Paul:
Your write up is first rate! Thank you.
I have a few additional comments to further describe processes and methods used in the manufacture of these dies.
Top die inserts:
Blanks are machined over size, and under size on ID's) prior to heat treat. There is a tangent radius incorporated at the junction of the neck diameter and the shoulder angle that is at minimum, .020" larger, and max .035" than what the reamer or chamber produces. This is to assure that the die never touches the Tbrass in this area. There is also a slight taper in the neck diameter of .0002 to .0003. The bottom of the diameter being the larger. This feature also helps with avoiding donuts.
ID's are honed with cbn stones to rough size, then finished with AL OX to achieve RMS surfs of less than 2.5
OD's are from cylindrical ground on arbors between dead centers. Roundness runs from 10 to 20 millionths and concentricity is always less than .0001.
Slip fit of the die inserts to the body are held from .0002 to .0005 at the extreme.
Head space of the top dies are held to -.0005 + .0000 You can swap out top dies with out having to re adjust for head space.
Body die inserts:
Same process prior to heat treat.
ID's are ground to exact size and taper for the brass on hand with and ID spindle capable of up to 50,000 rpm. with a head stock that is sine bar controled. A dead center arbor is ground to match the newly ground ID, then the OD is ground with the same results of roundness and concentricity as the top dies.
The ID spindle and the amount of control used to establish the body taper affords the ability to make any custom required die you may ever need.
Alan
PS: The dies are set up with no shims installed at -.005"
Your write up is first rate! Thank you.
I have a few additional comments to further describe processes and methods used in the manufacture of these dies.
Top die inserts:
Blanks are machined over size, and under size on ID's) prior to heat treat. There is a tangent radius incorporated at the junction of the neck diameter and the shoulder angle that is at minimum, .020" larger, and max .035" than what the reamer or chamber produces. This is to assure that the die never touches the Tbrass in this area. There is also a slight taper in the neck diameter of .0002 to .0003. The bottom of the diameter being the larger. This feature also helps with avoiding donuts.
ID's are honed with cbn stones to rough size, then finished with AL OX to achieve RMS surfs of less than 2.5
OD's are from cylindrical ground on arbors between dead centers. Roundness runs from 10 to 20 millionths and concentricity is always less than .0001.
Slip fit of the die inserts to the body are held from .0002 to .0005 at the extreme.
Head space of the top dies are held to -.0005 + .0000 You can swap out top dies with out having to re adjust for head space.
Body die inserts:
Same process prior to heat treat.
ID's are ground to exact size and taper for the brass on hand with and ID spindle capable of up to 50,000 rpm. with a head stock that is sine bar controled. A dead center arbor is ground to match the newly ground ID, then the OD is ground with the same results of roundness and concentricity as the top dies.
The ID spindle and the amount of control used to establish the body taper affords the ability to make any custom required die you may ever need.
Alan
PS: The dies are set up with no shims installed at -.005"
