User Panel
Posted: 8/29/2023 8:03:08 AM EDT
[Last Edit: jreinke]
Title says it all folks! I'm looking for 1.25" & 1.5" both with 0.083" walls.
|
|
|
That's a tall order. Have you tried McMaster-Carr?
|
|
|
I don't think you're going to find that, the hardening process is going to distort the fuck out of the long axis of the tubing.
|
|
|
You're most likely not going to find it. You can keep looking, but I'd focus on someone boring it for you.
Originally Posted By bgenlvtex: I don't think you're going to find that, the hardening process is going to distort the fuck out of the long axis of the tubing. View Quote No, it's a thing, runs are just typically reserved for special orders. This is not a stock item. |
|
|
So what you guys are telling me is that if I want a stainless tube, I'm stuck with either 304 or 316?
|
|
|
Originally Posted By jreinke: So what you guys are telling me is that if I want a stainless tube, I'm stuck with either 304 or 316? View Quote No, you can absolutely have someone bore round bar for you. You can call steel distributors and see if they happen to have a small stock of 17-4. Possibly, from an overrun, failed payment, etc. There are many other grades of SS that are used for tubing. You're just not likely to find them laying on a shelf somewhere, though. |
|
|
Originally Posted By jreinke: So what you guys are telling me is that if I want a stainless tube, I'm stuck with either 304 or 316? View Quote 17-4 isn't the problem, precipitation hardened is the problem 1.625" 17-4 round bar Any good machine shop can make your tubing out of this, but it won't be hardened |
|
|
I have the capability to bore out my own tube from barstock, I just didn't want to go through all the ass pain. I wouldn't think heat treatment would be necesarry for 9mm/subsonic 300 Blackout.
|
|
|
Originally Posted By jreinke: I have the capability to bore out my own tube from barstock, I just didn't want to go through all the ass pain. I wouldn't think heat treatment would be necesarry for 9mm/subsonic 300 Blackout. View Quote But that is what you are asking for, 17-4 (the alloy) PH (precipitation hardened) You can order any cut length you want of 17-4 rod/bar at the link above, I don't know where you would get 17-4 tubing |
|
|
Originally Posted By bgenlvtex:But that is what you are asking for, 17-4 (the alloy) PH (precipitation hardened) View Quote Not necessarilly. I do understand what you mean, though. However, even Cond-A is still considered 17-4PH. Although, it's not hardened, precipitation or otherwise. Regardless, there shouldn't be any issue throwing it into your oven @900F for a little over an hour. I've never bored a tube, but have made several large pieces and was never impacted w/ a dimensional change from hardening. The CTE is quite low. |
|
|
Would two hours be too long, that's the shortest cleaning cycle on my oven?
Never mind I read the manual, I can cancel the cleaning cycle manually. |
|
|
Originally Posted By jreinke: Would two hours be too long, that's the shortest cleaning cycle on my oven? Never mind I read the manual, I can cancel the cleaning cycle manually. View Quote The hour starts after the part(s) reach 900F. You should be able to cancel it at any time, with a stop or cancel button on the control board. |
|
|
Thanks
|
|
|
Originally Posted By jreinke: I have the capability to bore out my own tube from barstock, I just didn't want to go through all the ass pain. I wouldn't think heat treatment would be necesarry for 9mm/subsonic 300 Blackout. View Quote Aluminum is fine for 9mm/ subsonic 300 blackout, so why worry about the specific grade at all? |
|
|
Originally Posted By jreinke: I have the capability to bore out my own tube from barstock, I just didn't want to go through all the ass pain. I wouldn't think heat treatment would be necesarry for 9mm/subsonic 300 Blackout. View Quote Not sure if you’ve cut 17-4 before on your lathe but it really pretty nice to work with. Nicer than 416 IMO. No matter what I do to it the finish is great. Boring is a pain but it won’t take you that long. Upside is you can machine whatever steps or integral spacer you want as well. And it will be straight, which tube rarely is. |
|
|
