tolerance requirements for grinding machine ways - Page 2
Close
Login to Your Account
Page 2 of 3 FirstFirst 123 LastLast
Results 21 to 40 of 47
  1. #21
    Join Date
    Feb 2010
    Location
    ch
    Posts
    2,045
    Post Thanks / Like
    Likes (Given)
    187
    Likes (Received)
    267

    Default

    op, you keep talking about straightnes and flatnes. but alignment is more important, no? if you have a dip of a few mu in a flat way, it wont matter much. you should concern yourself more with alignmen parameters. also, i assume you have a 1/1000 mm indicator. go and play with it, to get a feeling of what 1 mu is. while its maybe not impossible to grind something to the tolerances your dreaming about, the part will look very different once you take it off the grider, even if you were to hang it in free air. and how do you intend to check the work anyway?

  2. #22
    Join Date
    Jan 2005
    Location
    The Netherlands
    Posts
    5,326
    Post Thanks / Like
    Likes (Given)
    220
    Likes (Received)
    1225

    Default

    If you pick your grinder shop make sure it is not situated in a industrial area with heavy trucking going on Nor near a railroad Or it should be bolted on solid rock perhaps This all affects your results
    I have heard from more as one grinder they can notice when a truck is driving by
    Then there is the issue of grinding the carriage. I have heard from someone with a Ruemema lathe but not yet got it confirmed that the carriage is ground to fit with a certain roughness and not scraped after that That makes the carriage so hard to move
    Can anyone confirm that
    Peter

  3. #23
    Join Date
    Feb 2010
    Location
    ch
    Posts
    2,045
    Post Thanks / Like
    Likes (Given)
    187
    Likes (Received)
    267

    Default

    no idea, but there is strange stuff going on with these schaublin grinds. e.g. you cannot conventional grind a 102 bed, it has to get a cross grind (kreuzschliff, sonnenschliff) so it holds oil. a 135 bed is ground smoth.

    btw, if you go to schaublin bevillard and ask about tolerances of they grinds, the answer you get is: the grinder has been reconditioned recently.

  4. Likes Monarchist liked this post
  5. #24
    Join Date
    Aug 2007
    Country
    UNITED STATES
    State/Province
    Wisconsin
    Posts
    1,966
    Post Thanks / Like
    Likes (Given)
    905
    Likes (Received)
    814

    Default

    For a machine bed of this size holding all the ways within a tolerance of .0005" over the entire bed should be do able. You will want to send this to a shop that has a way grinder so that it can all be done in one set up.

    Finish of 16 ra" or better can as well be achieved. All of this comes at a price please remember.

    Mattison 36" x 12" Surface Grinder - Knifemaker.com

  6. Likes Richard King, TNB, whidbey, Monarchist liked this post
  7. #25
    Join Date
    Jul 2005
    Location
    Cottage Grove, MN 55016
    Posts
    6,488
    Post Thanks / Like
    Likes (Given)
    3467
    Likes (Received)
    3842

    Default

    OT . Cash how are you feeling? I have had the worse crud bug this winter then I have had as far back as I can remember. I don't feel sick and the doctor has taken xray and ultra sounds and I can't shake a cough without some sort of over the counter cold remedy day/night. Im slowly but surely getting better, but have been ill since Christmas. Get winded after 10 walk. This winter has been miserable, it was -10 F a few hours ago. Luckily i am driving to Steve Watkins in Houston next week where there is a heat wave of 39 F now and high of 59 today...woo hooo :-) I have missed seeing your name on here....stick around my friend! Rich

  8. #26
    Join Date
    Sep 2008
    Country
    UNITED STATES
    State/Province
    California
    Posts
    1,065
    Post Thanks / Like
    Likes (Given)
    676
    Likes (Received)
    605

    Default

    Quote Originally Posted by ballen View Post
    Hi Tien,

    Well I don't know Kramer and you do, so I am sure that you are right. Personally, I would have hoped if sent just the lathe bed, and asked to regrind it in the best possible way that he could, that he would agree to do this, since he is not being asked to do something less than perfectly. But it's certainly his right to refuse.

