Exactly! As I'm always nagging: EVERYTHING is made of rubber. Wherever there is a force acting on an object there is always deflection however small. We in precision manufacturing constantly learn this the hard way. Way to go Stefan in the way you explain these basic truths of the trade.
+Forrest Addy Forrest! You here? I think I read your "Everything is made of rubber" on Practical Machinist once...and since then its always in the back of my head :) Thank you for watching and commenting!
+Stefan Gotteswinter I'm a fan, Stefan. I check your RUclips channel every couple days and I'm constantly referencing your relevant videos to people requesting trade related info. I reference other people too but you are a principle resource. Keep it up. Forrest
I didn't realize how sensitive metal could be until my instructor talked about clean rooms, leaving a part in over night untouched just so you can run one op and wait for it to cool back down, because the temp causes changes in the density of the material. It expands and contracts and in extreme precision applications, even the temperature of the part is a factor.
Stefan, great insight on vise deflection! Never thought they would move so much under clamping force. After watching the video, I decided to repeat your test on a Kurt 688 AngLock vise. Results are as follows. The numbers are not by any means close to scientific, only to provide the info you requested in the video. With "normal" torque on the handle, the back jaw deflection is 0.002", front jaw lift is 0.0006", angular deflection of back jaw is 0.0016"/0.0015" top and bottom over 80mm.
Nice to see a video explaining things that the vast majority of the self taught RUclips video producers never knew or even thought about.There is more to machining than just twiddling knobs (turning crank handles, for non flippant English speakers).
I have spent 7 years as a machinist going to expos and chatting with many different machinists from around the world, and today I have learned something new. I will be doing this test on one of my Kurt vices and I will be weary of my clamping force in the future. Thank you Stefan for the video and thank you to This Old Tony for recommending this video on his squareness video.
This is exactly why on precision part the table is the least risky place to fix parts, for the rest, paper or brass shims and tramming the part is a must, all depending on the required tolerances specified... You did a great demo... ;)
Very good video on vise deflection. That is something I bet most of us amateur machinists would never think about. I was not aware of it anyway. Thanks for the video.
This topic is a good element to add in when you are studying the elastic modulus. I once saw a film where a man screwed an inside mike crossways (lightly!) into an engine cylinder bore, he squeezed the ends of the iron engine block together and the mike fell down the cylinder! Your rubber band analogy is a valuable one.
Stefan, Thank you for demonstrating these experiments and for the books you recommended! I find this information fascinating! This is the type of stuff that "separates the boys from the men!" in the shop (rough machinists from the Tool-Makers). Please continue with these type of videos from time to time. The only other guy I know on RUclips that does anything near this is Tom Lipton, but I don't believe he goes that deep into precision and accuracy factors. Thanks, again!
Stefan! thank you! this was very timely as I was having trouble squaring some stock and found that my fixed jaw was moving significantly when I snugged down on it. I have since backed off on the pressure I was using and will be checking the torque of the bolts holding down the fixed jaw. It is a Kurt style clone and I was getting .002 inch deflection.
"Everything is made of rubber" Thats a great way to think about it :). Makes me think, once youve an idea of how flexible your vice is, a torque wrench might come in handy. Also ways to reduce the clamping pressure needed by using say paper between the part and jaws to increase grip. Have you seen 'hold downs'. I remember seeing them various old shaper books. Strips of metal with slight angle on the vise mount side so as when you clamp down, the face of the hold down aims to seat on the jaw surface, in turn pressing the part down on the vise or table surface. All fascinating stuff. Cheers :)
Stefan I did a series of videos(RUclips is Edge Precision) using a Kirt vise about squaring a part. I called them square me up to 90. Although the tests I showed aren't quite the same as yours they do show how the vise flexes with clamping force and what to do to actually get a part square in a vise. To really square a part I prefer a horizontal mill with a B axis with the part clamped directly to the table. I did do them on a small CNC mill but I have done the same on a manual machine as well.
Very interesting Stefan...one other variable that I notice is your setup in clamping down the Screwless vise and the normal Grinding vise...the Screwless vise has 4 clamps to hold it down and the normal Grinding vise has only 2 clamps holding it down placed very forward toward the fixed vise...But, I will now investigate all of my vises...Thanks so much for your videos...I have watched many in the past few days and enjoyed and learned something from each one.
Well, that information was a bit of a shock! I am off to my workshop to measure the deflection on my Vertex vice. Very interesting and clear as always. Thankyou!
after this video and brians today i placed an indicator on my import vice. i was surprised to see no lift at all....but not at all surprised to see five thou deflection of the rear jaw once some torque was applied. gonna have to work on the thing and see if some better quality bolts might help with the problem...or not. Colin :-)
great video, I'm learning so much from you! in particular I love your attitude, so meticulous and patient. I'm reckless by nature, but thanks to you I'm starting to think like a machinist :)
Good video and thoughts Stefan. something to consider when we mill in a shelf to the jaws to act as parallels, negating any tilt the company factored in. This may also be the reason for what looks like material flex when clamped. those figures surprised me... much higher than what we chase all day trying to precisely tram in the mill. Thanks for enlightening me:-)
Cool video. Great idea. My 100mm (4") Gerardi milling vise has a fixed jaw deflection of .013mm (.0005") and the same moving jaw rise. A thick parallel on end deflects only .018mm (.0007") at 100mm above the jaws. It has the angled floating jaws to suck the part down, but I have them screwed tight and I tap the part down instead.
Off to indicate my 8" Kurt on video for reference. I don't normally shoot for sub .oo1" work with my sledge hammer mill but on that 36" block plate I was able to hold it or I couldn't have put the slip fit liners in when I was done.
Hi mate. Food for thought again. I have always thought that minute changes would happen when clamping or tightening anything. Deformation will always happen to an extent. However, your right in the fact that knowing how much deformation you get is handy to know with making calculations. I doubt I will ever need it however. Thanks for an other mind bender.
