[Metrology] Ideas for home-friendly surface plate stand

[Rustrp]

Wondering what people think about sunlight and expansion and contraction of metal.
Perhaps this isn't an issue in Leekos application. But, regardless I'm curious.

Daryl
MN

To be specific regarding sunlight. I have a 10" brake that did sit near a southeast facing rollup door. I have it adjusted to bend 20 guage so the bending leaf is crowned a little. The sun would shine on the middle of the brake (which happens to be painted machine gray) around 10:30 in the morning if the door was up and create havoc with the bending angle on the lighter guages.

 

[12bolts]

I would think a steel frame for rigidity and then a nice timber veneer for appearance. You could even use polished ss or brass for highlights. Is it a granite or CI plate?

Cheers Phil

 

[Rustrp]

I would think a steel frame for rigidity and then a nice timber veneer for appearance. You could even use polished ss or brass for highlights. Is it a granite or CI plate?

Cheers Phil

I agree and I already have it fabricate in my head.

 

[Silverbullet]

Do you know to mount them level with only three points of contact under the granite. I forget the measurements to use for there location. But I figure if you come in 8" from each end put two on one end and one on the other. They can be made adjustable or should be.

 

[Bob Korves]

There is a standard for the mounting locations:
http://standridgegranite.com/forms/installation-instructions

 

[Glenn Brooks]

The three point mounting diagram provided by Bob is very interesting. Must go out tomorrow AM and change my set up to match.

Re mounting the surface plate in your home office. I wouldn't be afraid of framing up a simple, good looking, varnished, or stained, 3x3 or 4x4 clear grained fir, teak or spruce table frame and legs with a couple of horizontal supporting beams. Then set the plate on top with a 2x3 angle iron frame (similar to Bobs link with the necessary 3 point suspension). The purpose for making an angle iron frame is so that you can wedge or jack the sub frame to be truly flat and level - independently of the underlying timber or metal cabinet. You can also make jacking screws, but simple wood wedges are really quick to make, and don't require welding the screws to the frame. And you can drive them under the frame with a small tap hammer or screw driver as a lifting lever.

Making the wedges and leveling the surface plate all told shouldn't take more than 15 or 20 minutes. Latter in the year when your house changes shape due to seasonal moisture content in the flooring, etc. you can adjust the level again with very little effort. Good luck!

Glenn

 

[Bob Korves]

Making the wedges and leveling the surface plate all told shouldn't take more than 15 or 20 minutes.

You must not have the same OCD that many of us have, Glenn...

 

[Glenn Brooks]

Oops, forgot to mention, these aren't precision by any means. I made mine out of African hardwood, on the table saw. No measurement, just eye ball 3" long, 3/4" tall on the big end. I was surprised how well they work. Tap, tap, watch the bubble in the level. Stick in another, repeat.

 

[Rustrp]

I know we like pictures hanging straight, doors that open and close without sticking, along with all the other things we like plumb, level or square, but I think many miss the purpose of the three point support of the surface plate.

If the plate is supported as it's intended then no amount of being out of level will affect it's indended purpose of checking for straight, flat, etc. I wouldn't build a stand or support system out of square or want it leaning but out of level by a 1/16", there's no harm done. I'm not saying there's harm done (psychological is the exception) by wanting to level the plate but it isn't necessary. Instruments for measuring square, angles, heights etc. don't come equiped with a bubble for a reason.

 

[Bob Korves]

I know we like pictures hanging straight, doors that open and close without sticking, along with all the other things we like plumb, level or square, but I think many miss the purpose of the three point support of the surface plate.

If the plate is supported as it's intended then no amount of being out of level will affect it's indended purpose of checking for straight, flat, etc. I wouldn't build a stand or support system out of square or want it leaning but out of level by a 1/16", there's no harm done. I'm not saying there's harm done (psychological is the exception) by wanting to level the plate but it isn't necessary. Instruments for measuring square, angles, heights etc. don't come equiped with a bubble for a reason.

The purpose of the three mount method, in the designated places, is to minimize inaccuracies caused by sagging of the granite plate due to gravity. We are talking about very tiny inaccuracies here, but then the plate is more than accurate enough to make a difference if you are using it to its capabilities. The plates are calibrated mounted on those same points...