Stepped Baffles versus Cones

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
Historian
Silent But Deadly
Posts: 3233
Joined: Mon Mar 29, 2010 11:37 pm

Stepped Baffles versus Cones

Post by Historian » Thu Dec 19, 2019 12:33 pm

Last week after a match topic arose if the extra
effort some put into making stepped baffles
is measurably better than just straight cones.

First WAG would be that extra turbulence
induced should ... a weighted 'should' ....
cause a measurable sound reduction.

Any gray beards here have some technical
data?


Merry Christmas and Happy New Year to all.

User avatar
John A.
Silent But Deadly
Posts: 1123
Joined: Sun Dec 09, 2007 4:55 pm

Re: Stepped Baffles versus Cones

Post by John A. » Thu Dec 19, 2019 2:05 pm

I used double spring valve retainers in my first can if that qualifies as a step baffle in your discussion.

It sounds good.

It has held up well.

It is heavier than it needs to be :lol:
I don't care what your chart says

User avatar
Capt. Link.
Silent But Deadly
Posts: 2526
Joined: Wed Oct 17, 2007 10:05 pm
Location: USA.

Re: Stepped Baffles versus Cones

Post by Capt. Link. » Thu Dec 19, 2019 3:32 pm

Yes the stepped cone is better in terms of db numbers over the straight cone....without porting ! Clipping and or base porting is almost a new science and will alter performance of either baffle. I have been told that steps are best for high velocity ,my studies show they also work well for low pressure.

Without CNC ,stamping,casting or hydro-forming these are a pain in the ass to build with steps interior/ exterior but it may be worthwhile.A design/build dating back to 1983 used steps only on the interior surfaces featuring a very low volume ,Its is still Hollywood quiet.Fully formed step baffles that use space more efficiently should also have higher db losses than this 1983 design.
-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!

ECCO Machine
Silent But Deadly
Posts: 571
Joined: Tue Nov 28, 2017 7:34 pm

Re: Stepped Baffles versus Cones

Post by ECCO Machine » Thu Dec 19, 2019 10:04 pm

I use them in some models & builds. Not exclusively, though, because:
Historian wrote:
Thu Dec 19, 2019 12:33 pm
First WAG would be that extra turbulence
induced should ... a weighted 'should' ....
cause a measurable sound reduction.
It's more complicated than that. If they worked better than smooth baffles across the board, everyone would use them in everything. They may cause more turbulence on their profile, but that's no necessarily going to help with suppression, and could work against you. Smooth cones peel high pressure gasses off the centerline better.

It is my experience that they can work well when use in conjuction with other types, namely smooth conical baffles. I've had the most success with externally stepped cones using them as the second and third baffle. My Five By Five is that way, and I recently did a 1.6 x 6.5 .30 cal in a similar fashion. I wouldn't exactly call it quiet, but it's a .30 can the same size as the YHM Turbo (OK, OK, it has 0.040" larger diameter...) that didn't snap my ears on a semi auto .308 with a 13" barrel

Image

Image

Image
FFL07/02SOT Gunsmith & Machinist

Historian
Silent But Deadly
Posts: 3233
Joined: Mon Mar 29, 2010 11:37 pm

Re: Stepped Baffles versus Cones

Post by Historian » Fri Dec 20, 2019 8:24 pm

John A., Good Captain, and ECCO, your knowledge and guidance is a refreshing Christmas ( not Holiday :) )
present of knowledge.

My admiration for all of you is again ineffable!

ECCO,your machining talent is true eye-candy.
It took me a few seconds to process your inspiring
machining/design skills. Standing O, my friend.

When I look at my lovable 'door-stop' Atlas 618 lathe
and imagining your +5 Sigma lathe
I feel like Toad in Wind in The Willows, wide eyed at
seeing a Bentley and dreaming of driving one. :)

<< https://bookpalace.com/acatalog/info_RE0301.html >>

Many thanks to all for the replies from folks I hold
in the highest esteem.

ECCO Machine
Silent But Deadly
Posts: 571
Joined: Tue Nov 28, 2017 7:34 pm

Re: Stepped Baffles versus Cones

Post by ECCO Machine » Fri Dec 20, 2019 8:39 pm

Historian wrote:
Fri Dec 20, 2019 8:24 pm
When I look at my lovable 'door-stop' Atlas 618 lathe
and imagining your +5 Sigma lathe
I use the piss out of my little 618 for secondary ops. Finish boring on baffles & caps, filing/sanding/polishing, thread filing, chamfering, other things that are too laborious or not as well suited to the big machine with it's 13" 4 jaw. My Hardinge HCT would be good for that stuff if it had a smaller 3 jaw, but it's used almost exclusively for barrel work these days.

Nearly every part I make for suppressors gets chucked up on the 618 at least once.

