The Retractor

[MrWhoopee]

No, it didn't crash into the shoulder even though it was mere thousandths away. What did it in was that I was using a stop to trip the retraction so it retracted in exactly the same spot each time. At the instant that happened, I stopped the lathe mid cut so each pass built up a chip instead of exiting the cut creating a ramp. On the last pass, I was not quick enough and the built up chip slammed into the cutter. I was stopping and reversing the lathe instead of opening the thread feed at end of cut.

Now I am confused. In the search for the 16ER-AG60 insert I found this listing which pictures the exact "insert" that was in the tool holder. Note the listing describes it as an insert shim. Should I have installed an insert atop this instead of using it to cut the thread? If so, another newbie mistake.

View attachment 448842

As in something like this?

View attachment 448843

DanK

Ah, yes I see. Your tool should have arrived with an insert on it. It looks like from the picture that yours came without it. My bad. PM me your address and I'll send you a shim and a couple of inserts.

I'm pretty sure mine doesn't use the insert shim, just the insert. I'll swing by the shop after while and check it out.

Some did, some didn't. Different batch purchases.

 

[Just for fun]

I was mistaken, it does have a shim. I've never had to change one yet.

 

[RaisedByWolves]

I was mistaken, it does have a shim. I've never had to change one yet.

Its not really a shim, it is a hardened backer.

Its purpose is as a sacrificial seat that will break in a crash rather than rearing up the insert pocket. It is harder and more brittle than the insert on purpose so it shatters leaving the pocket unmolested.

 

[Dan Krager]

That's OK Mr. Whoopee. I've ordered the inserts and backers and should be here Tuesday. Thank you for the offer.

And, RBW, we now know that the "shim" (as called out by sellers), a hardened backer, works as intended! Snapped that little tooth right off and broke the rest like glass. And on my little bitty underpowered lathe, too. Inertia is powerful even at 150 rpm threading.
DanK