Butch Lambert
Active member
Ben wanted in a little more detail about my chambering method. This is a horse that has been beaten to death on this forum.
I have a 6913 Clausing 14x48 that I use for chambering. I have to have a cathead on each end to be able to chamber barrels as short as 20". My eight set screws in my catheads were given to me by Gene Bukys. He had installed copper tips in them. I believe that they are softer and hold better than brass. Depending on what I am looking for in the barrel determines how much that I take off the big end, never less than an inch. I also cut 1 inch off the muzzle. I do these on a Roll Inn saw. I do not part them off in the lathe. I run my lathe for about 15 minutes both forward and backward before doing any operations.I indicate both ends with Deltronic pins. I face off the back of the barrel and deburr. I use an inserted turning tool with VBMT 221 coated inserts. I use the same inserted tool to cut the tenon. I use my Trav A Dial to cut the length and double check with my Depth mic. On my Bats, I cut the tenon to 1.058 in diameter. My threading tool is a 5/8" Super Momax Cobalt HS tool steel that is ground for me by a friend at a tool grinding shop. I set my compound at 29.5 degrees and make sure that my tool has a minimal amount hanging out of the tool holder. I use about 100rpm to thread and use Texaco Transsultex high sulpher cutting fluid. I thread to the shoulder without a thread relief. I do not think a thread relief hurts though. I have a set of thread mics to check size. On my Bat I can also check the threads with a Panda thread insert that I purchased from Kelblys. I polish my threads with a rubberized abrasive stick. I drill the chamber with a drill that is about .040 less than the diameter of the shoulder and stop about .075 short. I put my Mitutoyo .0001 indicator approx. in the throat area and indicate the grooves. I check the land heights at the same time. I taper bore to within about .020 of finished diameter with a solid carbide boring bar. I do not use a tight fitting bushing on my reamer. I ream at about 75 RPM. I lock my carriage down and use it as a stop for my tailstock. This way I can slide my tailstock a long way back to be able to measure or whatever. My tailstock didn't come with graduations on the crank. I took the knee dial off a Bridgeport and adapted it to the crank. It has .100 for a full turn and matches the threads on the tailstock. I run the reamer in .100 per pass until I get to the shoulder. I will go in about .030 ea. time. Make sure you clean the reamer and chamber each time. I have a tool like a lot of you guys. It screws on the tenon and has a Mitutoyo micrometer head on it. If I am trying to match the headspace on an existing barrel I put the headspace gage in the old barrel and take a reading. I write that figure down and ream the new chamber until I have the exact same headspace. On the Bat I cut the 25deg bolt nose clearence and check it with my same tool only the device that I put in the chamber looks like a valve out of a small engine. I cut the 25deg. until I match the old barrel. I put a little cross hatch with worn 320 paper in the chamber. I polish the cone. I do break the edge with 320 on the transition from the cone to the chamber. My screw on measuring tool has 12 horizontal lines. I screw it on the old barrel and match the engraving on the old barrel with one of the marked lines. I screw it on the new barrel and mark the barrel with a Marks A Lot so that I can engrave it in the right spot.
When I turn the barrel around to cut the crown, I screw a sleeve on the tenon for the cathead screws to bear on and reach in and indicate the chamber wall and use a Deltronic pin in the muzzle. I use a wonderful cemented carbide tool that Jackie was gracious to grind for me to cut the crown. Sometimes I cut a flat and sometimes I recess it. Doesn't matter if it is sharp and square to the bore. I deburr the crown with the rubberized abrasive stick.
I am not claiming that this is the best or only way, but it works for me. Ben wanted a detailed account and here it is.
Butch
I have a 6913 Clausing 14x48 that I use for chambering. I have to have a cathead on each end to be able to chamber barrels as short as 20". My eight set screws in my catheads were given to me by Gene Bukys. He had installed copper tips in them. I believe that they are softer and hold better than brass. Depending on what I am looking for in the barrel determines how much that I take off the big end, never less than an inch. I also cut 1 inch off the muzzle. I do these on a Roll Inn saw. I do not part them off in the lathe. I run my lathe for about 15 minutes both forward and backward before doing any operations.I indicate both ends with Deltronic pins. I face off the back of the barrel and deburr. I use an inserted turning tool with VBMT 221 coated inserts. I use the same inserted tool to cut the tenon. I use my Trav A Dial to cut the length and double check with my Depth mic. On my Bats, I cut the tenon to 1.058 in diameter. My threading tool is a 5/8" Super Momax Cobalt HS tool steel that is ground for me by a friend at a tool grinding shop. I set my compound at 29.5 degrees and make sure that my tool has a minimal amount hanging out of the tool holder. I use about 100rpm to thread and use Texaco Transsultex high sulpher cutting fluid. I thread to the shoulder without a thread relief. I do not think a thread relief hurts though. I have a set of thread mics to check size. On my Bat I can also check the threads with a Panda thread insert that I purchased from Kelblys. I polish my threads with a rubberized abrasive stick. I drill the chamber with a drill that is about .040 less than the diameter of the shoulder and stop about .075 short. I put my Mitutoyo .0001 indicator approx. in the throat area and indicate the grooves. I check the land heights at the same time. I taper bore to within about .020 of finished diameter with a solid carbide boring bar. I do not use a tight fitting bushing on my reamer. I ream at about 75 RPM. I lock my carriage down and use it as a stop for my tailstock. This way I can slide my tailstock a long way back to be able to measure or whatever. My tailstock didn't come with graduations on the crank. I took the knee dial off a Bridgeport and adapted it to the crank. It has .100 for a full turn and matches the threads on the tailstock. I run the reamer in .100 per pass until I get to the shoulder. I will go in about .030 ea. time. Make sure you clean the reamer and chamber each time. I have a tool like a lot of you guys. It screws on the tenon and has a Mitutoyo micrometer head on it. If I am trying to match the headspace on an existing barrel I put the headspace gage in the old barrel and take a reading. I write that figure down and ream the new chamber until I have the exact same headspace. On the Bat I cut the 25deg bolt nose clearence and check it with my same tool only the device that I put in the chamber looks like a valve out of a small engine. I cut the 25deg. until I match the old barrel. I put a little cross hatch with worn 320 paper in the chamber. I polish the cone. I do break the edge with 320 on the transition from the cone to the chamber. My screw on measuring tool has 12 horizontal lines. I screw it on the old barrel and match the engraving on the old barrel with one of the marked lines. I screw it on the new barrel and mark the barrel with a Marks A Lot so that I can engrave it in the right spot.
When I turn the barrel around to cut the crown, I screw a sleeve on the tenon for the cathead screws to bear on and reach in and indicate the chamber wall and use a Deltronic pin in the muzzle. I use a wonderful cemented carbide tool that Jackie was gracious to grind for me to cut the crown. Sometimes I cut a flat and sometimes I recess it. Doesn't matter if it is sharp and square to the bore. I deburr the crown with the rubberized abrasive stick.
I am not claiming that this is the best or only way, but it works for me. Ben wanted a detailed account and here it is.
Butch
