|10-28-2016, 08:32 AM||#1|
Joined: Jun 2016
I put the PVC variant of the silencer in my book
altho I'd never actually done it. Later, it did get tested and proven. A pipe cutter makes a nice 90 degree cut in PVC, and that "trued" end is necessary for the alignment of the can with the barrel. The shoulder of the 3/4" long, 3/8" fine thread bolt is likewise a 90 degree angle to the long axis of the bolt. Said bolt is grade 8, so it has to be annealed before you can drill it. all you have to do is get it cherry red with a torch and then let it float for a while in molten lead, or let it sit in a pile of sand with a 1000F heat gun blowing on it for a while, then let it cool slowly. It can then be center-drilled in a lathe and the finished ID of .238" hole can be bored thru it lengthwise.
There has to be an empty thread groove cut into the bolt, at the end of the thread, near the bolt head, but a Harbor freight handgrinder and Dremel cutoff disks can handle that job. The only really tricky job to making the threaded on pvc silencer is drillling the 1/16" holes in the center of 3 of the 6 sides of the bolt head, as well as the matching holes in the PVC pipe. Then 3/8" long, 3/32"" OD roll pins can be crimped and ground to a bit of a bevel and then can be driven into the 1/16" holes. the holes in the pVC "wallow out" a bit, you see, So the hollow pins have to be expanded a bit on the ends that will be in the PVC, for a tight fit.
Then JB weld epoxy is used to seal up the 6 holes between the flats of the bolt head and the inside of the round PVC tubing as well as fill in the holes in and around the pins in the pvc. If the other end of the pvc has likewise been cut to a 90 degree end, the pipe can be clamped vertically in a vise, a level put across the end of the pipe, and the glue can then be left to set up. With the barrel counterbored and tapped, you then have a can-tube mounted on the barrel, ready to have the baffles made and installed in the tube. then the internal snap ring groove can be cut into the front end of the PVC. If your handheld electric grinder can't be run at low speed, you can use the Dremel mandrel mounted circular saw blade in a handheld electric drill. Too high RPMs of the grinder will melt the pvc instead of cutting it.
The thick walls of the PVC make it a perfect fit on the head of the 3/8" bolt and make the cutting internal snap ring groove less of a precise cut sort of deal. but they also make for a smaller ID of the can-tube, meaning you need about 8" of length for a .22 rifle, or 7" for a pistol, when 2" less of 1" steel tubing will suffice. but if you use steel, you'll probably have to weld the head of the bolt into the tubing, leaving the male thread projecting back out of the can-tube. The welding heat sometimes causes the tubing to warp a bit, pulling the can out of alignment with the bolt and thus, with the bore of your .22's barrel. That can require judicious use of a rubber mallet, applied at the right place, then re-tightening of the can on the barrel. You'll know if it's missaligned, cause any impact of the bullet with the baffles will rip the snapring and washer out of the groove in the can tube. :-) The steel tube can tolerate such impact, but it will probably break off the front end of a PvC tube, requiring you to again cut it off and recut the snapring groove.
Last edited by justme; 10-28-2016 at 08:43 AM.