ER25 collet arbour grub screw

[AdrianRParticipant @adrianr18614]

I have a Vertex ER25 collet arbour. When I removed a cutter today a M10 x12 hex key grub screw fell out. The MT is taped all the way through and it seems the grub screw was in the collet end. It does not seem to tighten against anything the thread just seems to get crunchy and I have not forced it further in.

The grub screw is not pointed, it is the type with a centre hole.

Any idea what the grub screw is for and which way round it should be in?

Thanks

Adrian.

[AdrianRParticipant @adrianr18614]

[John HaineParticipant @johnhaine32865]

It may be to make sure the cutter goes in at a repeatable projection from the collet. I have some ER16 collet chucks with something similar.

[AdrianRParticipant @adrianr18614]

The screw is very short for that, also it is not tight so would move.

[John ReeseParticipant @johnreese12848]

Posted by John Haine on 12/06/2019 20:42:27:

It may be to make sure the cutter goes in at a repeatable projection from the collet. I have some ER16 collet chucks with something similar.

Yes! It also prevents the tool backing up during a heavy cut.

[JasonBModerator @jasonb]

Or if the thread goes all the way through and is just become clogged with muck it may once have been used to eject the taper if the tooling was ever used in a tailstock. I put a grub screw in mine when using it that way.

[Author]

Posts