Some ? about building first form 1 can

Yes, it can be legal to make a silencer. For everything Form-1, from silencer designs that are easily made, to filing forms with the BATF, to 3D modeling. Remember, you must have an approved BATF Form-1 to make a silencer. All NFA laws apply.

Moderators: mpallett, bakerjw

Post Reply
milsurpcollector1970
Member
Posts: 22
Joined: Fri Sep 30, 2016 1:01 pm

Some ? about building first form 1 can

Post by milsurpcollector1970 »

Hello, first post Im a long time lurker. I finally sent in my 1st Form 1 request yesterday so im gathering some info about materials and such.

I have a lathe (grizzly 12-36) and bridgeport mill. I would call myself an advanced beginner when it comes to machining.

My first can will be a fixed mount on a SBR 10" bbl AR-15 45acp. I plan on shooting 9mm and 300 blackout at well.

Questions:

I plan on making a mount that can attach to all 3 calibers What are the drawbacks of this ?

I see that most people use stainless for corrosion resistance Is there any regular steel that would work? I dont want to use Ti

What is the correct tubing? DOM?

Is it necessary to weld the baffle stack? I have a tig welder but I would prefer to be able to take it apart.

if its not welded do you need an internal spring to keep the baffles together?

If i use stainless for internals 17-4 is the correct material to use?

Thanks for the replies
User avatar
Capt. Link.
Silent But Deadly
Posts: 2829
Joined: Wed Oct 17, 2007 9:05 pm
Location: USA.

Re: Some ? about building first form 1 can

Post by Capt. Link. »

milsurpcollector1970 wrote: Wed Dec 15, 2021 6:03 pm Hello, first post Im a long time lurker. I finally sent in my 1st Form 1 request yesterday so im gathering some info about materials and such.

I have a lathe (grizzly 12-36) and bridgeport mill. I would call myself an advanced beginner when it comes to machining.

My first can will be a fixed mount on a SBR 10" bbl AR-15 45acp. I plan on shooting 9mm and 300 blackout at well.

Questions:

I plan on making a mount that can attach to all 3 calibers What are the drawbacks of this ?

I see that most people use stainless for corrosion resistance Is there any regular steel that would work? I dont want to use Ti

What is the correct tubing? DOM?

Is it necessary to weld the baffle stack? I have a tig welder but I would prefer to be able to take it apart.

if its not welded do you need an internal spring to keep the baffles together?

If i use stainless for internals 17-4 is the correct material to use?

Thanks for the replies

DOM is wonderful but you must maintain a finish on it. 316 seamless tubing dose not require any finish.Aluminum must be anodized but would be fine including 7075 baffles. 17-4 ph-900 is often used without finish. Why the hate on Ti, it would make a fine .45acp can and baffles.
You don't need to weld nor do you need a spring? Barrel threading is normally 5/8x24 in .45 plus you will need a 1/2x28 to 5/8x24 for the 9mm and 7.62 caliber.
How long a suppressor tube is on the paper work?
The only reason after 243 years the government now wants to disarm you is they intend to do something you would shoot them for!
http://www.silencertalk.com/forum/viewtopic.php?f=10&t=79895
milsurpcollector1970
Member
Posts: 22
Joined: Fri Sep 30, 2016 1:01 pm

Re: Some ? about building first form 1 can

Post by milsurpcollector1970 »

Thanks for the reply.

I dont really have anything against Ti, I have heard its hard to machine and expensive.

My form 1 was for an 8" length can. I planned on a 1.5 inch diameter but i can make it a larger if thats better.

Sounds like i will need a mount for each caliber

I had read that as the suppressor heats up the caps will loosen hence the need for a spring

I was wanting to use 4130 for the tube so I can parkerize it.
User avatar
Capt. Link.
Silent But Deadly
Posts: 2829
Joined: Wed Oct 17, 2007 9:05 pm
Location: USA.

Re: Some ? about building first form 1 can

Post by Capt. Link. »

milsurpcollector1970 wrote: Thu Dec 16, 2021 12:28 am Thanks for the reply.

I dont really have anything against Ti, I have heard its hard to machine and expensive.

My form 1 was for an 8" length can. I planned on a 1.5 inch diameter but i can make it a larger if thats better.