Das war sehr interessant! Danke schön Stefan! Ich habe viel gut gelernt heute. Hoffentlich du kannst mein Schule Deutsch verstehen! Ich lerne etwas neues jeden zeit. Vielen dank. Mike (UK)
haha.. just found your channel via that old tony which i found via AvE.. Its strange.. if you want to see good infotainment about machining you need to search the english speaking youtube community.. german videos always are like Baumarkt Bohrmaschinen Werbevideos.. Stocksteif ;) now.. i found a german youtube doing awesome stuff.. ..speaking english :D It's like germans arent interested in how stuff works and want to "fab" it on their own...
haha AvE, ToT ( This old Tony ) Abom79 / 666MaDog also check out / clickspring , (he also has this ToT as a viewer) his is Australian like me, also engineer Burns ( no, or not many English subtitles ) but does cool stuff and funny vids. if your into a bit of fabrication check out make it extreme, ok
12:10 This raises a very silly yet interesting idea on the screwless milling vise: why not replace the fixed jaw with an identical movable jaw (ie: two movable jaws that don't lift or tilt). You'd get low positional repeatability but perhaps zero tilt for precise work. That is purely a hypothetical exercise though. Keep the awesome videos coming please!
Great video! "...everything is made of rubber..." very true. It is little known that all steels have the basically the same elasticity. Even hardened tool steels.
Good job Stefan, thank you. Fundamentals is a nice place to start. I added a couple links on where the books you mentioned can be found and one is free in PDF.
Hello Stephan. Really interesting video you made. I've quiet the same results with my vices but I currently use a torque wrench calibrated at 5 mN for steel. On my milling machine I use a good copy by Vertex of a Kurt vice (100 mm wide) for large and middle pieces, but for little parts I use a precision tool maker vice (50 mm wide). Regards - Didier
Very good point Stefan,.I think i.need to check my 30+ years old Abwood for lift , it's a 4" (100mm) and i know the fixed jaw deflects about 0.03mm but never really considered lift. i just kept the gibs rather tight. It's a dovetail design so easy adjustable for minimal play. Also got a very heavy 6" of similar design, so i think i am going to take some footage tomorrow....
I suspect too many novice machinists have only rudimentary understanding of physics. Such demonstrations present fundamental concepts in a manner that doesn't intimidate the viewer with the psychological barrier many have that physics is too complex for them to understand. Good job!
+Richard Freeze Hi Dicky boy, It's all very simple, If you have an interest in Physics then you will naturally learn, If you don't have that interest then you won't. Regards MoK
Hi, Moky. I expect most hobbyist machinists are less interested in physics than in making a part. Otherwise physics would be their hobby, not machining. Obviously learning a subject in which one is interested will come easier than one to which they are adverse. However, often is the case where some practical knowledge of a subject is relevant to the primary subject of interest. In this video understanding the effect of vise deflection is relevant. I think Stefan's practical explanation of the effects of the physics involved will be meaningful to even those who have no interest in physics per se. Interests spring from exposure to a subject. That exposure comes in many forms, school, travel, parents, friends and general life experience. One never knows when the smallest stimuli will provoke a life-long interest. Development of an interest depends on one's confidence in self to achieve a goal. That confidence comes from encouragement, not discouragement, and persistence which leads to more successes than failures. It's unfortunate that many young people who have much potential are limited because their environment and the people in it tell them they don't have the natural ability to learn about something that exceeds the available knowledge in their confined environment. That's why it is so satisfying to see someone like Stefan publish intelligent, useful information in a clear, concise manner. His rich, positive content far outweighs the trivial remarks that someone like you or I may make. Regards, Richard
+Richard Freeze Hi again Dicky boy, I am afraid you are preaching to the already converted. I am 75 years old took a Bsc degree and passed with Honours at 63 I am a practising Cosmology Physicist and am qualified in Hypnotherapy, Psychology, and lastly am a precision metal working engineer working down to drilling 0.01" holes. I have repaired things all my life, as being born during WW2 , the only way I was able to get things was to salvage and repair always trying to do things properly. During my childhood there was no extra education, so we had to do what we could , when we could. There was a shortage of food for at least 10 years after the end of the war during which period we each had a ration book, none of which detracts from the quality of Stefans work. Stefan is a High class engineer and I enjoy seeing him work as he reminds me somewhat of myself, so I think you can see that your lecture is of little importance and my remarks are far from trivia, so come on down from your high horse and join in with us Proper engineers and find out how to live your life to the full. MoK
I was surprised to see the gage block leaning towards the movable jaw in the screwless vice. It has me baffled. I thought on the third vice that this wouldn't happen do to the slight lifting of the movable jaw. Been on the lookout for both Moore books. This is the type of info we need to know if we are wanting to do persicion work.
Nice Video and like the other Viewer's said "U go on talking, Man" - 'cos we are all listening and learning. That's what matters. Very interesting and enough Food for Thought !! Some deflection we did not even think about. And now will have to consider every time we clamp any Part. Thanks for Your ideas and Sharing - much appreciated. MUCHAS GRACIAS !! aRM
Hi Stefan, I was thinking about your comment at 13:20 , and I think besides the movable jaw tilting less than the fixed (as you suggested), there must have some "Poisson effect" happening in the part when it's squeezed by the vice.
Hi Stefan Very interesting video I have a virtex vice on my milling machine and will be doing those tests just to see how much deflection I get but really I do not have the skill level to work to the tight tolerance that you work to. I would like to but I can only work with what I have. I have a six jaw adjust true chuck on my lathe and have dialed it in to 0.005 mm and that nearly sent me nuts for two weeks on and off. So now you have just given me more things to stress about LOL very much like your videos. Dave
+David Cashin : Hi David -I think you sell yourself short, you do have the skill to work to fine tolerances, you just have to convince yourself first. It all comes with learning and practice. Regards MoK
Stefan you mentioned that the shaper vice is tilting the part towards the indicator.... But if i see it correctly the dial moves anti clock wise... This would mean the part is tilting towards the fixed jaw and not towards the movable jaw
Very good point on vice flex. The best was to get around this is to use Starrett hold downs and you will be fine. Worked for me Stefan, maybe it will work for you too ???
Good grief, Kearny & Trecker hats make it to Bavaria :) .Seriously, I think that all metals are springs. Put enough force on a spring and it bends no matter how small the spring constant is. And I think you proved that quite conclusively. I am not at all surprised that bcbloc2's 100-Kilo vise did not deflect as much as the shaper vise, given the size. Deflection under load goes as square of length (in a horizontal beam, as depth square) and the Kurt has an awful lot of length and depth both. This is a lesson to me. Never trust a vise. The numbers were amazing, I did not expect .05 mm. Thank you very much!
Good stuff Stefan. I would be curious to see, if you had the indicator on the part, how the deflection effects the part if it is in the vise horizontally instead of vertically. I know that my Kurt vise is worthless for holding while face milling because of the upward movement of the moving jaw, however, I've never measured how much it actually moves.