    Cheers,
    Bruce
    I would assume Ruemema wouldn't just grind the bed, they want to avoid the inevitable thread in a years time "Ruemema reground my Schaublin bed and it still doesn't turn xxmm in xxxmm"

  9. Likes TNB liked this post
  10. #27
    Join Date
    Aug 2002
    Location
    France
    Posts
    1,551
    Post Thanks / Like
    Likes (Given)
    220
    Likes (Received)
    573

    Default

    You nailed it : "inevitable"

  11. Likes triumph406, Paolo_MD liked this post
  12. #28
    Join Date
    May 2009
    Location
    Canandaigua, NY, USA
    Posts
    2,508
    Post Thanks / Like
    Likes (Given)
    107
    Likes (Received)
    969

    Default

    Quote Originally Posted by Richard King View Post
    OT . Cash how are you feeling? I have had the worse crud bug this winter then I have had as far back as I can remember. I don't feel sick and the doctor has taken xray and ultra sounds and I can't shake a cough without some sort of over the counter cold remedy day/night. Im slowly but surely getting better, but have been ill since Christmas. Get winded after 10 walk. This winter has been miserable, it was -10 F a few hours ago. Luckily i am driving to Steve Watkins in Houston next week where there is a heat wave of 39 F now and high of 59 today...woo hooo :-) I have missed seeing your name on here....stick around my friend! Rich
    I had the flu some weeks ago and shaking the cough is hard. I know several other people with the same problem. It's very slowly getting better, but I've never seen anything hang on this hard. The flu was no picnic either.

    Anyway, on this bed accuracy thing, what designer would ever tolerance a lathe part to require that caliber of lathe to make it? That would limit the number of shops that could make the thing to a small handful at best, probably fewer, and none of 'em local. At that point, one designs for the grinder, not the lathe. Or, one assumes a CNC machine where errors can be programmed out. That said, I'm as much a fan of getting as close to perfection as possible, but there's a practical and financial limit.

  13. Likes Richard King, stephen thomas liked this post
  14. #29
    Join Date
    Jun 2012
    Country
    UNITED STATES
    State/Province
    Michigan
    Posts
    8,611
    Post Thanks / Like
    Likes (Given)
    2558
    Likes (Received)
    2922

    Default

    Quote Originally Posted by cash View Post
    For a machine bed of this size holding all the ways within a tolerance of .0005" over the entire bed should be do able. You will want to send this to a shop that has a way grinder so that it can all be done in one set up.

    Finish of 16 ra" or better can as well be achieved. All of this comes at a price please remember.

    Mattison 36" x 12" Surface Grinder - Knifemaker.com
    Note a way grinder or a big knife grinder has a tilt head spindle.. Often good for one set-up and every thing is true to that set up.Dressing new angles on big wheels could be very costly..

    Yes some such work can be done with tilt tables but often not as easy or as close as a tilt spindle.

    and some such work has a number of wheels close to angles needed so minimum dressing.
    I was looking at a 72" Thompson last year thinking about such work but then considering the wheel cost did not buy it...plus I'm retired

  15. Likes stephen thomas liked this post
  16. #30
    Join Date
    Jul 2005
    Location
    Cottage Grove, MN 55016
    Posts
    6,488
    Post Thanks / Like
    Likes (Given)
    3467
    Likes (Received)
    3842

    Default

    Quote Originally Posted by michiganbuck View Post
    Note a way grinder or a big knife grinder has a tilt head spindle.. Often good for one set-up and every thing is true to that set up.Dressing new angles on big wheels could be very costly..

    Yes some such work can be done with tilt tables but often not as easy or as close as a tilt spindle.

    and some such work has a number of wheels close to angles needed so minimum dressing.
    I was looking at a 72" Thompson last year thinking about such work but then considering the wheel cost did not buy it...plus I'm retired
    OT.
    I had paid money down on a Rockford planner with a Bridgeport head a couple of years ago. Then I started to add up, pouring a concrete floor in my pole barn, Insulating it, putting in heat and electric, having riggers pick it up and set it inside the shop...yikes it was $10 grand...just to mill a few Straight-edges I sell. Then adding up everything I called the guy who I paid down $500.00 and said I changed my mind and he could keep the money. Now I send them to Steve Watkins. UPS charge is paid by the buyer. I had went temporarily insane I figure....LOL

  17. Likes stephen thomas liked this post
  18. #31
    Join Date
    Aug 2007
    Country
    UNITED STATES
    State/Province
    Wisconsin
    Posts
    1,966
    Post Thanks / Like
    Likes (Given)
    905
    Likes (Received)
    814

    Default

    I am well overt the flu, went to the vet and all vitals are good.

    I still have cough on and off, just like you guys explain.

    Worst thing for me right now is exhaustion. I am sleeping well at night, get up and 2 hrs later I am totally wiped out. Hopefully in time this will get better. My problem is I just can't slow down too much, I coach down hill skiing, State is this up coming weekend in Lacrosse, the shop is still busy to boot.

    I am in good shape and this thing just has me beat, for now......

  19. #32
    Join Date
    Jul 2005
    Location
    Cottage Grove, MN 55016
    Posts
    6,488
    Post Thanks / Like
    Likes (Given)
    3467
    Likes (Received)
    3842

    Default

    Yes you look like an athlete. Thats super you teach more then grinding and scraping. :-)
    I started taking Multiple vitamins and calcium and vitamin C, fish oil, bee pollen and honey.
    If I can get out of the B&K class early on Friday the 16 I would love to get a tour of your shop.

