Drilling Misshap

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

cdakers
Member
Posts: 40
Joined: Fri Mar 27, 2015 1:56 pm

Re: Drilling Misshap

Post by cdakers » Wed Aug 23, 2017 5:25 pm

Historian wrote:
cdakers wrote:
Historian wrote:If you don't have a drill doctor, buy one.
What model did you purchase? I've been wanting/needing one, but have heard mixed reviews on the some of the lower end models.

"Drill Doctor® Model 750X Bit Sharpener, 3/32" to ¾""

This model covers full range of drills. I also purchased a spare diamond wheel as
back up ... always have a back up.

Just used it again yesterday prior to drill in SS + Castroil Moly.
'Like cutting butter' :)

Best
Thanks Historian, I'll give that model a go. I've got so many dull bits I could probably spend a weekend getting them all back in working order.

User avatar
yondering
Silent But Deadly
Posts: 364
Joined: Thu Aug 02, 2007 12:22 pm
Location: NW Wa. state

Re: Drilling Misshap

Post by yondering » Wed Aug 23, 2017 8:43 pm

T-Rex wrote:This is my Drill Dr :lol:
I sharpen mine by hand on the bench grinder too, although I don't even have one of those guides. I'm good down to ~3/16", smaller than that gets tricky for me to sharpen by hand.

User avatar
T-Rex
Silent But Deadly
Posts: 1718
Joined: Wed Oct 29, 2014 4:38 pm
Location: CT - The AntiConstitution State

Re: Drilling Misshap

Post by T-Rex » Wed Aug 23, 2017 11:57 pm

yondering wrote: I'm good down to ~3/16", smaller than that gets tricky for me to sharpen by hand.
For the Lil guys, I put them in a small vise. It has a V notch that runs horizontal, down the center of the jaws. Lock the bit with a cutting edge about level. Place the point gauge on the bench, under the bit, and align by eye. Then, use a myriad of stone and ceramic blocks to sharpen the bit, whilst keeping them lined up with the gauge. Not too bad cause the little ones usually need but a few passes.
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/

policetruck
Member
Posts: 34
Joined: Thu Apr 16, 2015 7:14 am

Re: Drilling Misshap

Post by policetruck » Sun Aug 27, 2017 10:12 am

Yes you need to use a center drill, slowly, and start drilling with the center drill down to the bigger angle. That will give your bit a good starting point and if the center drill goes through that alleviate some of the pressure on the drill point. Which will reduce some of the heat that builds up.

User avatar
mcmaster
Member
Posts: 18
Joined: Sun Jun 12, 2016 2:00 am

Re: Drilling Misshap

Post by mcmaster » Mon Aug 28, 2017 11:24 pm

I don't work with a lot of hard materials, but I have drilled holes in steel targets before (AR500).
Carbide, carbide, carbide. Something hard enough to actually cut the material without being damaged.

I drilled several holes with a center-cutting carbide end-mill, it worked just fine (in a mill). In a drill press I expect it would want to wander, lots of radial load. I'm sure someone makes carbide drill bits, though.

AbbandonZK
Member
Posts: 11
Joined: Sun Jul 23, 2017 12:36 am

Re: Drilling Misshap

Post by AbbandonZK » Tue Aug 29, 2017 4:31 pm

We couldn't save either of the baffles due to the holes already put in them. We put them on a bench sander and we got one to .42 and another to .47.

Image

Should I still consider using them?
I've already cut a spacer to replace them at the end off my can which measures 1.41 inches before the exit end cap.

User avatar
T-Rex
Silent But Deadly
Posts: 1718
Joined: Wed Oct 29, 2014 4:38 pm
Location: CT - The AntiConstitution State

Re: Drilling Misshap

Post by T-Rex » Tue Aug 29, 2017 6:09 pm

I don't see why you couldn't drill the baffles? Even if the metal was work hardened, 17-4 reaches a max Rc of >50. Carbide, even uncoated, is very capable of penetrating this. I thought there was mill access? If so, did you try trochoidal milling? That would definitely chewed threw even the hardest tool steel.

Anyway, onto your question. 2 baffles, even oversized, are better than none.
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/

AbbandonZK
Member
Posts: 11
Joined: Sun Jul 23, 2017 12:36 am

Re: Drilling Misshap

Post by AbbandonZK » Tue Aug 29, 2017 7:09 pm

T-Rex wrote:I don't see why you couldn't drill the baffles? Even if the metal was work hardened, 17-4 reaches a max Rc of >50. Carbide, even uncoated, is very capable of penetrating this. I thought there was mill access? If so, did you try trochoidal milling? That would definitely chewed threw even the hardest tool steel.

