changing from a er-25 collet to a r8??

[parkson]

hi,
my name is matt and i am new to your community. i work for a sign company and we have a larken 24x24 CNC router. it is equiped w/ a technomotion 3hp spindle and it has a er-25 collet. i machine face of signs and it takes forever w/ a 1in end mill. (thats the biggest i can find for my collet). i was looking into shell mills but i see that the bigger ones (3in and above) need to be used in a r8. my question is can i convert my spindle into an r8?

thansk in advance,

matt

[HuFlungDung]

How fast will this spindle be turning during the facing operation? There are speed limits on large diameter tooling. For example a 3" facemill might be restricted to 1/3 the rpm of a 1" dia tool. So the potential benefit is perhaps not as great as it would seem to be if a light single pass is all that is required.

[parkson]

the spindle is variable from 0 to 24000rpm

the 1in bit is spun at 16000 rpm w/ coolant and takes .040 per pass. i usually need to only mill .020 but occasionally i will need to mill .125 total depth depending if i am making custom plates.

thanks,
matt

[RCaffin]

An ER25 collet will hold 16 mm diameter. That's a limit.

However, what you are doing may not require a real milling cutter, nor a shell mill. Have you considered a *balanced* fly cutter? I use one for facing off sacrificial work surfaces with a 60 mm dia cut.

You can even make one of these very easily. To get it balanced, use a long bit of tool steel sticking out both sides about equally.

Cheers