Reply To: New Mill

[david pierce]

Tom,
If the mill spindle runs true and you have runout only after the chuck is inserted then the problem has to be with the chuck. Find a drill bit or a dowel pin that will fit properly into an R8 collet and put than into the spindle. If the runout is gone then there is definately a problem with the chuck. Was this an ENCO chuck and R8 chuck adapter or did it come with the mill. Separate the chuck and the adapter and put the adapter into the spindle hole. Check the runout on the Jacobs Taper of the adapter. If it is good then the problem is either with the chuck or the mounting of the chuck with the adapter. The chuck may be damaged. Have you ever hammered on the jaws of the chuck? Whenever you tap the chuck you should always retract the jaws into the body of the chuck and tap on the body only. Never the jaws.
Your Emai address at @wallace.edu bounced back for both Bob and me. Send Bob your correct Email address and get my phone number from him. Then give me a call tomorrow.
Also, if the spindle nut is too tight it will crunch your spindle bearings. The nut only needs to be tight enough to keep the spindle from moving under a cutting load.
david