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Can someone surface grind something for me? 4140 PH

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Cadillac STS

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I am going to make a base for my QCTP and take out the compound until needed. Looking for more rigidity.

I have a piece of 4140 PH that is about 2X2X6. I just need it surface ground on 2 opposing sides so it sits straight on the lathe cross. It can end up less that 2 inches as I will adjust the tool heights as needed.

Can anyone do this for me and what price? Please PM me through this site. Anyone in West Michigan so I can drop it off. Mail is good too.
287244
 

f350ca

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You may not want it ground. I made one from a chunk of cast iron and ground the top. Looks pretty but the hardened tool post likes to turn on it. A little roughness may help.

Greg
 

Dabbler

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Do you have a mill? You are just fine if you lap the top for measurement purposes. I agree with f350 about the bottom. Looks like a great project! -- What lathe are you mounting this on?
 

Cadillac STS

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I thought the ground surface would be better for holding the tool post and keep it from moving

It is a Wabeco D6000e German made precision lathe.
 

mmcmdl

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More friction milled than ground . I should say a better grip .
 

ddickey

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Might not be a bad idea to relieve the bottom..??
 

Dabbler

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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.
 

ddickey

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Looks like you have a pair of T-slots to mount your block to.
 

Cadillac STS

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Looks like you have a pair of T-slots to mount your block to.
Yes two T slots. I am going to just try two holes to T nuts. Might mill two mating tracks on the bottom of the base but I don’t think that will be needed. The compound does not have mating tracks.
 

Dabbler

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Consider milling 2 long T nuts and using 4 cap head screws to hold it down. Ground or not, it won't move at all. No need for mating keyways, and a lot of work (and precision) that will probably be unnecessary.

(Unless you'd like the challenge - then I bow to you!) ;)
 

jbolt

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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.
 

Cadillac STS

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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.
 

Dabbler

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Where does oe buy a DTM tool post? A web search didn't turn up anything relevant...
 

ddickey

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They're not made anymore. For years now.
 
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