30 cal Suppressor Build - Forum 1

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gun410
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Re: 30 cal Suppressor Build - Forum 1

Post by gun410 » Sun Jul 28, 2019 6:17 pm

ECCO Machine wrote:
Sun Jul 28, 2019 1:47 pm
Included means the combined angle of both sides of a taper; 6° per side, 12° included.

What that means on your lathe compound depends on how your compound scale reads, since not all lathes are the same. If I were to set any of my lathe compounds at 20°, I would cut a very obtuse 140° taper, basically a shallow dish. Most have 0° marked with the compound traveling parallel to the cross slide and 90° when it's traveling in line with Z axis, but some are backwards, and there may be others that do something completely different like a miter saw.

When I cut my 12° included taper, my compound is at 84°. For a 20° included, it would be set at 80°. To cut my 50° rifle baffles, the compound is at 65°. Remember, when cutting tapers, the cutting angle + the included angle will add up to 180° (unless you have one of those backwards marked lathe compound scales). 180-(84+84)=12, 180-(80+80)=20, 180-(65+65)=50

The part you modeled on Fusion showing 78° in relation to the base of the part would be 12° if measured from the side, ergo a 24° included taper. That's a bit obtuse if you want it to behave as a locking taper. Conversely, I wouldn't suggest going more acute than 10° included, especially if you use finer threads; it'll lock down too hard.
Oh, that clears things up, I'm using 12tpi so I'll go into fusion and cut the angle in half to be a 12° included. I checked my compound and 0° is parrel so basically you subtract half the included angle from 90°to get compound angle? I chucked up some of the 1" dia 17-4 and tried turning it to see what it is like, and my surface finish has lines running through it that you can feel with your fingernail, im using carbide inserts at 560 rpm. Anyone have advice on 17-4? I messaged the ebay seller i got the 17-4 from and they didnt know but thought it could be annealed or softer ht.
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ECCO Machine
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Re: 30 cal Suppressor Build - Forum 1

Post by ECCO Machine » Sun Jul 28, 2019 9:08 pm

gun410 wrote:
Sun Jul 28, 2019 6:17 pm
I checked my compound and 0° is parrel so basically you subtract half the included angle from 90°to get compound angle?
On most compound scales, yes, since they'd read 90° when travelling parallel to Z axis. But if your compound travels on Z axis when the scale is set to 0°, then you'll set it at 6°.
gun410 wrote:
Sun Jul 28, 2019 6:17 pm
I chucked up some of the 1" dia 17-4 and tried turning it to see what it is like, and my surface finish has lines running through it that you can feel with your fingernail, im using carbide inserts at 560 rpm. Anyone have advice on 17-4? I messaged the ebay seller i got the 17-4 from and they didnt know but thought it could be annealed or softer ht.
It's your feed rates. 17-4 turns beautifully in any condition with sharp tooling as long as it doesn't get too hot. What I see in your picture looks like a feed rate of about .015" per spindle revolution. My finish passes on small stock like that are done at 525 RPM with my power feed moving the carriage at about 2 inches per minute, which translates to around .0038" per spindle revolution.
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Re: 30 cal Suppressor Build - Forum 1

Post by #40Fan » Mon Jul 29, 2019 7:33 pm

If you can't slow the feed rate down any, try larger radii (radiused spelled correctly) tooling.

I was accidently sent some WNMG inserts. Seller told me to keep them and shipped the right inserts. Figured what the heck and bought a couple cheap holders. Had to mill the heck out of the holders to sit low enough in my tool post, but wow, do they make a nice finish. Use one edge for rough cuts, turn the insert 120° for final pass. Back to the roughing edge for the next part.