Anyway, onto your question. 2 baffles, even oversized, are better than none.
The holes already in the baffles prevented the lathe from staying center. I'll use these as blast baffles. Thanks for answering my question.

User avatar
T-Rex
Silent But Deadly
Posts: 1718
Joined: Wed Oct 29, 2014 4:38 pm
Location: CT - The AntiConstitution State

Re: Drilling Misshap

Post by T-Rex » Tue Aug 29, 2017 7:26 pm

For anyone who happens to find themselves in a similar situation:
Forego worrying about center, for the start.
Indicate the baffle from the OD
Using a facing cutter, move away from center, plunge into the work and move towards center (light cuts are fine)
Do this until there is a flat spot
Center drill, drill, and ream if need be

If you've managed to make a terrible hole w/ the center drill or a pilot drill, do the following:
Indicate the work as above
Mount and center a small end mill (.125") in a tool holder, w/ a cutting edge level
Move the end mill into the work and try to just catch the hole
Take light cuts, boring towards the chuck, and you'll eventually get a nice round hole
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
fishman
Silent But Deadly
Posts: 1360
Joined: Sun Dec 20, 2015 9:15 pm

Re: Drilling Misshap

Post by fishman » Tue Aug 29, 2017 11:20 pm

A face grooving lathe tool would've worked great here. Or just a boring bar plunged in on an angle.

Id destroy these two and start over.
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

User avatar
Jetaro
New Member
Posts: 2
Joined: Tue Oct 30, 2018 4:51 am
Location: North Berhen,NJ

Re: Drilling Misshap

Post by Jetaro » Fri Nov 09, 2018 10:31 am

Thanks for this information!
Drills come in many different sizes and qualities with chinese drills leading the pack of cheap disposable drills that dont hold an edge very long, so is true for carbide and cobalt drills, you get what you pay for..usually if you go to JandLindustrial.com theylists all their tools as either import or domestic. Machinists know the difference between import and domestic tooling` Import tooling wears out too fast but is a great substitute when setting up a production job where you may break a tool or 2.
All the best: https://mechanicguides.com/best-cobalt-drill-bit-sets/

Weldingbiker
New Member
Posts: 6
Joined: Sat May 25, 2019 5:25 pm

Re: Drilling Misshap

Post by Weldingbiker » Sat May 25, 2019 5:30 pm

Ok where to begin, lots of wrong info here on working stainless
Get some rapid tap cutting fluid, the key to drilling stainless , low rpms, correct drill pressure and the most important thing, a sharp bit. You dont need carbide, you dont need cobalt, it just needs to be sharp. Keep the pilot bit as small possible. Your final size you want to drill out as must material as you can. 300 series stainless steel will not harden. Make sure you are producing chips , if the but is dull or your barely give feed pressure , that is just friction which overheats the bit and material

ECCO Machine
Silent But Deadly
Posts: 475
Joined: Tue Nov 28, 2017 7:34 pm

Re: Drilling Misshap

Post by ECCO Machine » Sat May 25, 2019 5:45 pm

Weldingbiker wrote:Ok where to begin, lots of wrong info here on working stainless
Most of which is in your (necro) post.
Get some rapid tap cutting fluid, the key to drilling stainless , low rpms, correct drill pressure and the most important thing, a sharp bit. You dont need carbide, you dont need cobalt, it just needs to be sharp. Keep the pilot bit as small possible. Your final size you want to drill out as must material as you can. 300 series stainless steel will not harden. Make sure you are producing chips , if the but is dull or your barely give feed pressure , that is just friction which overheats the bit and material
Gear oil with sulfur is best for stainless (free machining grades are impregnated with sulfur to achieve that property), "low RPMs" is too ambiguous (match part material, cutter size, cutter profile, cutter material according to S&F), and austenitic grades absolutely do work harden-quite easily in fact.

If a part is already work hardened, HSS is easily smoked trying to punch it. Ergo the suggestion of carbide, which will easily chew through even the hardest steels with a lot more latitude for S&F variation.

