Touch hole too high?

[flinchrocket]

I would not weld on the frizzen it is hardened and tempered. If you notice on the bottom of the frizzen
next to the barrel there is a little notch cast into the bottom. That is where I put my touchholes, scribe a line across the top of the pan and the center. You are only 1/32 or so high, it will be just fine.
  Black powder burns at 4000 deg but it only takes 400 deg to ignite, the heat from your pan powder will set the main charge off faster than a low touchhole burning through like a fuse.

[kudu]

Now a good machinist would use a prick punch to locate the hole to be drilled, then a center punch to position or set that hole and then use a center-finder tool and drill with a center drill.

That said, I bought a used flinter with a touch hole too high, and went in with an end mill (on my Bridgeport) to lower the starting hole, then tap-drilled and tapped for a Chambers white
Lightening liner. Works flawlessly now! As this is a hunting arm and I too was concerned with fitment or location to the frizzen cover whilst closed.

Im good machinist and like you use my Bridgeport mill with the digital readout and all its hard to drill a hole where you didn't want it. Not impossible but just a little more predictable of a outcome.
I no longer hand cut and file dovetails for Sights or Lugs anymore I use a dovetail cutter from "Brownells" and they come out perfect straight across the barrel .055 deep or whatever depth you might want i cut one a while back only .035 deep and it was perfect.

[ddoyle]

Leaving that is not going to be satisfactory

I am great at getting holes in the wrong place, totally understand  how easy it is to think you are doing well only to find  things went awry.

Further to the advice given above about drilling procedure, some things I find help:

Have a magnifying glass on the bench. when you mark the hole with a scribe and likewise when you  make a punch mark check it with the aid of the magnifying glass. Is it exactly where you want it? If not move the punch mark. A punch mark will travel long distances. Make sure the last few punches are at 90 degrees to the work.

Punch the heck out of it and then punch it some more. You should have veritable crater available to grab the drill. Use a punch that has the same angle as the drill you are going to use- see below.

Use a STARTING drill- Center drills are ok but are not the best tool for the job. Center drills are wonderful because the are stiff but the best tool you will cherish is a Starting Drill. Costs  more and 90% of people will hand you a center drill when you ask for a starting drill but they aint the same. I think I paid 10 dollars for mine. It has one function to start a hole where you put the tip.

 

[Scota4570]

This may be the best solution.  I just found this idea.  Raise the pan with a washer like extension that surrounds the touch hole.  That avoids messing up the heat treatment on the frizzen.  The frizzen would be only slightly modified. 

http://americanlongrifles.org/forum/index.php?topic=46814.0