The Home Machinist!

ctwo wrote: ↑Thu Sep 10, 2020 9:46 pm ...maybe I will just mill out the center 1/4 of the span.

I agree with Harold. Don't do that. Don't even drill it.

safest thing to do it stick some adhesive rubber feet on the bottom...

I don't understand. It is a chord that I cut from a brake rotor, and I've milled half an inch into the top fins and around 100 thou into the bottom already. I feel as though I need to place it into a 500F oven for half a day and let it cool, and then lap it again on my surface plate. Milling it for four long feet instead of two rails would seem to be an easier thing to dial in.

I would not be surprised if it cracked in the oven though...

It is highly unlikely that the piece is free of stresses, in spite of the work you've done. If you wish to stabilize the stresses, the 500F you spoke of won't do it. What will do it is 550°C---650°C (1022°F ----1202°F).

Your fear of cracking is likely unfounded. So long as you don't thermal shock or heat cast iron unevenly, it normally doesn't crack from heating. Simply start with ambient temperature, soak for 1½ hours per inch of cross section (once temperature has been achieved), then, if you hope to not introduce any new stresses (from rapid or uneven cooling) simply allow the part to cool in the furnace.

H

ctwo wrote: ↑Sun Sep 13, 2020 7:44 pm I don't understand. It is a chord that I cut from a brake rotor, and I've milled half an inch into the top fins and around 100 thou into the bottom already. I feel as though I need to place it into a 500F oven for half a day and let it cool, and then lap it again on my surface plate. Milling it for four long feet instead of two rails would seem to be an easier thing to dial in.

I didn't realize you were talking a level you made rather than one you purchased. I'd go ahead and mill a bit off the center to make feet and then re-lap.

Bill Shields wrote: ↑Fri Sep 04, 2020 7:31 am sure it will...if the plate is truly level...then the level will show 'level' in both directions....

first $50 + shipping from 19734 takes it.

98 level.jpg

been in the box for 40 years....and I have 3!

which is a good thing since my 4th got broken in shipping 35 years ago.

It came a day early and I'm very pleased. Thanks Bill!

very good...put it to good use.

remember...bubble side up

Bill Shields wrote: ↑Wed Sep 16, 2020 7:23 am remember...bubble side up

Hmmm!
I wonder
Could that be part of the trouble I've had with levels?

H

It has a lot of miles on it..

Started in Mass...shipped to middle east (Saudi Arabia)...back
to Delaware then to California over 40 year time period.

And never been used

It is a world class level

I had not realized that there is a small vertical bubble in the center. I was reading about the cross bubble, but have not seen a use case for the vertical bubble (should say vial). I suppose I could put it on my mill or drill press quill.

All--

I got it! Thank you for all the help.

The secret was to find a stable surface on which to set my granite surface plate. I used one of the free-floating shelves I built in the new shop. Although the shelf is strong, I avoided touching it; the only thing I touched was the adjustment mechanism on the level and I used a dental pick to adjust that. Since the shop floor is concrete, there weren't any issues there.

I think a level with a better, much finer thread and easier to use adjustment mechanism would be a vast improvement. From looking at the pictures, it appears that Mitutoyo and Accusize use the same form factor as Grizzly. I'll bet their implementations are not as difficult to adjust, though.

--Bill

Fwiw my Mit uses a shcs Bill and I've never noticed much issue the few times it's needed adjusting.