I’m looking at getting a grizzly G0709 gunsmith lathe and I was just looking to find some good info on how get started I know I have to get the bore centered in the front but I’m not real sure we’re u mesure to get the back spider centered and just looking for some good info or even videos on chambering I have watched pretty much everything on YouTube that is on there I would even like to take a clas or school on it but there’s not much to chose from in TN any help will b great guys Thanks in advance
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Gunsmithing Getting started making my Own barrels
- Thread starter 6.5guys2
- Start date
1000 ways to skin the cat. Bear that in mind, there are a lot of ways to indicate a barrel in that will result in a hammer. Obviously there's also a lot of ways to fuck things up...
What I like to do is have a 4-jaw chuck and a 4-screw spider that are clocked to each other. In other words if one of the jaws on the chuck is at TDC, at the same time one of the screws on the spider are at TDC. It's not entirely necessary but it can make thing simpler. Numbering jaws/screws if they're not already is helpful, too.
I put brass pads between the barrel and the chuck jaws to act as a pivot point. I've seen people use thick copper or aluminum wire, also.
I like to take a long stem indicator (indicator stem at least 1" long. Longer is better, IMO) and place the ball on the indicator stem into the bore so that it's directly over the brass pivot pads that are on the outside of the barrel. I will then spin the spindle by hand and indicate that location in to <.001" TIR using ONLY the chuck. I usually go off of the grooves because there's a greater percentage of the circumference in the groove vs. the lands. You'll see it bounce between groove/land as you spin the spindle. I don't touch the outboard spider this entire time (other than initial setup, and eyeball centering the muzzle end in the spider).
After the pivot point is dialed in, I move the indicator out to the breech end, maybe 1/8" in from the breech face, and dial it in using ONLY the outboard spider.
4/5 times you're done at that point. Go back under the pads and double check that you're still running true. Sometimes it will move a little bit. Re-adjust the chuck if it has moved off of center, then go back to the breech, rinse, repeat as necessary.
That all being said... I've seen guys do it by indicating off of 2 points on a rod they stick in the bore. I've seen people indicate the muzzle end to <.0005" TIR via the spider then the breech end to <.0005" TIR via the chuck. At Long Rifles Inc. they toss the muzzle end into a collet that slides into the spindle bore and hope for the best, then dial in at one position on the breech end. I've seen where people will chuck up the muzzle end, hang the whole barrel over the bed on a steady rest, then ream it by hand... floating reamer holders, fixed tooling, coolant flows on the tooling, from the muzzle......
Like I said, everyone finds their own way that makes sense and most of the time as long as you're using your noodle just a little bit, it works out fine.
What I like to do is have a 4-jaw chuck and a 4-screw spider that are clocked to each other. In other words if one of the jaws on the chuck is at TDC, at the same time one of the screws on the spider are at TDC. It's not entirely necessary but it can make thing simpler. Numbering jaws/screws if they're not already is helpful, too.
I put brass pads between the barrel and the chuck jaws to act as a pivot point. I've seen people use thick copper or aluminum wire, also.
I like to take a long stem indicator (indicator stem at least 1" long. Longer is better, IMO) and place the ball on the indicator stem into the bore so that it's directly over the brass pivot pads that are on the outside of the barrel. I will then spin the spindle by hand and indicate that location in to <.001" TIR using ONLY the chuck. I usually go off of the grooves because there's a greater percentage of the circumference in the groove vs. the lands. You'll see it bounce between groove/land as you spin the spindle. I don't touch the outboard spider this entire time (other than initial setup, and eyeball centering the muzzle end in the spider).
After the pivot point is dialed in, I move the indicator out to the breech end, maybe 1/8" in from the breech face, and dial it in using ONLY the outboard spider.
4/5 times you're done at that point. Go back under the pads and double check that you're still running true. Sometimes it will move a little bit. Re-adjust the chuck if it has moved off of center, then go back to the breech, rinse, repeat as necessary.
