I thought I'd share my threading set up for some of the new guys just starting out or anyone else that may be interested.
First, I take numerous measurements to determine the tennon length, diameter and TPI. I insert the blank into the lathe and extend the breech just enough to work on. I use a .001" indicator first to dial in the OD of the blank. Here it is with the OD dialed in and prior to the range rod being inserted.
I then use a PTG Range Rod with removable pilots and twin Brown & Sharp .0001" Best Test Indicators to get the blank to .0002" or better. This particular barrel needed a .2560" bushing instead of the typical .2558" used on .264 barrels.
After being dialed in to .00005" on front indicator and .0001" on rear..........close enough for the girls I run with
Now, I turn down the tennon to the desired diameter and face it off the desired length as well.
Next, I slip the recoil lug onto the tennon. This allows me to do several things prior to threading. I also take this time to indicate in my threading tool holder in and set up center to the work piece.
Things I check at this point,
1. Recoil Lug slip fit.
2. Recoil Lug tight fit against the barrel shoulder. I use a magnifying glass to check my shoulder fit with a bright light shinning down onto a piece of white paper in the back ground.
3. Threading tool center
4. Indicate the threading tool in
5. Set my stopping point for my threads. The stopping point for the threads is first determined by lining up the threading tool cutting tip to a point under the recoil lug. I then place a stop line on my bad ways next to the wiper. I watch the blue line during threading and get out of the cut once the wiper hits that point. New blue line for each barrel / threading job. (Thanks Trilogymac)
Thread away, 1.0625" x 16 TPI and the final fit.
Bolt nose recess and chambering followed, I'll save that for another day.
First, I take numerous measurements to determine the tennon length, diameter and TPI. I insert the blank into the lathe and extend the breech just enough to work on. I use a .001" indicator first to dial in the OD of the blank. Here it is with the OD dialed in and prior to the range rod being inserted.
I then use a PTG Range Rod with removable pilots and twin Brown & Sharp .0001" Best Test Indicators to get the blank to .0002" or better. This particular barrel needed a .2560" bushing instead of the typical .2558" used on .264 barrels.
After being dialed in to .00005" on front indicator and .0001" on rear..........close enough for the girls I run with
Now, I turn down the tennon to the desired diameter and face it off the desired length as well.
Next, I slip the recoil lug onto the tennon. This allows me to do several things prior to threading. I also take this time to indicate in my threading tool holder in and set up center to the work piece.
Things I check at this point,
1. Recoil Lug slip fit.
2. Recoil Lug tight fit against the barrel shoulder. I use a magnifying glass to check my shoulder fit with a bright light shinning down onto a piece of white paper in the back ground.
3. Threading tool center
4. Indicate the threading tool in
5. Set my stopping point for my threads. The stopping point for the threads is first determined by lining up the threading tool cutting tip to a point under the recoil lug. I then place a stop line on my bad ways next to the wiper. I watch the blue line during threading and get out of the cut once the wiper hits that point. New blue line for each barrel / threading job. (Thanks Trilogymac)
Thread away, 1.0625" x 16 TPI and the final fit.
Bolt nose recess and chambering followed, I'll save that for another day.
