Crooked chambers/ uneven lands

[urbanrifleman]

It's pretty obvious to me that the major part of the cycle time of doing a barrel is the dialing in. And that cycle time doesn't change whether you do it on a manual machine or a CNC. It's dialed in exactly the same way if that video that was shown is any indication of how it's done.

In that sense a CNC machine for doing rifle tenons it's not going to save you a significant amount of time, because the majority of the time is in the dialing in of the barrel to get it ready to cut.

 

[DShortt]

So I'm not sure I follow the point you're trying to make? Once a CNC machine is dialed in you can make multiple parts that are identical provided nothing shifts or the tooling doesn't wear/break. That's where the quality control angle comes in.

With a standard set-up you have to check every individual piece and stand over it while it runs and manually operate the machine.

It's the difference between piece work and production work. With your background you already know all this so I'm confused. What point were you trying to make with your post?

You can cut and thread a tendon in 5 minutes once it's dialed in. Ok. Pretty decent times there but that has nothing to do with the capability of a CNC machine.

 

[urbanrifleman]

So I'm not sure I follow the point you're trying to make? Once a CNC machine is dialed in you can make multiple parts that are identical provided nothing shifts or the tooling doesn't wear/break. That's where the quality control angle comes in.

With a standard set-up you have to check every individual piece and stand over it while it runs and manually operate the machine.

It's the difference between piece work and production work. With your background you already know all this so I'm confused. What point were you trying to make with your post?

You can cut and thread a tendon in 5 minutes once it's dialed in. Ok. Pretty decent times there but that has nothing to do with the capability of a CNC machine.

No I don't believe you're correct. Unless I'm missing something each barrel would have to be indicated in separately because no two barrels are the same. That's the whole point of them of dialing them in.

And the point of my post was that for doing barrel work that most people do unless they're doing OEM style production the cycle times are not radically different In fact they're almost identical. For the average guy a CNC machine is not going to change his cycle time unless he likes to thread at 12 RPM

I thought the point was pretty obvious. It was just a cycle time comparison between cutting a tenon and threading it on a CNC machine versus doing it manually dialing in and all that other stuff doesn't change.

I'm still trying to figure out how you change barrels in the machine and " nothing moves ". Yeah I'd have to see that for myself because I don't think that's possible.

 

[DShortt]

It's pretty obvious to me that the major part of the cycle time of doing a barrel is the dialing in. And that cycle time doesn't change whether you do it on a manual machine or a CNC. It's dialed in exactly the same way if that video that was shown is any indication of how it's done.

In that sense a CNC machine for doing rifle tenons it's not going to save you a significant amount of time, because the majority of the time is in the dialing in of the barrel to get it ready to cut.

No I don't believe you're correct. Unless I'm missing something each barrel would have to be indicated in separately because no two barrels are the same. That's the whole point of them of dialing them in.

And the point of my post was that for doing barrel work that most people do unless they're doing OEM style production the cycle times are not radically different In fact they're almost identical. For the average guy a CNC machine is not going to change his cycle time unless he likes to thread at 12 RPM

I thought the point was pretty obvious. It was just a cycle time comparison between cutting a tenon and threading it on a CNC machine versus doing it manually dialing in and all that other stuff doesn't change.

I'm still trying to figure out how you change barrels in the machine and " nothing moves ". Yeah I'd have to see that for myself because I don't think that's possible.

OK, so you're accounting for irregularities on your supplied stock. That's fine. But once again, once you dial in the part to your satisfaction you can go look at something else while the CNC runs the program. If you're ready to change parts in 5 minutes when the cycle completes then you can dial in another and go again. If you're eating lunch or talking to someone or moving your bowels you don't have to be there the entire time monitoring the process.

There are tolerances in high volume production. So long as you are within those tolerances you've fulfilled your requirements. Is it the best anyone can do? No. But the customer isn't paying for the best. They're paying for their specifications and looking for a competitive price.

Good Lord. Why are we even having this discussion? If you have the background you say you do you already know all this.

Again, custom work is not the same as production work. If you aren't doing volumes of work then no, a CNC machine probably doesn't make sense. Can you do accurate custom work with a CNC once you have it? Absolutely! But that's not where a CNC shines.

 

[LVLAaron]

See how long it takes you to do a BR quality chamber job, on a shouldered barrel with a coned bolt.

 

[urbanrifleman]

Again, custom work is not the same as production work. If you aren't doing volumes of work then no, a CNC machine probably doesn't make sense.

I'm pretty sure that is what I just said. At least in terms of cycle time.

 

[DShortt]

I'm pretty sure that is what I just said. At least in terms of cycle time.

Well it would have been a much shorter discussion if you just said you did one-off custom work and while CNC machines can be just as accurate it doesn't make economic sense for you to invest in one at this point.

I still don't see any claims in this thread where anyone said they were more accurate or the preferred method unless you're doing high volume work.

 

[6MMsteve]

I had a barrel that shot great after I used a throater and mangled the lands, I had no buisness using a throater, I just stuck it there and started crankin...the bullet fit so I shot it. I guess it was good nough barrel that it worked I sold the throater and I will not do that no more

 

[urbanrifleman]

Well it would have been a much shorter discussion if you just said you did one-off custom work and while CNC machines can be just as accurate it doesn't make economic sense for you to invest in one at this point.

