Piston or Wedge QCTP.

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armscor 1
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Joined: Sun Jun 12, 2016 3:12 am

Piston or Wedge QCTP.

Post by armscor 1 » Thu Dec 05, 2019 5:38 pm

I ordered a Piston type QCTP and have I made a mistake?
Any of you guys using the Piston QCTP and your thoughts on it?
The lathe currently has a turret style tool post which accepts 1" tool bits and is very rigid.
The tool holder for the QCTP is maximum 3/4" tool bit.
Some of my tool bits are greater than 3/4" so what I am thinking is to use the turret tool post for parting and heavy cuts.
Use the QCTP for light machining.
This means I will have to swap tool posts which defeats the convenience of a QCTP.

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SteveM
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Re: Piston or Wedge QCTP.

Post by SteveM » Thu Dec 05, 2019 6:16 pm

In a word:
Wedge

All else equal, wedge is better.

That said, I bought a generic wedge toolpost and it wasn't as good as my piston Phase II, so I dumped it and went back.

I eventually got a Phase II wedge, and it's an improvement.

While parting, the toolholder would actually rock, as it wasn't being supported by as many surfaces as a wedge toolpost.

I actually have an older aloris piston tool post (it has only one place to mount a toolholder) and it's pretty solid.

Steve

LIALLEGHENY
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Re: Piston or Wedge QCTP.

Post by LIALLEGHENY » Thu Dec 05, 2019 7:01 pm

What series is the QCTP? Aloris has a holder for each series that is oversize. I have the CA series on my lathe, which is for 1" tooling, but they do offer holder for 1-1/4". I believe the CXA series is 3/4" but they have a 1" holder as well.
As far as wedge versus piston, I have used both and haven't seen much of a difference, but then again they were Aloris brand, I don't know how the competition stacks up.

Nyle

ChipMaker4130
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Re: Piston or Wedge QCTP.

Post by ChipMaker4130 » Thu Dec 05, 2019 9:29 pm

At home I use a Phase-II wedge. At work we use a piston. If all the holders fit properly and if it is all of good quality you will be happy with the piston. If I were to buy again, it would be another wedge. I like the way it pulls down & tight.

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BadDog
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Re: Piston or Wedge QCTP.

Post by BadDog » Fri Dec 06, 2019 12:54 am

I had an Phase II AX piston (AXA is actually wedge) that came on my first little lathe (G4000). It was fine, but the lathe was limp and underpowered.

I got a larger lathe (Rockwell 11), and another PII AX. This lathe was much more robust, allowing much heavier work, and I started noticing on hard interrupted cuts, it would jar loose. So in such cases I learned to keep my hand on the leaver.

I then decided that wasn't enough lathe and bought a 17x60 7.5 HP 4500 lb beasty. Having seen what happened on the 11, I never even considered a piston when I bought a PII CXA wedge. Technically the lathe is sized for a CA, but the largest cheap holders are CXA, and CXA does what I need.

I eventually ran across a smoking deal on an Aloris CXA wedge (I don't think they make a piston in CXA) with a handful of desirable holders, so that's what I use now.

Oddly enough, on the next size up from CXA, they call it a CA, even though they denote smaller pistons by dropping the last A.

That said, if I ever must outfit another lathe, and had to buy a post, it would be a wedge Aloris style, probably from PII. There are other options that are better in some ways, but the blocks will break the bank if you actually intend to use the "quick change" feature. I've got something like 15 now, with a handful or original Aloris, and the rest CDCO provided.
Russ
Master Floor Sweeper

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SteveM
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Re: Piston or Wedge QCTP.

Post by SteveM » Fri Dec 06, 2019 3:02 pm

BadDog wrote:
Fri Dec 06, 2019 12:54 am
...and the rest CDCO provided.
CDCO has the best price on toolholders, and if you don't have enough toolholders, it's not quick change.

As with most toolholders (including Phase II) replace the screws. Get a box if quality setscrews (e.g. HoloChrome).

Steve

armscor 1
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Re: Piston or Wedge QCTP.

Post by armscor 1 » Fri Dec 13, 2019 3:55 pm

Hi Guys, QCTP is mounted, had to mill the mounting block which they supplied to fit my "T" slot on the compound slide.
Bored out the old turret toolpost to accept the larger mounting stud and now can simply swap them by removing clamping lever.
Tried some trial cuts and parting 4140 and it is good and rigid.
Only have 1 tool holder at the moment but will order some more.
This may be a silly question but how do I disassemble the QCTP, want to make sure there is adequate lubrication?
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armscor 1
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Re: Piston or Wedge QCTP.

Post by armscor 1 » Sat Dec 14, 2019 4:13 pm

Hi Guys,
Read on another forum how to disassemble, remove allen screws and swing plates 90 degrees and tighten screws, pulls pistons away from cam and cam slips out.
Put plenty of moly grease and reassembled.
Have another question, the body has an M10 blind tapped hole, wondering what its purpose is?
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pete
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Re: Piston or Wedge QCTP.

Post by pete » Sat Dec 14, 2019 6:20 pm


armscor 1
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Re: Piston or Wedge QCTP.

Post by armscor 1 » Sat Dec 14, 2019 6:51 pm

Thanks Pete, very clever and can be done without a DRO Harold!

pete
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Re: Piston or Wedge QCTP.

Post by pete » Sat Dec 14, 2019 7:00 pm

No problem Armscor, as soon as I read your question I remembered reading that PM post not too long ago.

Harold_V
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Re: Piston or Wedge QCTP.

Post by Harold_V » Sun Dec 15, 2019 2:33 am

armscor 1 wrote:
Sat Dec 14, 2019 6:51 pm
Thanks Pete, very clever and can be done without a DRO Harold!
Chuckle!
Truthfully, almost all functions can. They just make it easier! :wink:

I realize I've harped on this subject a little---maybe even a little too much, but I used to do extremely challenging work, and all without the use of DRO's. As an example, take a look at this part, an electronics chassis that I made for Univac many years ago. Multiples were made, although fewer than ten. I do not recall the number. Top picture is the top, with the second picture the bottom. The (aluminum) plate is 1/4" thick, and it's one of the rare pieces I made those many years ago that I still happen to own. The part was good, and could have been shipped, but I was not aware at the time that Univac would accept overage. In spite of my cockiness in not making scrap, spares were always produced, just in case. It's much faster to make an extra or two than to make them from scratch after scrapping a needed one.

Take note that there are features within features, all held to ± 005". That's the kind of work that can be done sans DRO's, but you have to have a lot of experience and understand the methods employed in order to not make scrap. Patio made mention of grease pencils in another thread. They're used to mark locations on the machine, with the proper dial setting, so once you've made the setup, making multiple parts is dead easy and extremely fast (just as fast as a DRO, for sure). That's the method used in making these chassis, and the method I still use to this day.
chassis top.jpg
chassis bottom.jpg
If you're wondering about the color of the chassis, all aluminum was required to be finished by some means (typical of defense work), always specified by print. This one was alodined.

The chassis is standing on a pair of 1¼" copper sweat couplings, so you can judge size.

H
Wise people talk because they have something to say. Fools talk because they have to say something.

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