I have had my van Norman #12 milling machine for more than two years now but I still consider myself a complete beginner. Each time I use the mill there’s a new learning experience. I have most of the original van Norman 5V collets but I do not own any end mill holders at this time.
Recently I was using a half inch roughing end mill to clean up some rough edge cuts on hot rolled 3/4” steel (conventional not climb milling) and the end mill kept slipping down in the original Van Norman collet. I removed the collet, checked the spindle and the collet itself for cleanliness and oil and made sure the cutter was clean of oil and re-tightened the end mill with a significant amount of force. Again the end mill slipped.
I tried a different cutter and that also slipped in the collet. The collet was tightened with enough torque to bend my “pin” made from a grade 8 bolt that I use to hold the spindle. I realize that speed, feed and depth of cut and cutter condition all play a roll here and as I said I’m learning so they may have all played a roll in my problem.
I am also wondering about other issues. How do you know if a collet is too worn? Spindle taper wear ever an issue? Other thoughts? As you all know these collets are getting hard to find and new from Hardinge they are north of $200 each so before I order a new collet thought I would check with you more experienced VN owners.
Appreciate your thoughts.
John in Minnesota
Sent from my iPhone using Tapatalk
Recently I was using a half inch roughing end mill to clean up some rough edge cuts on hot rolled 3/4” steel (conventional not climb milling) and the end mill kept slipping down in the original Van Norman collet. I removed the collet, checked the spindle and the collet itself for cleanliness and oil and made sure the cutter was clean of oil and re-tightened the end mill with a significant amount of force. Again the end mill slipped.
I tried a different cutter and that also slipped in the collet. The collet was tightened with enough torque to bend my “pin” made from a grade 8 bolt that I use to hold the spindle. I realize that speed, feed and depth of cut and cutter condition all play a roll here and as I said I’m learning so they may have all played a roll in my problem.
I am also wondering about other issues. How do you know if a collet is too worn? Spindle taper wear ever an issue? Other thoughts? As you all know these collets are getting hard to find and new from Hardinge they are north of $200 each so before I order a new collet thought I would check with you more experienced VN owners.
Appreciate your thoughts.
John in Minnesota
Sent from my iPhone using Tapatalk