I still don't see any claims in this thread where anyone said they were more accurate or the preferred method unless you're doing high volume work.

I never said any of that. At all.

 

[AccelR8]

 

[DLT]

@DaveTooley,
Edit: I have 120 completed barrels sitting in my shop that the customer won't pay for. Now do the math there.
Give them 30 days to pay up or you'll sell them here.
I'm sure you would move a bunch of them.

Damn right

 

[DShortt]

Why would that make any difference? The post here are saying that CNC threads are superior to manual threads. Why would the action matter?

Are you talking about headspace?

Yeah, you did.

 

[WSnyder]

Good Lord. Why are we even having this discussion?

^^^This

 

[urbanrifleman]

Yeah, you did.

????

Because of my prefit barrel business people tell me all the time that I should spend my money on a CNC machine. So, I set about to understand what the CNC machine would do for my business. Some of these threads have been very educational, and now I better understand what a CNC machine for barreling would do. What it would look like. What the actual procedure for doing barrels would be. That video of the guy using a Harding CNC was very educational.

I've proven it to myself that it wouldn't change a single thing for me, and you would have to be into some pretty serious barrel production to actually REQUIRE A CNC MACHINE enough to the point that it would actually pay for itself (for barreling).

If a person were to acquire a CNC machine to do BARRRELS in a typical "gunsmith" business, the setup time or "dialing in" would be exactly the same for a manual machine as it would be for a CNC machine per barrel. It appears that the operator would still be using two spiders at either end of the barrel to fixture the barrel and get it concentric (If someone has information to the contrary please let me know, because I would be interested in knowing a fixturing arrangement that produces concentricity that doesn't involve two spiders at either end of the headstock). I was wondering how they were doing that. And the vast majority of the time for most of the process is in the setup time not in the cutting time (unless the operator is very slow).

Most people doing barreling work are not doing multiple barrels a day. That is my conclusion. There might be a handful of guys who post here that do more than one barrel a day on average. Certainly no one is doing 20 barrels a day that isn't working in some form of production.

Most people charge about $100 an hour to do barreling work. A barrel is typically $350 plus $100 for muzzle threading. I would say that's an average price that I hear. I would tell people if you can't do a barrel in 4 hours I wouldn't do it for a living.

I am still kind of chuckling at the fact that a decade ago it was my perception that the gunsmith community looked down their noses at anything that was made on a CNC machine. And now all of a sudden the CNC is the better mousetrap.

That happened very quickly.

 

[SKWERLZ]

Talking to my friend that does oem barrels on CNC everything is done on centers.
I’m betting 99% of barrels done on CNC is that way.

I personally indicate the end I’m working on for about 1.5” on muzzle and cartridge length+throat plus a bit forward of that on breech end.

As a gorilla without formal machinist training the indicating process is fairly fast to painful slow with inconsistent times being because I still mess up and move it the wrong way or get lucky and it all falls together.

How much of a difference in accuracy I get doing it that way I really don’t know but it’s how I was instructed by my barrel mentor and it seems a lot of competition oriented smiths do it that way as well and I’m sure a few of them have tested it.

 

[urbanrifleman]

Talking to my friend that does oem barrels on CNC everything is done on centers.
I’m betting 99% of barrels done on CNC is that way.

I personally indicate the end I’m working on for about 1.5” on muzzle and cartridge length+throat plus a bit forward of that on breech end.

As a gorilla without formal machinist training the indicating process is fairly fast to painful slow with inconsistent times being because I still mess up and move it the wrong way or get lucky and it all falls together.

How much of a difference in accuracy I get doing it that way I really don’t know but it’s how I was instructed by my barrel mentor and it seems a lot of competition oriented smiths do it that way as well and I’m sure a few of them have tested it.

I would like to see how barrels are chambered on centers on a CNC machine.

 

[SKWERLZ]

A similar process as this.

 

[GenePoole]

They only contoured the barrel between centers. Chambering was pretty much the same as most smiths do it on a manual machine.

I'd be curious to see how chambering would be done between centers on a CNC. On a manual, it usually involves a steady rest.

 

[LVLAaron]

Figure out how White Oak does it. Whatever they do is adequate.

 

[AlNyhus]

I am still kind of chuckling at the fact that a decade ago it was my perception that the gunsmith community looked down their noses at anything that was made on a CNC machine. And now all of a sudden the CNC is the better mousetrap.

That's because your "perception" is wrong.

I can't think of a single person I know that will or won't have someone do a barrel based solely on the type of lathe they own. Serious shooters and competitors don't give two shakes how a barrel is set up, machined or how fast or slow it takes to do it. It can be done on a table top 110 volt 10×26, a Haas CNC center, between centers, through the head stock, with a steady rest, with two spiders, threaded toward the shoulder or upside down and in reverse. It can be done in a greasy shop with a couple of 40 watt bulbs hangin' over a dude in bib overalls or in the moon light by Swedish virgins drinking Perrier.

The results are what matter. Talented people turn out great work with all sorts of equipment. They type of equipment they use or purchase is as individual as each person and their business circumstances.