ER collet nut torque specs

[GlennW]

Torque values for ER Collets, Retention Knobs, Milling Chucks, etc

http://www.techniksusa.com/metal/torque_chart.htm

[coal miner]

Been using the modified ( pass thru ) ER-40 adapter on the lathe for a while . I knew that they took over 100# torque and have not had a problem yet . Not very scientific , but , three raps w/ the 16 oz. Stanley orange deadblow and the piece seems to be well seated in the collect . No collects messed up , yet . Sure not recomending this procedure . When the piece gets loose in the collect , bad things happen ! A torque wrench adapter would insure that the specs were met . Thanks Glen .

[GlennW]

Holding a part or stock with a ER style chuck would not require nearly the amount of torque as a nice polished shank carbide end mill. The part or stock will most likely be considerably softer and will grip much easier at less torque.

The chart I linked to is primarily showing the torque requirement for cutters in ER type tool holders.

[coal miner]

Holding a part or stock with a ER style chuck would not require nearly the amount of torque as a nice polished shank carbide end mill. The part or stock will most likely be considerably softer and will grip much easier at less torque.

Point well taken . When I have the ER-40 w/ R-8 adapter in the mill 2 wrenches are used , one on the flats of the adapter and the other on the nut . Lots of torque applied . Don't have a torque wrench adapter , but I make sure the nut is very tight . The ER series seem to grip much tighter to the larger end mills than the regular R-8 .

On the adapter for the lathe the flats are covered by the chuck , hence the triple whack . The ER-40 beats a 5C hands down as for as gripping ability and also they can be used successfully if the part is sized some smaller ( around .040" IIRC ) .