Indicating A Barrel, How I Hold my Tube and Why!
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- เผยแพร่เมื่อ 15 ก.ย. 2024
- How you Hold a barrel in your lathe is just as important as how you indicate it. In this video I show how I hold my barrel and some of the mistakes that people make when trying to hold their barrels. There are a few key concepts that you must keep in mind when indicating a barrel. It needs to move to properly indicate it.
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Very good video! I have been GunSmithing for 37 years and this has been my preferred way to center a barrel. Thanks great information.
Thanks for the feedback!
I was off youtube for a few months , and i am happy to see your vids again , thank you to share this knowledge, me and others appreciate
Regards
Tony
Thanks for the info....-gunsmithing student
agree with, That's the way I was instructed to set it up... 100%
Thought you did an excellent job of explaining. The Vice visual is perfect.
Thanks, It was the best thing I could come up with at the moment.
If only some genius would invent a chuck with 4 independent jaws.
Hahahah. What sorcery that would be? In all seriousness, You can buy a china made four jaw for around 300-500 bucks. And they're plenty good enough for barrel work.
Very interesting, it's the first video I see explaining this 👍
Glad it was helpful!
Very informative. The only thing lackin is a view of what you are doing on the outboard end of the barrel to move it.
Yeah, 4 screw spider. Basically the same as the chuck side, you just move it in opposite directions of course to get it to where you need it.
Nice examples
The smaller contact area makes sense to dial in the spider. But, how do you account for uneven thickness in the copper, etc? That's almost guaranteed to be off center.
That doesn't matter because you indicate the barrel after it is clamped on place. The chuck I show in the video is an adjust-tru chuck, so I indicate the barrel by moving the chuck around after it's clamped solidly in place.
OK. I was thinking more along the lines of a standard 3-jaw chuck.
Gotcha. Nope that would not work at all in this case. You would be hoping for a miracle for it to line up with a non-adjustable 3 jaw.
Precision Machine Shed I too was wondering how you made a three jaw chuck center on the bore until I read that it was a adjust-tru jaw chuck. There’s probably a bunch of people thinking they’ll be able to do it with there stationary three jaw.
Use that same setup between drill chuck jaws and a drill bit and put some torque to it and see long your work stays centered and stationary in your chuck. Put copper between two steel parts with copper being a "lubricant" used in engine bearings for a reason and the copper is going to "hold fast" right up until its subjected to enough lateral or radial load to compress or shear it and then you're done.
From the several posts on numerous videos, I can tell that you have very little real world experience with anything that I do on my channel. Anyone else reading your comments will agree with that statement.
And this clown has no real training as a gunsmith!
We make soft jaws for the 4 jaw independent that only make contact to the workpiece for about .200" a 4 screw spiderchuck on the back end of the spindle for squaring. Lately Iv been grinding my own indicating rods so I get a good fit in the lands. I did a Mauser 98 in. 257 Roberts the other week and the blank they guy had was really off center, looked like an egg rolling around in a chuck. I like the wire tequnique I might ttry it when I runout of soft jaws
I've since made a spider for the chuck side of the spindle. I now have a spider on the outside and inside of the spindle.
excellent idea for the pivot
Thanks.
So what did you do on the back end of the headstock?
4 jaw spider.
Nice job! But even more interesting, is the "scraping" marks on your bed ways. Did you have the bed reground then hand scraped? Did you do this yourself or have it done? What kind of $$$? Thanks again for the tip. JB.
I had the bed reground and scraped by Rick Ardenberg, owner of A&D tool machine rebuilding in Roberts, WI. It was a couple years ago, so It is best to call Rick and talk to him if you are seriously thinking about having it done. I'm sure a price will depend on what you want done.
Great video, I always enjoy watching them. I am curious though... I know you are using the copper for a pivot point, but how do you keep from bending the barrel when adjusting the outboard spider?
It will move a little in the copper and pivot. You can move it by hand from the muzzle end around the spindle bore. The spider isn't there to jack the barrel around, but just to hold it in place once you have gotten it to where you want it. If you clamped the barrel straight into the jaws, then jacked the muzzle end around, then you would be bending the barrel without a doubt.
i do mine the same way but with a 4 jaw
Yeah, I did one the other day and just used the 4 jaw cause that's what I used last. Works just the same.
How it this different than using a 4 jaw and indicating off a dowel pin in the bore?
The only difference is that your clamping pressure on each jaw stays consistent VS. wrenching on each individual jaw on the 4 jaw. Other than that, you are achieving the same outcome.
