect on your measurements. Thanks again!
You could locate the grooves on the side by putting a large gauge pin in the v-block and finding the center of the v-block and tool height, then calculating the x and z values for the groove. You would be locating off the opposite side, so any problems in squareness or size would be multiplied.
Autocad to the rescue 🖒Nice work Tom.
Thank you as always sir!!! Btw thanks for sharing the .035” slot cutting. I know have an alternative way to finish a job for a customer other than using the waterjet.
Pretty good entertainment for me Tom ! Thanks for another great watch, Cliff
Old-school AutoCad... brings back memories!
Im all in for the 2d cad demo.
Thanks for mentioning RobRenz. I was wondering if he was still with us.
Thanks Tom, that was interesting.
Tom, I use cad in that way too, it's a great tool.
For the guys without CAD, a "wee-block" or vee-block sitting on the corner of the part (vee down) can get you very close with an edge finder.
great! great! great! more please
Teun
So how did you know I was planning to figure out how to position a v-grove this afternoon... thanks for the lesson... it will save me more times for making little clips out of big chips
Wow ..never seen a slot cut with a slitting wheel. You're bang on about the coolant though with it...cos when they grab...bang !! Goes the wheel especially .5mm
thanks tom!
very good lesson, thanks for the video ,,
What is that little clamp you used to hold the pin?
Tom, you had it right. Norbide is Boron Carbide.
My Machine Shop instructor over 40 years ago pronounced Johansson as yo-han-sun...so did an oldster toolroom workmate say his father did also. Don't know if they were correct though they did have some Swede in them? We had a huge Johansson hydraulic shaper in our HS machine shop.
AWDJR, Your shop instructor was correct.
When J is pronounced Y:
Jaeger: Sum versions the name use Y instead of J in order to elicit correct pronunciation buy English speakers; James Yeager th-cam.com/channels/h6iq_mOy33ZPp2EMhqQOeA.htmlvideos
Jorgensen: th-cam.com/video/h9WpqYVd1yE/w-d-xo.html
Johann: (Serbastian Bark) th-cam.com/video/abBbG39BNeE/w-d-xo.html
Johannes: Huss aka jan hus en.wikipedia.org/wiki/File:Cs-Jan_Hus.ogg
My very old AEG drill press has the same kind of locking mechanism (2 rings and a single screw) for the column connecting to the stand...just much bigger.
This precision work is where proper tramming of your vise is needed. If it’s off by just a touch, this whole job is junked.
And at 27. the pin was tipping out of the slot because the center of gravity of the pin was over the lower corner. e.g. Pushed out. Cool !!!
If you watch closely 11:52 the 0.250 pin rotates out of the grove when the depth mic touches it due to the soft pads of the clamp. It seems to me it should have worked and not to big, agree Tom?
How did you measure the location of the groove in the part you were making so it accurately corresponds to the set screws?
like the theoretical optical comparator function of cad... like a crystal ball. just a thought but if you had to be off in either direction i'd bring the lower flat up so the set screw bears on it and "locks" it down love that blade depth mic all good tom
Its already there. I set the slot high so the screws push it down. I don't think I mentioned it in the video however.
ya I kinda got you had a target CL your looking for accounting for a little surface grinding of the wear surfaces of the top and bottom and the set screw grooves that cut off wheel slotting was really cool
I'm guessing "cubic" was on the tip of your tongue with the boron nitride? Lots of useful info packed into this one, wish I had a grinder!
Is the other Johansson indicator yours or does it belong to the university?
Is the dressing stick Borazon?
Or is Borazon a trade name?
When I worked at Hardinge in the late '70's in the collet dept. we had Norton wheels that were rubber composition.......down to .002 thick. Used for 'webbing' the slots in collets with really small 'order holes'. I think the smallest Order Holes were .005 for a 5C collet. Some other collets, possibly 1C, went down to .003 on Order Hole size.
Years ago I read something about making collets, it may have been a PDF scan from google books. It said how on the smallest collets the final cut was done with paper disks, I am guessing there was some abrasive mixed in the slurry when the paper was made. But it may have been just a paper with a high percentage of clay in it.
There was a picture of a room with long benches with these machines, looked like 50 or 100 of them and a few people going from one machine to the next changing in disks and indexing and changing collets. I think the machines were powered by a small line shaft down the center of each bench with machines on each side.
I believe it is silicon carbide. Borazon is an old tradename for cubic boron nitride, and you sometimes find the name being used to describe old Soviet tooling which is coated with the same.
Hmmm… knowledge acquired with years of study… adroit skill, acquired with endless practice… driven by curiosity and discipline… results in, consummate mastery of leading edge technology. Or, a good grasp of old technology that few appreciate or even recognize. Still remember you talking about prime numbers when working out a solution to a machining problem in a past TH-cam vid. Nice one!
Brad
This is great
Thanks, Tom Very informative as to CAD. Real world, the smaller pin was the obvious solution. Getting the exact alignment from the fixture (i.e. angle of points) more difficult. Being that it's desirable to have the pins align with the sides and not the point.
