J
Jim, right before outside turning the neck for cases that have been necked up (6 to .30), had the shoulders pushed back (short 308's) or necked down (222 to .17 Javelina). Using Wilson reamers in specific sizes (.306, .307,.308, etc) fitted with a flanged pilot bushing....the case is held in a standard Wilson case holder and case trimmer.
A couple of caveats: Don't do this to previously neck turned and fired cases. On new cases, the neck has to be straight relative to the long axis of the case body (think f.l. resizing incl. the neck).
Good shootin'. -Al
A couple of caveats: Don't do this to previously neck turned and fired cases. On new cases, the neck has to be straight relative to the long axis of the case body (think f.l. resizing incl. the neck).
Good shootin'. -Al
Boyd Allen
Active member
Al,
Flanged pilot bushings? Could you post a picture?
Boyd
Flanged pilot bushings? Could you post a picture?
Boyd
Boyd, here 'ya go:
- .306 Wilson reamer:
- Reamer and flanged pilot bushing:
- Reamer with knurled head removed and pilot bushing on:
- Ready to use:
The point of this flanged pilot bushing is a more precise fit of the reamer in the Wilson trimmer. The i.d. of my Wlslon trimmer is nominally .500....a +.500 pin guage will not go in. This bushing is .4993-.4995 (depending on how I hold my tongue). The fit of the reamer o.d. to the bushing i.d. is also about half a thou. If the neck is straight, the reamer will go right down the middle of the inside neck and make it perfectly round. Once the i.d. is round, the outside of the neck will be exactly parallel to the inside (the Z axis) after turning (assuming a good mandrel fit). Another benefit of having the inside necks perfectly round is that you can get a better fit on the mandrel with as little as .0005 clearance w/o galling or building up heat. My .30 cal mandrels are from .3055 to .3080 in half thou. increments that I cut down from Siinclair .338 mandrels. The flanged bushing is something I made myself...dirt clod engineering.
It's also a great way to take out the occasional donut w/o touching any other part of the inside case neck.
I've never seen any 'on target' difference between necks I've done this way and pretty rudimentary neck up-turn-shoot cases (30BR's). There was a definite improvement with .30 WareWolf cases(.308W on Lapua brass shortened .165).
Measuring neck i.d.'s with simple pin guages can be rather revealing, for those so inclined.
Good shootin'. -Al
- .306 Wilson reamer:
- Reamer and flanged pilot bushing:
- Reamer with knurled head removed and pilot bushing on:
- Ready to use:
The point of this flanged pilot bushing is a more precise fit of the reamer in the Wilson trimmer. The i.d. of my Wlslon trimmer is nominally .500....a +.500 pin guage will not go in. This bushing is .4993-.4995 (depending on how I hold my tongue). The fit of the reamer o.d. to the bushing i.d. is also about half a thou. If the neck is straight, the reamer will go right down the middle of the inside neck and make it perfectly round. Once the i.d. is round, the outside of the neck will be exactly parallel to the inside (the Z axis) after turning (assuming a good mandrel fit). Another benefit of having the inside necks perfectly round is that you can get a better fit on the mandrel with as little as .0005 clearance w/o galling or building up heat. My .30 cal mandrels are from .3055 to .3080 in half thou. increments that I cut down from Siinclair .338 mandrels. The flanged bushing is something I made myself...dirt clod engineering.
It's also a great way to take out the occasional donut w/o touching any other part of the inside case neck.
I've never seen any 'on target' difference between necks I've done this way and pretty rudimentary neck up-turn-shoot cases (30BR's). There was a definite improvement with .30 WareWolf cases(.308W on Lapua brass shortened .165).
Measuring neck i.d.'s with simple pin guages can be rather revealing, for those so inclined.
Good shootin'. -Al
Boyd Allen
Active member
Thanks, it's fun to learn new stuff.
Boyd
Boyd
J
JRB
Guest
- Reamer and flanged pilot bushing:
The point of this flanged pilot bushing is a more precise fit of the reamer in the Wilson trimmer. The i.d. of my Wlslon trimmer is nominally .500....a +.500 pin guage will not go in. This bushing is .4993-.4995 (depending on how I hold my tongue). The fit of the reamer o.d. to the bushing i.d. is also about half a thou. If the neck is straight, the reamer will go right down the middle of the inside neck and make it perfectly round. Once the i.d. is round, the outside of the neck will be exactly parallel to the inside (the Z axis) after turning (assuming a good mandrel fit). Another benefit of having the inside necks perfectly round is that you can get a better fit on the mandrel with as little as .0005 clearance w/o galling or building up heat. My .30 cal mandrels are from .3055 to .3080 in half thou. increments that I cut down from Siinclair .338 mandrels. The flanged bushing is something I made myself...dirt clod engineering.
It's also a great way to take out the occasional donut w/o touching any other part of the inside case neck.
I've never seen any 'on target' difference between necks I've done this way and pretty rudimentary neck up-turn-shoot cases (30BR's). There was a definite improvement with .30 WareWolf cases(.308W on Lapua brass shortened .165).
Measuring neck i.d.'s with simple pin guages can be rather revealing, for those so inclined.
Good shootin'. -Al
Al, thank you for sharing, Great photos!
I have seen these reamers and not know what they where used for and why
I thought just taking out donuts!
Any how do you find that you take from only one side of the case? to true up and remove thickness variations?
I have just finished turning some new PPC cases and have use the pumpkin turner and expanders etc, which i have found vastly improved my end result.
I was concerened though, that when spinning the cases on a low speed drill about 250 rpm onto the mandrel, using a drop of oil each time, that there was considerable variations in fit, tightness and feel as the cases spun around, some where tight to withdraw back as i was tring to do this slowly as to improve the finish.
What lube do you suggest for the expander mandrel and also the turning mandrel? i have been using light machine oil.
Have you found that cutting the inside of the neck improves your mandel to case tension? i find my problem exists around the neck to shoulder junction, some are different to others.
A final question, why did you make up the flanged bushing? to give you more stability in the wilson trimmer.
Jim