Looking at those chips, I would expect to see a golden color. Sure it is 17-4?

gun410
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Re: 30 cal Suppressor Build - Forum 1

Post by gun410 » Tue Jul 30, 2019 10:32 pm

ECCO Machine wrote:
Sun Jul 28, 2019 9:08 pm
gun410 wrote:
Sun Jul 28, 2019 6:17 pm
I checked my compound and 0° is parrel so basically you subtract half the included angle from 90°to get compound angle?
On most compound scales, yes, since they'd read 90° when travelling parallel to Z axis. But if your compound travels on Z axis when the scale is set to 0°, then you'll set it at 6°.
gun410 wrote:
Sun Jul 28, 2019 6:17 pm
I chucked up some of the 1" dia 17-4 and tried turning it to see what it is like, and my surface finish has lines running through it that you can feel with your fingernail, im using carbide inserts at 560 rpm. Anyone have advice on 17-4? I messaged the ebay seller i got the 17-4 from and they didnt know but thought it could be annealed or softer ht.
It's your feed rates. 17-4 turns beautifully in any condition with sharp tooling as long as it doesn't get too hot. What I see in your picture looks like a feed rate of about .015" per spindle revolution. My finish passes on small stock like that are done at 525 RPM with my power feed moving the carriage at about 2 inches per minute, which translates to around .0038" per spindle revolution.
I forgot to change the change gears back to turning as they were setup for threading, but i got that fixed and the 17-4 turns beautifully now. One problem i'm having is my hss parting tool is not cutting the 17-4 and i've tried lowering and raising it and still ain't cutting at all. The only reason i can think of is because its hss and all the other tools i used on 17-4 were carbide. Also i've seen other people use acme threads for qd brakes, I've never done acme and i just started with v threads, would it be worth it to learn and buy the necessary tooling for acme threads?

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Re: 30 cal Suppressor Build - Forum 1

Post by ECCO Machine » Wed Jul 31, 2019 1:29 am

gun410 wrote:
Tue Jul 30, 2019 10:32 pm
I forgot to change the change gears back to turning as they were setup for threading, but i got that fixed and the 17-4 turns beautifully now. One problem i'm having is my hss parting tool is not cutting the 17-4 and i've tried lowering and raising it and still ain't cutting at all. The only reason i can think of is because its hss and all the other tools i used on 17-4 were carbide. Also i've seen other people use acme threads for qd brakes, I've never done acme and i just started with v threads, would it be worth it to learn and buy the necessary tooling for acme threads?
MGMN inserts in MGEHR holders are your friend for parting tough alloys like 17-4. You'll still need to be mindful of temperature, though, using lots of cutting fluid/coolant, and making offset plunges for really deep parting. I use MGMN300 inserts for most 17-4 work up to 2" OD.

ACME threads are great for can mounts, but there's nothing wrong with unified threads for it, either. ACME gives you more thread strength for a given minor & major, but if you don't have the space constraints, a nicely blunted or radiused V thread works just fine. My brake pattern is 1"-12 UNF, but I knock down the male threads to .975"-.980" so they're not so prone to crest deformation and less hazardous to hands.
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3strucking
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Re: 30 cal Suppressor Build - Forum 1

Post by 3strucking » Wed Jul 31, 2019 7:54 am

gun410 wrote:
Tue Jul 30, 2019 10:32 pm
ECCO Machine wrote:
Sun Jul 28, 2019 9:08 pm
gun410 wrote:
Sun Jul 28, 2019 6:17 pm
I checked my compound and 0° is parrel so basically you subtract half the included angle from 90°to get compound angle?
On most compound scales, yes, since they'd read 90° when travelling parallel to Z axis. But if your compound travels on Z axis when the scale is set to 0°, then you'll set it at 6°.
gun410 wrote:
Sun Jul 28, 2019 6:17 pm
I chucked up some of the 1" dia 17-4 and tried turning it to see what it is like, and my surface finish has lines running through it that you can feel with your fingernail, im using carbide inserts at 560 rpm. Anyone have advice on 17-4? I messaged the ebay seller i got the 17-4 from and they didnt know but thought it could be annealed or softer ht.
It's your feed rates. 17-4 turns beautifully in any condition with sharp tooling as long as it doesn't get too hot. What I see in your picture looks like a feed rate of about .015" per spindle revolution. My finish passes on small stock like that are done at 525 RPM with my power feed moving the carriage at about 2 inches per minute, which translates to around .0038" per spindle revolution.
I forgot to change the change gears back to turning as they were setup for threading, but i got that fixed and the 17-4 turns beautifully now. One problem i'm having is my hss parting tool is not cutting the 17-4 and i've tried lowering and raising it and still ain't cutting at all. The only reason i can think of is because its hss and all the other tools i used on 17-4 were carbide. Also i've seen other people use acme threads for qd brakes, I've never done acme and i just started with v threads, would it be worth it to learn and buy the necessary tooling for acme threads?
Your parting tool needs to be on center and square with the work. Use lots of cutting oil. I have switched to the same insert that ECCO uses and I like them much better than a HSS blade.