Sounds like i will need a mount for each caliber

I had read that as the suppressor heats up the caps will loosen hence the need for a spring

I was wanting to use 4130 for the tube so I can parkerize it.
Ti is not that bad to machine or in cost. Weight savings, strength and its corrosion resistance make it a popular choice. S.S. 17-4 is normally cut in the hardened condition, ph-900 is common. If you can cut hard stainless Ti will not be an issue.

Longer is better than fatter for suppressor performance. You might consider building a coaxial to maximize the length. This uses a smaller inner tube holding the baffles with a outer tube. The space between is the blast chamber. It amounts to folding the suppressor. The design is proven and flexible in baffle choice.

DOM should be fine it will take parkerizing and blue well.

The end caps should be checked after the first few shots after repacking it. Baffles and spacers are fitted cap to cap or a inner ring is used to keep the stack seated. No springs are needed in most designs. The suppressor mount being tight should be checked every magazine.

Mounts and thread adapters are not difficult to machine don't sweat it.

What baffles are you considering? Do you have interest in building a coaxial?
The only reason after 243 years the government now wants to disarm you is they intend to do something you would shoot them for!
http://www.silencertalk.com/forum/viewtopic.php?f=10&t=79895
milsurpcollector1970
Member
Posts: 22
Joined: Fri Sep 30, 2016 1:01 pm

Re: Some ? about building first form 1 can

Post by milsurpcollector1970 »

I will build whatever has the most sound reduction coaxial sounds good, Is there a design out there you reccomend.

I read K baffles are the best for subsconic which is what I will shoot in the 45 and 9mm. I also read they are the hardest to do properly

I was thinking about the Omega baffle if I could find a drawing

So 4130 for the tube is ok and you reccomend Ti.

Does Ti work harden like stainless ?

Any machining tips?
User avatar
Capt. Link.
Silent But Deadly
Posts: 2829
Joined: Wed Oct 17, 2007 9:05 pm
Location: USA.

Re: Some ? about building first form 1 can

Post by Capt. Link. »

K baffles are great and can be machined from mild to wild with variable performance. Current cone baffles are possibly the easiest to reproduce for performance but many are needed. The Omega baffle and its complicated porting is possibly the most difficult to execute well. You should ask permission from the inventor before you build, Joe Gaddini has been a friend to the amateur community and grants permission to reproduce.
Look through this to get familiar with the coaxial build. https://www.thefirearmblog.com/blog/202 ... st-subgun/ . A inner tube of 1 3/8 and a outer of 1.75-2.00 would be fine. These are made by several manufacturing company's.
The choice of baffle is up to you. I can talk you through machining any of them less the porting of the Omega.I have sources for materials as well.
-CL
The only reason after 243 years the government now wants to disarm you is they intend to do something you would shoot them for!
http://www.silencertalk.com/forum/viewtopic.php?f=10&t=79895
milsurpcollector1970
Member
Posts: 22
Joined: Fri Sep 30, 2016 1:01 pm

Re: Some ? about building first form 1 can

Post by milsurpcollector1970 »

That design looks good, hopefully I have the skill to pull it off

I will go with the M baffle.

Is the internal cone usually cut with a countersink?

I have watched videos where a countersink was used.

How many M baffles can I get in a 8” can?
User avatar
Capt. Link.
Silent But Deadly
Posts: 2829
Joined: Wed Oct 17, 2007 9:05 pm
Location: USA.

Re: Some ? about building first form 1 can

Post by Capt. Link. »

milsurpcollector1970 wrote: Fri Dec 17, 2021 9:20 am That design looks good, hopefully I have the skill to pull it off

I will go with the M baffle.

Is the internal cone usually cut with a countersink?

I have watched where a countersink was used.

How many M baffles can I get in a 8” can?
The M is harder to machine than a cone with a spacing shoulder. A cone with separate spacer is simpler to machine with the same qualities and less weight by the use of alloy spacers. Precision mass production of the baffles is easy if you build a simple fixture. Baffles of .040" thickness will be plenty strong if 17-4 is used.

I can't see using a countersink on hard stainless or like the sound it will make. I tried that on aluminum and the flutes jammed with swarf causing much heat and jamming in the work piece. I use a tool with a 45* rhomboid insert of M-7 for cutting cones. https://www.arwarnerco.com/

K baffles are very simple machining if you follow a good print. A mill table helps but basic fixtures can be made for accurate porting. K baffle yields the highest suppression"."

