stress to build in the barrel, and thus warp the barrel.
It is very important to keep any stress from build up in the barrel (Live centers, to tight centers, dull tool
bit, improperly sharpened tool bit, etc.) Now for the tool bit. I have used carbide most all the time in
turning barrels. I prefer a good grade of high-speed steel as they are sharper and cut better, but require
sharpening every pass, to keep a good edge. I had to use carbide due to the time saved.
I grind all my tools to the general shape. On high-speed bits I used only about .010-nose radius, stoned
on by hand. Set the tool up so it is about .010 above the tail stock center.
If I have the time, I usually use a feed of .004, but you will need to experiment to see which feed works
the best. Usually I do not take over .020 passes per each side on each pass.
What you have to watch for is that the cut is not heavy enough that it will cause the barrel to spring,
especially on the barrel that is half way turned down. This springing causes stress. Here is where a
good steady rest or a follower rest becomes important. With a follower rest, you will be able to cut the
outside of the barrel with no taper, which is caused by springing.
The tool must cut clean, for if it drags, or it is slightly dull it will cause the barrel to heat as it is turned.
When the bit is sharpened right you will get some heat build up, but not much.
Watch the chips, as they are coming off the barrel. If they turn a dark blue, you are taking too much a cut,
or the tool is dull.
Keep close watch on the pressure on the tail stock. It must be snug on the barrel, but not tight. As the
barrel heats its lengthens, and the tail stock must be loosened. If the tail stock center loosens too much,
the tool bit will chatter. After the barrel is turned to about, 3/4 finished; you will need to remove the barrel.
You will then check to see if the bore is straight, and straighten if necessary.
If you have kept a sharp tool and a light feed, it should be straight. You must, after ever pass from now
on the barrel should be checked to see if it is straight. If the barrel has warped, take a lighter pass after
it is straighten.