+Stefan Gotteswinter: Hi Stefan I have to mention that with a torque wrench there will still be deflection but the error will always be more or less at the same level.
Hi Stefan, thanks for the inspiration. I've just uploded a video testing 2 very well used ones, a 4" Abwood and a 6" of unknown brand (Both British made). Surprisingly the results are not much different from your's which looks alot better maintained yjan mine. I used a torque wrench to ensure the pressure is always the same.
One might characterize their vise and use that knowledge to implement sufficient compensation with shims placed appropriately to have the part clamped true when tightened up. That is only if one needs to do so for very precise work. PS: Great video!
So basically you're saying what I've told everyone is that there is no such thing as absolutely perfect... true perfection only exists in the person that says it's perfect. Another edit: I just realized this was was posted years ago but still very relevant.
All the years I've been around & I never considered "deflection in the vise???" But it makes sense if you're taking your machining tothat level. I got nothing but time to see jus how far I'm going to take machining.. I'm 62, disabled... I have loved Welding & Machining since my youth. Prison taught me that Welding without Machining is like a Peanut Butter Sandwich without the Peanut Butter & without the Bread...
Stefan Would the test be more subjective between the vices if you could measure the actual clamping pressure of the jaws with say a strain gauge/load cell , as I suspect the shaper vice has a greater clamping pressure than the toolmakers vice But as usual I may be wrong 😱 Keep up with the videos as I always find a useful bit of knowledge in every one My German is very poor and limited to technical stuff in electrical systems as we had a lot of Anton Piller equipment at the banks computer centre as had to work along side the very good female engineers they sent over One thing I do agree with every thing is flexible , just work with a optical bench that will show just how bad it can get Stuart A very aged electrical engineer now at 69 circuits around the sun
you should depressurize reductor of welding machine when not using it. keeping it under pressure for long time damages internals of reductor. just turn off gas tank valve and push TIG button to open solenoide valve and let argone or co2 leave reductor
Nice video.Did you hone the fixed jaw before testing the tilt?If there is a small burr low down it will be deformed when you clamp down hard.So in fact not bringing your test piece out of square, but closer to square. You only measure tilt change, not squareness.Distance from burr to top of jaw is small compared to distance between the instrument probes, so the deformation will be magnified.I assume you cleaned the part and jaw, or a tiny particle would have the same effect.
Great video, I now have to re-evaluate everything I took for granted in my shop. To be a little nit-pickey, could part of your shaper vise deflection been due to refrencing off the rear base of the vise where the screw loading could be actually bending the back half of your vise? Have you repeated this measurement using some other part of the machine for your magnetic bases? Sorry to be "that guy" but you're the one to get me thinking in the first place! Thanks.
cool video. i have a machine-shop physics question. perhaps you can answer here, or make a video on this topic if it is suitable. why is it that people suggest that a surface plate be mounted on three support points that are used between the plate and the supporting stand/cabinet that the plate is resting on? i get that a tripod is stable relative to a four-legged structure that can tip if one of the legs come off the ground; however, flatness has nothing to do with level. a surface plate hung from the wall of your shop would be perpendicular to the ground and it would still be flat, no? so why are three feet preferred and not four? if you have four adjustable feet you should have a more stable surface than a three-legged arrangement given that a weight can be put on any corner of the surface plate and it will not tip. if one of the feet loses contact with the ground for some reason, you can adjust it so that the foot regains contact as needed. the adjustable feet make sure that each foot can always retain contact with the floor or stand the plate is on. so why worry or prefer that there are three feet? my guess is that it really does not matter relative to flatness.
metals flex at some point after watching this my vise will flex thanks for showing me this now I know how to fix this problem make some parts adjustable to compensate for the movement this would be the 2 jaws at each end let me know what you guys think ?
Thank you, Stefan. So interesting. Never tested as you did, but always checking after clamping, because everything made from a rubber ;) There is Dan Gilbert RUclips channel with a series of video for prototype makers. Totally cool stuff
Would have been interesting to see the deformation of a part when clamping down (not just deformation of jaws)... regardless very cool and educational video...thanks... oops 12:40 you did it !!
thanks for the great vids Stefan big fan of your one comment please do yourself and us a favor DON'T USE A ALLEN WRENCH TO TIGHTEN YOUR VICE use a spanner wrench if that Allen wrench had broke no vids for a while and don't say it can't happen guy I worked with has a scar on. his forearm to remind not to again so thanks again and keep on talking
Have you measured moving jaw side movement? It can be a problem if you clamp a number of long parts in one vice lengthways, they will all be slightly different lengths and the longest one can 'kink' the moving jaw to one side. Really annoying error for me until I worked it out, all my holes near the moving jaw were randomly 0.05mm to the left or right depending on which side of the vice the long part was in.
Great video as always Stefan! For anyone who's interested, Moore's "Holes, Contours and Surfaces" is public domain and has been Google digitized. It can be read online, in its entirety, here: babel.hathitrust.org/cgi/pt?id=mdp.39015002958893;view=1up;seq=1 "Foundations of Mechanical Accuracy" is out there and available as a pdf download, but I'm not sure if it's public domain so I won't include a link. However, a quick Google search of "Foundations of Mechanical Accuracy pdf" will turn up some options.
+R Balderson : Hi, A good point, set the dial gauge on the workpiece but base the dial gauge holder on the table as it's the table that should be zero referenced to the quill. Regards MoK
very interesting video. even though vise flex may never be an issue with the home shop machinist, it's good information. do you think that vise jaw flex is the reason that it is sometimes impossible to get both sides of a part to sit down tight to paralells?
+larry sperling Might be, but most of the time its a small burr, a few atoms of swarf or the wrong moon-phase. When this happens I try to wiggle the loose parallel up and down to feel if its very much off and if I can live with it...
the first book you listed is very hard to find in USA I found reference to one copy on AMAZON and the price is $1200.00 "Foundations of mechanical accuracy" The closest copy i could find in a library was in a School library 70 miles from my home. Must be a great book If you have one you have a small fortune.
+flineman You can get the book here: totallyscrewedmachineshop.com/documents/FoundationsofMechanicalAccuracy.pdf for free, and I recommend everyone do that and actually read it!
+bx2200 Sad, I was able to download it there earlier. It is available in the download section on Hobby-Machinist, but you will need to be a member there with some number of posts (10?) to access it. I suggest you hurry if you are interested...
cont'd from below: ...to one side of the vise centre, for a start. Only ever trust the back grip of the vise, but know its limitations, is what I say. How many need a precision of better than 0.005mm that often?