If you read the article you may notice that GSL dropped the M baffle from the MK-9K. I'm throwing allot of info at you that should be known before the first chips are made.
The only reason after 243 years the government now wants to disarm you is they intend to do something you would shoot them for!
http://www.silencertalk.com/forum/viewtopic.php?f=10&t=79895
milsurpcollector1970
Member
Posts: 22
Joined: Fri Sep 30, 2016 1:01 pm

Re: Some ? about building first form 1 can

Post by milsurpcollector1970 »

Well if I can find a good print for a K I will do that one then.

When I said M I was thinking of the 2 pieces cone with a spacing shoulder. That would definetly be easier to build.

I plane on making the outer sleeve out of 4130 maybe the inner one as well.

Do the baffles need to be made from stainless. Could i use 4130 for the while thing?

Is there a reason you dont use carbide. That company only sells HSS

I appreciate all the info you are telling me. By the time I get approved I might be ready to make some chips
User avatar
Capt. Link.
Silent But Deadly
Posts: 2829
Joined: Wed Oct 17, 2007 9:05 pm
Location: USA.

Re: Some ? about building first form 1 can

Post by Capt. Link. »

milsurpcollector1970 wrote: Fri Dec 17, 2021 11:57 pm Well if I can find a good print for a K I will do that one then.

When I said M I was thinking of the 2 pieces cone with a spacing shoulder. That would definetly be easier to build.

I plane on making the outer sleeve out of 4130 maybe the inner one as well.

Do the baffles need to be made from stainless. Could i use 4130 for the while thing?

Is there a reason you dont use carbide. That company only sells HSS

I appreciate all the info you are telling me. By the time I get approved I might be ready to make some chips
I think you will be happy with the K baffle I'll find a print or help you draw one. Don't be intimidated by the machining, the right setup and a solid plan will see you through. This is from a old post.....enjoy
Image ( viewtopic.php?t=138952 )
You can build using carbon steel or alloys that resist corrosion (recommended). I would use a cone blast baffle that is hardened.This can be carbon or stainless.

A carbide tools edge is destroyed with any vibration. They are designed for a continual cut without stopping or starting unlike what is common with smaller machines. The cost can be very high if you only get one pass before the edge is gone and the insert was costly. I do use carbide,ceramic,diamond tools when nothing else will do the job.

I do not believe that carbide is economical for most lathe work. I will teach anyone who cares to learn to grind their own. A HSS tool of 5-15% will handle most jobs and last for a very long time.
The only reason after 243 years the government now wants to disarm you is they intend to do something you would shoot them for!
http://www.silencertalk.com/forum/viewtopic.php?f=10&t=79895
milsurpcollector1970
Member
Posts: 22
Joined: Fri Sep 30, 2016 1:01 pm

Re: Some ? about building first form 1 can

Post by milsurpcollector1970 »

I cant wait to get started (but i will because i dont want to go to prison) My fingerprints should be at the BATFE tomorrow

I have some of the material ordered and am sourcing the rest. End pieces are ordered.

I will use Metals supermarket for the dom tubing

Ebay is the cheapest i have found 17-4 stainless for the baffles

Does anyone have other suggestions for the material.

I actually have a heat threat oven i got at an auction just need to replace the controller
User avatar
Capt. Link.
Silent But Deadly
Posts: 2829
Joined: Wed Oct 17, 2007 9:05 pm
Location: USA.

Re: Some ? about building first form 1 can

Post by Capt. Link. »

milsurpcollector1970 wrote: Wed Dec 22, 2021 9:36 pm I cant wait to get started (but i will because i dont want to go to prison) My fingerprints should be at the BATFE tomorrow

I have some of the material ordered and am sourcing the rest. End pieces are ordered.

I will use Metals supermarket for the dom tubing

Ebay is the cheapest i have found 17-4 stainless for the baffles

Does anyone have other suggestions for the material.

