30 cal Suppressor Build - Forum 1

[gun410]

Flipping the tool would allow you to get it on center without needing to hang the tool post holder off the edge of the compound.

I'm not exactly sure what you can do to get past the layer. If it happened to me, I'd slow the lathe down and with a new tool tip, give her hell.

Can you get any of your other tools in the grove? Maybe you can chip away some material with them before going back to the parting tool.

The only insert tooling for turning on OD is this https://rover.ebay.com/rover/0/0/0?mpre ... 2827780149 aswel as hss and some carbide that wouldn’t work in the grove.

[#40Fan]

Tough to tell what depth your groove is already, but either the threading tool or the neutral tool should fit in there.

Still, there is a lot of stick out from the chuck without tailstock support.

[gun410]

Tough to tell what depth your groove is already, but either the threading tool or the neutral tool should fit in there.

Still, there is a lot of stick out from the chuck without tailstock support.

The grove isn’t that deep, but I’m out of town until tomorrow. When I get back I’ll put in the live center put some oil on it and go to town with the carbide and see how much I can accomplish. Otherwise if that doesn’t work I’ll have to makeshift something with a dremel.

[gun410]

I was thinking about the suppressor design.
So far i haven’t designed any internals yet. I know I’m going to do some version of a 60° baffle(17-4 & Gr5 Ti) but I’m not sure what to do for the blast spacer. I’ve heard the spacer takes the most of the initial blast with brake mounted suppressors. I’ve found this https://solventtrapsdirect.com/4-inch-a ... rom-14-95/ which would work for my 1.36” Id tube if I got the “D size” but the spacer is only .036” thick, would that be strong enough for a 30 cal? Also I have no idea how long to make the blast chamber. As I’ve been doing more research I’ve found that most suppressors are over-sized the last couple baffles and the end cap to prevent strikes. So far my plan is to just ream everything to .375, will I be fine or should I oversize, suggestions?

[fishman]

Yes, 0.036" is enough, especially since it is also supported by the tube.

[gun410]

Ok, thanks fisherman wanted to verify.

I put some work into the break last night, completing everything besides the OD threads and the brake port holes (changed to 10° included taper). I've only threaded once on a lathe and it didn't go super well (4140). So I am a little overwhelmed and i'm pretty sure i already screwed myself . I built the break with the muzzle end facing towards the chuck (should be flipped) and if i'm thinking about this right won't i get the wrong hand thread (left hand) in this configuration? I've seen people use 1/2-28 mandrels in a chuck and lock tight the break on it, but I don't believe i can do that because this 17-4 has stayed in the 3-jaw chuck since i've started to help keep things concentric and the to-be threaded section is already at the exact width needed for 7/8-12 threads (.87"). I'm leaning against the mandrel because i'm thinking the threads wouldn't be 100% concentric to the previous sections turned in the 3 jaw. Also will i have to heat treat all my 17-4 parts including the blast baffles, because i dont have a heat treat oven (70/30 they came annealed).


Also having problems with the rigidity of the compound rest > https://youtu.be/3UOBA0gUEOM

[fishman]

No, the threads will be fine that way.

[gun410]

My carbide threading tool doesn’t fit and hss does t cut well on 17-4. Guess I’ll have to find another tool

[ECCO Machine]

if i'm thinking about this right won't i get the wrong hand thread (left hand) in this configuration?

As long as you're threading toward the spindle with the lathe running forward, you get right hand threads. If you thread away from the spindle running forward, you will cut LH threads.

[#40Fan]

Also having problems with the rigidity of the compound rest > https://youtu.be/3UOBA0gUEOM

I'd be looking at whatever that is under the compound.

[harris32]

So how come I can’t find any CAD files for .30cal cans? I have looked and looked but came up empty. Is there a reason for this.

[daviscustom]

So how come I can’t find any CAD files for .30cal cans? I have looked and looked but came up empty. Is there a reason for this.

While the folks here are generally very helpful, spoonfeeding the masses with CAD files generally doesn’t happen.

Gun410, I know it will waste material, but if you would cut your material down to shorter lengths it would help your cause in parting off and turning in general. Size your material so you have enough length to get a good grip in the chuck and end up parting off as close to the chuck as possible.... your material will be much more rigid and cut more consistently. The difference will be noticeable, especially in parting off..... also be careful trying to use the tail stock when parting off, things can bind up and go bad very quickly when it gets thin in the middle.

[gun410]

So i messed up the threads a little on the brake but i had to beef up the design to accommodate a larger 5/8 tapped hole. It was fine for 1/2-28 but for 5/8-24 there wasn't enough material at the thread relief with a 7/8 - 12tpi so I beefed up the design going to a 15/16 - 16tpi with 5-6 threads for the quick detach. This way the qd-thread relief is .85" dia instead of .75" dia. I've been looking at other designs and it seems like my taper with a 1" fat end is kinda small but i only have 1" and 1.5" dia 17-4 is it worth it to make it out of the 1.5" stock to get a little wider dia at the fat taper end? I was about to start turning some 1" 17-4 but i checked the runout and about 2 tho next to the chuck and 5.5 tho 2.4" out from the chuck. This has got me worrying about how concentric turning a break would be when the 3 jaw chuck is running out that bad. What other ways could i hold this stock while making the brake that would be more concentric and rigid?

[#40Fan]

When turning on the lathe, everything ends up concentric as long as all of the work is done in one setup.

https://www.youtube.com/watch?v=K67bZQSETiE

[gun410]

I’ve been working on a couple attempts and re-designs of the brake but I finally have it finalized. It took a while to get used to threading on the g0602. But I’m about to start on the tube and previously I was going to thread it 1 3/8-24 or 28 tpi but I’m not sure if my 1.36” id x 1.5 od tube has enough thickness for those threads. How do you calculate bore diameter for internal threading is it just the minor diameter of the thread?

[gun410]

I finished the suppressor design, since this is going to be used with mostly supers from 5.56/30cal/6.5creed a 60 degree cone seemed like the best option. the baffles are .08 thick the first 2 blast baffles are 17-4 and the rest of the baffles will be gr5 ti, all baffles will be reamed .375". I'm anxious to start building after getting the tax stamp back but i want to make sure i have the design perfect before i build.