I went through it when I first picked it up, have added Z axis DRO, Z axis power feed and made an oversize compound wheel. Other than that, just the AXA QCTP and the 5" 3 jaw I trued to the spindle. The little English made 4" 3 jaw was a decent chuck, but just didn't have enough clamping force, kept flinging parts. The heavier 5" also reduces chatter.

Image

This is, of course, the workhorse machine, which I recently switched from a 3 HP motor to a 5 HP.

Image
FFL07/02SOT Gunsmith & Machinist

Historian
Silent But Deadly
Posts: 3233
Joined: Mon Mar 29, 2010 11:37 pm

Re: Stepped Baffles versus Cones

Post by Historian » Sat Dec 21, 2019 10:37 am

ECCO, many thanks for the eye-popping images of your dream
shop! What a lovely visual Christmas gift you have given.

I so enjoyed your "..Nearly every part I make for suppressors gets chucked up on the 618 at least once. .."

When I first bought my 618 from my friend's widow many-years ago
I set out to get a back up (..old habits die hard be they tools, PPK back up,
small Randall, etc. :) :) ).

From eBay I built another 618 from NOS parts: lathe bed, head stock, etc. Cherry, as
we 'delinquent' hot-rodders in the 1950s called our engine builds.

Of course I had to have 2 milling attachments, one which I modified to hold
a machinist's vise.

Got a set of ER25 metric collets after which I added 2MT ER40 chuck and collets
that can hold up to 1"+ stock.

Like my hero Barry Goldwater, extremism in a man's purchasing of tools is no vice!
And moderation in buying the best tools and weapons is no virtue. :)

"“I would remind you that extremism in the defense of liberty is no vice!
And let me remind you also that moderation in the pursuit of justice is no virtue!

― Barry Goldwater

Again, thank you for the the eye-candy, my friend.

Matt in TN
Silent Operator
Posts: 59
Joined: Tue Jun 09, 2015 10:11 am

Re: Stepped Baffles versus Cones

Post by Matt in TN » Sat Dec 21, 2019 9:02 pm

ECCO Machine wrote:
Fri Dec 20, 2019 8:39 pm
... the 5" 3 jaw I trued to the spindle.
Can you expand on this a little? How did you do this, and how repeatable are the results? 0.010" tolerance, or 0.001" tolerance?

It never occurred to me that this was even possible!

#40Fan
Silent But Deadly
Posts: 182
Joined: Tue Nov 20, 2018 6:41 pm

Re: Stepped Baffles versus Cones

Post by #40Fan » Sat Dec 21, 2019 9:29 pm

Matt in TN wrote:
Sat Dec 21, 2019 9:02 pm
ECCO Machine wrote:
Fri Dec 20, 2019 8:39 pm
... the 5" 3 jaw I trued to the spindle.
Can you expand on this a little? How did you do this, and how repeatable are the results? 0.010" tolerance, or 0.001" tolerance?

It never occurred to me that this was even possible!
Youtube chuck grinding.

Historian
Silent But Deadly
Posts: 3233
Joined: Mon Mar 29, 2010 11:37 pm

Re: Stepped Baffles versus Cones

Post by Historian » Sun Dec 22, 2019 12:01 pm

Addendum: I upgraded my QCTP set to OXA* from AXA. They are steel and
not Aluminum. Put latter on back-up NOS Atlas 618 I assembled.



* <<https://littlemachineshop.com/products/ ... &category= >>

ECCO Machine
Silent But Deadly
Posts: 571
Joined: Tue Nov 28, 2017 7:34 pm

Re: Stepped Baffles versus Cones

Post by ECCO Machine » Sun Dec 22, 2019 12:21 pm

Historian wrote:
Sun Dec 22, 2019 12:01 pm
Addendum: I upgraded my QCTP set to OXA* from AXA. They are steel and
not Aluminum. Put latter on back-up NOS Atlas 618 I assembled.



* <<https://littlemachineshop.com/products/ ... &category= >>
I've never seen an aluminum AXA post. Are you thinking of those really small ones like this?: https://www.amazon.com/JWGJW-Tooling-Pa ... Caps%2C201

AXA is the size I have on my 618. It's larger than OXA, and really a bit big for the 618.
FFL07/02SOT Gunsmith & Machinist

#40Fan
Silent But Deadly
Posts: 182
Joined: Tue Nov 20, 2018 6:41 pm

Re: Stepped Baffles versus Cones

Post by #40Fan » Sun Dec 22, 2019 8:14 pm

The aluminum ones are essentially an OXA. I had one on my HF mini lathe and even that tiny lathe tore that aluminum POS up. The metal OXA is a perfect fit for it.

On my slightly bigger lathe (8x16) I have an AXA. Just a hair too big for it, but the OXA would be too small for me, so I had to trim the holders to get the tooling to sit low enough.

Post Reply