That all being said... I've seen guys do it by indicating off of 2 points on a rod they stick in the bore. I've seen people indicate the muzzle end to <.0005" TIR via the spider then the breech end to <.0005" TIR via the chuck. At Long Rifles Inc. they toss the muzzle end into a collet that slides into the spindle bore and hope for the best, then dial in at one position on the breech end. I've seen where people will chuck up the muzzle end, hang the whole barrel over the bed on a steady rest, then ream it by hand... floating reamer holders, fixed tooling, coolant flows on the tooling, from the muzzle......
Like I said, everyone finds their own way that makes sense and most of the time as long as you're using your noodle just a little bit, it works out fine.
My son is just about through with gs school.
I told him to get the grisly rods ect but the old school master showed him some other way.
0.0005 or less is gtg no matter how you get there.
I saw where grisly had a whole class on digital for doing it like 60$ ?
It's kind of a light lathe but the built in rear spider looks like a good idea to me.
I told him to get the grisly rods ect but the old school master showed him some other way.
0.0005 or less is gtg no matter how you get there.
I saw where grisly had a whole class on digital for doing it like 60$ ?
It's kind of a light lathe but the built in rear spider looks like a good idea to me.
Some people will use a precision ground rod in the chamber end and indicate on that at two points. Others may use extended reach test indicators and dial in the chamber end of the bore in the rifling grooves themselves.
Regardless of how you achieve it, the bore must be running true for where you are cutting. Rifle barrel bores most of the time are not perfectly straight, nor is the outside always concentric with the bore. The chamber end can be dialed in perfectly and the muzzle may be whipping .010 or far more on some barrels.
Regardless of how you achieve it, the bore must be running true for where you are cutting. Rifle barrel bores most of the time are not perfectly straight, nor is the outside always concentric with the bore. The chamber end can be dialed in perfectly and the muzzle may be whipping .010 or far more on some barrels.
Knock yourself out. There's some good advice and some not so good advice. 130 pages of different ways to chamber a barrel.
That's a good one to review.
My biggest piece of advice, look at as many ways as you can, and use the one that you actually understand and makes the most sense to you. Never pick your way simply because some random person on the internet said it's the way to do it. I have some photos on that link from years ago. I no longer use those methods, and have refined my process.
I've never made a barrel... thought it's been an itch at times.
I am surprised that a half thou (.0005") is an acceptable tolerance. I'd think it would be tighter than that.
That said... I've never made a barrel. I have NO CLUE what a real tolerance is on a barrel. But in my imagination, I would have thought it would be tighter than that. A couple of tenths at the most.
Please, don't think I am denigrating barrel makers or precision rifle gunsmithing. I have no clue what your barrel tolerances are. I, for some reason, just thought that tenths were like meters in the precision building world.
So I'd be interested to know what are the tolerances folks work to in barrel fitting/machining? I guess it makes sense that between internal ballistics, harmonics, crowning... lots of factors... a few tenths is very reasonable. It's just that I never really thought about it. Because I never did it.
Interesting discussion.
Sirhr
Bought this ten years ago.
Through the spindle, between centers- once you understand the objectives behind each machining process, you'll realize there's usually several ways to "get there".
www.brownells.com
Through the spindle, between centers- once you understand the objectives behind each machining process, you'll realize there's usually several ways to "get there".
JOHN HINNANT THE COMPLETE ILLUSTRATED GUIDE TO PRECISION RIFLE BARREL FITTING | Brownells
John L. Hinnant. 8½" x 11". Revised third edition 304 pages. Self-covered. Not fancy but a very well illustrated, well written, in-depth analysis that provides both the advanced and beginning student a complete and informative shop manual. Covers ...
www.brownells.com
Well first off, I'd like to make the separation between "making a barrel" and "Threading/chambering a barrel". I have never rifled a gundrilled blank and have no qualifications in the way of "making a barrel", but I've chambered and/or threaded tens of barrels now. Some professionally, but most for myself and friends/family. Also, I shoot for fun, for PRS/NRL style plate matches, and for hunting. I'm not talking about F-class or BR-level OCD here.
Secondly, when you get to measuring resolution much below 0.001" there exists a rabbit hole of "how are you measuring that" and "what variables can cause distortion in your measurements"... My long stem indicator doesn't have as good of resolution as many short stem indicators... But how perfect is the fit of a rod in your bore for you to use a short stem indicator? Not saying one way is better or worse, just that there's limitations both ways. I don't have a known measurement on what spindle slop/runout I have on the lathe. I can't really tell how out of round I'm making the barrel by variable clamping force on the chuck jaws. I never check alignment AFTER I've cut the threads/crown/chamber, nor measured before/after running the lathe to see the effects of temperature. So exactly how precise I can say what I'm doing is limited...