I actually have a heat threat oven i got at an auction just need to replace the controller
If I can't talk you into a total stainless build I can give you some pointers and choices. The outer DOM tube can be .040 as it needs no threads. Baffles from 416 SS cuts like butter yet hardens well. You might use 7075 aluminum for the end caps and baffles or most of the baffles. The inner tube should have a thicker than normal wall so you may cut a threading bed that is larger than the interior. This way baffles don't drag over the threads. Lapping threads with compound and fitting them for a high engagement factor is stronger and feels like a million bucks. You can lighten tubes by running a thread full length inside or outside.
Do you need jigs to do the radial milling. Copying the AAC K baffle as close as possible is what you want so kidney bean cuts are the order of the day.
The only reason after 243 years the government now wants to disarm you is they intend to do something you would shoot them for!
http://www.silencertalk.com/forum/viewtopic.php?f=10&t=79895
milsurpcollector1970
Member
Posts: 22
Joined: Fri Sep 30, 2016 1:01 pm

Re: Some ? about building first form 1 can

Post by milsurpcollector1970 »

I have a rotary table i can mount a milling vice on, and i have several small milling vices.

By a jig, do you mean a square Al block with a circle cut out the same size as the baffle that can hold a baffle?

I can certainly make one.

It seems like I should make it out of stainless so I will. I will just powder coat it.

From the pics you linked it looks like the outer tube is threaded on the inside? How else would it stay on.
User avatar
Capt. Link.
Silent But Deadly
Posts: 2829
Joined: Wed Oct 17, 2007 9:05 pm
Location: USA.

Re: Some ? about building first form 1 can

Post by Capt. Link. »

milsurpcollector1970 wrote: Fri Dec 31, 2021 4:54 pm I have a rotary table i can mount a milling vice on, and i have several small milling vices.

By a jig, do you mean a square Al block with a circle cut out the same size as the baffle that can hold a baffle?

I can certainly make one.

It seems like I should make it out of stainless so I will. I will just powder coat it.

From the pics you linked it looks like the outer tube is threaded on the inside? How else would it stay on.
Pictures are for illustration of a coaxial suppressor and a high grade K baffle.
A fixture that can hold either end of a K baffle flat to the milling table will work fine.
Stainless is a good material if you wish to take apart the suppressor and clean it. Without needing a finish you can't scrub off what you don't have. If you have your heart set on carbon tubes do it, I will support your decision.

You have a few choices in how you put this together. Each end cap is complex as many accurate machining steps are needed but each step is basic. The end cap requires three threaded surfaces that must be parallel and seats that must be square to the threads for the tubing. The best way is to machine it is in-situ. Then mandrel mount it to do the exterior and finish cuts. This first piece is the corner stone and will dictate the remaining build.
Questions
The only reason after 243 years the government now wants to disarm you is they intend to do something you would shoot them for!
http://www.silencertalk.com/forum/viewtopic.php?f=10&t=79895
milsurpcollector1970
Member
Posts: 22
Joined: Fri Sep 30, 2016 1:01 pm

Re: Some ? about building first form 1 can

Post by milsurpcollector1970 »

Makes sense,

Since im going to swap the can onto 3 different uppers I will need to make a mount that i can install on all 3 uppers. Any ideas for the internal threads for the endcap? My biggest caliber is 45acp

What set of threads on the endcap do i do first? Internal threads for installing it then part it off swap it around, install on a mandrel indicate it and cut the 2 external threads for the tubes
User avatar
Capt. Link.
Silent But Deadly
Posts: 2829
Joined: Wed Oct 17, 2007 9:05 pm
Location: USA.

Re: Some ? about building first form 1 can

Post by Capt. Link. »

milsurpcollector1970 wrote: Sun Jan 02, 2022 11:20 am Makes sense,

Since im going to swap the can onto 3 different uppers I will need to make a mount that i can install on all 3 uppers. Any ideas for the internal threads for the endcap? My biggest caliber is 45acp

What set of threads on the endcap do i do first? Internal threads for installing it then part it off swap it around, install on a mandrel indicate it and cut the 2 external threads for the tubes
The threads are 5/8x24 then two adapters for the 1/2x28 stuff.
The all of the end-caps threads are cut in-place from the inside,then swap it around with the mandrel for the outside cuts.
The only reason after 243 years the government now wants to disarm you is they intend to do something you would shoot them for!
http://www.silencertalk.com/forum/viewtopic.php?f=10&t=79895
milsurpcollector1970
Member
Posts: 22
Joined: Fri Sep 30, 2016 1:01 pm

Re: Some ? about building first form 1 can

Post by milsurpcollector1970 »

Got the stamp on Tuesday I’m buying stock on Monday

It’s my understanding that I will bore and thread the end cap and thread for the internal tube since I am building a coaxial
Post Reply