Thursday, December 1, 2011

Heavy Barrel Sleeve for a BAM B26-2 Part 1

I've had a piece of steel for this project on hand for some time now.
Not sure as of yet just how far I'll go with it--more on that later.












The old .22 cal BAM B26-2 from a Pyramyd Air open house several years ago.












Aside from maybe needing a new blue job, there was nothing particularly wrong with the existing muzzle brake, just wanted something different.

















Removed















Barrel band for the sling, too.












Gonna start with a 7/8" OD DOM (Drawn Over Mandrel) steel tube.  The ID is 0.635".












Bought it because it's virtually a perfect fit over the barrel.
















Should've bought an even longer tube, though I'd like it to eventually be the same length as the barrel.















I realized that it was slightly too large in diameter at the breech block and would need to be tapered.















Except the tube is longer than the bed of the Taig lathe.















Here's where another inch of length would've helped.  I have about half an inch to chuck.  I'm going to cut the taper just in front of the 3-jaw chuck.  I set a carriage stop as well as set the compound crosslide at the very end of it's travel.  Critical to check clearances to avoid running into the headstock.  Could've easily used a mandrel inside the tube, but I saw that this would work--just barely.















Light cuts--necessary anyway when cutting a taper.















Ground a round-tipped tool bit.  Played with the edge geometry a bit.















The steady rest fingers were greased with moly to help avoid scoring the tube.  Just don't run them dry.
















Don't try this at home.  Wiped a file across the taper to blend it in.  Next to the spinning 3-jaw, this is horrible idea.  Seriously, don't do this.















This is also a bad idea--remember, there's very little material chucked in the jaws. 















A quick shine with some 220 grit.  Note the lathe bed is protected with foil from the grit.














 
Low speed and I kept the work supported.  Un-chucked and cut the stub off the end.















Since it's too long to face down in the lathe, I cut the tapered end off squre using the mill.
















Test fit.















Barely too long at the business end--and a bit uneven.































About 0.124" too long.   Could've used that in the chuck...















Scratched a line in the layout blue.  Just provides a witness line to cut to.















Touched the cutter to the end of the work then dialed in 0.118" into the table and made the cut.  Switched to a higher speed and made a couple more passes taking off a couple thousandths each time until I hit the line.

I could just drill and tap for a few set screws, blue it and it's done.  Or maybe I'll lose my mind and try fluting it.  I'll try some test cuts on another piece of steel and see what kind of finish I can get.

More soon.





2 comments:

Phil Schmidt said...

Need to JBWeld that sleeve on. Would really stiffen the barrel

Phil Schmidt said...

You should JBWeld the sleeve on. It would really stiffen the barrel.