Originally Posted By jreinke: Title says it all folks! I'm looking for 1.25" & 1.5" both with 0.083" walls. View Quote I have looked for 17-4 tubing in the past. Contacted every vendor I could find that lists 17-4 tubing and no one sells small quantities. Maybe you will get lucky. Your spec for 0.083" wall is excessive for a magnum rifle cartridge. 17-4 H900 has >3x the yield strength of 300 series SS and maintains its strength better at high temperatures than 300 SS. A 0.035" wall tube of 17-4 H900 would be equivalent to at least 0.100 wall 316 SS. Most rifle cans that use 316 run 0.065" walls. For a pistol can 17-4 is overkill. Use 300 series SS if you want corrosion resistance or Titanium if low weight is your goal |
|
|
Originally Posted By BASE: Not sure if you’ve cut 17-4 before on your lathe but it really pretty nice to work with. Nicer than 416 IMO. No matter what I do to it the finish is great. Boring is a pain but it won’t take you that long. Upside is you can machine whatever steps or integral spacer you want as well. And it will be straight, which tube rarely is. View Quote View All Quotes View All Quotes Originally Posted By BASE: Originally Posted By jreinke: I have the capability to bore out my own tube from barstock, I just didn't want to go through all the ass pain. I wouldn't think heat treatment would be necesarry for 9mm/subsonic 300 Blackout. Not sure if you’ve cut 17-4 before on your lathe but it really pretty nice to work with. Nicer than 416 IMO. No matter what I do to it the finish is great. Boring is a pain but it won’t take you that long. Upside is you can machine whatever steps or integral spacer you want as well. And it will be straight, which tube rarely is. I've worked for a couple companies (including current employer) where the machinists machine 17-4PH in condition H900. Despite its hardness (low-mid 40s HRC) it cuts quite well. My buddy says you can definitely feel the difference when you're turning handles on a lathe. Even in Condition A it is not soft - it's in the 30s rockwell. |
|
|
17-4 tube can be had, but it's a special mill run with minimum quantities, so you'll buy several hundred feet, and it'll be 3x the price of round bar by weight. Even for those of us who need quite a bit it's not worth it.
Originally Posted By brownbomber: I've worked for a couple companies (including current employer) where the machinists machine 17-4PH in condition H900. Despite its hardness (low-mid 40s HRC) it cuts quite well. My buddy says you can definitely feel the difference when you're turning handles on a lathe. View Quote 100%. You also see it in the axis load indicators on a CNC. And H900 condition will eat tooling about twice as fast as annealed or H1150, comparable to titanium. The beauty of 630 series is the low temperature heat treat means it won't scale if treated in atmosphere and it's extremely stable: very, very little distortion. If you had a part that just barely went annealed, it might not after heat treat, but it's nothing like the distortion and growth we see with 400 series alloys or medium and high carbon steels. I can make a plug gauge from 17-4 and heat treat, be within .0003" of the annealed measurement. With 440C, it can change by 10 times that (and warp), so we have to hard turn critical dimensions, which is a motherf*er with low 60s Rc hardness. As in, I have trashed 2-3 edges of Kennametal carbide threading inserts on a SINGLE gauge. Of course, 17-4 h900 in that role is very limited use, won't hold up like full hard 440C or other tool steels. |
|
Suppress all the things!
|
We machine the tube housings out of solid bar stock.
They are pretty tough though. In a recent test a foreign government ran them ten times to 1850-1900f and burned the cerakote off the tube of an HRT can without bulging the tube. Its not a cost reduced process like putting a piece of tube on a rear mount. It should be cut annealed and then heat treated. There is almost no size change for 17-4, so to machine it H900 would be really dumb. I’ve seen people machine it H900, it sounds like they are cutting ceramic. Clicks and end mills cutting with a loud hard click on every contacting tooth, indicate a lot of process difficulty. Its an ugly sound to hear 17-4 get cut in H900. |
|
Austin, Managing Partner - www.GriffinArmament.com
|
Duplex stainless might be an option.
