Hi,
I'm baffled and can't understand how following is possible. I've tried to make slitting saw holder for use in ER25 collet chuck, but no matter how I do it there is ~0.15mm concentricity error which is alot. First of all the part is like this:
I've actually tried three times to do this and every time I get the same error. First time I turned it in two different grips on 4 jaw chuck. It was properly indicated to run true before starting to machine the other end. When installed to ER25 collet chuck with 0.08 AA collets it had runout of ~0.15mm
Second time I machined it with one grip. In the picture chuck end was on left side and all three diameters were turned on one grip. Got the same error when attached to collet chuck.
Third time on precision Bison 3 jaw scroll chuck and with one grip. This time so that the 25mm stock was around 55mm extended from chuck and supported from other end by the tailstock. First turned the biggest diameter to 24mm then the 16mm diameter for the slitting disk. Then 15mm diameter for the collet. Next drilled the hole and threaded M8. At this point I indicated the slitting disk shoulder and it had 0.01mm runout. Last I parted it off. Put it in the ER collet and again ~0.15mm runout! Btw. that 15mm diameter was turned with parting tool in last two cases. Lathe is Harrison M450. Material 17-4PH.
I've tried in two different milling machines and two different collet chucks and collets. Still the same. This is driving me nuts. What in earth is going wrong?
Your help is greatly appreciated.
I'm baffled and can't understand how following is possible. I've tried to make slitting saw holder for use in ER25 collet chuck, but no matter how I do it there is ~0.15mm concentricity error which is alot. First of all the part is like this:
I've actually tried three times to do this and every time I get the same error. First time I turned it in two different grips on 4 jaw chuck. It was properly indicated to run true before starting to machine the other end. When installed to ER25 collet chuck with 0.08 AA collets it had runout of ~0.15mm
Second time I machined it with one grip. In the picture chuck end was on left side and all three diameters were turned on one grip. Got the same error when attached to collet chuck.
Third time on precision Bison 3 jaw scroll chuck and with one grip. This time so that the 25mm stock was around 55mm extended from chuck and supported from other end by the tailstock. First turned the biggest diameter to 24mm then the 16mm diameter for the slitting disk. Then 15mm diameter for the collet. Next drilled the hole and threaded M8. At this point I indicated the slitting disk shoulder and it had 0.01mm runout. Last I parted it off. Put it in the ER collet and again ~0.15mm runout! Btw. that 15mm diameter was turned with parting tool in last two cases. Lathe is Harrison M450. Material 17-4PH.
I've tried in two different milling machines and two different collet chucks and collets. Still the same. This is driving me nuts. What in earth is going wrong?
Your help is greatly appreciated.