Critique my Neilson device

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
User avatar
McLarenross
Silent But Deadly
Posts: 550
Joined: Mon Aug 06, 2007 2:22 pm
Location: Temple TX

Critique my Neilson device

Post by McLarenross » Thu Jan 01, 2015 1:31 pm

Ive had my F1 sitting here for my 45 can for 2 months now while debating material choices. I wanted to use Titanium but Ive never machined Ti and its expensive. Were expecting a baby in a few weeks so my wife wouldnt let me spend $250 on Ti anyway. I had all the stainless needed except the tube so I just decided screw it and went for stainless throughout. Gonna be a little heavier but whats another 18oz when Im putting it on a 5" double stack 1911! lol. The Can will be 1.375 OD / 1.245 ID and ~8" long. I started yesterday by spinning the Neilson device. Here is the final product. The piston Im using is from an Octane/Osprey, the spring is from McMaster-Carr.

Image
Image
Image
Image

Im still torn on the baffles Im gonna use. I really like the CTA style baffles cause they keep the tube clean but I cant do the radius on the nose. I can fit 11 of the CTA baffles in the length though. TiRant style K baffles are my other option but I can only fit 6 in the length. The CTA baffles weigh about 0.50 oz each for a total of 5.5oz in the baffles. The TiRant baffles weigh 0.65oz each for a total of 4oz in the baffles. That extra 1.5oz probably isnt gonna be discernible in the hand but I think nearly 2 times the baffles will be discernible to the ear. Opinions?

Image
Image
There are no "ex-Marines", just Marines who arent active anymore.

Historian
Silent But Deadly
Posts: 3198
Joined: Mon Mar 29, 2010 11:37 pm

Re: Critique my Neilson device

Post by Historian » Thu Jan 01, 2015 2:03 pm

Sir, you surely do nice machining.

Impressive.

I am curious about the spring you are using. How
did you pick its K ( Happy HOOKER* :) ) spring constant? From the image it
looks beefy. If you have reference tables for the springs proper for
different calibers please post.


* Hooke's Law SPRUNG to mind. :)
[ "Doesn't that bloody Yank have any shame?" - UK 1968 ]

User avatar
McLarenross
Silent But Deadly
Posts: 550
Joined: Mon Aug 06, 2007 2:22 pm
Location: Temple TX

Re: Critique my Neilson device

Post by McLarenross » Thu Jan 01, 2015 2:19 pm

Thank you for the complements.

The spring is kinda an experiment in this. Very little information available on the spring weights used in the industry unfortunately. From what Ive seen though the spring needs to be fairly stiff. I choose a spring from McMaster that is 66lb/in and 1.5" long. We will see how it holds up.
There are no "ex-Marines", just Marines who arent active anymore.

User avatar
T-Rex
Silent But Deadly
Posts: 1723
Joined: Wed Oct 29, 2014 4:38 pm
Location: CT - The AntiConstitution State

Re: Critique my Neilson device

Post by T-Rex » Thu Jan 01, 2015 2:38 pm

Looks very professional.

If you remove put some milled cuts down the boosters long axis, you will add some volume to your blast chamber.

You could make your end cap like this
Image

and get rid of the need for a dis-assembly tool.
Obviously get rid of the internal threads.

Very nice work.
Completed Builds www.silencertalk.com/forum/viewtopic.php?t=79895
Burst Calculator www.engineersedge.com/calculators/pipe_bust_calc.htm
Silencer Porn www.instagram.com/explore/tags/silencerporn/

Hatchetjoe
Silent But Deadly
Posts: 179
Joined: Mon Jul 07, 2008 7:12 pm

Re: Critique my Neilson device

Post by Hatchetjoe » Thu Jan 01, 2015 3:02 pm

How are you keeping the piston from rotating? If the spring is too stiff the booster wont work, as long as you have other springs in the same size to fit your assembly and have different wire thicknesses you will be all set, at that weight I think you would need a lighter than industry standard. As for the baffles well that is up to you personally I think the Ti-rant K baffles are quieter to my ear, and BTW most of that stack is Al so lighter.

User avatar
Capt. Link.
Silent But Deadly
Posts: 2503
Joined: Wed Oct 17, 2007 10:05 pm
Location: USA.