|
|
|
Austin, Managing Partner - www.GriffinArmament.com
|
Originally Posted By Green0: 17-4 is essentially in the duplex family of alloys. That is what they call alloyed stronger stainless steels in Europe and Australia. View Quote View All Quotes View All Quotes |
|
|
Originally Posted By Green0: We machine the tube housings out of solid bar stock. They are pretty tough though. In a recent test a foreign government ran them ten times to 1850-1900f and burned the cerakote off the tube of an HRT can without bulging the tube. Its not a cost reduced process like putting a piece of tube on a rear mount. It should be cut annealed and then heat treated. There is almost no size change for 17-4, so to machine it H900 would be really dumb. I’ve seen people machine it H900, it sounds like they are cutting ceramic. Clicks and end mills cutting with a loud hard click on every contacting tooth, indicate a lot of process difficulty. It’s an ugly sound to hear 17-4 get cut in H900. View Quote I’m guessing that was a conservatively high temp for testing purposes? I’m curious what a reasonable temp for a hard use sbr suppressor would be. I always forget to bring along an IR thermometer when I’m abusing mine. |
|
|
Originally Posted By BASE: I’m guessing that was a conservatively high temp for testing purposes? I’m curious what a reasonable temp for a hard use sbr suppressor would be. I always forget to bring along an IR thermometer when I’m abusing mine. View Quote Without full auto, around 1000°F, maybe up to 1,200 for really spirited shooting with multiple mags. That'd be for very brief periods, though. Cans stay too hot to touch for a good while, but thin parts will drop from those very high temps quite quickly once the heat input ceases. |
|
Suppress all the things!
|
Originally Posted By ECCO_Machine: Without full auto, around 1000°F, maybe up to 1,200 for really spirited shooting with multiple mags. That'd be for very brief periods, though. Cans stay too hot to touch for a good while, but thin parts will drop from those very high temps quite quickly once the heat input ceases. View Quote If the tube is at 1000oF the tip of the blast baffle is much hotter and consequently softer promoting erosion. Many expect their can to be fully usable while glowing red hot. With the possible exception of belt fed machine guns this is an unreasonable expectation in my opinion. The rate of fire required to heat a can to incandescence will quickly wear out the barrel and is really just a stunt. I understand the cool factor in doing this but making a can that can take that abuse cost more and is heavier that 99% of users will ever need. Just my 2 cents. |
|
|
Originally Posted By ECCO_Machine: Without full auto, around 1000°F, maybe up to 1,200 for really spirited shooting with multiple mags. That'd be for very brief periods, though. Cans stay too hot to touch for a good while, but thin parts will drop from those very high temps quite quickly once the heat input ceases. View Quote Thanks, that gives me a good starting point anyway. I didn't want to derail this thread too far but those numbers caught my eye. I've been looking at some of the materials elevated temp strength and heat treat requirements but really wasn't sure what was a reasonable assumption there. |
|
|
Originally Posted By BASE: Thanks, that gives me a good starting point anyway. I didn't want to derail this thread too far but those numbers caught my eye. I've been looking at some of the materials elevated temp strength and heat treat requirements but really wasn't sure what was a reasonable assumption there. View Quote 17-4, Inconel 718 and cobalt-6 all have similar strengths at elevated temps, though Stellite tensile strengh is well below the other 2 at lower temps. 17-4 actually has a higher melting point than Inconel or Stellite, but it's not as abrasion resistant in the 800-1,200° range, which is why the superalloys will fare a little better when run that hard, particularly with open tine flash hiders. But they'll still suffer, we see no shortage of badle eroded Inconel baffles in AAC cans that were run hard with flash hider muzzle devices. That's why I always recommend a muzzle brake muzzle device with short barrels, regardless of baffle material. One of these days I'm going to figure out how to get tungsten carbide tips on baffles, been a goal of mine for some time. But there are many hurdles to incorporating this super hard material that can withstand extreme temperatures but which is also very brittle and not weldable. |
|
Suppress all the things!
