Tool Posts..... Piston or Wedge?

[Glenn Wegman]

I have a Yuasa BXA size piston tool post and am not very impressed with the repeatability. I am considering an Aloris Wedge type and can't seem to get an answer as to weather it will be any better. I spoke to a distributor that said there is no difference between piston and wedge as far as repeatability. I called Aloris and was told that they had never been asked what the repeatability was on their tool post!!!!!!!!! I went a little farther up the Alaois food chain and was told it was probably around .002" which seems huge and not really any better than the Yuasa Piston type I already have.

Anyone with an Aloris BXA Wedge type got any input on what they really are in the real world as far as repeatability?

Thanks,

Glenn

 

[toolmakerjim]

ditch the piston tool holder and get the Aloris wedge and you'll never look back.
ive run jobs using multiple tools for diameters and note my hand wheel targets and they are very repeatable as long as you dont get a stray chip somewhere...jim

 

[SteveM]

The piston toolpost registers the holders on the dovetail by pulling them into the dovetail. The wedge pulls back and the dovetail holds it against the toolpost, so it has much more area supporting it.

I have a piston toolpost and have seen it rock under heavy load (yes, it's only a Phase II AXA, but I think the difference between piston and wedge applies to all brands).

When I get the chance, I'm trading up to a wedge.

Steve

 

[dsergison]

the wedge is far superior in repeatability and ridgidity. i would expext .0005 easily.

the piston is just an unnacceptibly poor comprimise. it shouldnt even be listed on the same page of a cataloge, let alone use the same holders. -for ANY brand

which is ot to say the piston isnt servicable, and handy, but it's not repeatible, or ridgid.

 

[rj newbould]

Ditto......

 

[Marc_Stokeld]

After dropping serious (to me) money on a good deal of Aloris tooling, i would get a Phase II wedge post and Phase II holders. I am going to sell at least one of my Aloris BXA'a and some of the holders, and use that money to buy more Phase II gear. You won't go wrong with Aloris, but from what I have held in my hands, I honestly do not see how it is better than the cheaper product. If I thought it was better I would keep it and get more Aloris gear, but as it is I am paying more for equal quality.

I think piston posts are less rigid than rocker tool posts. A wedge is infinitely better.

 

[precision tools]

I don't know who you talked to at Aloris, but a quick scan of their catalog states "Guaranteed lasting repetitive accuracy to within millionths."

Their precision indexing holders state accuracy to 0.00005".

 

[Carl Darnell]

I have used both and prefer the wedge type. I never have done a test on repeatability but I think the wedge would be better.

 

[rj newbould]

Just a P.S. to my ditto. Here is a boring bar I made for my wedge type. I think I would have to weld it to the compound to get more solid.

I put a screw on the bottom to fix the height and be out of the way.

 

[Carl Darnell]

That's interesting but why would you need a boring head on the tool post when a boring bar in a tool holder does the same job??

 

[Milacron]

Aloris piston vs wedge...only been discussed here about 100 times already over the years.... do a search... Zzzzzzzzz....

 

[rj newbould]

That's interesting but why would you need a boring head on the tool post when a boring bar in a tool holder does the same job??

I change from one tool holder to another making my products. I needed a REALLY solid boring bar for this one form tool plunge operation. A 1" dia. boring bar that is the max. capacity of my tool holder would not do the job, nor would it hold a big enough form tool.

 

[Carl Darnell]

I can't see where a boring bar in a boring head could be more rigid than a boring bar in a holder. The distance from the holder to the cutter has to be shorter with a boring bar and holder than the distance from the dovetail to the cutter with the boring head. included and then there is the issue of the dovetail in the boring head.

If it works for you go for it but we'll agree to disagree.

 

[dsergison]

oh crap. that is a boring BAR. it just looks like a boring HEAD cause it's so big. holy moly.

 

[rj newbould]

oh crap. that is a boring BAR. it just looks like a boring HEAD cause it's so big. holy moly.

Doggone, you're right. I missed the fact that he thought it was a boring HEAD. Guess I need to read more carefully.

 

[Carl Darnell]

excuse me, your right. I didn't look for the dial feed, just saw the mass and the familar shape.

SORRY, MY MISTAKE.

 

[toolmakerjim]

Carl;
look at it i just resembles a boring head but what a great application.

i think when i make one i'll use a hex head screw to make adjustment easier, or not...jim

 

[rj newbould]

Carl;
look at it i just resembles a boring head but what a great application.

i think when i make one i'll use a hex head screw to make adjustment easier, or not...jim

That screw on the bottom is jammed in place and ground to the right height for my lathe. If I ever use it on another lathe, there is another tapped hole on the top that I can used for an adjustable stop.

 

[Carl Darnell]

I agree, it's a great idea and believe me that I am storing that idea for future use. For ID plunge cutting it would be great and super rigid.

 

[toolmakerjim]

EXCELLENT but im not surprised Mr. Newbould as all your work exhibts well thought out designs, good to see you...jim