# Home Made Qctp



## Holt (Mar 19, 2016)

I have shown this in the Colchester-Clausing area, but some of you might not read that. Those of you that have seen it, just jump on to the next tread.
Last Christmas I decided it would be a good time to mount my home made QCTP that have been lying almost completed for well over a year.
One of the reasons was I didn't own a 4 jaw chuck, but finally I found the right size for a reasonably price, and although I don't have a back plate for it, I mounted it in the 3 jaw and trued up the center cube for drilling and turning the center hole.
The Colchester's compound had a 54mm or 2 1/8" shaft 50mm high the old toolpost rotated about, but I only had space for a 50mm shaft with a height of 20 mm, so it had to be turned down.
The Colchester couldn't swing the compound, and even if it could, I had no place to mount my tooling, but fortunately, I can borrow the machines at work, and the big manuel lathe had no problems swinging that little compound. 
Here we have a couple of pics showing the almost finished mount, I have been making some height adjusters, and need some milling on the locking shims, that are to be mounted on the eccentrics.





I have 10 more or less finished holders, and the clamping side made in two bars, where I think there can be 6-8 holders made.





Here we have the first ten height adjusters.





The design is based on the Rapid toolpost http://www.rapidoriginal.it/

The original purpose of the cube was as a insert for a plastic injection mould (mold in some regions) but it didn't clean up when it was ground, it was sat aside for another project, but the costumer decided that another material was to be used in the future, this material is Impax supreme, a well known tool steel when you want to avoid hardening.
It's origin is the reason for the threated holes 15 mm from the bottom, they where intended for water cooling, I just have to live with them.
I milled two slots on each side, the cube was put in the wire cutter, and all corners were cut in one setup, leaving it very accurate at the mounting areas. 





I am keeping the original spindle, because it have a nice feature, when tightening the cube, a spring loadet dowel pin with a tapered end is released, centering the cube at the right angle, and securing it from turning under heavy load. The opposite hole is for a spring loaded ball for helping centering the cube before tightening.





I have a 7mm thick shim under the cube, here will be made tapered holes for the locking pin, four holes for zero, 90, 180 and 270 degrees, on the two opposite sides, there will be holes made at 30 and 60 degrees, and the two other sites, 45 degree holes will be made.
If I had to make all the holes on each side, they would interfere with each other

I had to mill some grooves on the locking rings, but i haven't got a rotary table, and my mill isn't working yet, so I had to use the lathe for milling.
I mounted a 20mm shaft in the toolholder with the V-groove at the bottom, I used a piece of 5 mm plate from the scrap bin, and drilled a couple of pilot holes for the spanner bolts, they have a point at the end, that fits the pilot holes, so the plate stays in place when the shaft is turned.





A small vice got the job as handle to turn the shaft.





The touchDRO was of little use for this setup, just showing the cut depth, but a label on the shaft with lines for start and stop points was perfect for the job.



 

Here tree is in place, and the fourth is ready to leave the shaft.


----------



## Silverbullet (Mar 20, 2016)

I have this same type and I like it mine came from enco many years ago. I lucked into it from an eBay deal. I had been looking at qctp and different models. The only one that was perfect I just couldn't come up with there cost the ones with 40 positions that's almost round like abom79 uses. Those I think are Swiss but not certain . I will make a few of the tool holder to some day. Lots of things left to do, if I ever get them done ill be a hundred and twenty years old I think. Yupp I like your lathe and your tool post set up . Thanks


----------



## Holt (Mar 20, 2016)

Silverbullet - Thank you for your kind words, they are much appreciated.
I know exactly what kind of QCTP you are referring to, its the Multifix, we have them on three of our four manual lathes at work, and I would love to have one on my Colchester, but I would have to buy  all of it, because I think making them myself is beyond my skills. If I were to buy 15-20 holders, it would be quite expensive.
I have a link to a company that claims to sell the original model, but it is quite difficult to find its exact origin, it seems to be a French design manufactured in the Swiss, but today, a German company claims to manufacture the original ones.  http://www.createtool.com/list.asp?cid=33  and then there is a lot of clones around as well.


----------



## T Bredehoft (Mar 20, 2016)

Holt said:


> A small vice got the job as handle to turn the shaft.



Nice, make-do should be the more common practice.


----------