  20. Likes cash liked this post
  21. #33
    Join Date
    Sep 2009
    Location
    barcelona, spain
    Posts
    2,186
    Post Thanks / Like
    Likes (Given)
    446
    Likes (Received)
    1230

    Default

    Have it reground by anyone with a modern good cnc grinder.
    Ask the cnc grinder reps/importers for a client of theirs in your area.

    Modern 5 axis grinders have 0.7 micron resolutions.
    A client of mine had 2 - used to make carbide tools for stamping tuna cans, of all things.
    The die is solid carbide, and runs 400 parts / minute.
    Amazing.

    I am reasonably confident any modern cnc grinder will plane any lathe parts to better / equal than they were new on an old lathe.
    The best ones will be very much better than the old hand-fit lathe parts ..
    I have seen such work and grinders at the emo mt show in germany.
    The ground sample metal piece, under cover, was a perfect shiny optical mirror.

    If you want to do better, optical flats and monochrome lights and interference test kits are cheap.
    200$ +/- ..
    Endless hobby guys do mirrors and lenses to 0.1 microns or better.
    See astronomy / telescope hobby stuff.

  22. #34
    Join Date
    Aug 2007
    Country
    UNITED STATES
    State/Province
    Wisconsin
    Posts
    1,966
    Post Thanks / Like
    Likes (Given)
    905
    Likes (Received)
    814

    Default

    Quote Originally Posted by Richard King View Post
    Yes you look like an athlete. Thats super you teach more then grinding and scraping. :-)
    I started taking Multiple vitamins and calcium and vitamin C, fish oil, bee pollen and honey.
    If I can get out of the B&K class early on Friday the 16 I would love to get a tour of your shop.
    Give me a shout, I will be around on Friday. I may be meeting with Joe G on Wednesday in Chicago, I bought a new toy he wants to have a look at for quoting rebuild.

    I take multi vitamin, airborne, D, E and C daily. Still got sick.

  23. #35
    Join Date
    Jun 2012
    Country
    UNITED STATES
    State/Province
    Michigan
    Posts
    8,611
    Post Thanks / Like
    Likes (Given)
    2558
    Likes (Received)
    2922

    Default

    OT: I think bee pollen is good for general health and iodine with just painting a bit on you skin enough perhaps once a month.... I went to a trade show last week end and seem to have picked up a bug from my sick partner Nick. Yesterday woke with a bad sour throat..I gargled with an iodine solution and sour throat was gone in less then two hours…and no sour throat this morning .No I’m not recommending that.
    There is not much in modern , or even in old tribal medicines that takes away a sour throat.. but I found better..i know it is poison..

    I think nothing beats an old heavy iron scraped oil way grinder for holding as flat as flat can be.. The big old Thompson surface and broach grinders and Colonial broach grinding machines had very good scraping (among others). Some oil-way iron grinders would make ring-together parts. And think nothing beats an old plane bearing spindle once warmed up..Perhaps an air bearing spindle but I have never used one in a grinder head,

    But yes scraping make the best flat because it does not put in stresses, heat or pressure like grinding may..even with the best machine and using poor process.
    Last edited by michiganbuck; 02-10-2018 at 12:22 PM.

  24. Likes ballen, cash liked this post
  25. #36
    Join Date
    Sep 2009
    Location
    barcelona, spain
    Posts
    2,186
    Post Thanks / Like
    Likes (Given)
    446
    Likes (Received)
    1230

    Default

    My recall is that ring-together gage parts are somewhat lapped to 0.01 microns .. according to Moore.
    Moore is imho an authority.

    I think all the really good new grinders today are different.
    They are also used to make things like the silicon flats intel microprocessors come out of..
    And pv cells - same feedstock stuff (very good polysilicon).

    I see scraping as an excellent way to make very flat parts, very accurate, manually, slowly.
    With cheap equipment.
    And perhaps lapping improving it - manually.
    And both able to do large parts bigger than many common machine work envelopes.

    In 1985 intel processors did 1 um accuracies with cnc, and now in 2018 approx 10 nm, or 0.010 um.

    Moore (0.3 um), Mori (0.7 um DCG), and diamond airspindles for optics (==0.7 um or better) all demonstrate sub-micron total accuracies on complex workpieces.
    (Thorlabs optics lenses for one.)
    Endless amateurs hand lap optics to sub micron accuracies for hobby telescopes.
    People also lap surface plates to under 1 micron accuracies.

    I also think the old oil-way grinder is fast and cheap - as you said - .. if one has access to a place with one .. and will make an excellent flat of maybe around 2 um error peak on the surface, and potentially on the straightness.