Finally, a tip: Don't sign up on a board just to condescendingly argue with it's members in your very first post. Doesn't make people want to listen to you, just paints you as an A-hole.
FFL07/02SOT Gunsmith & Machinist

User avatar
T-Rex
Silent But Deadly
Posts: 1718
Joined: Wed Oct 29, 2014 4:38 pm
Location: CT - The AntiConstitution State

Re: Drilling Misshap

Post by T-Rex » Sat May 25, 2019 6:04 pm

ECCO Machine wrote:...
Spot on.
300 series stainless work hardens if you look at it wrong, even 303.

A sharp bit should always be used, never mentioned.
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/

Weldingbiker
New Member
Posts: 6
Joined: Sat May 25, 2019 5:25 pm

Re: Drilling Misshap

Post by Weldingbiker » Sun May 26, 2019 6:37 pm

It does not work harden , doesn't have the correct properties
400 series is hardebable and that's why its useful for a knife, again the nickle in 300 is soft and stabalizes the metal in a non magnetic non harden state
Not arguing dude,trying to educate
The reason you smoke a bit, its dull, no lube and most important too high rpms
I've drill so many holes with just a black oxide and stainless

Weldingbiker
New Member
Posts: 6
Joined: Sat May 25, 2019 5:25 pm

Re: Drilling Misshap

Post by Weldingbiker » Sun May 26, 2019 6:55 pm

Austenitic stainless steel is a specific type of stainless steel alloy. Stainless steels may be classified by their crystalline structure into four main types: austenitic, ferritic, martensitic and duplex.[1] These stainless steels possess austenite as their primary crystalline structure (face centered cubic). This austenite crystalline structure is achieved by sufficient additions of the austenite stabilizing elements nickel, manganese and nitrogen. Due to their crystalline structure austenitic steels are not hardenable by heat treatment and are essentially non-magnetic.[2]

There are two subgroups of austenitic stainless steel. 300 series stainless steels achieve their austenitic structure primarily by a nickel addition while 200 series stainless steels substitute manganese and nitrogen for nickel, though there is still a small nickel content.

300 series stainless steels are the larger subgroup. The most common austenitic stainless steel and most common of all stainless steel is Type 304, also known as 18/8 or A2. Type 304 is extensively used in such items as, cookware, cutlery, and kitchen equipment. Type 316 is the next most common austenitic stainless steel. Some 300 series, such as Type 316, also contain some molybdenum to promote resistance to acids and increase resistance to localized attack (e.g. pitting and crevice corrosion). The higher nitrogen addition in 200 series gives them higher mechanical strength than 300 series.[3]

Other notable austenitic stainless steels are Type 309 and 310,[4] which are utilized in high temperature applications greater than 800°C.

Alloy 20 (Carpenter 20) is an austenitic stainless steel possessing excellent resistance to hot sulfuric acid and many other aggressive environments which would readily attack type 316 stainless. This alloy exhibits superior resistance to stress-corrosion cracking in boiling 20–40% sulfuric acid. Alloy 20 has excellent mechanical properties and the presence of niobium in the alloy minimizes the precipitation of carbides during welding.

Austenitic stainless steel can be tested by nondestructive testing using the dye penetrant inspection method but not the magnetic particle inspection method. Eddy-current testing may also be used.

See also
References
External links

ECCO Machine
Silent But Deadly
Posts: 475
Joined: Tue Nov 28, 2017 7:34 pm

Re: Drilling Misshap

Post by ECCO Machine » Mon May 27, 2019 11:27 am

Weldingbiker wrote:It does not work harden , doesn't have the correct properties
You don't seem to understand what work hardening is, how it happens.

https://www.bssa.org.uk/topics.php?article=122

You're not educating anyone here, just propagating misinformation. C&P of Wikipedia articles doesn't help your case, either. While a great starting point when one has interest in a topic, a comprehensive, accurate resource it is not due to the ability of anyone with internet access to edit an article.
FFL07/02SOT Gunsmith & Machinist

User avatar
fishman
Silent But Deadly
Posts: 1360
Joined: Sun Dec 20, 2015 9:15 pm

Re: Drilling Misshap

Post by fishman » Mon May 27, 2019 11:45 am

Weldingbiker wrote:[300 series stainless] does not work harden , doesn't have the correct properties
The stainless steel information center
The 300 series stainless steel can be "hardened" BUT only by "work hardening."
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

Weldingbiker
New Member
Posts: 6
Joined: Sat May 25, 2019 5:25 pm

Re: Drilling Misshap

Post by Weldingbiker » Mon May 27, 2019 2:00 pm

Lots of metal can "work harden" but in the true sense that tiny amount is not harden

ECCO Machine
Silent But Deadly
Posts: 475
Joined: Tue Nov 28, 2017 7:34 pm

Re: Drilling Misshap

Post by ECCO Machine » Mon May 27, 2019 2:41 pm

Weldingbiker wrote:Lots of metal can "work harden" but in the true sense that tiny amount is not harden
Now you're just making a fool of yourself. When you're dead wrong about something, it's better to admit it than double down or try to use semantics to wiggle out of the tight spot you put yourself in.

