Barrel set up

S

singleshotom

Guest
For years Ive set up a barrel in a lathe for fitting and chambering between centers as taught by a old target gun smith.
As I read most posts here for the past year or so I see what I think is the majority of people seem to do this work through the head stock.
I just wonder if I'm old fashioned or what?? Just curious......
SST
 
"between centers" is an old method that still can work well with quality barrels but for the best you can wring out of a barrel requires a chamber that is centered and lined up with the throat area of the barrel... and this seems to be most easily accomplished through the head stock...
 
I understand some of that but, what i have seen with a few guns that I worked on that other smiths have done, seem to have a bit of runout in chambering and I'm wondering if ths happens when they are trying to fit the action on the barrel....... and without knowing it the barrel has missaligned .....
due to the fact that the barrel cant be held very tight in the spider or the jaws....
Just what I worried about when I did it in the head stock.... Where as between centres the barrel is returned and can retain a fairly consistant alignment....
Or do most of you realign the barrel after each trial of the action fitting?
sst
 
SST, I do not know your level of expertice as a Machinist, but in the Machinist World, we try to avoid what is referred to as "stacked tolerances".

I see the set-ups used by various craftsmen, and I have a feeling that many do not understand this concept........jackie
 
Tell me about runout. Are you talking about an out of round chamber? How can you make that happen even trying. I will buy a chamber that is a little large at the base, but oval?
Butch
 
Butch Lambert said:
Tell me about runout. Are you talking about an out of round chamber? How can you make that happen even trying. I will buy a chamber that is a little large at the base, but oval?
Butch
Click to expand...

Butch, realize that a 6-flute reamer can also be a single-point tool if it is ground so just one flute is cutting, which is not unusual. Now then, lets set that barrel tenon up in a steadyrest to where the steadyrest is running on an out of round tenon that was machined from the result of an out of round center, not uncommon.

Now then, as the tenon rotates through its now orbital path the now one flute cutter scoops out more material on one side than the other, not uncommon if you are using one of these famous floating holders that do not float. Just like cutting a cam!!!

Granted, this is an over simplification but you get the idea.
 
Thanks Jerry for explaning how an out of round chamber might happen. The camming effect clears things up

Hal
 
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