Hi Stefan, I have been watching a number of your videos which I might add are great, and have I have been taking a great interest in your own vise (Screwless I think they'r called). I am very intreigued with the clamping mechanism, I wonder do you have any drawings of the internal mechanism and if so, or if you know the principle could you please send any copies of them or even a rough drawing from which I may complete a working design. Many thanks in antisipation. MoK
I do sloppy joe work. My machines are 80 years old and wore out. I get by doing work for myself and the local farmers. I've noticed things that are very accurate seem to be ground to size. I did notice a very big difference in the new Kurt clone import 6"vice compared to a "to wore out for Die Tech" Real Kurt. Kurt is much better than a Kurt copy and 10X the price.
Stefan! A vice is something you always want to deflect as much as possible! Away from yourself! Vices are bad! Conversly, a good vise will have minimal deflection when used properly.
Very interesting! I've always loved physics, and often find it sad how little people know about even the "6 simple machines" you learn about in Earth Science in the 7th grade... I suppose if they can open a bottle of beer or wine, they can take it for granted that all of the thinking has been done for them, LOL! Oh, on a side note I have a very important question for you. Do you know what you call the air in the top of a bag of chips?
G'day Alexandre, I know it's been a long time since you typed this but... :) Because the moveable jaw is lifting slightly as force is applied, that means it is probably pivoting on the jaw's lower back edge (nearest the crank). This would mean that, at the gripping face, the top of the jaw is pushed a fraction further back than the bottom edge. Cheers Duncan
Reminds me of a good episode on Keith fenders channel on torque lbs on a dry bolt versus bolt that had oil on them. Basically shit the average idiot like me would never figure in. The old guys I admire always said you can learn 1 of 2 ways, fuck it up yourself or learn from someone who fucked it up and is willing 2 teach your dumbass. Thx for vid
Just a newbie question: if the movable chuck of the screw-less wise is so perfectly rigid, why don't they make the wise with two symmetric movable chucks? Looks like the 45 degrees downward screw really does a great job at keeping things tight...
It is common to use the fixed jaw of a vice as a reference index so it is possible to load multiple parts in succession without the need to set up each part individually. Having two moveable jaws would severely reduce confidence in the setup over time. Tandem vices with two opposed moving jaws and a common fixed jaw are available but are regarded as specialty types.
If you took off the replaceable jaws and did the measurement against the part of the shaper jaws permanent parts of the jaws, do you still see the same deflection? Just curious on how much of the play is due to how the replaceable jaws are bolted on to the vise?
Hi Stefan, I think you read in my mind. I was just looking for which is the better vise design. And, yes, I have read on forums people who say that grinding vices or toolmakers vices (how do you call them) are not good for general milling pourpose. But your advice now opens my mind and push me in the direction of that style of vice. The only difficult is that a lot of imported ones doesnt't have longitudinal slots like yours for clamping on milling table, they have just holes. So, is there a solution to clamp them? I have seen some special clamp block for that vices, but just one or two sellers have it.
+Cosimo Marotta Since the objective is to just hold the vice to the table why not just clamp on top of bed (with protection) or make some clamps that engage the holes? Maybe pass a bar through an empty hole to clamp on. Most drill press vices have no means of clamping so all of mine have acquired holes on each side so they can be used on all machines. Mike (o\!/o)
Hi folks, searching through the offers of sellers, barely all of them sell a model, in various sizes, with clamping falts just in front and rear of the vice. Along sides there are only holes (parallel to the plane). So it is hard to clamp the vice perpendicular to X axis. For this reason, someone have develop a pin style clamp, but I don't like it much. Stefan's vice has two parallel flat allow you to clamp the item to the table, but this design is difficut to find. That's was my doubt.
Hi Cosimo, In the UK you can get side grooved vices from www.arceurotrade.co.uk/Catalogue/Workholding/Machine-Vices/Precision-Tool-Vices-Type-2 If you wonder about lack of holding down recesses, remember they are really meant to be held on a magnetic chuck hence the (false) thought that they should not be used on a milling machine.
Exactly! As I'm always nagging: EVERYTHING is made of rubber. Wherever there is a force acting on an object there is always deflection however small. We in precision manufacturing constantly learn this the hard way.
Way to go Stefan in the way you explain these basic truths of the trade.
+Forrest Addy Forrest! You here? I think I read your "Everything is made of rubber" on Practical Machinist once...and since then its always in the back of my head :)
Thank you for watching and commenting!
+Stefan Gotteswinter I'm a fan, Stefan. I check your RUclips channel every couple days and I'm constantly referencing your relevant videos to people requesting trade related info. I reference other people too but you are a principle resource.
Keep it up.
Forrest
I didn't realize how sensitive metal could be until my instructor talked about clean rooms, leaving a part in over night untouched just so you can run one op and wait for it to cool back down, because the temp causes changes in the density of the material. It expands and contracts and in extreme precision applications, even the temperature of the part is a factor.
You don't need to stop talking, your teaching is very valuable and there is never a dull moment. Thank you for the book references.
Stefan, great insight on vise deflection! Never thought they would move so much under clamping force. After watching the video, I decided to repeat your test on a Kurt 688 AngLock vise. Results are as follows. The numbers are not by any means close to scientific, only to provide the info you requested in the video.
With "normal" torque on the handle, the back jaw deflection is 0.002", front jaw lift is 0.0006", angular deflection of back jaw is 0.0016"/0.0015" top and bottom over 80mm.
Nice to see a video explaining things that the vast majority of the self taught RUclips video producers never knew or even thought about.There is more to machining than just twiddling knobs (turning crank handles, for non flippant English speakers).
I have spent 7 years as a machinist going to expos and chatting with many different machinists from around the world, and today I have learned something new. I will be doing this test on one of my Kurt vices and I will be weary of my clamping force in the future. Thank you Stefan for the video and thank you to This Old Tony for recommending this video on his squareness video.
This is exactly why on precision part the table is the least risky place to fix parts, for the rest, paper or brass shims and tramming the part is a must, all depending on the required tolerances specified...
You did a great demo... ;)
Very good video on vise deflection. That is something I bet most of us amateur machinists would never think about. I was not aware of it anyway. Thanks for the video.
