Can someone surface grind something for me? 4140 PH

When I made the solid tool post riser on my PM-1440gt I turned the top and bottom using the 4-jaw chuck. With careful measuring and adjusting I was able to get the top/bottom within .0002" this way.

I agree with Dabbler on using a single long T-nut on both sides with 2 screws each. If you feel the need to key it, I would slot the bottom of the riser block and then make the T-nuts taller to also act as a key.

How wide is the QCTP? 2" seems kind of narrow for a riser block.
 
When I made the solid tool post riser on my PM-1440gt I turned the top and bottom using the 4-jaw chuck. With careful measuring and adjusting I was able to get the top/bottom within .0002" this way.

I agree with Dabbler on using a single long T-nut on both sides with 2 screws each. If you feel the need to key it, I would slot the bottom of the riser block and then make the T-nuts taller to also act as a key.

How wide is the QCTP? 2" seems kind of narrow for a riser block.

It is an AXA post. It does hang over a bit in the one direction but I think it will be ok.

It is a DTM tool post. DTM was made up of Aloris guys that went and made their own post from what I read. It is excellent, precise and solid.

I decided to try it as it is, it has one side that is very flat better than I could get it with my mill. Then if it doesn't work that way I'll have it ground. Someone over private message agreed to grind it if needed.
 
Where does oe buy a DTM tool post? A web search didn't turn up anything relevant...
 
They're not made anymore. For years now.
 
I've never tried relieving the bottom. For minimum chatter you'd think that having as much metal-to-metal contact as possible is the way to eliminate minute movements due to flex in available gaps.

My 4-way and both my QCTP have never slipped. Both of them are 'smooth', by which I mean they are coarse ground so grinding marks are seen. I'd be just as happy with a face milled bottom.
Contact is one thing, flat is another. Such as trying to face off a 6" diameter, only to find as you approach the centerline, it's higher than the periphery. Simple mechanics, no matter what feed rate [feed per revolution] is selected, it remains constant across the face, creating lower feet per minute. Examine a cylinder square, they are relieved to insure perfection after grinding.
 
We're necroposting but I have to agree with Toolmaker re relieving the bottom of something that sustains torque. Back when I bought a TS Engineering tool post for my Sherline lathe, I had a problem with the post turning with a big cut, a big cut on a Sherline being about 0.050" - 0.060" radial cut in mild steel. The post would turn no matter how tight you cranked on the center stud. The answer was to cut a circular relief into the inner surface of the base, leaving a 1/4" wide rim of material at the edges. After that, just normal snugging of the center stud locked the post solidly.

As for grinding, I use a fair amount of precision ground steel stock to make tools with. The reason for this choice is because it takes very little clamping force to lock two ground surfaces solidly. Quite often, I will use a single screw to lock two ground pieces together, while also allowing them to be quickly adjustable by loosening the screw.

For a plinth, grinding it is not a bad idea if you also grind the base of the tool post; better yet, relieve the base and then grind the rim left behind. Bet that post will lock with very little effort.
 
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