People also ask
What does er stand for in collets?
What size is er40 collet?
How to determine er collet size?
What is er 40?
ER40 dimension spring-type collets to securely hold your router bits.
I think the general idea is you machine custom bores/features to fit production parts with the pin in so its stabilized. Then remove the pin so it has free ...
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Missing: rangate. spring-