This topic is a good element to add in when you are studying the elastic modulus. I once saw a film where a man screwed an inside mike crossways (lightly!) into an engine cylinder bore, he squeezed the ends of the iron engine block together and the mike fell down the cylinder! Your rubber band analogy is a valuable one.
Stefan, Thank you for demonstrating these experiments and for the books you recommended! I find this information fascinating! This is the type of stuff that "separates the boys from the men!" in the shop (rough machinists from the Tool-Makers). Please continue with these type of videos from time to time. The only other guy I know on RUclips that does anything near this is Tom Lipton, but I don't believe he goes that deep into precision and accuracy factors. Thanks, again!
Stefan! thank you! this was very timely as I was having trouble squaring some stock and found that my fixed jaw was moving significantly when I snugged down on it. I have since backed off on the pressure I was using and will be checking the torque of the bolts holding down the fixed jaw. It is a Kurt style clone and I was getting .002 inch deflection.
Great video! I've had the two books by Moore that you mention for a good number of years, they are indeed indispensable.
You have confirmed that nothing I ever make will be precision. But "good enuff" will come into play a lot 😊
Danke für deine Ausführungen! Die Abweichung vom Maschinenschraubstock hätte ich so nicht erwartet.
"Everything is made of rubber" Thats a great way to think about it :).
Makes me think, once youve an idea of how flexible your vice is, a torque wrench might come in handy. Also ways to reduce the clamping pressure needed by using say paper between the part and jaws to increase grip.
Have you seen 'hold downs'. I remember seeing them various old shaper books. Strips of metal with slight angle on the vise mount side so as when you clamp down, the face of the hold down aims to seat on the jaw surface, in turn pressing the part down on the vise or table surface.
All fascinating stuff.
Cheers :)
Excellent analysis Stefan - a most useful subject - very logical physics approach.
I'll be looking at my vises now!
+ChrisB257 : Hi Chris, didn't think you had any vises, well not the non metal ones anyway.
Talk soon .
Regards Mo
Interesting video. Things I never thought about (not a machinist) but can still consider.
Outstanding video! Please Make more like this. I enjoy your projects and your style of making a video. Keep up the good work.
Stefan I did a series of videos(RUclips is Edge Precision) using a Kirt vise about squaring a part. I called them square me up to 90. Although the tests I showed aren't quite the same as yours they do show how the vise flexes with clamping force and what to do to actually get a part square in a vise. To really square a part I prefer a horizontal mill with a B axis with the part clamped directly to the table. I did do them on a small CNC mill but I have done the same on a manual machine as well.
Very interesting Stefan...one other variable that I notice is your setup in clamping down the Screwless vise and the normal Grinding vise...the Screwless vise has 4 clamps to hold it down and the normal Grinding vise has only 2 clamps holding it down placed very forward toward the fixed vise...But, I will now investigate all of my vises...Thanks so much for your videos...I have watched many in the past few days and enjoyed and learned something from each one.
Well, that information was a bit of a shock! I am off to my workshop to measure the deflection on my Vertex vice. Very interesting and clear as always. Thankyou!
after this video and brians today i placed an indicator on my import vice. i was surprised to see no lift at all....but not at all surprised to see five thou deflection of the rear jaw once some torque was applied. gonna have to work on the thing and see if some better quality bolts might help with the problem...or not.
Colin :-)
great video, I'm learning so much from you! in particular I love your attitude, so meticulous and patient. I'm reckless by nature, but thanks to you I'm starting to think like a machinist :)
Taking precision to a new level_thank you an important factor.
Good video and thoughts Stefan. something to consider when we mill in a shelf to the jaws to act as parallels, negating any tilt the company factored in. This may also be the reason for what looks like material flex when clamped. those figures surprised me... much higher than what we chase all day trying to precisely tram in the mill.
Thanks for enlightening me:-)
Great video, Stefan! Please talk more, not less, as you wish. You are a valuable resource to all of us.
Cool video. Great idea.
My 100mm (4") Gerardi milling vise has a fixed jaw deflection of .013mm (.0005") and the same moving jaw rise. A thick parallel on end deflects only .018mm (.0007") at 100mm above the jaws. It has the angled floating jaws to suck the part down, but I have them screwed tight and I tap the part down instead.
Off to indicate my 8" Kurt on video for reference. I don't normally shoot for sub .oo1" work with my sledge hammer mill but on that 36" block plate I was able to hold it or I couldn't have put the slip fit liners in when I was done.
Hi mate. Food for thought again. I have always thought that minute changes would happen when clamping or tightening anything. Deformation will always happen to an extent. However, your right in the fact that knowing how much deformation you get is handy to know with making calculations. I doubt I will ever need it however. Thanks for an other mind bender.
Das war sehr interessant! Danke schön Stefan! Ich habe viel gut gelernt heute. Hoffentlich du kannst mein Schule Deutsch verstehen! Ich lerne etwas neues jeden zeit. Vielen dank.
Mike (UK)
Great video Stefan and very interesting to see the movement on the vises that you showed us .
...blacksmith precision...! That made my day :+1:
haha.. just found your channel via that old tony which i found via AvE..
Its strange.. if you want to see good infotainment about machining you need to search the english speaking youtube community.. german videos always are like Baumarkt Bohrmaschinen Werbevideos.. Stocksteif ;) now.. i found a german youtube doing awesome stuff.. ..speaking english :D It's like germans arent interested in how stuff works and want to "fab" it on their own...
haha AvE, ToT ( This old Tony ) Abom79 / 666MaDog also check out / clickspring , (he also has this ToT as a viewer) his is Australian like me, also engineer Burns ( no, or not many English subtitles ) but does cool stuff and funny vids. if your into a bit of fabrication check out make it extreme, ok
12:10 This raises a very silly yet interesting idea on the screwless milling vise: why not replace the fixed jaw with an identical movable jaw (ie: two movable jaws that don't lift or tilt). You'd get low positional repeatability but perhaps zero tilt for precise work. That is purely a hypothetical exercise though. Keep the awesome videos coming please!
Great video! "...everything is made of rubber..." very true. It is little known that all steels have the basically the same elasticity. Even hardened tool steels.
Thanks for the video. This is something I am definitely going to be checking on my vises.
Good job Stefan, thank you. Fundamentals is a nice place to start. I added a couple links on where the books you mentioned can be found and one is free in PDF.
