Surface plate support quick question

So do they diamond lap cast iron plates? Or how do they get them to the proper grade? I have a decent understanding of how they do this on granite.

I can't believe they have handles for those huge plates... there is even a handle for the 900+ pound version. Must be machine lifting points?

Paul

I'm not sure how the "precision ground" surface plates are finished. I do know a hand scraped one costs about 1/3 more than the same size precision ground one. The list price for a 24" x 36" precision ground one is about $2,000.00. The same size hand scraped one is about $3,000.00. As for the handles, there is typically a lifting tool that slips over them. The tool is then raised by a crane or lift. Here's a link to a smaller plate available on e bay. Note the lifting tool that comes with it.

http://www.ebay.com/itm/CHALLENGE-1...urface-Plate-Very-Nice-W-Hanger-/351891804736
 
Short answer is the table that the surface plate & it's '3 point rest system' can sit upon any table supported with as many casters as you like. The 3 point leveling should only be of such height as to avoid any interference from said table top. 2" should be plenty. Carry on!
 
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...a hand scraped one costs about 1/3 more than the same size precision ground one. The list price for a 24" x 36" precision ground one is about $2,000.00. The same size hand scraped one is about $3,000.00...

That would be 50% more. ;)
 
Okay, here goes: I called Standridge Granite today, and talked to one of the technical people... Apparently in living mempry they have always used 3 points to calibrate and mount surface plates. My information from a website misidentified Standridge where it was another company.

Now for why: This all goes to a Federal standard. If you do work for the government (military, etc) you must use a calibrated surface plate that meets very specific criteria - chiefly that it uses a 3 point support system. Standridge and others calibrate and prepare surface plates to use this system. For extra money, Standridge will calibrate to 4 points - which is not allowable in the Federal standard.

Mathematically, 4 points is better. From a business POV, 3 is better. For a small shop, what-you-want. My new plate will be calibrated and supported on 4 points. My Mitutoyo, it turns out, must be on 3 points (!).

There is a lot of good stuff on cleaning and maintenance in the standard, so by the grace of Standridge (who sent it to me) here it is:
 

Attachments

  • fed spec GGG-P-463c GRANITE SURFACE PLATE.pdf
    1.1 MB · Views: 16
OK guys my 24x24 plate is on it's way from Standridge. I need 3 levelers to build into the top of a stand I'm going to make for it. You guys may have pointed me to a place to buy them but I can't find it for the life of me. .125 walled box tubing should work for the stand shouldn't it?

Paul
 
You can use machine leveling screws upside down, and they are available with rubber cushions or solid delrin type plastic. I would avoid that because od the slippage factor. The rubber feet would grip and not allow the plate to slide around on the mounts. Easy enough to weld nuts the crossmembers of the frame. And yes, that tubing is sufficient for your stand. You gave only the wall, but I am guessing it's at least 1 1/2" square.
 
You can use machine leveling screws upside down, and they are available with rubber cushions or solid delrin type plastic. I would avoid that because od the slippage factor. The rubber feet would grip and not allow the plate to slide around on the mounts. Easy enough to weld nuts the crossmembers of the frame. And yes, that tubing is sufficient for your stand. You gave only the wall, but I am guessing it's at least 1 1/2" square.

Sorry about that. Yes I was thinking either 1.5" or 2.0" square. I'm watching Shandon HKW make his now. Looks pretty straight forward. Also he mentions there are stand instructions included on the back of the Standridge certification.
 
It occurred to me today that leveling my plate could be a challenge as my garage drink/beer fridge has been out there for years and is so out of level the door swings open after you let go.... :concerned::eagerness:
 
If you aren't doing static balancing on it there are a few woodworking (yes, woodworking) levels that are accurate to .004 per foot. I ended up buying several over the years, but I have now forgotten which of my woodworking levels are that accurate! (I guess I could check if you can't find one). Buying offshore machinists levels have some problems: the one I bought was so far out and nearly impossible to make right. It took a bunch of hours to free the gimbals, and more to calibrate it, due to the very coarse adjustment screws.
 
If you aren't doing static balancing on it there are a few woodworking (yes, woodworking) levels that are accurate to .004 per foot. I ended up buying several over the years, but I have now forgotten which of my woodworking levels are that accurate! (I guess I could check if you can't find one). Buying offshore machinists levels have some problems: the one I bought was so far out and nearly impossible to make right. It took a bunch of hours to free the gimbals, and more to calibrate it, due to the very coarse adjustment screws.

Bob has offered to lend me his level short term to level the lathe once I get the legs and the pan together. Although like the plate I'm leaning towards buying one. I'll have to level the mill soon as well. So I will need it several times. Sounds like enough to warrant buying it. ....and maybe a 4"...a 6"...an 8"...a 12" :)
 
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