I've seen a lot of... less-than-stellar machining that still shot amazing, and I don't believe in the dogma of obsessing to the .0001" for the sake of "it can't hurt". I do it for others as a courtesy (maybe not .0001", but within a few tenths, indicated), but for myself, given the choice between dialing it in for an hour or dialing it in for 5-10 minutes... I take the latter. Good enough is good enough. For crowns/chambering alignment, honestly if it fights me, but I can get it within .001" in 2 locations I start cutting. Some instances like short barrels that don't reach all the way through the headstock present opportunities where I only indicate in 1 location, and make a bushing for the side of the barrel that's inside the spindle bore to hold it roughly centered. Those barrels shoot just as well as the others, and have had no issues running 9" cans off the muzzle ends...
I have done flat crowns, I've done 11 degree crowns, I've done 13 degree crowns, 30 degree crowns, DEEP 45 degree crowns, saw cut and deburr tool crowns... Saw no stark differences in performance other than what can be seen from one barrel to the next. Some are just better than others, but I haven't correlated that to any crown angle, or "trueness" while dialing in. In fairness, the saw cut/deburr tool crowns never produced stellar accuracy, but cleanly sub-MOA for 5 and 10 shots. Everything else is 5/8" or less for 10 shots at 100. I have left chambers as-reamed, I've done 220 grit, 320 grit, 400 grit... No real difference noted on the user end, though I have read that FEA paper that's been around for a while now, and agree with what it says as far as bolt thrust goes (a whole different rabbit hole).
Often enough there is variation in bore O.D. vs. I.D. location, and that variation is variable along the length of the barrel. Some barrels you can watch cork-screw or hoola hoop as you look down the bore and run the lathe slowly. I've seen as bad as .020-.030 out. Most are .008" or less. They all shoot. It's not entirely uncommon that there can be a measured difference in groove depth. One of the grooves can't be "dialed away" and is always different from the others. You CERTAINLY can set things up in a manner that deflects/bends the barrel between the chuck and spider, inducing even more hoola hooping.
There is a lot of stuff that if most people here saw, they'd bitch to the barrel makers and smiths... and you see it at least monthly with more and more people getting bore scopes ("Does this chamber job/gas port/throat/barrel look okay?"). Truth of the matter is that the same stuff was going on before they could see it and the proof on target never had anyone worried about it. There's a gap between the perfection most folks have in their mind, and the reality of what some standard practices produce.
Anyway, I'm not saying shoddy work is acceptable, just that there's normal manufacturing variance, nothing is absolutely perfect, and when it comes to a piloted reamer following a pre-made hole, obsessing to the ten-thousandth.. mehh maaaybe doesn't matter as much as you'd think. There are certainly folks on this site with much more experience than myself, who I'm sure will rectify any false statements here. I'm always learning, too.
Secondly, when you get to measuring resolution much below 0.001" there exists a rabbit hole of "how are you measuring that" and "what variables can cause distortion in your measurements"... My long stem indicator doesn't have as good of resolution as many short stem indicators... But how perfect is the fit of a rod in your bore for you to use a short stem indicator? Not saying one way is better or worse, just that there's limitations both ways. I don't have a known measurement on what spindle slop/runout I have on the lathe. I can't really tell how out of round I'm making the barrel by variable clamping force on the chuck jaws. I never check alignment AFTER I've cut the threads/crown/chamber, nor measured before/after running the lathe to see the effects of temperature. So exactly how precise I can say what I'm doing is limited...
I've seen a lot of... less-than-stellar machining that still shot amazing, and I don't believe in the dogma of obsessing to the .0001" for the sake of "it can't hurt". I do it for others as a courtesy (maybe not .0001", but within a few tenths, indicated), but for myself, given the choice between dialing it in for an hour or dialing it in for 5-10 minutes... I take the latter. Good enough is good enough. For crowns/chambering alignment, honestly if it fights me, but I can get it within .001" in 2 locations I start cutting. Some instances like short barrels that don't reach all the way through the headstock present opportunities where I only indicate in 1 location, and make a bushing for the side of the barrel that's inside the spindle bore to hold it roughly centered. Those barrels shoot just as well as the others, and have had no issues running 9" cans off the muzzle ends...