Hello Stephan. Really interesting video you made. I've quiet the same results with my vices but I currently use a torque wrench calibrated at 5 mN for steel. On my milling machine I use a good copy by Vertex of a Kurt vice (100 mm wide) for large and middle pieces, but for little parts I use a precision tool maker vice (50 mm wide).
Regards - Didier
Very good point Stefan,.I think i.need to check my 30+ years old Abwood for lift , it's a 4" (100mm) and i know the fixed jaw deflects about 0.03mm but never really considered lift. i just kept the gibs rather tight. It's a dovetail design so easy adjustable for minimal play. Also got a very heavy 6" of similar design, so i think i am going to take some footage tomorrow....
I suspect too many novice machinists have only rudimentary understanding of physics. Such demonstrations present fundamental concepts in a manner that doesn't intimidate the viewer with the psychological barrier many have that physics is too complex for them to understand.
Good job!
+Richard Freeze Hi Dicky boy, It's all very simple, If you have an interest in Physics then you will naturally learn, If you don't have that interest then you won't.
Regards MoK
Hi, Moky. I expect most hobbyist machinists are less interested in physics than in making a part. Otherwise physics would be their hobby, not machining.
Obviously learning a subject in which one is interested will come easier than one to which they are adverse.
However, often is the case where some practical knowledge of a subject is relevant to the primary subject of interest. In this video understanding the effect of vise deflection is relevant.
I think Stefan's practical explanation of the effects of the physics involved will be meaningful to even those who have no interest in physics per se.
Interests spring from exposure to a subject. That exposure comes in many forms, school, travel, parents, friends and general life experience. One never knows when the smallest stimuli will provoke a life-long interest. Development of an interest depends on one's confidence in self to achieve a goal. That confidence comes from encouragement, not discouragement, and persistence which leads to more successes than failures.
It's unfortunate that many young people who have much potential are limited because their environment and the people in it tell them they don't have the natural ability to learn about something that exceeds the available knowledge in their confined environment.
That's why it is so satisfying to see someone like Stefan publish intelligent, useful information in a clear, concise manner. His rich, positive content far outweighs the trivial remarks that someone like you or I may make.
Regards,
Richard
+Richard Freeze Hi again Dicky boy, I am afraid you are preaching to the already converted. I am 75 years old took a Bsc degree and passed with Honours at 63 I am a practising Cosmology Physicist and am qualified in Hypnotherapy, Psychology, and lastly am a precision metal working engineer working down to drilling 0.01" holes. I have repaired things all my life, as being born during WW2 , the only way I was able to get things was to salvage and repair always trying to do things properly. During my childhood there was no extra education, so we had to do what we could , when we could. There was a shortage of food for at least 10 years after the end of the war during which period we each had a ration book, none of which detracts from the quality of Stefans work. Stefan is a High class engineer and I enjoy seeing him work as he reminds me somewhat of myself, so I think you can see that your lecture is of little importance and my remarks are far from trivia, so come on down from your high horse and join in with us Proper engineers and find out how to live your life to the full.
MoK
Moky,
The first thought that came to mind after reading your response was, "Beware of ships that blow their own horn".
Have a good day, old man!
Thanks Stefen, very informative!
Very nice video Stefan. Found your comments on the 'toolmakers' vise very helpful.
Bob
I was surprised to see the gage block leaning towards the movable jaw in the screwless vice. It has me baffled. I thought on the third vice that this wouldn't happen do to the slight lifting of the movable jaw. Been on the lookout for both Moore books. This is the type of info we need to know if we are wanting to do persicion work.
Nice Video and like the other Viewer's said "U go on talking, Man" - 'cos we are all listening and learning.
That's what matters.
Very interesting and enough Food for Thought !!
Some deflection we did not even think about. And now will have to consider every time we clamp any Part.
Thanks for Your ideas and Sharing - much appreciated.
MUCHAS GRACIAS !!
aRM
Thank you!
It looks to me like there's lots of room out there, in the marketplace, for a vise that has built in adjustments to correct for deflection.
loving the deutsche post yellow box..what a classic ;)
Get better mic bud!! Your are an absolute treat to watch and learn from!!! Shout out to tot for pointing you out to us!!!
Hi Stefan, I was thinking about your comment at 13:20 , and I think besides the movable jaw tilting less than the fixed (as you suggested), there must have some "Poisson effect" happening in the part when it's squeezed by the vice.
Very interesting. I really like your videos, I'm learning a lot, especially that my accuracy suck. 😅 Cheers from Sweden.
Hi Stefan
Very interesting video I have a virtex vice on my milling machine and will be doing those tests just to see how much deflection I get but really I do not have the skill level to work to the tight tolerance that you work to. I would like to but I can only work with what I have. I have a six jaw adjust true chuck on my lathe and have dialed it in to 0.005 mm and that nearly sent me nuts for two weeks on and off. So now you have just given me more things to stress about LOL very much like your videos.
Dave
+David Cashin : Hi David -I think you sell yourself short, you do have the skill to work to fine tolerances, you just have to convince yourself first. It all comes with learning and practice.
Regards MoK
Wow you are awesome. I learn a lot from what you share. Thank you very much. Keep making more.
Stefan you mentioned that the shaper vice is tilting the part towards the indicator....
But if i see it correctly the dial moves anti clock wise...
This would mean the part is tilting towards the fixed jaw and not towards the movable jaw
I sure have to agree about both those Moore books Stefan.
Very good point on vice flex. The best was to get around this is to use Starrett hold downs and you will be fine. Worked for me Stefan, maybe it will work for you too ???
Good grief, Kearny & Trecker hats make it to Bavaria :) .Seriously, I think that all metals are springs. Put enough force on a spring and it bends no matter how small the spring constant is. And I think you proved that quite conclusively. I am not at all surprised that bcbloc2's 100-Kilo vise did not deflect as much as the shaper vise, given the size. Deflection under load goes as square of length (in a horizontal beam, as depth square) and the Kurt has an awful lot of length and depth both. This is a lesson to me. Never trust a vise. The numbers were amazing, I did not expect .05 mm. Thank you very much!
Good stuff Stefan. I would be curious to see, if you had the indicator on the part, how the deflection effects the part if it is in the vise horizontally instead of vertically. I know that my Kurt vise is worthless for holding while face milling because of the upward movement of the moving jaw, however, I've never measured how much it actually moves.
Very nice! Thanks! Will it help precision if you use a torque wrench to make sure you always use the same force to fix your parts?
+Zorgoban Yes, absolutely! This is what you see in production enviroments a lot.