Re: Critique my Neilson device

Post by Capt. Link. » Thu Jan 01, 2015 3:26 pm

Outstanding work.
You can place vents in the side to make it lighter and it should add to the suppression.
PM inbound for spring tuning tip.
Knowledge cast's out the shadows in one's own mind -CL

User avatar
john.t.little1
Silent But Deadly
Posts: 243
Joined: Thu Nov 24, 2011 2:13 pm
Location: florida/iraq

Re: Critique my Neilson device

Post by john.t.little1 » Thu Jan 01, 2015 4:00 pm

Looks ok send it to me for further testing and review :D
"A man is known by the silence he keeps. - Oliver Herford"
"Gunpowder, treason and plot. I see no reason why gunpowder, treason
Should ever be forgot..."

User avatar
McLarenross
Silent But Deadly
Posts: 550
Joined: Mon Aug 06, 2007 2:22 pm
Location: Temple TX

Re: Critique my Neilson device

Post by McLarenross » Thu Jan 01, 2015 7:07 pm

Thanks for the compliments guys.

Joe - the plan is to insert a set screw or pin from the front to index the piston with. I havent done it yet, cause I honestly had forgotten. It will be done before complete though.
There are no "ex-Marines", just Marines who arent active anymore.

User avatar
whiterussian1974
Silent But Deadly
Posts: 2678
Joined: Sun Sep 29, 2013 12:37 am
Location: On 8th line of eye chart.

Re: Critique my Neilson device

Post by whiterussian1974 » Thu Jan 01, 2015 11:17 pm

Can't really Critique it. But SURE Can PRAISE IT!!!
Beautiful work and highly efficient use of materials vs weight. :)
The Darkest Corners of Hell are reserved for those who remain Neutral!-Dante
The Death of One is a Tragedy, a million only a statistic.-Stalin
Well I AM 1/16 Demon on my Father's Side!-Dresden Files

User avatar
apd855
Member
Posts: 11
Joined: Sun Oct 21, 2012 11:16 pm

Re: Critique my Neilson device

Post by apd855 » Fri Jan 02, 2015 12:31 am

Should there be a rubber o-ring in the bore of the cap to prevent gases from leaking out?

User avatar
gunny50
Silent But Deadly
Posts: 784
Joined: Wed Jan 23, 2008 7:11 am
Location: EU

Re: Critique my Neilson device

Post by gunny50 » Fri Jan 02, 2015 8:12 am

apd855 wrote:Should there be a rubber o-ring in the bore of the cap to prevent gases from leaking out?

That is an option, Not all silencer manufacturers use one.
With a piston like the one used (SilencerCo Osprey / Octane as far as I can recall), with the cut along the cylindrical part it might not work, as it could cut the O ring fast.

Gunny

Historian
Silent But Deadly
Posts: 3198
Joined: Mon Mar 29, 2010 11:37 pm

Re: Critique my Neilson device

Post by Historian » Fri Jan 02, 2015 10:06 am

apd855 wrote:Should there be a rubber o-ring in the bore of the cap to prevent gases from leaking out?
You raise an interesting point in can design as there have
been some obscure ones with actual cuts strategically placed
to facilitate pressure reduction and in turn reduce report. As it was explained
" ... like puncturing a balloon with many pins simultaneously, hisses not blast.".

Again, masterful work.


Best.

User avatar
gunny50
Silent But Deadly
Posts: 784
Joined: Wed Jan 23, 2008 7:11 am
Location: EU

Re: Critique my Neilson device

Post by gunny50 » Fri Jan 02, 2015 10:55 am

gunny50 wrote:
apd855 wrote:Should there be a rubber o-ring in the bore of the cap to prevent gases from leaking out?

That is an option, Not all silencer manufacturers use one.
With a piston like the one used (SilencerCo Osprey / Octane as far as I can recall), with the cut along the cylindrical part it might not work, as it could cut the O ring fast.

Gunny

as used by me in the MK23 can as posted what back.

Image

Gunny

User avatar
L1A1Rocker
Silent But Deadly
Posts: 3578
Joined: Wed Feb 21, 2007 7:40 pm
Location: Texas Hill Country

Re: Critique my Neilson device

Post by L1A1Rocker » Fri Jan 02, 2015 5:15 pm

Very very nice.

