lathe compound pedestal thoughts

Ironman

Ultra Member
I dug mine out of the mess yesterday and am thinking about using it again. I'm interested in feedback from people who have used this device, and any changes they would make. Pictures are nice too.
My lathe is a 14 x 48 and the one I made was a round one from some 4" shafting. That's what I had at the time. I have a square block of 3.5 x 5 soft iron now. As I recall, round was a bad idea and prevented close in work to the chuck.. It was more solid but that was a pain that forced me to return to the compound for one job and then it stayed there.
 

Chipper5783

Well-Known Member
What is the purpose of replacing the compound with a pedestal? Is there a problem with the function of thee compound? I have a similar size (15” swing) lathe, not a very heavyweight version, but works great. Parting off works fine, etc. Just for fun, I bought a rear tool post (which is a pedestal style - it worked fine, but not really any better - I finally took it off because it was in the way for one job, never put it back on.
 

thestelster

Ultra Member
Premium Member
Here is what I did a while ago:


It hs its advantages and disadvantages as I noted in the thread.

I'm planning to modify it to make it more refined and give me greater flexibility for the positioning of the tool cutter relative to the headstock and tail stock. @PeterT has been helping me with the design aspect with his fantastic computer skills.
 

Susquatch

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@PeterT has been helping me with the design aspect with his fantastic computer skills

He is pretty amazing isn't he! What impresses me most is his ability to whip together a design just to answer a question or make a point!

And just think! He always starts with a sketch! LOL! Prolly more to his advice about that than meets the eye!
 

Susquatch

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I dug mine out of the mess yesterday and am thinking about using it again. I'm interested in feedback from people who have used this device, and any changes they would make. Pictures are nice too.
My lathe is a 14 x 48 and the one I made was a round one from some 4" shafting. That's what I had at the time. I have a square block of 3.5 x 5 soft iron now. As I recall, round was a bad idea and prevented close in work to the chuck.. It was more solid but that was a pain that forced me to return to the compound for one job and then it stayed there.

This sounds like you are talking about a plinth to replace the entire compound. For certainty, are you talking about the kind that replaces the whole compound or just the toolpost on the compound?
 

Ironman

Ultra Member
Yes, this replaces the entire compound, unless I'm doing a taper or threading and I might have to try the straight in method. I've seen it work, never done it.
 

Darren

Ultra Member
Premium Member
I built one for my Emco V10P. The rigidity improvement was quite noticeable. I didn't really miss the compound and usually found ways around using it. It's easy enough to swap back though. I don't think i'd do it on my 16" SM lathe, as the compound is quite rigid, but may do it on my 13" Emco.
 
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Ironman

Ultra Member
Here is what I did a while ago:


It hs its advantages and disadvantages as I noted in the thread.

I'm planning to modify it to make it more refined and give me greater flexibility for the positioning of the tool cutter relative to the headstock and tail stock. @PeterT has been helping me with the design aspect with his fantastic computer skills.
It definitely improves rigidity. Can you share your details with us? I'd like to do this only twice and get it right this time.
Your cast iron one looks like mine, and I may just need to tweak it.
 

whydontu

I Tried, It Broke
Premium Member
Mine is a chunk of 4” aluminum bar. Lots of fun turning an 2” eccentric in a 6” four jaw. Spinning the rigid post allows lots of adjustment to get more or less clearance as needed. Also gives me greater span for the tool holders, the offset allows me to drop the bottom edge of the holder below the bottom of the tool post body. Really helpful when using a tangential tool holder.

I don’t think I’ve used the original compound slide once in the last five years. My original concern was losing the accuracy of X travel without the compound, but with a DRO and the handwheel on the lead screw of my B2227 I can get 0.001” definition. Adding @jcdammeyer ‘s ELS system makes X position a snap.

IMG_6956.jpeg
 

Ironman

Ultra Member
The mistake I made on mine was cutting out the huge Tee slot for the CXA, when I could have done what you guys did and just thread a hole, so much simpler, and easier to position the QC.
 

Ironman

Ultra Member
Well now, it's a bit over a month later and the 20mm taps have arrived, and I got the holes for the post threaded and done. I had a grim time trying to find a drill that would give me somewhat the right sized hole for threading. I needed .702 and settled for using an endmill at .712. I did not want to set up and bore two 1 inch deep holes with a boring head.
 

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Susquatch

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I forgot whether your thread was course or fine. This is for soft steel for next time......

Screenshot_20240204_203643_Tap And Drill Chart Calculator.jpg

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PeterT

Ultra Member
Premium Member
Looks good. Are you dowel pinning your tool post to the block or using any kind of external angle bracket? I noticed a lot of guys went that way (mimicking Rob Renzetti & Stefan.G) who pointed outthat is another potential degree of slip. My own thought was to use 2 Mitee Bite eccentric fixture clamps on either side of the corner.
 

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Ironman

Ultra Member
Looks good. Are you dowel pinning your tool post to the block or using any kind of external angle bracket? I noticed a lot of guys went that way (mimicking Rob Renzetti & Stefan.G) who pointed outthat is another potential degree of slip. My own thought was to use 2 Mitee Bite eccentric fixture clamps on either side of the corner.
No, I'm not planning to pin it. There is a hole for a pin on the underside of the block, and when I bought it a pin was included but that is long gone. If I see any need for doing so I will pin it. I would like the freedom to move around on the top of that pedestal and I have a centerline hole as well as the offset hole, and an external bracket puts paid to any of that fancy footwork. You may have noticed that there is a thrust bearing that was wandering around and I put it under the locking nut, and that truly was an amazing difference in clamping power. I will be surprised if it moves out of line with this, but now that I got power to cut more than 50 thou we'll see.
I'll machine a plastic skirt to keep the crud out of the thrust bearing sometime.

Boy, we've come a long way from that nasty old lantern tool post, haven't we?

John, this is a 20 x 2mm thread and 18mm would have been good but I'm thinking that this is not high stress so hope I'll be fine.
 
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