I don't even understand why you brought up playing with 300 series when the thread is about poking holes in 17-4, a precipitation hardening martensitic alloy that behaves nothing like 300 or 400 series.

If you want to discuss building suppressors, we're all game.

If you want to discuss metallurgy and machining, gonna have to forget what you "know" and start over.

If you're going to continue on your present path, there's nothing here for you.
FFL07/02SOT Gunsmith & Machinist

User avatar
T-Rex
Silent But Deadly
Posts: 1718
Joined: Wed Oct 29, 2014 4:38 pm
Location: CT - The AntiConstitution State

Re: Drilling Misshap

Post by T-Rex » Tue May 28, 2019 7:12 am

Weldingbiker wrote:Lots of metal can "work harden" but in the true sense that tiny amount is not harden
Wait a minute. You just said:
Weldingbiker wrote:It does not work harden , doesn't have the correct properties
Well, which is it?
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/

Weldingbiker
New Member
Posts: 6
Joined: Sat May 25, 2019 5:25 pm

Re: Drilling Misshap

Post by Weldingbiker » Wed May 29, 2019 9:33 pm

I explained it quite clearly. The tiny, that means small , amount is not considered hardened

alordnapa
Senior Silent Operator
Posts: 109
Joined: Tue Sep 30, 2014 12:01 pm

Re: Drilling Misshap

Post by alordnapa » Wed May 29, 2019 9:50 pm

I have had almost every form of SS work-harden. Occasionally to the point where high quality tools self destructed in further attempts to machine it, and cutting tools dulled or broke. Is there some suggestion that the "hardening" seen in friction-induced heating is metallurgically different than the intentional hardening of standard carbon steels? I can't believe that anyone working with stainless finds the amount of "hardening" to be trivial, it has brought many a machinist, pro and amateur, to head-banging fits of anger when nearly completed work suddenly starts to hate your guts!

User avatar
T-Rex
Silent But Deadly
Posts: 1718
Joined: Wed Oct 29, 2014 4:38 pm
Location: CT - The AntiConstitution State

Re: Drilling Misshap

Post by T-Rex » Thu May 30, 2019 9:00 am

Weldingbiker wrote:
Wed May 29, 2019 9:33 pm
I explained it quite clearly.
The only thing you, clearly, explained is your lack of knowledge in this field.
There are many of use here who do more with metals than simply make silencers.

Personally, I design burners for, among other things, Oil, NG, and Coal fuel industrial boilers and kilns. These are usually for energy producers or the world's largest mining operations. Our parts are produced in everything from Aluminum to Ceramic composites. Knowing the metals and materials is a huge part of our job.

While the project fizzled away, several years ago we messed with surface hardening 300 series SS, via the Nitriding process. IIRC, the 2 types we tested were 302 and 321. The latter gave stellar performance. All aspects of the base metal were improved, from wear resistance to weldability. Albeit to a minimal depth, the part was absolutely hardened.

And, like so many have also reported, 300 series SS can very much work harden. It takes only a small amount of time with machine tools to learn this.
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/

a_canadian
Silent But Deadly
Posts: 1073
Joined: Fri Oct 11, 2013 4:09 pm

Re: Drilling Misshap

Post by a_canadian » Fri May 31, 2019 12:50 am

Yeah, I only face drilling stainless a few times per year in my work, but I've learned the hard way how easily 304 and similar cheap commercial grade stainless steels can work harden with the wrong speed, even when well oiled and using brand new bits. Bringing the surface up to something close to case hardened when a complex part is almost complete is extremely frustrating. Especially on a Sunday when there's nowhere open to buy a carbide bit. Weldingbiker seems to be determinedly stuck in a defensive position, when he'd be better off doing a bit of reading on the subject and learning from pros like ECCO.

Post Reply