    Endless top manual fitters, like Rumema germany, hand-fit and scrape parts together demonstrating 1 micron accuracies over actual movement like a tailstock barrel.
    This is an amazing achievement .. and needs better than 1 micron local accuracies to avoid tilt/bend/wobble volumetrically in 3d over say 150 mm movement.

    So complex skilled scraping handwork is imho better than old grinders ..
    -(but is slow and expensive in hours or money),
    -or lapping can reduce errors to amazing levels via moderate skills and time/skills/tools,

    -and big modern grinders are rare, expensive, and hard to find.
    -But modern grinders make better parts, much faster.
    -and top modern tooling on even moderate cnc equipment may make better parts than old grinders, in many cases, even in production quantities 100.000+ parts / year.
    With custom diamond tools, optimised process, stable input blanks.

    Quote Originally Posted by michiganbuck View Post

    I think nothing beats an old heavy iron scraped oil way grinder for holding as flat as flat can be.. The big old Thompson surface and broach grinders and Colonial broach grinding machines had very good scraping (among others). Some oil-way iron grinders would make ring-together parts. And think nothing beats an old plane bearing spindle once warmed up..Perhaps an air bearing spindle but I have never used one in a grinder head,

    But yes scraping make the best flat because it does not put in stresses, heat or pressure like grinding may..even with the best machine and using poor process.

  26. Likes Richard King, Paolo_MD liked this post
  27. #37
    Join Date
    Jun 2012
    Country
    UNITED STATES
    State/Province
    Michigan
    Posts
    8,611
    Post Thanks / Like
    Likes (Given)
    2558
    Likes (Received)
    2922

    Default

    I agree new CNC grinders are great and I have run microns on them..still a machine big enough to grind even a small lathe is more than most one-up shops can afford..
    The likes of an old Mattison or Thompson (and many others) can do good enough work for far less cost per hour machine.
    Good enough perhaps .0005 and better in 31" or more.

  28. #38
    Join Date
    Jul 2006
    Location
    Hillsboro, New Hampshire
    Posts
    4,730
    Post Thanks / Like
    Likes (Given)
    1064
    Likes (Received)
    3258

    Default

    Quote Originally Posted by michiganbuck View Post
    I agree new CNC grinders are great and I have run microns on them..still a machine big enough to grind even a small lathe is more that most one=up shops can afford..
    The likes of an old Madison or Thompson (and many others) can do good enough work for far less cost per hour machine.
    I would think that more important than having a amazing grinder is having staff who know how to set up and fixture a machine bed so that stress is minimal during the grinding process. A badly clamped bed may be straight while still on the machine, but pull it off and it's bowed or twisted - the best equipment in the world won't prevent that.

  29. Likes michiganbuck, Paolo_MD liked this post
  30. #39
    Join Date
    Jun 2012
    Country
    UNITED STATES
    State/Province
    Michigan
    Posts
    8,611
    Post Thanks / Like
    Likes (Given)
    2558
    Likes (Received)
    2922

    Default

    Suspect leveling and the right foundation would be important for a very long grinder..Cash and Richard would know much more about..
    I remember once we had to cut the floor away from the rest of the shop because we were getting vibration from a machine from a far distance away..

  31. Likes cash liked this post
  32. #40
    Join Date
    Oct 2012
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    10,375
    Post Thanks / Like
    Likes (Given)
    5843
    Likes (Received)
    4596

    Default

    Quote Originally Posted by Milland View Post
    I would think that more important than having a amazing grinder is having staff who know how to set up and fixture a machine bed so that stress is minimal during the grinding process. A badly clamped bed may be straight while still on the machine, but pull it off and it's bowed or twisted - the best equipment in the world won't prevent that.
    We could take the same ball, figuratively, and run clear off the field of play as to the lathe hand being able to compensate - or not - for an imperfect <<Schaublin or any other lathe>>.

    Pragmatically, the point arrives where straight turning hits the cost/benefit wall, regardless.

    Rather than chasing diminishing returns, the part, rather than the lathe bed, should be sent out for grinding. Or even grinding + lapping.

    Blustery, dick-swinging Sergeant, first day in a new job I had just placed him in comes to mind:

    "If you don't meet my standards, I will have your ass!"

    Superbly confident Crew Chief, one David C. B__. Wheeling, WV responded:

    "A question, then Sergeant W__. Once you "have my ass" ? Just what is it you expect to be able to DO with it?"

    One might ask the same question of 20,000 large Euro worth of Schaublin goodness vs sending any seriously challenging parts out for precision grinding, and just being grateful that it is a rather seriously better lathe than average - requiring little or no "compensation" - the other 300-odd days of any given year.

    IOW A "real world" need? Or just bragging rights?

    "Hoped for" bragging rights, we should say. There is always a more accurate machine or a bigger dick, even if it is CNC driven - or filter-feeds off krill instead of steak n'cheese sandwiches.

  33. Likes TNB liked this post

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •