Okuma LS Adventures Part 5: Installing Cross Slide DRO and explaining the Abbe Error
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- เผยแพร่เมื่อ 12 ก.ย. 2024
- Part 5 of my Okuma LS Adventure Series where mount a Sony Magnescale DRO on the Cross Slide and the Display above the Headstock with some instructions and a short explaination of the Abbe Error.
#AbbeError
#Manuallathe
#Lathedro
wait what? 25+ years of using calipers but 13:55 was new to me. that is brilliant, thanks!
I learned it 5 years ago. So your not 25 years behind 😁
Wow! I watched a couple of guys mount DRO scales. They didn’t spend nearly the time and care shown here. I never would have guessed it would make such a difference. Very impressive. Really. BTW, early in the video when Bart was talking directly to the camera the thought hit me: “He looks exactly like Vincent Van Gogh in his self portrait!” Certainly some art on display here. By all means be careful of your ears!
Thanks, and I will be careful with my ears ;-)
Bart
Nice work, I agree the scale should be as close possible to the tool. Check out a mil some time that has the screw and scale off to the side of the spindle, creates a lot of error. One must pretend there is no DRO and always approach your numbers from the same direction.
Also now that you have used the DRO a while, think about mounting your readout on the carriage. Eliminates wires hanging into the chip pan and everything travels with the carriage.
I did one lathe with the readout as you have, and after a short time remounted it to the carriage. Now all 5 of my lathes readouts are on the carriages.
Gday Bart, throughly enjoyed watching, thank you for explaining the error situation, it was interesting how much things move with force, love the details up you go to to make fitting as good as accurate as possible, excellent job and excellent video, thanks mate, cheers Matty
Thanks Matty. Cheers!
Technically speaking then yes your obviously correct about that Abbe error Bart. But I'd counter argue that no machine will track and take cuts to what the dro displays as the theoretical exact tool tip position during every cut. Compounding that problem are different depths of cut in various density's of material that allow changing deflection amounts within the machine and part. Because of those built in and unavoidable issues, a dro on a lathe or mill simply can't be depended on to make 100% accurate dimensional cuts. It's then almost always a cut, measure and make slight compensations for the machine and part deflections under those cutting forces.I still applaud your efforts in going to the trouble of measuring and then showing the possible error and doing the job to the highest accuracy you and your tooling are capable of. Because of the far less cutting forces and higher accuracy that is available, I certainly think that Abbe error might be something to definitely consider with grinding equipment.
For myself and with the chances of many more chips, cutting fluids along with a better protected area I think I'll be mounting my dro to the tail stock side of the cross slide when I finally add one. You also may have a programming function on that dro that allows error compensation, so even with a measurable Abbe error the dro might allow it to be automatically corrected for. My Newall dro on my mill allows that, but the best I can do is run linear checks against what the dro displays verses what a stack of good brand name gauge blocks measure. So with what I have available I'm still unable to run error checks over the full table travels.
Hi, thanks for taking the time to write all this. I like that. The argument of the 'balanced cuts' is correct and I think it's still needed for accurate work. There are many variables beside the Abbe Error. But I try to get as close as possible so it makes it a bit easier and less depended on the cutting procedure. This DRO also has a correction function but that is linear, a fixed offset. I measured it under different axial and radial forces and the error is not linear so hard to correct. I see this a bit like Lathe backlash. It's still possible to do accurate work on a machine with a lot of backlash but you have to take more care and time in the process. Without backlash live would be a bit more relaxed. Errors can add up and be large if you combine them. My machine has little backlash (can be adjusted and is about 0,03 mm), and with a DRO under the tool and a solid toolpost to delete the compound movement it think this will be a very nice machine to use. The measurement was also functional to get a better feeling for the machine. I think this will also help me running the machine, understanding the movements a bit better. I encourage others to do a similar test that I did in this video to know how big the error can be.
@@bartharkemametalworks2299 Then my apology's Bart as I'd assumed the error might be able to be programmed out. Both Stefan and Robin Brenze have shown ample reasons why removing that compound slide is of benefit so that should also help a lot with an uncertain tool point position. There's an older TH-cam video around that I can't seem to now re-find that was done by a Russian and with a cyrillic lettered channel name. It should still be available, but I've spent a few hours searching for it without any success. Because of it being done in Russian, the standard English search terms don't seem to bring it up. I really should have saved it.
But he did a large amount of testing on what looks to be a fairly heavy, well made and still in very good condition Eastern European lathe a bit larger than yours. Very informative video as it showed cutting force deflections throughout the machine and in areas you wouldn't think they would show up. For heavy feeds and depths of cuts, one of my UK written books makes a good argument for choosing to use the standard non quick change 4 position tool post over any QCTP because of it's much better tool support. My lathe is no where near the size, accuracy and quality of yours, but I very much agree about that 4 tool turret showing some worth while benefits also. When I do have a lot of material to remove I do still use mine. The QCTP's are a great convenience and time saver, but there still not the absolute best method of tool holding.
