How does it look (in progress)

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cdhknives
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How does it look (in progress)

Post by cdhknives »

I got the endcap, blast cone, and a couple (one shown) of baffles done over the weekend. Any comments that I need to fix before I get too far? Boring those cones, especially the internal, took some figuring out but seems to be coming together. I missed the step for the spacer on the blast cone...will have to do that later. It is 17-4PH but I'll still probably need to machine a disk to support the internals...the skirt is only about .035" thick and I can't run collets over 1/2" in my 3C collet chuck. I'll need to ream the bores to final dims too, but that will wait until they are all done, and then clipping the nose for the last operation. They fit the tube nicely...about .004" undersize.

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YHM Phantom 30 cal, 22lr form 1 build, 45 cal form 1 in progress
Atlas 10x36
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fishman
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Re: How does it look (in progress)

Post by fishman »

Instead of reaming the bores last, I recommend BORING the bores and doing it before you cut the cone off of the bar. This will guarantee that the OD of the cone is perfectly concentric with the bore holes.

It looks nice so far
300 blackout form 1: http://www.silencertalk.com/forum/viewtopic.php?f=10&t=137293

5.56 form 1:
http://www.silencertalk.com/forum/viewtopic.php?f=10&t=141800&p=955647#p955647
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John A.
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Re: How does it look (in progress)

Post by John A. »

A lot less time cutting them into sections too.
I don't care what your chart says
cdhknives
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Re: How does it look (in progress)

Post by cdhknives »

I didn't think I could control the bore that deep in the cone. I am already having a heck of a time with bit positioning getting the internal cone cut. I don't see a good way with my tooling and skill level to know when the bit makes contact to start measuring the amount of metal removed. I am really tempted to part off the skirts and make the rest of them 2 piece for just that reason. Opening up a 1/4" hole a small but controlled amount an inch deep...intimidating at my skill level. I've done similar with a ground down 3/16" HSS bit but that was at the surface. I'll try on my next one...we'll see if I can get it sharp enough to prevent flex/chatter from being a problem.
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fishman
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Re: How does it look (in progress)

Post by fishman »

I personally don't cut my cones and spacers as one piece. This saves me time, tool wear, and material cost.

I recommend grinding a custom tool if you want to bore a 1/4 hole that deep. You can use a solid HSS 1/2" boring bar and grind the tip of it down to 1/4" wide. It will be as rigid as a 1/2" bar but can cut a shallow 1/4" hole.

Alternatively, you could make your spacer and cone one piece but make the spacer behind the cone, not in front of it. You'd need to make or buy a special face grooving tool.
300 blackout form 1: http://www.silencertalk.com/forum/viewtopic.php?f=10&t=137293

5.56 form 1:
http://www.silencertalk.com/forum/viewtopic.php?f=10&t=141800&p=955647#p955647
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Re: How does it look (in progress)

Post by ECCO Machine »

cdhknives wrote: I missed the step for the spacer on the blast cone...will have to do that later. It is 17-4PH but I'll still probably need to machine a disk to support the internals...the skirt is only about .035" thick and I can't run collets over 1/2" in my 3C collet chuck.
It'll be fine. I put much thinner walled cones in a 3 jaw. Just chuck it as deep as you can and take light passes so you don't pull it out of the chuck.
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Re: How does it look (in progress)

Post by ECCO Machine »

I filmed this today, might be helpful for you regarding order of operations. The process would be similar for a skirted cone.

Apologies for the machine noise, it's kinda loud with the 3600 RPM motor

https://www.youtube.com/watch?v=h5v8Gj- ... e=youtu.be
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cdhknives
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Re: How does it look (in progress)

Post by cdhknives »

Thanks for that! Your order is not terribly different (I use the tailstock instead of a drill holder in the QCTP) from what I am doing, though your machines are much bigger (your 10 minutes takes me half an hour once things are set up) and your 3 jaw must run a lot truer than mine. I don't trust it for operations requiring this level of concentricity so I have to dial in the 4 jaw all the time unless I turn everything at once before parting off the bar.
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Atlas 10x36
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Re: How does it look (in progress)

Post by ECCO Machine »

cdhknives wrote:I use the tailstock instead of a drill holder in the QCTP
The QCTP MT holders are worth their weight in gold. I use the tailstock when boring with drills over 1", but otherwise always the QCTP.
cdhknives wrote:though your machines are much bigger (your 10 minutes takes me half an hour once things are set up) and your 3 jaw must run a lot truer than mine. I don't trust it for operations requiring this level of concentricity so I have to dial in the 4 jaw all the time unless I turn everything at once before parting off the bar.
Yes, material removal goes much faster on that 17x60 than your (appears to be) 10" Atlas machine.

