Threading between centers.

A couple of comments the them as you wish.
I support your effort but I'd be very concerned about posting this questions on a public forum. I'd bet big $ there are computers searching a very corner of the wwwfor keywords that include the topic you posted. I know laws vary state to state but the feds are always looking for a reason to take away our rights IMO and this type of modification is taboo in many areas.
As for the work you are doing I can only offer my very limited knowledge. I put a dead center in a three jaw and turn it new every time. I leave it in there and I use a homemade lathe dog. Look these up as they are super easy to make with two pieces of steel, two clamp bolts and another bolt the threads into one side/end of the clamp. This bolt hits one of the jaws as the chuck turns and drives the work. Threading on centers is the same operation as threading in the chuck.

Thank You for your help. I already have some dogs that I bought so I have that part covered. Machining has a pretty steep learning curve. I wish that my work schedule would allow me to take some classes. But working swing shift.......

While I will agree that the Fed's watch everything, I do not care. Politics aside, the reason we as free people have had our freedom and liberty taken from us is because many of us are scared to make any waves or rattle our little cages.:panic: Heck I wonder how the founders of this nation would respond to the powers that be today.

Anyhow owning a suppressor is perfect legal here in Alabama And yes I own a couple. I do so legally so yes I have approved form4's with the pretty lil stamp that cost me $200.00 and a 6 month wait. I am seriously thinking of sending off a form1 then when it is approved making a suppressor with a baffle design that I have thought about. Now if I can get my machining skills up to speed. :))

Thanks everyone for all the advice. If anyone can see anything wrong with my thought process please let me know. I take constructive criticism very well.:thumbzup3:
 
I got home from work and decided to get to it. Here is the setup. I put tape on the lower handguard retainer and the rear sight leaf to hold them in place and keep them from moving tmp_14734-KIMG00771709005493_zps1wggfs4q.jpg




Here the Front sight base is turned to diameter as well as tmp_14734-KIMG00801607426935_zps07cwe8sn.jpg


Here is the finished product threaded 1/2 x 28. Please excuse the carbon on the threads. I had test fit the quick detach several times and neglected to clean it before the tmp_14734-KIMG0083-1636960333_zpsbn9mezka.jpg

Quick detach tmp_14734-IMG_20150203_2023011906001365_zpsxkpqacip.jpg


Looking through the supressor to check barrel can alignment. This is a hard shot to get trying to get the phone and barrel/suppressor assembly into the same alignment plane. It looks a little off in the picture but in hand it is perfect. tmp_14734-IMG_20150203_2034461428172437_zpsasdmgxkb.jpg

Thanks for all the help and guidance!:thumbsup2: All I have to do now is make a thread protector that matches the factory fsb diameter and thread pattern.

I have to turn a piece down then thread internally. I then have to put the thread protector on the barrel and turn it to diameter and pick up the threads on the factory FSB then the project will be done.

:))

tmp_14734-KIMG00771709005493_zps1wggfs4q.jpg

tmp_14734-KIMG00801607426935_zps07cwe8sn.jpg

tmp_14734-KIMG0083-1636960333_zpsbn9mezka.jpg

tmp_14734-IMG_20150203_2023011906001365_zpsxkpqacip.jpg

tmp_14734-IMG_20150203_2034461428172437_zpsasdmgxkb.jpg
 
Last edited:
I finished the thread protectors today. They are made from some pre-hardened 4140.

tmp_21963-KIMG0099844545705_zpsueppfyum.jpg
tmp_21963-KIMG0102-443774879_zpsgfiioycz.jpg

tmp_21963-KIMG0103985704447_zpschh67khc.jpg

tmp_21963-KIMG0104-807692400_zpsnqviegd0.jpg


I had to add some blue locktite to keep the thread protector from unscrewing while threading. Because of the front sight base I had to thread from headstock end to tailstock. That was a new experience but enjoyable. I also did not trust myself not to crash into the front sight when I was reversing so I threaded using hand power using a crank.
tmp_3721-KIMG0114844545705_zpsc9ljgdrc.jpg
tmp_3721-KIMG0115-443774879_zpsvkztune4.jpg
tmp_3721-KIMG0116-1657191243_zpsxwnapu5i.jpg

tmp_21963-KIMG0099844545705_zpsueppfyum.jpg

tmp_21963-KIMG0102-443774879_zpsgfiioycz.jpg

tmp_21963-KIMG0103985704447_zpschh67khc.jpg

tmp_21963-KIMG0104-807692400_zpsnqviegd0.jpg

tmp_3721-KIMG0114844545705_zpsc9ljgdrc.jpg

tmp_3721-KIMG0115-443774879_zpsvkztune4.jpg

tmp_3721-KIMG0116-1657191243_zpsxwnapu5i.jpg
 
Last edited:
Your threading job looks great! I'm about to thread a .300 AAC Blackout barrel for a suppressor mount myself - the mount I have is also 1/2x28, but I've been cautioned by a few people about turning the barrel down that far for a .30 caliber bore. It doesn't leave a whole lot of "meat" in the barrel.

Would any of the other experienced guys here care to weigh in on that topic? Just how weak IS it to take the last half-inch of barrel and turn it down a bit extra. I think my concern on a very accurate barrel would be more about distorting the muzzle and ruining the accuracy than creating any particular risk of barrel rupture, blowing the muzzle device off, etc. Although, if you hang a heavy suppressor off a weakened barrel, that might not be a good idea either.
 
Your threading job looks great! I'm about to thread a .300 AAC Blackout barrel for a suppressor mount myself - the mount I have is also 1/2x28, but I've been cautioned by a few people about turning the barrel down that far for a .30 caliber bore. It doesn't leave a whole lot of "meat" in the barrel.

Would any of the other experienced guys here care to weigh in on that topic? Just how weak IS it to take the last half-inch of barrel and turn it down a bit extra. I think my concern on a very accurate barrel would be more about distorting the muzzle and ruining the accuracy than creating any particular risk of barrel rupture, blowing the muzzle device off, etc. Although, if you hang a heavy suppressor off a weakened barrel, that might not be a good idea either.

Honestly the best thing that I think you could do would be to call the suppressor manufacturer and ask them. I have also wondered about quick disconnects that are .30 cal threaded 1/2x28. Get their blessing or get a different mount are really your only options.
 
Yes, as stated above 5/8-24 is the usual for 30 cals.

A little more material thickness and no chance of threading on a 1/2-28 .223 can.
 
I don't do gunsmithing work but turning/threading between centers isn't much different than anything else. The nicest thing about threading between centers is that you can remove the workpiece from the lathe & test fitment if needed, then retrun it back to the lathe & continue threading without loosing your index.

The most import thing to check when threading between centers, if your faceplate has more than one slot & you need to remove the work from the lathe, be sure to place it back in the lathe with the dog drive in the same slot it came out of.

When tunring between centers, be sure your tailstock has enough pressure on the work so that the dog drive does not flop around in the drive plate slot. It's should have just enough pressure/friction where you can still move it by hand but not flop around in the slot.
---------------------------------------------------------------------------------------------------
In the old books they used leather straps to tie the lathe dog to the faceplate so they wouldn't rattle. Be sure to tighten the clamp bolt(s) of the tailstock so under pressure it doesn't slip back. Been there but caught it before any damage was done.

If you were making 20 or more consider a making a simple fixture that has a soft live center and faceplate. I usually refaced my centers when using a three jaw chuck by skim cutting the 60 degree nose. That way even a center in a poor chuck would run true.
 
Back
Top