gun410
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Re: 30 cal Suppressor Build - Forum 1

Post by gun410 » Wed Jul 31, 2019 2:07 pm

ECCO Machine wrote:
Wed Jul 31, 2019 1:29 am
gun410 wrote:
Tue Jul 30, 2019 10:32 pm
I forgot to change the change gears back to turning as they were setup for threading, but i got that fixed and the 17-4 turns beautifully now. One problem i'm having is my hss parting tool is not cutting the 17-4 and i've tried lowering and raising it and still ain't cutting at all. The only reason i can think of is because its hss and all the other tools i used on 17-4 were carbide. Also i've seen other people use acme threads for qd brakes, I've never done acme and i just started with v threads, would it be worth it to learn and buy the necessary tooling for acme threads?
MGMN inserts in MGEHR holders are your friend for parting tough alloys like 17-4. You'll still need to be mindful of temperature, though, using lots of cutting fluid/coolant, and making offset plunges for really deep parting. I use MGMN300 inserts for most 17-4 work up to 2" OD.

ACME threads are great for can mounts, but there's nothing wrong with unified threads for it, either. ACME gives you more thread strength for a given minor & major, but if you don't have the space constraints, a nicely blunted or radiused V thread works just fine. My brake pattern is 1"-12 UNF, but I knock down the male threads to .975"-.980" so they're not so prone to crest deformation and less hazardous to hands.
As of right now i have .875" - 12 UN threads on my brake design and if there isn't a big benefit with acme threads i think it would not be worth it. And i can't go any bigger on the threads because im making them out of 1" Dia round stock (17-4). I'll check out the MGMN inserts but it sucks that hss doesn't work because i cant do to much for the brake until i get the thread relief cut. What inserts (if you use em) do you use for threading? I heard U or UNJ inserts are the way to go to save wall thickness?

gun410
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Re: 30 cal Suppressor Build - Forum 1

Post by gun410 » Wed Jul 31, 2019 2:24 pm

I was looking around the lathe and i found this carbide parting tool. It is a different style than yours but there can't be too big of a difference?Image

Matt in TN
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Re: 30 cal Suppressor Build - Forum 1

Post by Matt in TN » Wed Jul 31, 2019 3:51 pm

gun410 wrote:
Wed Jul 31, 2019 2:07 pm
ECCO Machine wrote:
Wed Jul 31, 2019 1:29 am
gun410 wrote:
Tue Jul 30, 2019 10:32 pm
I forgot to change the change gears back to turning as they were setup for threading, but i got that fixed and the 17-4 turns beautifully now. One problem i'm having is my hss parting tool is not cutting the 17-4 and i've tried lowering and raising it and still ain't cutting at all. The only reason i can think of is because its hss and all the other tools i used on 17-4 were carbide. Also i've seen other people use acme threads for qd brakes, I've never done acme and i just started with v threads, would it be worth it to learn and buy the necessary tooling for acme threads?
MGMN inserts in MGEHR holders are your friend for parting tough alloys like 17-4. You'll still need to be mindful of temperature, though, using lots of cutting fluid/coolant, and making offset plunges for really deep parting. I use MGMN300 inserts for most 17-4 work up to 2" OD.