Norbide = Hot Pressed Boron Carbide (B4C) As used in armour plate. Not as hard as Boron Nitride, or diamond.
tom, could you please tell us what type of metal you are using on these projects and why thank you Love your videos
Hi Tom, thank you for putting together such fantastic videos. They are incredibly informative and interesting. I noticed your comments about losing diameter on the cutting wheel. I was wondering exactly the same thing, but in relation to the grinding wheel when doing precision grinds. Obviously there are many factors, but how much can you expect to lose on a grinding wheel? Also, what CAD program was that? Cheers, Al
Hi Al. There is a formula out there somewhere but I don't think it applies to cutting discs. There were quite a few grooves and I was pushing it a bit so the wear factor was oxified somewhat. The CAD program was old reliable AutoCAD LT.
Hey Tom! Great video. CEJ also made a very similar comparator stand but instead of the adjustment screw on the bottom they used a flexture in the arm of the comparator holder. And we all love flextures isn't that right Tom!? :) Mr Trendzetter (Renzetti) has helped make sure of that :)
Question - I noticed the, what appears to be, abrasive material on the back rail of the surface grinder. What's up with that, never heard you talk about that before. Nice video, including the cad.... Thanks
Seems like your next project should be a heat treat oven :)
I think it's a big deal for any machine shop to get a cloud based(online) drafting solution capable of running on tablets or smartphones. I tried Autocad 360 just for giggles but it ended up saving my ass on a irregular bolt pattern. You just open the sketch and you can measure things in every imaginable way and some more too!
"We got a groove on the other side". Was that groove actually small enough to let the micrometer base hit both sides ? If not you are measuring for the CAD comparison/correction in an not straight line, which you should base your CAD correction on.
One thing I didn't understand though. Why wasn't the piece clamped using the v-grooves as a reference to surface grind the top and notches, since it will zeroed in on these when mounted.
Would you not want the grooves to be above the center of the cone screws to force the anvil downward upon tightening?
They are. I don't think I mentioned that in the video.
No, you didn't but we knew you would have thought of it. :>)
Tom, two quick questions, first I see the thermometer tape stuck to the front of your magnetic chuck, can you explain what you use that for in a video sometime or let me know if you talked about it in the past and I just missed it. I understand the need to keep track of thermal growth, and I found that to be an interesting place to keep track of.
Second, I really like the cutoff wheel in the grinder, is there a down side to using that compared to a slitting saw when making grind reliefs in tools etc.? It always seems like slitting saws are very finicky and can be slow and that cutoff wheel looks like a good alternative.
Thanks for the CAD geekness. R.J.
The cutoff wheel is a lot less fussy than an .035 slitting saw. Also I wanted a rounded bottom to the groove which the cutting disc produces all on its own. The thermometer tape just allows me to monitor changes in temperature as I work. Depending on what I might be doing I might take a break to let things cool off.
Thanks Tom
Why would you choose to creep feed a part like this for the grooves rather than traverse like you typically would on a grinder and bring the Z down?
Also, I know of some tweezers that might help you keep hold of that pin hehehe.
Since the block is held at a 45° angle, wouldn’t it be possible to indicate both sides/flats at each side of the upwards facing corner (at the same height of course) to find the exact Center line of the corner to use as a datum?
Best regards from Mr. Johansson ✌🏻 in Sweden.
That is possible but it only locates you in one direction. You need an accurate Z as well to get it all to come together.
Am I mistaken or did I here "25 and 14, that's 34" when you measured the .25" pin with the depth mic?
The reason you have a error with the larger pin, is because the offset isn't exactly .125". The corner of the groove is keeping the pin from being measured accurately. The bottom is inside the radius and the side is outside the radius making your center line off and introducing your error. Moral of the story, if your groove is not symmetrical, make sure your pin is inside the radius on both sides of your grove to get a accurate center line :)
Tom,
Wouldn't you need to finish grinding and lapping the top and bottom surfaces first before adding the side grooves if using them for references? Enjoyed the video.
they are only to allow the pointed set screws to retain the block. They do not form a V block.
When using the regular micrometer you had it resting on the flat, not straight across the block, right? Doesn't that cause a cosine error? You're measuring the hypotenuse but wanting the adjacent side length. It will be a small error, but it will cause an error.
Not following you here. It was measuring from the opposite side of the block bridging the groove on the opposite side. It was a small spot and took a second to find the true position.
I just stumbled on your channel and its very nice. I'm wondering, since you do many different work in your shop, some quite dirty and some requiring extremely clean environment, if you ever condsidered using a laminar fux with some very fine filter. Its a bit areospace and all but it may save you some time.
Norbide® Hot Pressed Boron Carbide (B4C) is one of the hardest materials known
A machinist walks into a bar and says "I despise tipping the head"... :D
Buy that man a drink!
