Page 5 of 5 FirstFirst 12345
Results 61 to 69 of 69
  1. #61
    Join Date
    Jun 2016
    Location
    Sydney
    Posts
    283

    Default

    Yes, I forgot to say how big my working plate is: about 400 mm x 400 mm. Weighs a ton too!
    As to how it is supported - on a fairly flat bit of softish old chipboard. Distributed support. Shock horror of course, but considering the very light loads I put on it, that is quite enough.

    Yes, I do have a smaller genuine surface plate, but I rarely use it. I rarely work at the 1 micron level, so why bother? I also have some genuine broken tombstone plates, but haven't used them for ages either.

    Cheers
    Roger

  2. #62
    Join Date
    Aug 2011
    Location
    Melbourne
    Posts
    4,779

    Default

    Hi Roger,

    Yep when its all said and done ultimately as long as you're happy with your setup and it achieves what you need then thats all that matters.

    Simon

    Sent from my SM-G900I using Tapatalk
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  3. #63
    Join Date
    Oct 2011
    Location
    Norwood-ish, Adelaide
    Age
    59
    Posts
    6,541

    Default

    The 3 points are sometimes referred to as 'airy points' (or something similar). The idea is that they are the locations where the table has minimum total deflection (highest point to lowest), so it is likely to be flattest. A precision plate will be supported on the same three points when made (and measured) so it is all the same. Supporting a plate on a flat surface is not an issue but if plate is thin in metrological terms and the support is not flat or rigid then it could deflect. It depends on circumstance but deflections are not big and probably would not be noticable for typical workshop use.
    I remember hearing a story about Mr Mitutoyo showing some people how to scrape an ultra precision surface plate. He'd take a swipe and then leave it for some minutes just so the heat from the cutting action did not affect the profile. Top grade plates have variation measured in the fractions of micron region. At this level it comes down to knowing that something is precise just so measurements made can be repeated without worrying that the surface is influencing the result.

    Michael

  4. #64
    Join Date
    Nov 2011
    Location
    Adelaide
    Posts
    103

    Default

    CMM

    went to an auction yesterday, and this went (I think) for c. $240

    The plate was c 250mm, and the backing 150mm-200mm. Would be a bugger to move, but NICE granite.




    CMM MACHINE, GIDDINGS & LEWIS
    SHEFFIELD MEASUREMENT
    MOD: CORDAX1808-MMEA
    WITH MANUALS
    (NOTE: RENISHAW HEAD NOT FOUND)
    (POINTS ONLY)
    SLAB SIZE: 163 x 74cM
    Attached Images Attached Images

  5. #65
    Join Date
    Sep 2011
    Location
    Ballarat
    Age
    65
    Posts
    3,103

    Default

    Quote Originally Posted by Stustoys View Post
    Yet to be decided.
    Hope it's not a cameo Stu, always enjoyed your posts though you have reminded me that a thick piece of glass on a towel on the bench just doesn't cut it .
    Apologies Simon for the pseudo hijack.

    Phil

  6. #66
    Join Date
    Aug 2011
    Location
    Melbourne
    Posts
    4,779

    Default

    No apologies necessary Phil.

    Im keen to see more posts from Stu on a regular basis too.

    Just keep asking him questions, we'll get him back by stealth. He wont even realise his back until its already too late!!!

    Simon



    Quote Originally Posted by Steamwhisperer View Post
    Hope it's not a cameo Stu, always enjoyed your posts though you have reminded me that a thick piece of glass on a towel on the bench just doesn't cut it .
    Apologies Simon for the pseudo hijack.

    Phil
    Sent from my SM-G900I using Tapatalk
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  7. #67
    Join Date
    Jul 2010
    Location
    Melbourne
    Posts
    9,088

    Default

    Quote Originally Posted by Steamwhisperer View Post
    you have reminded me that a thick piece of glass on a towel on the bench just doesn't cut it
    I hope thats not what I said
    It all depends what you're trying to do (and also so, sometimes the "right" tools just make things easier. That doesn't mean they aren't possible without)(but you know that). I knew a guy that (if I recall correctly) used a setup like that to lap the head/block of early holden 6's so they could be run without head gaskets. Maybe even some of the first repco hipower* heads, I believe some the the records that car set still stand. I'd have to check.

    Simon
    I see I cover my points in the in the earlier thread. Wow its hard to make any sense of some of my posts without the pictures, or maybe its just me lol

    Re the taper. The way I see it if you try and make a round socket there are 3* possible outcomes.
    1. You get it "spot on". At the level I'm thinking would be required I think thats unlikely.
    2. Your radius is to large. Now the bearing has a point contact on the bottom of the socket and can move in two axis.
    3. Your radius is to small. Now the bearing has line contact around the top of the socket. Depending how deep you made your socket I'm thinking its POSSIBLE you'd end up with a selflocking taper.

    No points for you

    *ok there are at least 4 more outcomes, one of them possibly better than a straight taper, for the rest the result would be the same as 2 or 3, but my head starts to hurt lol. That doesnt include tool height effects on "shape"
    See why I took the easy way yet?

  8. #68
    Join Date
    Sep 2011
    Location
    Ballarat
    Age
    65
    Posts
    3,103

    Default

    Quote Originally Posted by Stustoys View Post
    I hope thats not what I said
    Nah Stu it's just that when you were making the stand I was using a piece of glass on a towel...I'm still using it.

    Phil

  9. #69
    Join Date
    Aug 2011
    Location
    Melbourne
    Posts
    4,779

    Default

    Thanks Stu. I see what you mean. And yes I read the post on your previous thread but without the pics it was missing 80% of the information!

    In truth, you are quite good at explaining things but I'm very much a visual person.

    So, welcome back Stu?

    Simon
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

Page 5 of 5 FirstFirst 12345

Similar Threads

  1. Surface Plate
    By BrazOmatic in forum WANTED TO BUY
    Replies: 2
    Last Post: 4th Jul 2018, 12:38 PM
  2. surface plate stand
    By eskimo in forum METALWORK GENERAL
    Replies: 13
    Last Post: 25th May 2016, 09:19 AM
  3. Granite Surface Plate S.A.
    By DSEL74 in forum EBAY, GUMTREE, and other off forum sales sites
    Replies: 1
    Last Post: 9th Feb 2016, 01:25 PM
  4. what do you think of my surface plate
    By welder in forum METALWORK GENERAL
    Replies: 11
    Last Post: 21st Nov 2011, 05:33 PM

Posting Permissions

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