ACME threads are great for can mounts, but there's nothing wrong with unified threads for it, either. ACME gives you more thread strength for a given minor & major, but if you don't have the space constraints, a nicely blunted or radiused V thread works just fine. My brake pattern is 1"-12 UNF, but I knock down the male threads to .975"-.980" so they're not so prone to crest deformation and less hazardous to hands.
As of right now i have .875" - 12 UN threads on my brake design and if there isn't a big benefit with acme threads i think it would not be worth it. And i can't go any bigger on the threads because im making them out of 1" Dia round stock (17-4). I'll check out the MGMN inserts but it sucks that hss doesn't work because i cant do to much for the brake until i get the thread relief cut. What inserts (if you use em) do you use for threading? I heard U or UNJ inserts are the way to go to save wall thickness?
I've had no issues cutting and parting 17-4 with HSS. Do you have a pic of your setup?

gun410
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Re: 30 cal Suppressor Build - Forum 1

Post by gun410 » Wed Jul 31, 2019 4:04 pm

Matt in TN wrote:
Wed Jul 31, 2019 3:51 pm
gun410 wrote:
Wed Jul 31, 2019 2:07 pm
ECCO Machine wrote:
Wed Jul 31, 2019 1:29 am


MGMN inserts in MGEHR holders are your friend for parting tough alloys like 17-4. You'll still need to be mindful of temperature, though, using lots of cutting fluid/coolant, and making offset plunges for really deep parting. I use MGMN300 inserts for most 17-4 work up to 2" OD.

ACME threads are great for can mounts, but there's nothing wrong with unified threads for it, either. ACME gives you more thread strength for a given minor & major, but if you don't have the space constraints, a nicely blunted or radiused V thread works just fine. My brake pattern is 1"-12 UNF, but I knock down the male threads to .975"-.980" so they're not so prone to crest deformation and less hazardous to hands.
As of right now i have .875" - 12 UN threads on my brake design and if there isn't a big benefit with acme threads i think it would not be worth it. And i can't go any bigger on the threads because im making them out of 1" Dia round stock (17-4). I'll check out the MGMN inserts but it sucks that hss doesn't work because i cant do to much for the brake until i get the thread relief cut. What inserts (if you use em) do you use for threading? I heard U or UNJ inserts are the way to go to save wall thickness?
I've had no issues cutting and parting 17-4 with HSS. Do you have a pic of your setup?
Yeah, I put it in the background of the picture above

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Re: 30 cal Suppressor Build - Forum 1

Post by ECCO Machine » Wed Jul 31, 2019 5:28 pm

gun410 wrote:
Wed Jul 31, 2019 2:24 pm
I was looking around the lathe and i found this carbide parting tool. It is a different style than yours but there can't be too big of a difference?
Same style, but that's a holder for MGMN200, which are 2mm wide. 200s are a little light, and the -2 holders don't have as much reach for parting larger stock. But give it a go!
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gun410
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Re: 30 cal Suppressor Build - Forum 1

Post by gun410 » Wed Jul 31, 2019 5:50 pm

ECCO Machine wrote:
Wed Jul 31, 2019 5:28 pm
gun410 wrote:
Wed Jul 31, 2019 2:24 pm
I was looking around the lathe and i found this carbide parting tool. It is a different style than yours but there can't be too big of a difference?
Same style, but that's a holder for MGMN200, which are 2mm wide. 200s are a little light, and the -2 holders don't have as much reach for parting larger stock. But give it a go!
I wasn't too familiar with grooving inserts, but I have been doing research and I get it now. I ordered a holder for 3mm wide inserts. What inserts do u buy for threading that have a radius and not a sharp v?

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Re: 30 cal Suppressor Build - Forum 1

Post by #40Fan » Wed Jul 31, 2019 7:05 pm

That tool you have pictured in your hand is what I use. But, I am only cutting smaller pieces like yourself.

Also, it makes the threads look better if you have an angled relief on the back as well as the front.

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Re: 30 cal Suppressor Build - Forum 1

Post by ECCO Machine » Wed Jul 31, 2019 9:14 pm

gun410 wrote:
Wed Jul 31, 2019 5:50 pm
What inserts do u buy for threading that have a radius and not a sharp v?
There are pitch specific inserts for both external (NTCR24E, for example, is for cutting 24 pitch right hand external threads) and internal (16IR24 would be a 24 pitch laydown insert).

