Myfords used to do a toolholder with a reduced portion underneath the dovetail part which allowed greater height adjustment when using larger tools. I have done this to 2 of mine as I couldn’t seem to find any at the time. they were done on a shaper.

Hi Gabriel, I would use the largest tool shank you can, if it’s a fraction to high you can always machine a fraction of the bottom.

However, I would recommend a rear tool post for parting as Steve mentioned above. The George Thomas design from Hemingway’s is a good choice.

If you don’t want to make one, you could try to obtain a Myford one, they would take a tool shank up to about 16mm.

Andy.

Parting off for me was revolutionised by two things.  First, buying an inserted-tip parting tool.  At the time these were quite expensive but good ones are now quite reasonable from Arc (e.g.) like this one.  It is available with different shank thicknesses – mine is 12mm and fits a standard Dickson QC holder.  I use it in the front toolpost without problems.

The other thing was reading George Thomas who tells you to part at higher speed if at all possible and use self-act crossfeed. On my S7 big-bore speed was 215rpm and slowest self-act.  The first time I engaged the feed I was sure that was going to be a frightful bang and something would break, but actually it was a non-event, just a clean cut and a pile of curly chips.

The worst thing to do IMHO is to use manual feed and slow back gear.  When you first try it you are frightened by all the horror stories so your hand is unsteady and you approach the work v-e-r-y slowly, and find that the tool just starts rubbing and squealing.  So you apply more cut and suddenly it digs in because it’s too much and everything stalls.  You need the material to be moving quickly enough for the tool to cut which means that enough heat is generated at its edge to locally melt the material.  The feed needs to be even to get a sensible “tooth load”.

Now my S7 has CNC control so I can feed at any speed I like, and I have a VFD so I’m not limited by the fixed pulley speeds.  I often part small diameters at 800 rpm and about 4 – 5mm/minute feed rate.

I have got a rear parting tool holder but it seldom gets used.  If you do go that route it is well worth forming a shallow “scallop” on the top face of the tool from the cutting edge back using a diamond needle file – this makes sure that the swarf curls inwards so it’s narrower than the cut width which helps it fall away and prevents clogging.

The ArcEuro blade clamps in the sizes you are talking about hold the tool-tip at the same height as the thickness of the block – I don’t know whether the Glanze one is the same.

Dim.’e’ here;

https://www.arceurotrade.co.uk/Catalogue/Cutting-Tools/Lathe-Turning-Tools-Indexable/ARC-Indexable-Turning-Tools/SLTBN-Part-Off-Blade-Tool-Blocks-with-Part-Off-Blade

Edit – I use a blade-type backwards/forwards/up down etc. if you can get the tip on c/height it will be fine.