Having read your earlier post and having many years experience of the Multifix tool system. I would not entertain trying to modify the toolholders. From memory these are case hardened steel. Removal of 3 mm of material from the tool slot will leave a soft clamping area for the tooling.

Removal of this amount of material from the base of each toolholder, such as to retain the versatility of the system does not come without problems.

You may find the removal of this material distorts the ground mounting face which may affect the repeatability. For my part I would sell this item and obtain something more suitable. Or use smaller tooling.

When I had my own 254, Myford supplied it with a fitted Dickson system.

Regards

Gray,

On 8 August 2024 at 11:31 Graham Meek Said:

Removal of 3 mm of material from the tool slot will leave a soft clamping area for the tooling.

Let us assume he is using a 12mm square shanked tool, maybe 60mm long.

That is 720 square millimetres of bearing between tool and holder. How would a soft or a case hardened surface make any difference here? It is not like pressing a fence post into a concrete slab and pressing the fence post into a wet lawn. The tool is not going to sink into the holder.

If anything needs hardness, it is the top of the tool itself, so the ends of the clamping screws do not dent it.

It is also not entirely clear from his post whether this is the surface he proposes reducing. It could be the underside of the holder (the bit that would contact the top of the top slide).

An inventive/holistic option might be to start at the top of the cross slide and see if and where there is any opportunity to lower the overall height (maybe a little off the underside of the swivel base, a little off the top of the compound slide). If he can gain 1.5mm, the problem when he reaches the toolpost itself is halved.

How many tools do you have that are too tall? Is skimming some material off the bottom of those an option, most insert holders are not so hard that carbide won’t cut them.

Back to the tool holders again I have seen Dickson and Aloris types have their bottoms reduced with carbide insert tooling so may not need to go as far as grinding.

Like DC I have also suggested machining the topslide in the other thread and for once I kind of agree with him about the surface the tool sits on, if you are anything like me the tool goes into the holder once and does not come out again except for a couple I keep for little used tools and they are generally small HSS specials. So lack of cas ehardening would not really be an issue as there is little wear.

I’ve not really read anything Gray has ever posted I’d disagree with. I’m sure he’s forgotten more than I’ll ever know. Compared to the ubiquitous 4 way tool post design, the weak link with qctp’s is that tool holder hanging out in space with no rigid connection between the tool holders bottom and the top slide surface. The actual cutting tool rigidity verses it’s cross section would still be far stiffer and much more resistant to our cutting loads than almost any of us would ever be subjecting them to on our more hobby sized lathes, against just how rigid those tool holders are. I’d modify the cutting tools height before ever touching the tool post or tool holders. It’s obviously a whole lot harder to put metal back on than it is to take it off should you ever need the tool post and tool holders for use on another lathe. Modify the cheapest and smallest part first is a fairly good general rule in my opinion.

I bought a left hand replaceable tip tool manufactured by Mitsubishi some years ago. It was a couple of mm’s too large to fit my Emco compact 5 tool holders and still be on the lathes center line. All I had for a mill was the little C5 round column and HSS end mills. Instead I just slowly fly cut that tool the necessary amount with a cheap braised carbide tool. If that mill can modify industrial grade and hardened lathe tool shanks, then doing the same on the lathe itself or with any other small mill, it should certainly be possible. I’ve not found even good brand name lathe tool shanks that were extremely hard. I doubt they ever would be. Yes there still hardened a fair amount for durability and toughness, but using some logic, then too hard would seriously risk the tool breaking during use.