The 3 jaw on my little 618 runs amazingly true, only .0003" to .0005" runout outside clamping and .0008" to .0010 inside clamping. You can true your chuck, though, if it has a removable backing plate. If it's a quality chuck in good condition, the scroll should be pretty consistent over a range of diameters, but dial in your runout with the size of stock you turn most frequently.

I do run 4 jaw on the big lathe most of the time, since I'm regularly threading 36 pitch with wall thickness of only .035". Where baffles are concerned, though, being off by a couple thou OD to bore concentricity or having minor thickness variation from one side of the cone or skirt to the other is inconsequential.
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Re: How does it look (in progress)

Post by Historian »

Compliments on great tutorial. Thank you for
inviting us into your workshop to admire and learn
from your skills.

"The 3 jaw on my little 618 runs amazingly true, only .0003" to .0005" runout
outside clamping and .0008" to .0010 inside clamping."

As with you I have found my 'door-stop' Atlas 618 to have amazing
capabilities in spite of its size.

For true running, as measured with DTI, I upgraded my ER25 collet system
to ER40 which allows clamping over 1" rod. Found a NOS lathe bed which I shall
be installing to get accuracy I shall never really be worthy of. You understand
it is a 'guy thing' to do. Much like never coming near to the accuracy achievable
with NM .45 or M41. But, it is fun anyway.

Admiration.


Best.
cdhknives
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Re: How does it look (in progress)

Post by cdhknives »

I ended up butchering the previous tube...and took y'all advice on thinner tubing so the baffles were toast too. Good thing, I am getting better each time! This time I got the tube finished before starting baffles...

Image
Image
YHM Phantom 30 cal, 22lr form 1 build, 45 cal form 1 in progress
Atlas 10x36
Historian
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Re: How does it look (in progress)

Post by Historian »

Photo shows nice, clean, single point threading.

Compliments.

With HPA lying 'comatose' your post is
a pleasant visual lagniappe*
keeping our interest alive.


* (Thank you Louisiana French for great word )
cdhknives
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Re: How does it look (in progress)

Post by cdhknives »

I got the whole family together for a picture...just don't take the micrometer to those cones! Yes I intend to have some variable geometry...longer spacing nearer the blast chamber progressing to closer spacing near the exit. The spacers are all interchangable of course, so that can be adjusted.

Image

The stack is a bit long, only 8 baffles fit instead of the 9 expected. Now I decide if I shorten the spacers or live with 8. Tube is engraved (electroetched actually) so the only things left are final fit (including clips to cone nose) and cerakote. I so badly want to go see how it sounds...but need to finish fit up just to be safe.
YHM Phantom 30 cal, 22lr form 1 build, 45 cal form 1 in progress
Atlas 10x36
cdhknives
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Re: How does it look (in progress)

Post by cdhknives »

3-3/4 Oz all up. Needs a range test...LOL
YHM Phantom 30 cal, 22lr form 1 build, 45 cal form 1 in progress
Atlas 10x36
cdhknives
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Re: How does it look (in progress)

Post by cdhknives »

First range trip. Sorry, no vid, need to get a better camera. Using a Ruger American bolt action rifle and subsonic ammo this thing is truly 'firing pin is loud' quiet. All I can hear is the firing pin snap and the bullet hitting the target. I'm sure there is a bit of a puff from the side, but at the shooter's ear the firing pin is the loudest noise! That sure adds to the satisfaction of 'rolling my own'!!!! :D :D :D
YHM Phantom 30 cal, 22lr form 1 build, 45 cal form 1 in progress
Atlas 10x36
Paco664
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Re: How does it look (in progress)

Post by Paco664 »

awesome congrats...
ant3000
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Re: How does it look (in progress)

Post by ant3000 »

Yeah this looks great man. Good work on the lathe too.
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Re: How does it look (in progress)

Post by mcrump »

If you have access to a milling machine and a rotary table you might want to consider the undercut as shown in the photo. Ignore the integrated muzzle brake as this build is for a 17 hornet/hmr. You can do the cut on the lathe but when I tried plunging this deep chatter always gave me a fit. I used a 3/16" ball end mill for this cap .187 deep. Not only will you get a little better performance but keep the mantra "Mind the grams and the ounces will take care of themselves" in mind.

[url=https://ibb.co/ioej1U][img]https:/ ... .jpg[/img][/url]
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Re: How does it look (in progress)

Post by fishman »

Or just drill blind holes in the cap
300 blackout form 1: http://www.silencertalk.com/forum/viewtopic.php?f=10&t=137293

5.56 form 1:
http://www.silencertalk.com/forum/viewtopic.php?f=10&t=141800&p=955647#p955647
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