Solid Tool Post Riser for my 13"x40" lathe

Buffalo21 said:
It would never work for me, I use the compound on a regular basis and am constantly pivoting the QCTP on my 14 x 40 Jet.
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I'm planning to add a separate retainer plate that will prevent rotation, but you could always use the block without it and rotate the tool post. I'm planning to leave my compound set up with the QTCP stud in place so that I can pull the tool post off, unscrew the 4 hold down bolts, pull the block off, thread set screws in the holes and then drop the compound back on. It sounds like a lot, but I think I can get it down to a minute or two.
 
Buffalo21 said:
Chris,

Interesting design and concept, when I bought my QCTP, I was told the weak joint is at the compound/carriage, but we do the best we can. It would never work for me, I use the compound on a regular basis and am constantly pivoting the QCTP on my 14 x 40 Jet. Still I’m very interested to see the results.
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I use my compound as well. I just swap between the tool block and the compound as the project dictates. It takes about the same amount of time as swapping chucks.
 
I made a solid post for my Hardinge HLV, I do notice improved finishes when turning but a big difference parting. With the compound installed I have to be gentle parting, with the solid block it never grabs. Switch back to the compound for threading to get the quick retract mechanism.

Greg
 
My block is held to the xslide with four 3/8 x 16 capscrews. All the compound mounting features are right under it. Takes a cupla minutes to swap out. I rotate the QCTP to get angles when using the tool block.
 
Yesterday I finally took the plunge and started machining the riser out of the prepped stock. I have all of the shaping done. I used a 3/8" 4 flute carbide end mill to rough machine and then finish the top of the step. Then I used a 1/4" 4 flute carbide ball mill to radius the corner where the step and the riser meet. I used the same ball mill to face the 45 degree sloped section taking roughly 60x .0125" DOC passes. Finally, I spot drilled all of the holes.

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This morning I drilled the five large holes 5/8" deep with a 1/4" HSS drill. I'll finish those on my drill press. Then I started pocketing the holes for the hold down screws with a 1/4" 4 flute carbide end mill. I got the front pair done but realized that I might have interference between the tool holder and the back edge of the riser so I stopped. I'm probably going to have to use a 3/8" end mill so I have more reach to get those back pockets done.

After that I just need to chamfer all of the edges and I'm done with the top on the mill.
 
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I got the pockets machined and chamfered all of the edges. The block is looking really good. I should have taken a picture before I moved on.

Next, I put the block in my 4 jaw chuck, got it as parallel and centered as I possibly can and then mounted the entire assembly on the lathe. It must weigh about 50-60 pounds. I adjusted chuck until the block was centered and then pulled my parallels out from behind the chuck.

I drilled a small center mark and then mounted my live center. I think I should go back and make a deeper center drill though.

The plan is to turn .150" off the back leaving a 1.565" diameter x .150" deep journal that will seat into the compound pocket in the cross slide.

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Last night I got the back side faced and turned the lug that will fit into the hole in the cross slide.

This morning I finished drilling all of the holes from the top. Then I turned a tapping guide out of 1.75" diameter aluminum to help keep the threads straight. At that point I attempted to tap the 5/8-11 hole to mount the tool post. I'm running in to a couple issues. First, the biggest tap handle I own is only about 8" long so it's hard to get enough torque on it to actually tap the steel. Second, even with the tapping guide I'm having trouble getting the tap started straight into the hole. I need to think about this for a while. My first instinct is to mount it in the 4 jaw and thread it on the lathe. That's probably the safest route. I'll have to see if I can offset the block in the 4 jaw and still clear the bed.

I've make a couple mistakes but so far none of them have been insurmountable. Hopefully I can get over this next hurdle.
 
Most of the folks on the forum that have added solid plinths to their lathes report improvements in rigidity, though I suspect
the smaller, lighter machines benefit the most. I found benefits in greater DOC, less chatter and better parting. Because
it's smaller than the compound, it's nicer to work around and there's no danger of bumping the handle and changing
tool position.

It looks like you're doing a great job on yours. Looking forward to seeing the finished product.
 
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