Cheap Chinese face mill?

I bought a cheap (CAD$150) 3" diameter 5 insert face mill about a year ago and recall it not working very well. So I put it away thinking I would look at it in the future but after reading your post I was curious and went to the shop to see if I could figure out why I had an issue with it. I should have taken a pic. I snugged all the inserts up to their stops and then took a very light facing cut on some mild steel to form a reference surface. It sounded like my fly cutter. Then I moved the face mill close to the edge of the surface that was just milled so I could rotate the head and check the clearance for each insert. What a POS. I didn't need feeler gauges to measure the gap between the insert and the surface. A tape measure would have been good enough.:eek 2: At least 1/16" gap between the low and the high. Plus there was a huge difference in cutting diameter. I'm guessing about 1/8".

So I figured I would try to get all the edges lined up vertically and horizontally by making a jig and rotating the face mill to set each insert, one at a time and setting both the depth and diameter of cut. After way too much time doing this, I figured I had it nailed and took a light cut on the same material. The result was slightly better but a total waste of time. Maybe some day I will try to figure out how to make this better or it will be relegated to the dumb a$$ drawer of stuff I bought.
 
Were they these same (APxx 1604) inserts or something different? I have to think the pockets themselves control 99% of the insert height relative to cutting plan datum. Maybe there is a way you can get a DTI in the top corner of each pocket to compare. If that checks out, then maybe the screw hole is low & drawing the insert down? (but you would visibly see a gap on top of insert).

Just a thought, have you calipered the inserts themselves to see if they are identical? If for example you had different nose radii other geometric feature, would that account for different contact height? I really don't know how these are designed. Maybe the contact position is supposed to be identical. Or maybe the parallelogram is the same but a larger nose radius would effectively shorten the height?

SNAG-12-20-2017 0009.jpg
 
Wow... I'm really glad I only spent $20 on these...

This second one I got is better than the first. I just tried it on some aluminum. A bigger piece than before. 3 flutes cutting at once rather than the 1 maybe 2 I tried before. Much quieter, but still a rough finish. Better than before. But you can still tell there is a carbide low. Feels like a fly cutter fed too fast. Slightly shiny, but looks like ripples. No matter how slow I fed.
But, I think it's acceptable. I'm not cutting mirrors... It'll do what I want it to, I think.
 
If you don't have a DRO on your Z axis, rig up a DTI or dial indicator upside down so the plunger is pointing up. Rotate each insert over the ball by hand (probably backwards would be best). That should tell you everything about relative depth setting between them. You may have some other issue like the head s cocked on the arbour or pockets milled incorrectly, but at least this should point you in right direction.
 
petertha said:
Were they these same (APxx 1604) inserts or something different? I have to think the pockets themselves control 99% of the insert height relative to cutting plan datum. Maybe there is a way you can get a DTI in the top corner of each pocket to compare. If that checks out, then maybe the screw hole is low & drawing the insert down? (but you would visibly see a gap on top of insert).

Just a thought, have you calipered the inserts themselves to see if they are identical? If for example you had different nose radii other geometric feature, would that account for different contact height? I really don't know how these are designed. Maybe the contact position is supposed to be identical. Or maybe the parallelogram is the same but a larger nose radius would effectively shorten the height?
Click to expand...

petertha; I think you were responding to me, in which case the answer is no. They are equilateral inserts that are held with wide head screws on the edge of the insert (not through the middle) and of course there are no numbers on them. I can clearly see one of the inserts protruding more than the others. I'm pretty sure it is a pocket issue vs an insert issue.

Wish I kept the receipt. I would return it to the dealer.
 
I’d throw it at him if it were THAT crappy.
 
Let’s come back to this, is there a way to adjust one tooth up a thou or so without grinding the insert?
 
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