I don't generally bother with pitch specific internals, just knock down the 11IR inserts I'm using for 24 & 28 pitch a little, and I use larger inserts like 16IR for courser pitches and do the same. For external, I do keep NTC3R24E and NTC3R28E on hand because I do a lot of barrel threading, and they need to be perfect class 3 threads. For most other external pitches, I just use NTC3R or NTF3R inserts.
#40Fan wrote:
Wed Jul 31, 2019 7:05 pm
Also, it makes the threads look better if you have an angled relief on the back as well as the front.
Also this. A little bit of undercut/counterbore with 45°-60° bevel where the threads begin will look better and help prevent thread deformation & cross threading.
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gun410
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Re: 30 cal Suppressor Build - Forum 1

Post by gun410 » Thu Aug 01, 2019 4:23 pm

ECCO Machine wrote:
Wed Jul 31, 2019 9:14 pm
gun410 wrote:
Wed Jul 31, 2019 5:50 pm
What inserts do u buy for threading that have a radius and not a sharp v?
There are pitch specific inserts for both external (NTCR24E, for example, is for cutting 24 pitch right hand external threads) and internal (16IR24 would be a 24 pitch laydown insert).

I don't generally bother with pitch specific internals, just knock down the 11IR inserts I'm using for 24 & 28 pitch a little, and I use larger inserts like 16IR for courser pitches and do the same. For external, I do keep NTC3R24E and NTC3R28E on hand because I do a lot of barrel threading, and they need to be perfect class 3 threads. For most other external pitches, I just use NTC3R or NTF3R inserts.
#40Fan wrote:
Wed Jul 31, 2019 7:05 pm
Also, it makes the threads look better if you have an angled relief on the back as well as the front.
Also this. A little bit of undercut/counterbore with 45°-60° bevel where the threads begin will look better and help prevent thread deformation & cross threading.
I guess I’ll just knock down my 11ir inserts. But the 2mm growing tool I posted above wont even get Low enough to be centered (not even close). So I know my 3mm one coming won’t work either, what can I do?
Also what class threads should the suppressor end caps and muzzle brake QD threads?
Image
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Re: 30 cal Suppressor Build - Forum 1

Post by ECCO Machine » Thu Aug 01, 2019 5:57 pm

gun410 wrote:
Thu Aug 01, 2019 4:23 pm
I guess I’ll just knock down my 11ir inserts. But the 2mm growing tool I posted above wont even get Low enough to be centered (not even close). So I know my 3mm one coming won’t work either, what can I do?
Move your tool post over so the holder can drop down past the compound.
gun410 wrote:
Thu Aug 01, 2019 4:23 pm
Also what class threads should the suppressor end caps and muzzle brake QD threads?
3 is great if you can maintain the tolerances the length of the threads, but it's gonna be tough with the lighter machine. Class 2 will be fine, especially for the brake, since it's gonna get dirty and the alignment is a function of the taper anyway. You don't want it to be hot dog-down-a-hallway, but as long as there's enough engagement to keep things where they need to be, don't worry too much about being in spec for a thread class. Save that concern for your muzzle threads.
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Re: 30 cal Suppressor Build - Forum 1

Post by #40Fan » Thu Aug 01, 2019 6:49 pm

I had the same issue with my AXA tool post and the parting tool. I already removed some material from the bottom of the holders, but it wasn't enough. I ended up milling some off of the bottom of the tool as well.

If you have a 4 jaw chuck, turning down the holder on the lathe is a piece of cake. You can still do it with a three jaw if you get a little creative with some shims.

The closer you can get the tool to the tool post the better. Shove it in the tool holder as far as it will go.

ETA: What is that under your compound? Is that an aftermarket piece or did the lathe come with that?

gun410
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Re: 30 cal Suppressor Build - Forum 1

Post by gun410 » Fri Aug 02, 2019 2:22 am

#40Fan wrote:
Thu Aug 01, 2019 6:49 pm
I had the same issue with my AXA tool post and the parting tool. I already removed some material from the bottom of the holders, but it wasn't enough. I ended up milling some off of the bottom of the tool as well.

