Wedge or piston type quick change tool posts?

[firbikrhd1]

The threaded steel piece for the "T" slot that came with the wedge type from CDCO was so hard I couldn't machine it.

A friend of mine bought one of the CDCO piston type QCTP and since he did not have a mill at the time he sent the steel piece to me to mill for him. We have the exact same lathes so I could just mill it to fit my lathe. I ruined at least three end mills trying to mill that piece of steel until it finally dawned on me that it must be hardened steel. I took a file to it and could barely make a mark on it. I should have known before I started milling it because when I first looked at the steel plank I thought to myself that it had that pattern on it like it had been surface ground. Live and learn, I guess. :-[

Ed

In my case I tried to machine that piece with HSS in a Shaper and immediately learned it was too hard. I had never tried annealing and thought this might be a good opportunity. The piece was heated with a large propane torch to it's critical temperature, which was discerned when a magnet would no longer stick to it. The part was then placed in a cast iron pot filled with heated sand, covered with more sand, a cast iron lid, the entire thing covered with insulation and left to cool overnight. The next morning it was cool and machined beautifully. I left it in annealed condition as it is surely strong enough that way.

 

[Chucketn]

Anyone have any good plans for making a wedge type QCTP?
Forgot to add, this would be for a MicroMark 7x14 lathe.

Chuck in E. TN

 

[benmychree]

If you are talking "real" Alois tool holders, the only difference between the two types is repeatable accuracy; the wedge type is much more accurate, but this is not of great importance for most work, especially hobby. The piston type is no more ridgid than the wedge; at times I have changed holders and forgotten to lock them down tight, or at all, and there was no more tendency to chatter than when firmly locked. I have the CA series on a 19" Regal Leblond lathe. Yes Alois is expensive, buy I feel it is worth the price; I've been using them since the early 1970s, and like them in every way, except that their threading tools do not project far enough out to permit small diameter threads to be cut with the live center in place; fo this, I have a old Pratt & Whitney form relieved threading tool with a long straight shank that I hold in one of the openside holders. I have only one offbrand holder, a Armstrong that holds the tool at about 15 deg angle in the horizontal plane. Thought it was a good idea for HSS roughing tools, but have used it very little.

 

[jamie76x]

The piston type are not that bad when you have short turning tools or making light cuts. When you are holding longer tools like a boring bar or trying o take a heavier cut, the always jump around on you messing with your tool height. I would pend the extra bucks on a wedge...

 

[LEEQ]

Anyone have any good plans for making a wedge type QCTP?
Forgot to add, this would be for a MicroMark 7x14 lathe.

Chuck in E. TN

I have been looking, I'll let everyone know if I find a set. I hope you share your project when it comes to be. Good luck, lee.

 

[Uncle Buck]

I have read tons of complaints about the performance of piston type QCTP. Personally, I bought a BXA Phase II piston and I have never had one issue with mine. I have been totally satisfied with the performance and as I said really never have had even one issue. That has been my experience with a piston type QCTP

 

[jbrubaker911]

I have to side with Uncle Buck. I bought a Phase II AXA QCTP for my 9" South Bend about 10 or 12 years ago and never once had a problem with it. I still have it and use it on my Grizzly G4003G lathe that I now have. The Grizzly came with a "generic" BXA QCTP but I seldom use it because I only have a few toolholders that fit. So in view of the fact that I am perfectly happy with what I have, I can't see spending the $$ on a wedge type of any brand. I'm sure that the money could be spent to a better advantage on other tools. I'm nearly 75 years old and I've spent my entire life in the trades. For tools that I used on a daily basis - I bought the best. For tools that saw only occasional use, I bought lesser quality. In my shop I have a box of worn out Snap-On, Proto and Plumb wrenches. Worn out from daily use. In contrast, I have a set of combination wrenches up to 2-1/2 inches - very cheap, made in Taiwan, over 30 years old, and in excellent condition. While I like good tools, I don't feel I need them gold plated if I can do just as well with plain chrome ones. Just my two bits worth.

 

[martik777]

I made a bunch like this one - they work great and cost nothing to make! Just size it for your lathe, maybe add a quick change lever instead of the bolt.


http://www.swarfer.co.za/lathe/toolpost.php

Commercial version:
http://www.krfcompany.com/

Anyone have any good plans for making a wedge type QCTP?
Forgot to add, this would be for a MicroMark 7x14 lathe.

Chuck in E. TN

 

[jamie76x]

One more point I want to make on this....

As I mentioned earlier, light turning with short tooling will not test the boundries of the piston type tool post. Longer tools an boring bars will cause the holders to shift, causing you problems.

Re-reading this post this morning I suddenly realized a huge problem the piston tool post can cause, PARTING.
More people have trouble parting than anything else. When parting, if the tool tips just a little bit you will break the insert or chip the tip off the HSS blade. My first QCTP was a piston and I learned the hard way, I always had trouble parting with it. I pointed the finger at the machine and not the tooling. Once I found a wedge type for that machine, Parting was never a problem after that .

 

[Uncle Buck]

One more point I want to make on this....

As I mentioned earlier, light turning with short tooling will not test the boundries of the piston type tool post. Longer tools an boring bars will cause the holders to shift, causing you problems.

Re-reading this post this morning I suddenly realized a huge problem the piston tool post can cause, PARTING.
More people have trouble parting than anything else. When parting, if the tool tips just a little bit you will break the insert or chip the tip off the HSS blade. My first QCTP was a piston and I learned the hard way, I always had trouble parting with it. I pointed the finger at the machine and not the tooling. Once I found a wedge type for that machine, Parting was never a problem after that .

So how much boring bar length is it supposed to take to cause a problem? I have used a boring bar as well as parting tools with my piston and never experienced the problems you speak of. Maybe I was just one of the lucky few to not experience these problems. I will concede that I own an Atlas 12" commercial machine so generally speaking I am not hogging off the same amount of material in each pass that guys with heavier more industrial machines might. If that is the reason I have not experienced these problems then I guess the piston QCTP makes a good match for the capabilities of my Atlas.