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Aloris type (import) QCTP barrel gets unscrewed

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PurpLev

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I have an Aloris type QCTP on my lathe, and always had this issue that at times when I release the nut to change position the internal barrel gets attached to the nut and gets unscrewed as well:
IMG_20130104_201044.jpg
at first I didn't make much of it and just let it go, but this thing is starting to get old. I tried adding a washer between the barrel and the nut:
IMG_20130104_201122.jpg
But unfortunately this did not resolve the issue.

I am not sure of the maker of my TP as I got it with my previous lathe. all my tool holders are PhaseII but the TP itself isn't marked. I am guessing it is a phase II, but am not 100% positive.
I notice on the top of the barrel 2 rounded slots that look like there should be some keyed wrench to tighten this barrel to the tool post (better?) but I do not have any such key.

I suppose I should make one if this is the solution, but was wondering if anyone ever experienced anything like this and/or have any other ideas how to keep this from unscrewing every so often?

Another thing that I seem to be experiencing is the stud itself is threaded on both ends, one end goes into the T-nut, while the other goes into the top lock nut. Often when I try to release the lock nut, what ends up happening is that the stud is being released from the lower end T-nut and the lock net stays in place. this might be related to the fact that the top lock nut gets "attached" to the TP barrel, and this also makes releasing the TP to change angle quite difficult...

and this thing is supposed to be a "quick change"...UGH...

any thoughts/ideas/help is greatly appreciated. not a shot stopper but it's getting frustrated

:whiteflag:
Thanks in advance

IMG_20130104_201044.jpg IMG_20130104_201122.jpg
 

Ray C

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Sharon,

... Not sure about how that cylinder bolt gets screwed in but, I have a cheapo QCTP that has a 5/8" double-ended threaded rod that screws into a plate that slides into the compound dovetail. In the discourse of unscrewing the top nut for normal reasons, the bolt would unscrew from the plate down below. I just cleaned/degreased those bottom threads and put Loctite Red on e'm. -No more problem.

Ray
 

David Kirtley

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Not sure of all the internals but the first thing I would do would be to go though it with some solvent and clean out any dried oil residue. Also run a tap through any threaded holes and clean them out. The wedge might also be off one thread on the worm from someone else disassembling it (Like one jaw being started on the wrong thread of a scroll chuck.) and keeping something from seating properly. Also check that the top threads of the bolt are not binding. There is not much in there to go wrong.
 

PurpLev

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I did use blue locktite before, and now that I checked it seems to be holding up well (stud is still securely attached to t-nut). I also checked for the top nut threading, and it was slightly binding. I retapped the lock nut, but it was still pulling the internal cylinder with it when unlocking. I cleaned the cylinder thread that connects it to the TP body, and tried to tighten the thread with a piece of flat bar - tightening it real hard seemed to have helped as now that I lock and release the post everything works as expected. I guess I'll have to make some sort of proper wrench for it to really tighten it down properly, maybe add some blue locktite to this as well.

thanks for chiming in guys.
 
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