Just finished my QCTP.

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websterz:
I suggest making a tool holder first, then building the tool post to fit it. The reason being you need to make sure your dovetail cutter is small enough to cut the female dovetail in the holder. I went the wrong way and made the post with my fancy inserted dovetail cutter that I made last year. It did a bang-up job on the post but I made the male dovetail narrower than the OD of my cutter so using it for the holders was impossible. Luckily I found a resharpened 60* cutter in my stuff that was small enough. It was no longer 60* though, closer to 55*. I dressed the toolpost with it so that the angles match. I don't plan on using holders other than the ones I make so the angle isn't critical...it just has to be consistent.

NickG:
Thanks, i've got a normal 45 degree one that's definitely small enough, I know they are not supposed to be as good as the dovetail won't be quite as strong but it should do the trick.

Rob.Wilson:
GREAT JOB websterz :thumbup:

Looks like it will give you good service for life :clap: :clap: nice one :thumbup:

Regerds Rob

websterz:

--- Quote from: Rob.Wilson on January 17, 2010, 04:02:36 PM ---GREAT JOB websterz :thumbup:

Looks like it will give you good service for life :clap: :clap: nice one :thumbup:

Regerds Rob

--- End quote ---
Thanks Rob! :D :thumbup:

I tried it out yesterday for the first time. Normally I like to do all of my parting off with a rear mounted toolpost, so I thought that would be a good test for rigidity. My usual shop work consists of lots of 9/16" 4140 round stock. It's not uncommon for me to make 100 parting cuts a day on my (heavily modified) 7x12 lathe. I ran 50 parts in just under 2 hours with the same old parting tool, but mounted in the "normal" position using my new QCTP. Rigidity was excellent and the cutter stayed on center throughout the course of the job. I noted that I need a little extra clearance between the back side of the holder and the sliding face of the toolpost, as there was a bit of binding when I removed and replaced the holder to test repeatability. The holder is a trial piece made from 7075 with the intention of using steel in the future. If the aluminum holds up under repeated use (and I expect it to) I may forgo the steel and stay with aluminum for it's ease of machining. I will be reworking the pistons before I am finished tweaking the post. The small round pistons don't have enough bearing surface for my liking and I will replace them with much larger rectangular ones that should provide a more even pressure.

chuck foster:
great looking QCTP :thumbup: :thumbup:

i have thought about making one but thought it would be next to impossible........................but you have give me the incentive to give it a try :dremel:

so i might be bugging you with some questions :) :)

chuck :wave:

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