|
Originally Posted By ECCO_Machine: 17-4, Inconel 718 and cobalt-6 all have similar strengths at elevated temps, though Stellite tensile strengh is well below the other 2 at lower temps. 17-4 actually has a higher melting point than Inconel or Stellite, but it's not as abrasion resistant in the 800-1,200° range, which is why the superalloys will fare a little better when run that hard, particularly with open tine flash hiders. But they'll still suffer, we see no shortage of badle eroded Inconel baffles in AAC cans that were run hard with flash hider muzzle devices. That's why I always recommend a muzzle brake muzzle device with short barrels, regardless of baffle material. One of these days I'm going to figure out how to get tungsten carbide tips on baffles, been a goal of mine for some time. But there are many hurdles to incorporating this super hard material that can withstand extreme temperatures but which is also very brittle and not weldable. View Quote That is a neat idea. I guess a thermal spray coating wouldn't be thick enough? That might not be feasible for low volume parts either I guess. I'm pretty good at embedding tiny chunks of carbide into holes... |
|
|
Originally Posted By ECCO_Machine: One of these days I'm going to figure out how to get tungsten carbide tips on baffles, been a goal of mine for some time. But there are many hurdles to incorporating this super hard material that can withstand extreme temperatures but which is also very brittle and not weldable. View Quote I have thought about using HSS (M2) for the blast baffle. It's machinable in the annealed state and if you harden then temp it back to Rc~58 or so it wont be too brittle. I once used T15 HSS "washers" on a 3 chamber muzzle brake. This was used for a 223 rifle and they have zero ware after many rounds. I had the washers made by Arthur R. Warner . |
|
|
Originally Posted By BASE: That is a neat idea. I guess a thermal spray coating wouldn't be thick enough? That might not be feasible for low volume parts either I guess. I'm pretty good at embedding tiny chunks of carbide into holes... View Quote View All Quotes View All Quotes Originally Posted By BASE: That is a neat idea. I guess a thermal spray coating wouldn't be thick enough? That might not be feasible for low volume parts either I guess. I'm pretty good at embedding tiny chunks of carbide into holes... The issue would be substrate deformation and thermal expansion/contraction fracturing the coating and breaking the bond. Same reason ceramic coating doesn't work in this application. The inside of a suppressor is just a very violent environment! Originally Posted By Rich_V: I have thought about using HSS (M2) for the blast baffle. It's machinable in the annealed state and if you harden then temp it back to Rc~58 or so it wont be too brittle. I once used T15 HSS "washers" on a 3 chamber muzzle brake. This was used for a 223 rifle and they have zero ware after many rounds. I had the washers made by Arthur R. Warner . The trouble with tool steels is that the wonderful properties they exhibit go away at high temps. I've experimented with 440C baffles; they're very hard, but the working range is below 500°F. At 1,000°, the material is softer, more brittle and less corrosion resistant. I've also used 422 stainless, which is actually a great choice for baffles, but there are two things that make it challenging: 1, weldability is not great, and it needs annealed and re-treated afterward. Thats tough to do with an assembled suppressor. 2, availability. It sucks, period, and when I do find it, it's usually tempered, so I'd have to anneal before machining unless I want to really destroy tooling with a tough, 50 Rc material. |
|
Suppress all the things!
|
Originally Posted By ECCO_Machine: The trouble with tool steels is that the wonderful properties they exhibit go away at high temps. I've experimented with 440C baffles; they're very hard, but the working range is below 500°F. At 1,000°, the material is softer, more brittle and less corrosion resistant. I've also used 422 stainless, which is actually a great choice for baffles, but there are two things that make it challenging: 1, weldability is not great, and it needs annealed and re-treated afterward. Thats tough to do with an assembled suppressor. 2, availability. It sucks, period, and when I do find it, it's usually tempered, so I'd have to anneal before machining unless I want to really destroy tooling with a tough, 50 Rc material. View Quote I think you read my post incorrectly. I was referring to high speed tool steel, i.e. M2 used for endmills, drills etc. not typical tool steels like D2 A1 etc. |
|
|
From what Ive heard and what is on the website, XRT is going to have 17-4 tubes available soon...
|
|
|
Originally Posted By ECCO_Machine: One of these days I'm going to figure out how to get tungsten carbide tips on baffles, been a goal of mine for some time. But there are many hurdles to incorporating this super hard material that can withstand extreme temperatures but which is also very brittle and not weldable. View Quote |
|
Critical thinking is dead.
|
Sign up for the ARFCOM weekly newsletter and be entered to win a free ARFCOM membership. One new winner* is announced every week!
You will receive an email every Friday morning featuring the latest chatter from the hottest topics, breaking news surrounding legislation, as well as exclusive deals only available to ARFCOM email subscribers.
AR15.COM is the world's largest firearm community and is a gathering place for firearm enthusiasts of all types.
From hunters and military members, to competition shooters and general firearm enthusiasts, we welcome anyone who values and respects the way of the firearm.
Subscribe to our monthly Newsletter to receive firearm news, product discounts from your favorite Industry Partners, and more.
Copyright © 1996-2024 AR15.COM LLC. All Rights Reserved.
Any use of this content without express written consent is prohibited.
AR15.Com reserves the right to overwrite or replace any affiliate, commercial, or monetizable links, posted by users, with our own.