Hard times - machining toolholders down to size.

Now that I've bought a dozen toolholders from AliExpress, I have the task of machining them down to the required height for the Tree lathe. These are all 20mm x 20mm x 125mm sized, yet the Tree turret is designed for 3/4" (19.05mm) tooling, as it originated in the US in the 1980s. Not much demand for imperial tooling these days but the difference is only ~1mm, so I will skim them down on The Shiz.

Quick test with the hardness tester suggests they are generally hardened to something like 40-45HRC. So carbide inserts it is. 

CAM setup:
It would be entirely possible to use Centroid conversational programming to set the machine up for this but it's simple enough to do it in Fusion and I'm more familiar with this process currently.

There's only one tool (BAP300 50mm face mill) involved, so I simply need to probe the corner of the stock and check the tool length offset (Tool #25) is still correct, then off I go. 2500rpm and 0.06mm per tooth, with step down of 0.2mm. So that requires 5 passes and just under 2 minutes. This isn't good for the inserts (hardened steel, interrupted cuts etc), so no need to push it any further and I will need to deburr the parts, which will keep me busy while the next part is being machined.

Machine setup:

Firstly, before I start, how flat is the vise / parallel setup? The Renishaw probe isn't much use here, as it only indicates a threshold. The Mahr 3D DTI gives a visual (analogue?) indication.

Answer - pretty good.

How close to the alleged 20mm are these Chinesium things? Pretty reasonable.

So, off we go:

Here's the first example. Not a bad finish but the inserts are all new of course.

Measuring pretty close to the required 3/4":

So off we go again. I have 12 of these AliExpress specials plus another couple of existing tools to do....

Getting there. I deburred as we went. The inserts were clearly suffering, as I found they became hotter as I progressed through them. I was machining them dry to keep the mess down and not thermally shock the inserts so I ended up wearing gloves.

This Teknik trigon holder from Cutwel has through coolant, which complicates matters. As I have a couple of trigon holders already machined, I'll leave this one for now. Apart from the various plugs that would get in the way, the coolant coupling would foul the turret on the Tree, so it's questionable I'd be able to use it there anyway.

How was it, Fatty?

Bottoms up:

Right way up:

Good. That wasn't too bad and I didn't start any fires in the workshop.

Any damage?

Sure enough, 4 out of 5 of the inserts are chipped. Seems a reasonable price to pay for the work, not least as these are genuine Mitsubishi parts from AliExpress that didn't cost an arm and 10 legs. Here's one of them:

Good. Now let's think about setting up the tool touchoff system on the Tree. For now I think I'll simply mount the DIYO probe in the tailstock rather than dick about making up a pukka assembly. I've not been able to make a lot of progress recently for various reasons, so I'll cut a few corners for the time being in order to see some swarf sooner than later.