Holding large milling cutters in an R8 spindle

[lfoggyParticipant @lfoggy]

I've just acquired a 'job lot' of new milling cutters consisting of mainly 6-20mm slot and end mills. Included however were 7 new Dormer end mills with 25mm and 1" threaded shanks. I have a mill with an R8 taper and usually use R8 collets to hold cutters. Max size for these is 20mm I believe. These new cutters are too good to waste so I need to find a way of holding them. Looks like I may need to buy an ER40 collet chuck and holder but are there any other options?

Regards

[lfoggyParticipant @lfoggy]

[colin branniganParticipant @colinbrannigan54160]

There is a R8 collet which will take either 25m or 1" dia cutters can't remember which, but I don't like them have seen too many break under decent cuts, go for ER 40 R8.

Colin

[Chris Evans 6Participant @chrisevans6]

ER 40 is most likely the best option. I use a Clarkson chuck for my 1" shank stuff on the R8 equipped Bridgeport, downside is that with threaded shanks you cant easily get that extra 1/4" reach without turning up a centred spacer to fudge the job. ER 40 are cheap now so decision is easy.

[Mike PooleParticipant @mikepoole82104]

A carbide lathe tool will turn the shank of a HSS cutter down to a suitable size.

Mike

[Bob AstillParticipant @bobastill76884]

I use one of these for light work and for £14 you cant go wrong

https://www.ebay.co.uk/itm/25-mm-R8-MILLING-COLLET-SUITS-BRIDGEPORT/332539949140?epid=1793202107&hash=item4d6cecf054:g:WtEAAOSwMNxXUCqu

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