User avatar
T-Rex
Silent But Deadly
Posts: 1723
Joined: Wed Oct 29, 2014 4:38 pm
Location: CT - The AntiConstitution State

Re: Critique my Neilson device

Post by T-Rex » Fri Jan 02, 2015 5:23 pm

gunny50 wrote:
apd855 wrote:Should there be a rubber o-ring in the bore of the cap to prevent gases from leaking out?

That is an option, Not all silencer manufacturers use one.
With a piston like the one used (SilencerCo Osprey / Octane as far as I can recall), with the cut along the cylindrical part it might not work, as it could cut the O ring fast.

Gunny
The Octane does use an o-ring inside the booster end cap.
But you are right to worry about the spring compression length and the milled cuts hitting the o-ring.


You could put the drill rods, from the removal tool, inside the booster assembly to index the piston and keep it from rotating.
Drill shallow holes around diameter of piston's "semi-circle/moon" cut-outs, cut short pieces of rod and tap into holes with drift punch.
Completed Builds www.silencertalk.com/forum/viewtopic.php?t=79895
Burst Calculator www.engineersedge.com/calculators/pipe_bust_calc.htm
Silencer Porn www.instagram.com/explore/tags/silencerporn/

User avatar
McLarenross
Silent But Deadly
Posts: 550
Joined: Mon Aug 06, 2007 2:22 pm
Location: Temple TX

Re: Critique my Neilson device

Post by McLarenross » Fri Jan 02, 2015 5:39 pm

Hmm I hadnt considered the gas seal at the piston. Never seen a piston endcap with an o-ring in it. I just cut the clearance in the cap to have about 0.0015 per side to facilitate free movement. With the lengthwise cuts in the piston Im not sure if an o-ring in the ID like Gunny showed would seal. I think Im gonna try it as is and if I have a lot of gas leakage I will put an o-ring groove in the ID of the endcap and install one. Thanks for pointing that out for me.
There are no "ex-Marines", just Marines who arent active anymore.

User avatar
Bendersquint
Industry Professional
Posts: 11359
Joined: Sat Jan 07, 2006 9:19 pm
Location: North Carolina
Contact:

Re: Critique my Neilson device

Post by Bendersquint » Sat Jan 03, 2015 4:27 am

McLarenross wrote:Hmm I hadnt considered the gas seal at the piston. Never seen a piston endcap with an o-ring in it. I just cut the clearance in the cap to have about 0.0015 per side to facilitate free movement. With the lengthwise cuts in the piston Im not sure if an o-ring in the ID like Gunny showed would seal. I think Im gonna try it as is and if I have a lot of gas leakage I will put an o-ring groove in the ID of the endcap and install one. Thanks for pointing that out for me.
Just about all piston endcaps have orings.

User avatar
oneindianrider
New Member
Posts: 8
Joined: Fri Jan 31, 2014 5:21 am
Location: Somewhere in a Cornfield in Ohio

Re: Critique my Neilson device

Post by oneindianrider » Sat Jan 03, 2015 8:39 am

BEAUTIFUL work
I am waiting on my first Form 1 and been looking for plans on making this for a pistol can Ill be making as soon as it gets approved so thanks for the great pictures! Keep us posted how it works please!!!

baba
Member
Posts: 22
Joined: Sat Dec 13, 2014 12:12 am

Re: Critique my Neilson device

Post by baba » Sat Jan 03, 2015 11:51 am

great work!

Would you mind posting general dimensions of that piston? I have been playing around in my cad program trying to draw up a booster of my own and i feel like I'm over doing it. I'm not looking to copy their design, just get an idea of the dims. Like the OD of the shaft and OD of the tines on the end.

Thanks,
Brian

User avatar
McLarenross
Silent But Deadly
Posts: 550
Joined: Mon Aug 06, 2007 2:22 pm
Location: Temple TX

Re: Critique my Neilson device

Post by McLarenross » Sun Jan 04, 2015 11:59 am

Sure. The Piston OD is 0.75" and overall length is 2". The OD of the flange at the front is 1.0" and it is 0.125" thick with 10 cuts through it that are 0.250" diameter each.
There are no "ex-Marines", just Marines who arent active anymore.

baba
Member
Posts: 22
Joined: Sat Dec 13, 2014 12:12 am

Re: Critique my Neilson device

Post by baba » Sun Jan 04, 2015 10:31 pm

Thanks!

Post Reply