Surface Plate Stand

MrWhoopee

H-M Supporter - Gold Member
H-M Supporter Gold Member
Joined
Jan 20, 2018
Messages
3,311
About a year ago I inherited an 18x24 granite surface plate from my friend Chris. It's been taking up space on the bench in the "dirty" part of my shop for want of a stand. I've been looking for a cheap roll-away toolbox for that purpose, but none have shown up, so I decided it was time to build a something. It needed to be on wheels because my "clean" shop is very small. The concrete floor in my shop is VERY rough, so I was about to order some expensive, large diameter soft casters when it dawned on me that I had some, and they were already attached to a frame. I had received it from my BIL along with a bunch of other metal and it was nearly the right size. It was long enough, but had to be narrowed by about 5.5 inches, so off I went. The rest of the stand was built from some pre-painted angle that came in the same load. I wish I had taken pictures during the build, but I get so involved that I just can't tear myself away.

20210403_112129.jpg

Total out of pocket was $8 for paint and about $10 worth of argon.
 

DavidR8

Soaking up knowledge!
H-M Platinum Supporter
Joined
Oct 16, 2019
Messages
4,468
Here I am searching the site for surface plate stands and boom, you post yours!
Well done sir!
 

benmychree

John York
H-M Supporter Gold Member
Joined
Jun 7, 2013
Messages
6,400
What is the purpose of the angled tabs at the bottom of the left hand legs?
 

Toolmaker51

Registered
Registered
Joined
Nov 12, 2017
Messages
270
Portable surface plates are a great idea. Some, at 9" x 12" by hand, to set down anywhere. At around 18" x 24", transport becomes an issue, granite is almost 170 pounds per ft³ or 77kg per 0.03 m³. While ~90 lbs not issue for many, it remains a cumbersome package.
Use that figure when building a cart for sufficiently rated casters, including material.

Even small plates have points of contact underneath, that help maintain flatness. It's worthwhile utilizing those even in a cart. If floor is rough, drill and tap frame vertically near corners for jackscrews; not for level, but control rocking of the plate. The instruments will appreciate that. Finger tight is sufficient, with a bit of cardboard between.
Those contact points are referred to as Bessel Points, suspending an object 0.5594 of the length at two points, that uses extremities to counteract sag in-between. Normally 3 are found to create a tripod footprint.

Some will chide this incidental picking at nits; others find thrill in broad expanse of available knowledge. A third party exists too.
Like a yard employee placing stickers in lumber, notices one arrangement straighter than another, proper name not so important, he can see it.
YMMV. DAMHIKT. IMNSHO.
 

MrWhoopee

H-M Supporter - Gold Member
H-M Supporter Gold Member
Joined
Jan 20, 2018
Messages
3,311
Even small plates have points of contact underneath, that help maintain flatness. It's worthwhile utilizing those even in a cart. If floor is rough, drill and tap frame vertically near corners for jackscrews; not for level, but control rocking of the plate. The instruments will appreciate that. Finger tight is sufficient, with a bit of cardboard between.
Those contact points are referred to as Bessel Points, suspending an object 0.5594 of the length at two points, that uses extremities to counteract sag in-between. Normally 3 are found to create a tripod footprint.
The surface plate did have three round pads to serve as feet at some point in its life, only two currently remain. I had considered additional cross members for suspension points, but I was fortunate/skilled enough to get the top frame sufficiently flat that, to my surprise, the plate does not rock. The last date of calibration is unknown and I have no plans for it in the future. It will be used principally for layout and perhaps simple inspection, but nothing of a critical nature. I will leave concerns about the fourth decimal place and beyond to the next owner.
 

ErichKeane

Making scrap at ludicrous speed.
H-M Supporter Gold Member
Joined
Aug 3, 2017
Messages
1,419
I have no idea, they were part of the pre-existing base. I though about cutting them off, but it was just too much effort.
From the looks of it, it appears that it is supposed to keep the piece of plywood from being able to lift on that edge for some reason. It looks like the plywood is supposed to be removable, but only tipped form 1 edge? Perhaps they were worried that the board in there would flip upward based on some weight put on the far side?
 
It can take up to an hour for ads to appear on the page. See our code implementation guide for more details. If you already have Auto ad code on your pages there's no need to replace it with this code
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock