bbl liner-touch hole????????'s

[dbutch]

Just received a relined 42" A weight gm swamped bbl(R.A Hoyt)at the
Freischutz Shop....700 Fairfield Station Rd Fairfield,Pa.
717-642-6696
212.00 shipped to my door.
went from 36 to 32 cal. 1-40 twist round radius.
need to remove whats left of the old touch hole liner and redrill and tap the new bbl liner...

Question..is there any special I should do or watch for during the drilling and taping???
All imput welcome..Thank You.....Dan

 

[Shifty]

I would talk to Robt about that I think,but probly the only trouble you would have is getting the new hole drilled into the liner centered with the old touch hole liner hole.Does that make sense to you.

 

[galamb]

There is still remnants of the old liner there or you are just drilling/tapping for a larger liner?

If there is some (residue) in there I would try and drill it out with a drill smaller than the tap size drill you will ultimately use - don't want a larger hole than intended.

If you are just drilling/retapping, just take it easy with your tap drill - keep it as "squared up" as possible.

There is a special counter sink bit with a pilot that will greatly assist putting the slight chamfer on the hole, but you can simply use a bit larger bit with some care (usually instructions with the liner if you buy a decent one).

You can do it all with a single tap. I like to use two, a (normal) tapered tap which gets you started quite well, but I finish with a plug tap, which ensures that the innermost threads are cut properly (the tapered tap will sometimes hit the other side of the bore while the tapered part is still not clear of what you are trying to thread).

Oh ya - don't drill too far unless you want a vent hole on the other side as well :rotf:

 

[excess650]

If you have access, I would plunge the existing liner with an end mill. This will prevent your drill from walking off center. You could use a center drill to enlarge the existing touch hole to act as the pilot hole....be careful when tapping, and especially if you're not centered perpendicular to the bore.

 

[dbutch]

Thanks Guy's for the input!!
Drilled out the old 1/4" to 5/16's taped and seated...
all went well!!!..Bonus!
picture of A weight gm 42" flint 1-40 twist 32 cal bbl lined....