Squareness comparator from a 1-2-3 block

[twhite]

The second dial indicator mount is a nice add too. I’ve been thinking of making one so I can use it as a height gage, but I found a proper electric gage head and amplifier with a height gage recently at auction so that project probably won’t happen.

T white, I would strongly suggest cast iron or steel for the base unless you inset 3 points of ball bearings and surface grind them flat. Aluminum will wear rapidly on the granite. The weight of the iron base is helpful during use too making it more stable.

What I will most likely do is machine 3 small pockets to accept ball bearings. I have a mess of 9/32 then swedge them in. I made a spherometer like that for measuring curvature of telescope mirrors. Works great and very little resistance moving around.

I would use steel or iron if I had some. I just utilize what I have laying around. It is more fun that way trying to make things with what you have on hand.

I have had my real one for 30 years. The man that I apprenticed under made it. He unfortunately passed away at the age of 35. That was the one tool I was able to acquire.


Cutting oil is my blood.

 

[GT-6 Racer]

Sorry to hear about the loss of your mentor. The tools we make surely will far outlast us. That’s why I do an engraving on the nice stuff

 

[twhite]

Done just needs to be cleaned up.

Cutting oil is my blood.

 

[GT-6 Racer]

That looks very nice. Excellent job. It should be a good addition to the surface plate.

 

[twhite]

The only drawback to the 3 ball base is. It is ULTA sensitive to any plate imperfections. A flat base can overcome that.


Cutting oil is my blood.

 

[GT-6 Racer]

Might try surface grinding the balls to a flat leaving enough below the body say 0.030”. Will then span pits on granite. Just a thought.

 

[twhite]

Good idea. Unfortunately I have no access to a surface grinder. I could mount a cup wheel to the mill and use it as a primitive Blanchard type grinder. i might do that if I find I have an issue. My surface plate at home is much better than the one in the shop. I could use inspection’s surface plate if needed at work.


Cutting oil is my blood.