+Stefan Gotteswinter: Hi Stefan I have to mention that with a torque wrench there will still be deflection but the error will always be more or less at the same level.
Hi Stefan, thanks for the inspiration. I've just uploded a video testing 2 very well used ones, a 4" Abwood and a 6" of unknown brand (Both British made). Surprisingly the results are not much different from your's which looks alot better maintained yjan mine. I used a torque wrench to ensure the pressure is always the same.
One might characterize their vise and use that knowledge to implement sufficient compensation with shims placed appropriately to have the part clamped true when tightened up. That is only if one needs to do so for very precise work.
PS: Great video!
Thought provoking.
Thank your for this.
Cheers.
So basically you're saying what I've told everyone is that there is no such thing as absolutely perfect... true perfection only exists in the person that says it's perfect.
Another edit: I just realized this was was posted years ago but still very relevant.
All the years I've been around & I never considered "deflection in the vise???" But it makes sense if you're taking your machining tothat level. I got nothing but time to see jus how far I'm going to take machining.. I'm 62, disabled... I have loved Welding & Machining since my youth. Prison taught me that Welding without Machining is like a Peanut Butter Sandwich without the Peanut Butter & without the Bread...
great video and i thought i just had a shit vice.
that explains why i always have a 1 or 2 thou difference on some large parts that get machined
Really enjoyed that
Stefan
Would the test be more subjective between the vices if you could measure the actual clamping pressure of the jaws with say a strain gauge/load cell , as I suspect the shaper vice has a greater clamping pressure than the toolmakers vice
But as usual I may be wrong 😱
Keep up with the videos as I always find a useful bit of knowledge in every one
My German is very poor and limited to technical stuff in electrical systems as we had a lot of Anton Piller equipment at the banks computer centre as had to work along side the very good female engineers they sent over
One thing I do agree with every thing is flexible , just work with a optical bench that will show just how bad it can get
Stuart
A very aged electrical engineer now at 69 circuits around the sun
very good. when i recover will check my kurt. squaring is not easy
Enjoyed...educational.....IMO...."stop talking???"...you should continue talking! as you just continue teaching
you should depressurize reductor of welding machine when not using it. keeping it under pressure for long time damages internals of reductor. just turn off gas tank valve and push TIG button to open solenoide valve and let argone or co2 leave reductor
Nice video.Did you hone the fixed jaw before testing the tilt?If there is a small burr low down it will be deformed when you clamp down hard.So in fact not bringing your test piece out of square, but closer to square. You only measure tilt change, not squareness.Distance from burr to top of jaw is small compared to distance between the instrument probes, so the deformation will be magnified.I assume you cleaned the part and jaw, or a tiny particle would have the same effect.
My Proxxon's Primus 100 machine movable jaw is lifting quite much. Did not expect that from a German made product though and in that cost
Your awesome. I love your videos.
Great video, I now have to re-evaluate everything I took for granted in my shop. To be a little nit-pickey, could part of your shaper vise deflection been due to refrencing off the rear base of the vise where the screw loading could be actually bending the back half of your vise? Have you repeated this measurement using some other part of the machine for your magnetic bases? Sorry to be "that guy" but you're the one to get me thinking in the first place! Thanks.
cool video.
i have a machine-shop physics question. perhaps you can answer here, or make a video on this topic if it is suitable.
why is it that people suggest that a surface plate be mounted on three support points that are used between the plate and the supporting stand/cabinet that the plate is resting on?
i get that a tripod is stable relative to a four-legged structure that can tip if one of the legs come off the ground; however, flatness has nothing to do with level.
a surface plate hung from the wall of your shop would be perpendicular to the ground and it would still be flat, no? so why are three feet preferred and not four?
if you have four adjustable feet you should have a more stable surface than a three-legged arrangement given that a weight can be put on any corner of the surface plate and it will not tip.
if one of the feet loses contact with the ground for some reason, you can adjust it so that the foot regains contact as needed. the adjustable feet make sure that each foot can always retain contact with the floor or stand the plate is on.
so why worry or prefer that there are three feet?
my guess is that it really does not matter relative to flatness.
metals flex at some point after watching this my vise will flex thanks for showing me this now I know how to fix this problem make some parts adjustable to compensate for the movement this would be the 2 jaws at each end let me know what you guys think ?
Very interesting. As always, rigidity the key.
Thanks, I will be checking my vises. Checked my lathe, it must be made out of rubber. wow
Thank you, Stefan. So interesting.
Never tested as you did, but always checking after clamping, because everything made from a rubber ;)
There is Dan Gilbert RUclips channel with a series of video for prototype makers. Totally cool stuff
+Andrii Podanenko It is Dan Gelbart that does the prototypes. The guy is great on this sort of stuff.
GaryGrumble yeah, sorry about messed up with his name.
Would have been interesting to see the deformation of a part when clamping down (not just deformation of jaws)... regardless very cool and educational video...thanks... oops 12:40 you did it !!
thanks for the great vids Stefan big fan of your one comment please do yourself and us a favor DON'T USE A ALLEN WRENCH TO TIGHTEN YOUR VICE use a spanner wrench if that Allen wrench had broke no vids for a while and don't say it can't happen guy I worked with has a scar on. his forearm to remind not to again so thanks again and keep on talking
what an interesting video .
´precisely´ ...lol
Good video Stefan
Grtz from the netherlands Johny geerts
Very interesting! I have to test mines
Excellent......I don't do metric. So the relationships were not as clear as I understood them.
Have you measured moving jaw side movement? It can be a problem if you clamp a number of long parts in one vice lengthways, they will all be slightly different lengths and the longest one can 'kink' the moving jaw to one side. Really annoying error for me until I worked it out, all my holes near the moving jaw were randomly 0.05mm to the left or right depending on which side of the vice the long part was in.
Great video as always Stefan!
For anyone who's interested, Moore's "Holes, Contours and Surfaces" is public domain and has been Google digitized. It can be read online, in its entirety, here:
babel.hathitrust.org/cgi/pt?id=mdp.39015002958893;view=1up;seq=1
"Foundations of Mechanical Accuracy" is out there and available as a pdf download, but I'm not sure if it's public domain so I won't include a link. However, a quick Google search of "Foundations of Mechanical Accuracy pdf" will turn up some options.
It all goes to impress that items should be set up using a dial guage on the item, not the vise. I'm not surprised at all where items are clamped
+R Balderson : Hi, A good point, set the dial gauge on the workpiece but base the dial gauge holder on the table as it's the table that should be zero referenced to the quill.