Using a four jaw, you can dial indicate and center the bore with the centerline of the lathe. Using a three jaw, it is highly unlikely that the bore is perfectly centered with the centerline of the lathe. That is a huge difference and the three jaw method is less than ideal.
GREAT VIDEO !!! SHOW INDICATING , PLEASE .
YOUR WAY MUCH BETTER -- OTHER LEAVES SPEED BUMPS IN BORE , 50 PSI + HARDENED ROD = 1 ZILLION PSI ??
Thanks, I can't remember if the guy mentioned used shims or wire under his pins or not.
How do you stop the muzzle end from moving?
It gets dialed in to zero with the adjustable buck chuck and the outboard spider.
The soft copper between the jaws/barrel will indeed allow a good degree of barrel movement/ adjustability when used this way to center the bore axis.
However, once you've got the bore axis dialed-in and want to actually begin working on the muzzle, the slightest amount of force applied to the muzzle end will cause the very same soft copper to deform and throw the bore alignment off.
In chambering several dozen barrels with the method, I have not witnessed what you are talking about both before during and after machining of the barrel. I have always ended up with zero run-out, or less than a couple tenths. You must remember, you are not hogging off material when you are doing barrel work. If you were taking 0.200-0.300 cuts, yes, I would expect it to move.
I can’t see there being much better than .010-.015 runout on the chamber end. Sloppy chamber. Plus by using anything soft you WILL end up with runout at some point in your operation. But if you’re using a 3 jaw you’re not worried about runout
Never had an out of round chamber! The bearings on your lathe will move more than the crushed wire after they warm up! The 3 jaw is an Adjust-tru chuck. If you don't know what those are, you can adjust them to Zero run out!
@@precisionmachineshed I don't have a adjust-tru chuck. Can I use a independent 4 jaw chuck?
Of course you could also use a cat's head (or even a 4-jaw, or a cat's head in the 4-jaw!) to do a better job at centering than a 3-jaw. The 3-jaw seems like the weak link. Isn't the main point of using a spider on the outboard and a cat's head at the spindle to give precise alignment? Not just centered, but to know that the bore of your barrel is aligned with your lathe spindle.
Your lathe looks nice, did you scrape the ways or is that original flaking?
I think a lot of people are missing the fact that this is a 3 Jaw Buck Chuck Adjust-Tru chuck. It basically acts like a 4 jaw. I can adjust the chuck about 30-40 thou in any direction with 4 set screws without removing the clamping pressure on the barrel. Yes a standard 3 jaw would be useless in this example and would not allow you to align the bore perfectly to the spindle. The reason I use this instead of a cats head or a 4 jaw chuck is because I can get a constant clamping pressure all the way around the barrel and then indicate it in from there using both the adjustable 3 jaw and the outboard spider. A 4 jaw or a cats head would work, but then you are just about guaranteed to have different clamping pressure on the two opposing jaw sets. Getting all 4 aligned and properly indicated will not allow all 4 jaws to have perfectly even clamping pressure on each jaw. Does that matter, maybe not, but who's to say when you are cutting a $350-$500 rifle barrel.
I had the lathe re-ground and then scrapped in by a guy that specializes in it in Wisconsin.
Maybe so, but you can adjust a 4-jaw 3"-4" without worry. :)
The fact is that your adjust tru will never be as true as you can get a 4-jaw.
I usually indicate my barrels down to less than 0.0002" anything beyond that is great, but it comes down to the person dialing it in. I can't get a 4 jaw any more accurate than I can get the buck chuck. I don't need 3-4" of travel ether with a rifle barrel.
I'd say you're a good machinist if you're able to get a South Bend lathe accurate to 2 tenths, when the machine itself if probably accurate to .001".
I had my lathe professionally rebuilt for the purpose of barrel work. Yes, my spindle has 0.001" play in it for lubrication purposes, but thats in across any one axis. Worst case scenario is I will get half thou run-out if I'm really pushing my material and not cutting it. I don't take heavy cuts and I have measured my work after the fact and it holds 2-3 tenths. Most old SB lathes will not perform as well as mine.
Why didnt you show how you're supporting it on the back end?
Didn't think of it at the time. Just a 4 screw spider with brass tipped and rounded off ends.
dial indicator tells all
nice job brilliant idea
big fan of ur channel and videos
i need an advice about a project im working on
can contact you on email ??
Sure anytime. precisionmachineshed@gmail.com
This is just plain wrong.
What part?
Precision Machine Shed all of it.
seems plausible to me. I will try this next time I work on a barrel.
Use a spindle instead
Not sure what you mean by a spindle. The chuck and the spider mount to the spindle, so technically, I am already using one.