@@turningpoint6643 No Apology's needed. It is a interesting subject with many different factors. I like the discussion and if you ever find the Russian video again then let me know. The QCTP that I have is a Parat RD3. That is one of the best (better then Multifix) and also used on CNC machines up to 25kw / 33HP. This one is very accurate and strong build. but there is always a more solid option then an QCTP. But I don't think my origional holder is stronger or give better tool support. One idea that I want to try is make a solid insert holder that directly mounts to the QCTP body without the the toolholder in between. But that may be a bit to much the make a difference in real life. This lathe is 'only' 10HP. I'm looking forward to do some heavy cuts and see where the limit of this machine is.
@@bartharkemametalworks2299 Yes if I ever do re-find that video I'll be sure to add a link here Bart. Whoever the video producer was he seemed extremely knowledgeable about what he was demonstrating. Even while not knowing any Russian at all I got a lot out of it.Someone that does know Russian with a Cyrillic capable computer could probably find it fairly easy. I'd guess whatever Russian words used for lathe deflection might be a good start for a search. If my memory isn't faulty I believe the American made Aloris, Dorian and probably some European QCTP manufacturers offer tool body's that take inserts directly. So the idea must be worth while. Most ultra large specialty lathes used in large tubine work, ship building etc never seem to use a compound slide or even a QCTP system. Obviously with cnc a compound slide isn't needed anyway. This is a fairly old video re-uploaded to TH-cam, it's also far outside of any practical use for people like us. th-cam.com/video/j0XVExlaYoU/w-d-xo.html But it does show a lot of mostly unknown and less well understood issues in machine tool design that you should find interesting.
I've also seen a few videos and forum posts where large lathe tools were machined to directly fit the QCTP dovetails. Since I don't know anything at all about your Parat RD3 system I'm not sure if that idea would be even any use for you. The one website I did check about the Parat system shows they seem to have a similar dovetail design to others. But very large used lathe tools about 2"-3" x 2"-3"" or 50-75 mm x 50-75 mm and larger seem to go for cheap money since few have the machines to use them. Your lathe does have the mass and rigidity with about 5 times the horse power as what I have so it just might be worth trying. My lathe only weighs about 400 lbs/180 kilos and it would have no real world benefit to me other than saving on buying more tool holders.
Excellent work, Bart.
Thanks 👍
Always love your videos, thanks
Thank you!
My Okuma dealer has one in Houston.
What????? You drilled holes in the lathe?????? 😮🤨😋 Well thought out there Bart. By the way, if you do a lot of mounting on sheet metal I suggest rivenuts, they are like pop rivets but with a thread. They work great and make for a clean install. FYI. Thanks for sharing.
Yes, drilling holes!! Not really fun but as long as you upgrade with the same quality or higher then the machine was build it feels ok. And thanks for the rivenuts suggestion.
Hi Bart enjoying learning from your project. 👍
Thanks!
Hi Bart! Excellent video, thank you for your contributions, very good channel, good Job!
Thanks!
Thanks Bart, enjoyed watching.
Thank you
Hallo Bart, mooie video vooral het gedeelte wanneer je met een stang de dwarsslede beweegt en de meters op "tilt" sloegen er komt nog wat bekijken om een DRO te instaleren 👍👍
Dank je. En klopt, er komt nog best wat bij kijken. En er zit meer beweging in zo'n grote draaibank dan je zou denken. Maar de meters zijn ook wel erg gevoelig met 0,001 mm.
Great care taken , excellent result 👍
Thanks!
Nice... You sure have patience! 👍
Btw. What kind of camera You are using? Some focus issues in this video. Can You use manual focus on general sections?
Thanks. And yes a have some focus problems. I use a Panasonic G80 with kit lens. Normally this is a nice set but I damaged it and made some repairs. This or to much grinding dust gives me some problems. I tried manual focus but that is difficult to set correct and I got mixed results. I need to buy a new lens / camera but I don't have the money for it at the moment.
@@bartharkemametalworks2299 Oh ok, that sucks... Can You adjust the aperture in video mode to get broader depth of field? I think You need smaller aperture for that. In my old Nikon D5200 I have to preselect the aperture before starting live view. I am starting to get into the video slowly... Nothing to show yet though...
Keep up the good work!!! 👍
@@arisalo89 Yes I can adjust the aperture but it will also change the ISO for video. Will give it a try. Thanks.
Those Japanese love Sneeze Shields!! 33:36
Maybe but I think this is a european safety regulation add on.
Nice work. Shouldn't you push on the bar and not pull to replicate the cutting tool?
Thanks. And you are correct about the force but push or pull did not made a lot difference. A did a lot of testing afterwards but this video showed the error the best. The forces are actually complicated. The radial force will rotate the toolpost counterclockwise but the axial force wants to push it in clockwise rotation and also gives more pressure on the cross slide ways to make it more ridged. This all depends on the tool position. So many variables but fun to test some of them. I will make a more detail video on this in the near future.
Super!
Precision for sure, near enough is not good enough.
Thanks. I try to at least make it quality work on the same or higher level then the machine was build.