Caution!!!!!!! plunger quick change tool post

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sliverr2

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Just a word of caution for any beginner and seasoned machinist. The little nuances that dont show up at first glance can be dangerous. I learned one and i feel its important to share. I have two lathes in my shop and for the longest time only had one tool post. Its a nice dtm cxa post. When changing holders it was just a matter of a quick counter clockwise whack on the handle and remove and replace the holder with the next one. I wanted to buy another for the other machine and not wanting to buy knew i waited to see if i could find good used.Well i ran across an import plunger style and decided what the hell i need it now and bought and installed on the other lathe. zFirst downfall i notice was (other than the import metric set screws seem unwilling to happily accept sae or metric allen wrenches) the dtm holders will not fit the import plunger style, the dtm wedge will hold the imports because the wedge will pull up enough to become small enough for the imports. All these can be dealt with but the most important issue to be aware of is if you are used to the wedge style the lever will disengage the holder and only rotate so far and then stop but the import will go round and round and in my case i gave it the usual slap and around into the rotating chuck it went. luckily just a shatter of the plastic knob. I then shut everything down and checked to see how bad it could possibly get. In my case it would be catastrophic very easily could the handle hit the law in suck a manner that something would have to give
 
Hmmm. My Grizz G4003G came with the button type QCTP and that was an issue I never encountered. They clocked pretty much as my import wedge type does now. Have you opened it up to see what the problem may be?
 
Thanks for sharing. Something is definitely not right. Although I'm not a fan of piston type QC tool posts I've never encountered that issue with the ones I have used.
 
Piston type tool posts use an eccentric mechanism inside to manipulate the piston. There are no stops. I know that the handle will freely rotate 360° with no toolholder on it, but are you saying that yours did with a toolholder on it?

And before someone else says it.....Stop your machine before changing tools. Never know when you might drop the holder into the danger zone, for instance. I've juggled a few, and now I stop the spindle if I am anywhere near the chuck.
 
Tony Wells said:
Piston type tool posts use an eccentric mechanism inside to manipulate the piston. There are no stops. I know that the handle will freely rotate 360° with no toolholder on it
Click to expand...

Interesting! I learned something new today. I have used a few different (mfgd) piston types before (never owned one myself) but never knew they could do that. I guess I never thought they would & never tried turning them that far without a holder.
 
Tony Wells said:
Piston type tool posts use an eccentric mechanism inside to manipulate the piston. There are no stops. I know that the handle will freely rotate 360° with no toolholder on it, but are you saying that yours did with a toolholder on it?

And before someone else says it.....Stop your machine before changing tools. Never know when you might drop the holder into the danger zone, for instance. I've juggled a few, and now I stop the spindle if I am anywhere near the chuck.
Click to expand...


Yes with holder in it ,it goes far enough before tightening again to hit the chuck when working close. i since drilled and reamed for a dowel pin to stop the lever after release. Also great advice STOP THE CHUCK FIRST !!!!!
 
Was it a Yuasa?

One of those came with my Monarch 16x126. I could not get Aloris or Dorian tool holders to fit on it. It's now sitting on the shelf as I bought an Aloris CXA wedge and now everything slips right on.

The Phase II tool holders did fit the Yuasa post.


Mark
 
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