If you have a 4 jaw chuck, turning down the holder on the lathe is a piece of cake. You can still do it with a three jaw if you get a little creative with some shims.

The closer you can get the tool to the tool post the better. Shove it in the tool holder as far as it will go.

ETA: What is that under your compound? Is that an aftermarket piece or did the lathe come with that?
I had another tool that was slightly too high and i too some off but only a little amount was taken off. There is nothing aftermarket under the compound

gun410
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Re: 30 cal Suppressor Build - Forum 1

Post by gun410 » Fri Aug 02, 2019 2:38 am

..
Last edited by gun410 on Fri Aug 02, 2019 11:28 am, edited 1 time in total.

gun410
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Re: 30 cal Suppressor Build - Forum 1

Post by gun410 » Fri Aug 02, 2019 11:25 am

ECCO Machine wrote:
Thu Aug 01, 2019 5:57 pm

Move your tool post over so the holder can drop down past the compound.

The only way that works is if i have the cross slide set 90 degrees (perpendicular to spindle axis). The cross feed and compound feed handles get in the way of each other. Do not know what i can do.
ECCO Machine wrote:
Thu Aug 01, 2019 5:57 pm
3 is great if you can maintain the tolerances the length of the threads, but it's gonna be tough with the lighter machine. Class 2 will be fine, especially for the brake, since it's gonna get dirty and the alignment is a function of the taper anyway. You don't want it to be hot dog-down-a-hallway, but as long as there's enough engagement to keep things where they need to be, don't worry too much about being in spec for a thread class. Save that concern for your muzzle threads.
Alright that's good to know, for the muzzle brake threads i bought taps to be sure i got good threads.

BUT I stil can't grove or cut this d*mn 17-4 ss even with the carbide I don't know why the 2mm carbide insert won’t cut. The video lost volume but it was screeching with oil but hardly cutting at all. https://youtu.be/wjEYaGrob9o
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Re: 30 cal Suppressor Build - Forum 1

Post by #40Fan » Fri Aug 02, 2019 4:20 pm

I didn't think about it until now, but you could have flipped the tool upside down and reversed the lathe.

Sounds like you work hardened the SS with the HSS parting tool. Gonna need to break through that layer of hardness.

Might bring in your tailstock to give it a little more rigidity.

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Re: 30 cal Suppressor Build - Forum 1

Post by 3strucking » Fri Aug 02, 2019 5:06 pm

I have tried the upside down parting before and it worked fine, but my lathe weighs over a ton. Rigidity is key as always.

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Re: 30 cal Suppressor Build - Forum 1

Post by gun410 » Fri Aug 02, 2019 6:51 pm

#40Fan wrote:
Fri Aug 02, 2019 4:20 pm
I didn't think about it until now, but you could have flipped the tool upside down and reversed the lathe.
What difference does flipping the tool make to cutting?
#40Fan wrote:
Fri Aug 02, 2019 4:20 pm
Sounds like you work hardened the SS with the HSS parting tool. Gonna need to break through that layer of hardness.

Might bring in your tailstock to give it a little more rigidity.
Ah, that makes sense. Is there anything I can do to help get through the hardened layer?

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Re: 30 cal Suppressor Build - Forum 1

Post by #40Fan » Fri Aug 02, 2019 7:06 pm

Flipping the tool would allow you to get it on center without needing to hang the tool post holder off the edge of the compound.

I'm not exactly sure what you can do to get past the layer. If it happened to me, I'd slow the lathe down and with a new tool tip, give her hell.

Can you get any of your other tools in the grove? Maybe you can chip away some material with them before going back to the parting tool.

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Re: 30 cal Suppressor Build - Forum 1

Post by a_canadian » Fri Aug 02, 2019 8:36 pm

You could spin up the lathe and use a cutoff wheel in a Dremel to grind through the hardened layer. Not fun, makes a lot of dust, but those little fiber cutoff wheels are cheap and a few minutes of grinding should get you through.

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