I have done flat crowns, I've done 11 degree crowns, I've done 13 degree crowns, 30 degree crowns, DEEP 45 degree crowns, saw cut and deburr tool crowns... Saw no stark differences in performance other than what can be seen from one barrel to the next. Some are just better than others, but I haven't correlated that to any crown angle, or "trueness" while dialing in. In fairness, the saw cut/deburr tool crowns never produced stellar accuracy, but cleanly sub-MOA for 5 and 10 shots. Everything else is 5/8" or less for 10 shots at 100. I have left chambers as-reamed, I've done 220 grit, 320 grit, 400 grit... No real difference noted on the user end, though I have read that FEA paper that's been around for a while now, and agree with what it says as far as bolt thrust goes (a whole different rabbit hole).
Often enough there is variation in bore O.D. vs. I.D. location, and that variation is variable along the length of the barrel. Some barrels you can watch cork-screw or hoola hoop as you look down the bore and run the lathe slowly. I've seen as bad as .020-.030 out. Most are .008" or less. They all shoot. It's not entirely uncommon that there can be a measured difference in groove depth. One of the grooves can't be "dialed away" and is always different from the others. You CERTAINLY can set things up in a manner that deflects/bends the barrel between the chuck and spider, inducing even more hoola hooping.
There is a lot of stuff that if most people here saw, they'd bitch to the barrel makers and smiths... and you see it at least monthly with more and more people getting bore scopes ("Does this chamber job/gas port/throat/barrel look okay?"). Truth of the matter is that the same stuff was going on before they could see it and the proof on target never had anyone worried about it. There's a gap between the perfection most folks have in their mind, and the reality of what some standard practices produce.
Anyway, I'm not saying shoddy work is acceptable, just that there's normal manufacturing variance, nothing is absolutely perfect, and when it comes to a piloted reamer following a pre-made hole, obsessing to the ten-thousandth.. mehh maaaybe doesn't matter as much as you'd think. There are certainly folks on this site with much more experience than myself, who I'm sure will rectify any false statements here. I'm always learning, too.
Just wondering why no one wants to work in a machine shop and learn how to machine first.
Where you located? If you are local to Wi I’ll give you a free lesson. Chad Dixon posted many times about his manual process as well as his Cnc methods, there’s lots of little bits here and there to pick up on and implement. Do what you think works best or what you like, there’s a lot of ways to get the job done.
I’d assume it’s because most people are already long settled into their job/career long before the idea of fitting their own barrels pops into their head.
That’s the best way to go about it. Barrel work is less complicated than most work, day in and out that a machinist performs. Go to a trade school for machinist trade, it will pay off better long term than a “gunsmithing” school. I’ve kind of always laughed at the “gunsmithing” schools. You’re either an engineer, a machinist, or both.
As many have said, there's plenty of ways to skin this cat. I've chambered a few barrels that all shot well using a fixture that resembles the Viper fixture. I understand it's limits and take my time and make light cuts since it's not the most rigid setup.
Unfortunately I have a lathe with a large headstock so a barrel won't reach the outboard side to use a spider and I don't have a steady rest to turn between centers.
Work with in the confines of your machine, pick a method of chambering that offers the most rigid setup based on the equipment you have. Have patience when dialing things in, and take small cuts as you're learning. It's really not very difficult, just don't rush things, the more careful and diligent you are the better the end result will be.
Unfortunately I have a lathe with a large headstock so a barrel won't reach the outboard side to use a spider and I don't have a steady rest to turn between centers.
Work with in the confines of your machine, pick a method of chambering that offers the most rigid setup based on the equipment you have. Have patience when dialing things in, and take small cuts as you're learning. It's really not very difficult, just don't rush things, the more careful and diligent you are the better the end result will be.
And I've talked many an engineer and so called machinists off the ledge when it comes to barrel work....Mileage varies.
Later
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