Regards MoK
very interesting video. even though vise flex may never be an issue with the home shop machinist, it's good information. do you think that vise jaw flex is the reason that it is sometimes impossible to get both sides of a part to sit down tight to paralells?
+larry sperling Might be, but most of the time its a small burr, a few atoms of swarf or the wrong moon-phase. When this happens I try to wiggle the loose parallel up and down to feel if its very much off and if I can live with it...
I always assumed that was just that the faces were not square and it was just referencing off the fixed jaw. But I can go with wrong moon phase too.
the first book you listed is very hard to find in USA I found reference to one copy on AMAZON and the price is $1200.00
"Foundations of mechanical accuracy"
The closest copy i could find in a library was in a School library 70 miles from my home. Must be a great book If you have one you have a small fortune.
+flineman The books are available directly from Moore Tool, they cost $65 and $150. You can find them at mooretool.com/publications.html
-Chris
+flineman You can get the book here:
totallyscrewedmachineshop.com/documents/FoundationsofMechanicalAccuracy.pdf
for free, and I recommend everyone do that and actually read it!
The document appears to have been removed.
+bx2200 Sad, I was able to download it there earlier.
It is available in the download section on Hobby-Machinist, but you will need to be a member there with some number of posts (10?) to access it. I suggest you hurry if you are interested...
+flineman Hi our kid, You don't need that book, all you need is intelligence and common sense. Of which you appear to have both.
Regards MoK
cont'd from below: ...to one side of the vise centre, for a start. Only ever trust the back grip of the vise, but know its limitations, is what I say. How many need a precision of better than 0.005mm that often?
which one is better,blacksmith precision or woodturner precision :)
Hi Stefan,
I have been watching a number of your videos which I might add are great, and have I have been taking a great interest in your own vise (Screwless I think they'r called). I am very intreigued with the clamping mechanism, I wonder do you have any drawings of the internal mechanism and if so, or if you know the principle could you please send any copies of them or even a rough drawing from which I may complete a working design.
Many thanks in antisipation.
MoK
I do sloppy joe work. My machines are 80 years old and wore out. I get by doing work for myself and the local farmers. I've noticed things that are very accurate seem to be ground to size. I did notice a very big difference in the new Kurt clone import 6"vice compared to a "to wore out for Die Tech" Real Kurt. Kurt is much better than a Kurt copy and 10X the price.
Not suitable for milling... I use the hell out of a Shars version of that vise for milling. It works incredibly well!
Stefan! A vice is something you always want to deflect as much as possible! Away from yourself! Vices are bad! Conversly, a good vise will have minimal deflection when used properly.
Very interesting! I've always loved physics, and often find it sad how little people know about even the "6 simple machines" you learn about in Earth Science in the 7th grade...
I suppose if they can open a bottle of beer or wine, they can take it for granted that all of the thinking has been done for them, LOL!
Oh, on a side note I have a very important question for you. Do you know what you call the air in the top of a bag of chips?
+Knolltop Farms: Hi, In the UK the air in the top of the bag of chips is called "A wonderful aroma"
Here in the USA, it's called the "Snack-mosphere", LOL!
very interesting topic
18:10 How can the deflection be 2/100 mm at the bottom (near the jaws) and 1/100 at the top... does not compute.
G'day Alexandre, I know it's been a long time since you typed this but... :) Because the moveable jaw is lifting slightly as force is applied, that means it is probably pivoting on the jaw's lower back edge (nearest the crank). This would mean that, at the gripping face, the top of the jaw is pushed a fraction further back than the bottom edge. Cheers Duncan
Reminds me of a good episode on Keith fenders channel on torque lbs on a dry bolt versus bolt that had oil on them. Basically shit the average idiot like me would never figure in. The old guys I admire always said you can learn 1 of 2 ways, fuck it up yourself or learn from someone who fucked it up and is willing 2 teach your dumbass. Thx for vid
Did you try watching the center of the base for lift (indicating bending) on the grinding vises as they were tightened??
Just a newbie question: if the movable chuck of the screw-less wise is so perfectly rigid, why don't they make the wise with two symmetric movable chucks? Looks like the 45 degrees downward screw really does a great job at keeping things tight...
It is common to use the fixed jaw of a vice as a reference index so it is possible to load multiple parts in succession without the need to set up each part individually. Having two moveable jaws would severely reduce confidence in the setup over time. Tandem vices with two opposed moving jaws and a common fixed jaw are available but are regarded as specialty types.
Makes perfect sense. Thank you so much!
If you took off the replaceable jaws and did the measurement against the part of the shaper jaws permanent parts of the jaws, do you still see the same deflection? Just curious on how much of the play is due to how the replaceable jaws are bolted on to the vise?
Hi Stefan, I think you read in my mind. I was just looking for which is the better vise design. And, yes, I have read on forums people who say that grinding vices or toolmakers vices (how do you call them) are not good for general milling pourpose. But your advice now opens my mind and push me in the direction of that style of vice. The only difficult is that a lot of imported ones doesnt't have longitudinal slots like yours for clamping on milling table, they have just holes. So, is there a solution to clamp them? I have seen some special clamp block for that vices, but just one or two sellers have it.
+ Cosimo Marotta They often have the slots at each end, well at least mine does.
+Cosimo Marotta Since the objective is to just hold the vice to the table why not just clamp on top of bed (with protection) or make some clamps that engage the holes? Maybe pass a bar through an empty hole to clamp on. Most drill press vices have no means of clamping so all of mine have acquired holes on each side so they can be used on all machines.
Mike (o\!/o)
Hi folks, searching through the offers of sellers, barely all of them sell a model, in various sizes, with clamping falts just in front and rear of the vice. Along sides there are only holes (parallel to the plane). So it is hard to clamp the vice perpendicular to X axis. For this reason, someone have develop a pin style clamp, but I don't like it much. Stefan's vice has two parallel flat allow you to clamp the item to the table, but this design is difficut to find. That's was my doubt.
Hi Cosimo, In the UK you can get side grooved vices from www.arceurotrade.co.uk/Catalogue/Workholding/Machine-Vices/Precision-Tool-Vices-Type-2
If you wonder about lack of holding down recesses, remember they are really meant to be held on a magnetic chuck hence the (false) thought that they should not be used on a milling machine.
Thanks LWSH, just putted in my aim.