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Lathe chucks

Acsr

Silver $$ Contributor
Been using a 4 jaw chuck, takes me a long time to dial in a barrel, is there a better option as far as chucks go? Any tips would be very much appreciated.!
Thanks ACSR
 
Been using a 4 jaw chuck, takes me a long time to dial in a barrel, is there a better option as far as chucks go? Any tips would be very much appreciated.!
Thanks ACSR
You could look at the True bore alignment system. I dont know if it is any faster than the way you are doing it now but you can evaluate that. I usually dial in on a pin then drill and bore to make room for the indicator. Dial the throat , true up the bored hole and then ream. I have a 6 jaw adjust true a four jaw and a spider chuck for me they are all about the same in terms of manipulating the position of the bore
 
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It gets easier, is all I can say. Perfection takes time and that's what you're after. Some barrels go better than others for a few reasons. A really, really straight one seems like it indicates itself in at times. We are trying for perfection in an imperfect world here. What does your lathe spindle runout measure? We toss around numbers on shooting forums that true tool and die people that have done it all of their life, in lab environments at times, don't work with every day. And we want it from a cheap lathe in our basement? Hmmm. Look up the specs on your lathe if it was bought new. If so, it should've come with an inspection report. I bet the spindle had over .00015 runout when it left the factory! Just check and see.
 
Keep at it, and remember your lathe may be looser than you think. I would skip right past the Tru Bore, I have had one for a few years and never use it on barrels. I did make a new back plate for it and run it on a CNC for a non gun related part. Its a well made system, but when you look back at the basics of machining, its a solution for a problem that does not exist.
 
just wondering why would anybody use 6 jaw chuck ? in the 45 years in a machine shop i've only seen
one or two and one of them had three jaws off the chuck. half my that time was in a tool room. is it the
more the better theory. or am I missing something. i've often wondered when I see these nice setups
for do barrel work .
 
Short of going true bore alignment system, 4 jaw is what you want. It gets easier. I tried a bunch of things, gordy rods etc... Fastest/easiest way is dial it on the OD, then go ID and you'll be close.. fine tune and go.

If it seems impossible to get it right... make sure everything is clean and the stylus isnt rubbing...
 
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just wondering why would anybody use 6 jaw chuck ? in the 45 years in a machine shop i've only seen
one or two and one of them had three jaws off the chuck
I have and use a 6 in the shop for thin tubing and delicate parts that you don’t want to clamp too tightly. I would not buy one specifically for regular machining or barrel work. One downside to them is they won’t hold as small of diameter parts as a 3 jaw. Maybe some have a 6 for the same reason I have one and then use it for barrel work?
 
I have and use a 6 in the shop for thin tubing and delicate parts that you don’t want to clamp too tightly. I would not buy one specifically for regular machining or barrel work. One downside to them is they won’t hold as small of diameter parts as a 3 jaw. Maybe some have a 6 for the same reason I have one and then use it for barrel work?
I have a Buck 6 jaw that I bought when I was stupid. It's a gorgeous piece of machinery. I love it. It has its place in the shop, for sure, but I don't think it can hold less than 5/8ths.

Gator 6 jaw will hold a pretty small piece. It's got really pointy jaws
 
It does get easier. I spent many years working in a busy hydraulics shop. Virtually everything was set up in the four jaw chucks; either through the headstock or in the steady, and you had to be fast. I don't know what you might be using to hold the barrel, between the barrel and the jaws. I use brass or soft iron rod. This allows the barrel to pivot in the chuck as you align the muzzle end.
I was fooling around one day and found that I had some of those old Bushnell adjustable arbors, the ones they made for their boresighters. The darn things are surprisingly precise and repeatable, so I use them quite often, on the muzzle end.
For little things, I have a four inch three jaw which I hold in the four jaw. Once it is dialed in on a given diameter, it works great. For tiny pins etc., I hold a drill chuck in the four jaw. WH
 
The guys are right, first you want to check your bearings. Your spec sheet wont tell you this, it will just tell you spindle runout which is the id of the taper and only matters when using a collet. Thats also measuring how well the spindles ground. Dialing in a part with a 4 jaw isolates the bearings. So dial in a gage pin or some other precision ground part and see how good the bearings are. You know you have isolated the bearings because the high spot on the part will move as those rollers roll around the races. You'll always chase that number if its in the bearings. It will drive you mad. So check that and fix it if need be.
 
I’ve often wondered about a very fine adjust 4 jaw… contemplated going about making one… haven’t done it yet though
 
I use gage pins exclusively for dialing in the muzzle. -.0005" under nominal bore diameter fits every barrel. Occasionally I'll get an odd ball on the large side that I'm not comfortable with and then I pull out the bushing box.
Now all you naysayers calculate the angular misalignment in a 26".

What no love for an inboard spider?

As inexpensive as these are everyone should have one.
 
I use gage pins exclusively for dialing in the muzzle. -.0005" under nominal bore diameter fits every barrel. Occasionally I'll get an odd ball on the large side that I'm not comfortable with and then I pull out the bushing box.
Now all you naysayers calculate the angular misalignment in a 26".

What no love for an inboard spider?

As inexpensive as these are everyone should have one.

Seen guys just clamp them in a 4 jaw and use this instead to dial barrels in for the finer adjust of screws
 
I use gage pins exclusively for dialing in the muzzle. -.0005" under nominal bore diameter fits every barrel. Occasionally I'll get an odd ball on the large side that I'm not comfortable with and then I pull out the bushing box.
Now all you naysayers calculate the angular misalignment in a 26".
I use a reamer bushing to dial in the muzzle on the outboard side.

I have bushings and Gordy rods for most of my reamers but I rarely use them any more. I now prefer to just use the Interapid direct.
 
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