I'm curious Tom, you moved the .250 pin relative to the slot, but your dimensions were taken from the pin, so you know where it sits relative to the block. What I'm thinking is you can still use that pin to determine the current slot position by moving the slot instead of the pin, it wouldn't be sitting on the flat, but it would still be bearing on the two corners. It would be interesting to check the intersection between the two "slots" as they are indicated by the two pins. TL;DR, the big pin is where you measured it, the slot therefore isn't where you drew it
There are two components to the slot. Position and depth. They both have to come out right at the same time.
Agreed!
The measurements you are taking with the pin is to determine (mill) offset in X and Z to achieve the final location from the measured location.
You have drawn the pin location correctly using .145 depth mic and 1.582 thickness gauge.
My suggestion is that instead of moving the pin, or drawing tangents off the pin to establish where the slot is currently,
instead use the intersection of the pin circumference and the un-machined face of the block, then draw two 45 degree extensions to intersection.
As this is the physical, measured location of the pin, that is where the block must be machined to.
Measuring the perpendicular distance between that and the desired end location will then give you your X and Z offsets to machine to the correct depth.
The difference I believe is that instead of drawing tangents from the pin, (wrong location due to the pin size as you suggest) draw from the intersection of the circumference to the block face.
Groovy
It’s early in the morning, so maybe I’m missing something, but: why are the scribe lines unequally spaced at the start of milling? The two interior surfaces should intersect the outside face at equal spaces from the centerline, because both are 45°, I think. The “center” line might bound roughly equal volumes when milling, but I would be surprised if that was a concern for a notch this small. Or maybe it’ll all be clear once I’ve had caffeine…
Hi Josh. I moved the layout off camera and increased the vertical position of the groove. I didn't bother to redo the centerline since it gets blown away instantly.
oxtoolco Ah, that makes more sense, thanks! As the softest of soft hands (I got a math degree), everything else here made perfect sense and was great. Thanks for doing the thorough CAD demo: hopefully more folks will see the beauty and power of mathematics and geometry. Or at least that it’s not (all) voodoo and has not-so-expected practical applications.
I have a stupid question. if someone wants to buy or build a lathe. is it necessary that the floor (location) on which the lathe will sit should be perfectly leveled ?
can you help with a photo ? schematic or drawing ?
thanks. I found some videos on youtube about this. I was so involved in the magic of the lathe that it never occured to me to search XD.
The 2 top knobs on the comparator seem to be made of green plastic... are they original parts?
Yes they are original as far as I can tell.
Thanks Tom. I though plastic was chosen for thermal conductivity/expansion reasons, but the fine adjust knob at the bottom is made of metal... so that can't be the reason. Plus, I imagine it costs more to make those 2 parts out of plastic than to make them out of metal. Anyone care to venture a reason as to why the company made the 2 bottom knobs in metal but the 2 top ones in plastic?
Does anyone know what has happened to James Kilroy's channel? His last post was five months ago. I think highly of him and I'm a worrier!
Hey Tom -- around 13:45, I noticed that the screw in the rotating handle of your micrometer was rotating as you were rotating the handle itself. I'm not a machinist/engineer/toolmaker, so I'm not sure if this is anything that'd throw off your measurements, but just wanted to mention it jic. Does that guy need to be tightened for the mic to be as precise as it can be?
It's part of the friction drive thimble. It moves with the adjusting screw but once the dial hits a certain torque, it stops and lets the thimble slip. It keeps you from over tightening the anvil and getting erroneous readings.
Oh wow -- that's a pretty clever mechanism. Thanks for the information =)
Boy I'm glad this got answered. I was just about to go back and watch that video AGAIN.
+oxtoolco Hey Tom -- Sorry to worry you, hahaha. Big ups to +SuperSecretSquirell for educating me there =)
Ever considered doing a few video tutorials on how to use CAD? I know I'd be infinitely grateful if you did. Perhaps using Sketchup as it's a freely distributed CAD program and easily relatable to many other programs such a Fusion, CorelCAD, etc.
See me I am lazy. I would center punch thru the bolt holes to mark 4 points then drill at 90deg with a 90deg spotting drill to the desired depth then put it in the v blocks and come in with the end mill till I cleaned the hole edges up and run it. No math or computers to hurt my head that way. :-)
bcblock........... LOL .... Just have to comment LOL
I had a similar reaction but I took Tom's demonstration as an exploration in metrology and good measurement techniques as opposed to the Keith Fenner "get her done" approach.
There's definitely room for both but how much room depends on how much time, talent and money is available for the given project.
Yes I love the Toms tutorials. I appreciate the sophisticated style too. :-)
Interesting but the location of those V grooves do not need to be so accurate. It is actually a + ~.010 - 0.0 tolerance. Those cone screws are designed to pull the block down on the carrier, not to hold it in a position so all the V grooves have to do is be high enough that they are above the screw cones so the cones bear only on the lower surface of the V.
I use the same AutoCAD. Easy and it works.
which autocad is it?
Robert Engl AutoCAD 2000 edition. I have the full 3d version. His might be 1 or 2 years newer but basically the same.
A picture is worth a million numbers! lol
Amen!