Fitting Multifix QCTP

Hi everyone
I am going to fit my Multifix QCTP over Xmas and as the holders will take up to 12mm shank and I only use 4-5-6mm tool bits I need to pack and I am wondering if there is any advantage/ disadvantage to where the tool bit goes, I have square stock for the packing but do I put the bit in the holder on top and pack at bottom or bit on bottom and packing on top .
Peter at PeWe tools suggested that I put 8mm on top of compound to fix the QCTP on and someone else suggested 12mm so obviously where the tool bit goes will determine what size plate I put on compound.
Thanks Dell.

Dell

I think you need to work back from the centre height dimension of the lathe above the compound, take into account that for any tool size used the height adjustment of the tool is within range to be on centre height.

Draw a sketch and look at the dimensions needed before getting the sub-plate material.

Emgee

I would try to avoid packing altogether after all that is why QCTPs have height adjustment. My not Multifix holders take upto 1/2" tooling yet I only need to use packing if I fit 3mm toolbits and the packing goes under the toolbit as there is not enough adjustment to get the QCTP higher

You may need to look at putting a packer under the whole tool post rather than in the individual holders but bear in mind things like boring bars which unless you are only doing small shallow hole swill tend to have shanks over 6mm.

EDIT Just had a look and the Aa has 6mm of height adjustment. If you set the toolpost so that when the holders are  at their lowest position you can get 10mm tools in then the adjustment will then bring the bottom of the holder upto 4mm. 12mm Boring bars will still be OK as the cutter is not at the top of the shank

Edited By JasonB on 23/12/2021 18:37:06

Thanks for the replies and advice,I only repair antique clocks that’s why I normally use the smaller tool bits but I want to start hopefully making my own tools when I can.

Dell

In that case I would position it so when raised to top of adjustment the bottom edge of the tool holder is approx 3mm below ctr height which will allow for some material being ground off the tops of your 4mm toolbits and would happily allow 8mm tooling to still be used as the holder will drop to 9mm below ctr height.

Thanks JasonB That makes sense because there may be times that I need to use 8mm tooling although not very often but it’s good to have the option..

thanks and merry Xmas Dell

Here is my set up with the apAa pew multifix. It’s an 8 mm tool bit sat on a 1.5 mm packing no particular reason for this, Plenty of adjustment above and below as can be seen. I generally use 8 & 10 mm. toolbits. I have found the toolpost system both incredibly rigid and accurate in repositioning tools. The base is a replacement for the topslide, and is perhaps a bit big, for the much smaller multifix set up,  it was made for the previous toolpost. I rarely use the topslide now with a DRO, it gets in the way and introduces another possible lack of rigidity..

The project is making cooling fins on a v8 Whittle engine

ps does anybody know if the Chronos holder will fit this post correctly? Don’t want to pay the import duty again and handling fee!

Edited By Zan on 24/12/2021 12:36:25