tapered touch hole article in latest (May) Muzzleblasts

[bgf]

This has come up before here, so I was interested in the topic and thought others would be interested in seeing the article.  In summary, Jack Brooks ("Ask the Master" column) saw an original with a touchhole in good shape (not shot much) and it was tapered roughly 1/8" to 1/16" with the larger diameter on the outside.  He used a tapered reamer to produce the same hole and tried it out.  This kind of a touch hole makes sense to consider for those who don't want to use a liner or cone hole from the inside.  I believe it was J.W. Everett who suggested this method (or a similar one) for making a touch hole.

[LRB]

 That's SOP with Caywood guns. It is their opinion that vent liners are deadly missles waiting to be launched. I disagree, but that's their position.

[Dphariss]

I bet actual testing will show they are slower and less reliable than the WL type.

The only people who really seemed to do much with vents and locks to improve speed and reliability back in the day were the English. Nock, the Mantons and a host of gun and lock makers through the 18th c and into the 19th. These improvements were driven by WING SHOOTING as a sport of the rich and famous.
The high end English guns invariably have a version of the WL by about 1770-1780, either gold or platinum lined after this metal was available.
Some of the stuff was just window dressing, but the Nock Breech, the lock improvement over decades, and the vent liners were real. The recessed breech was thought to speed ignition but it really allowed narrower, ligher guns, especially double barrels.
And yes this "English" stuff WAS used here by some makers.  But the average pig farmer had no interest in high end guns here or in England.
Dan

[Kelhammer]

I was excited to see that article.  From what I understand, conning from the inside works because you are moving the powder in the chamber closer to the flash in the pan.  Also it shortens the distance of the smallest diameter hole, thru which the pan flash must travel.  It obviously works.  However if left to my own devices conning from the outside seems simpler, and makes more sense in my mind.  I say this as I imagine the flash would be funneled into the chamber.  You have also still shortened the distance from flash, to chamber.  I would love to hear some real thoughts on this, from guys with the experience.

Andy

[T*O*F]

The high end English guns invariably have a version of the WL by about 1770-1780,

I think you've got it backwards this time, Dan.  The Egg obviously came first, not the WL.

(ps...this is subtle humor for those of you who don't get it)

[smylee grouch]

Good one TOF.      I also would trust someone with real experince and thats why I also agree with Dan and Pletch. The WL liner is the fastest out there acording to the tests. The others will generaly work, just not as good or fast.

[Ky-Flinter]

Not knowing any better, I used a 1/4-28 allen set screw to make the vent liner of my first flintlock, circa 1997.  The allen socket was sort of an outside cone, then I coned the inside.  The resulting channel was shaped like an hourglass with a very short "waist".  I know this is subjective, but a lot of fellow shooters have commented how fast that gun shoots.

-Ron

[Larry Pletcher]

I was glad to see the article too.  This gives me two tests to do that are opposites of each other, but very likely work beautifully. I have a Mike Miller rifle with a vent made with Tom Snyder's tool. It has not been timed; I have another barrel that I'll use for that test. My plan for it is to time it as it's being cut to see what effect the web length has on ignition. BTW the Miller flint's ignition seems very fast to me, but I always distrust my senses.

A vent cut with Jack Brook's reamer would be a great comparison. Both methods allow the two charges to get close to each other. I also like the funneling effect that this vent may provide.  I look forward to playing with this idea.
Regards,
Pletch

[MScott]

I think a touchhole coned on the inside acts much like a shaped charge  directing the majority of the ignition inward.

[Bob Roller]

We should all be glad that there were enough "High End" guns to
admired by later generations.As one author wrote,"Tiny gold plated pans,Platinum
flash holes and small,powerful locks" made for an external ignition system that
was as reliable as could possibly be made.

Bob Roller

[little joe]

I have coned several from the outside and had good results most of the time. On a couple it hindered ign. time.Carefully locate the hole and if it doesn,t do good drill it out and put a liner in.

[billm]

My most used gun is done this way and works really well.Its fast and reliable.If the hole ever opens up or I am unsatisfied I can install a liner. For me I dont like the way a liner looks.So if this method works,which it does,then why not.

[Dphariss]

My most used gun is done this way and works really well.Its fast and reliable.If the hole ever opens up or I am unsatisfied I can install a liner. For me I dont like the way a liner looks.So if this method works,which it does,then why not.

You may find its difficult to tell when its eroded. I had an vent that still would not pass a number drill larger than it was drilled with but was eroded just the same. The hole was no longer round and had little gas cut grooves in it as well when I REALLY looked at it. This would be harder to check if the small diameter is back in a hole.
This is yet another place where people try to improve something that reached its pinnacle in the late 18th c.
Dan

[woodboxmaker]

I like to start with a #1 center drill, which the pilot is slightly smaller than 1/16". the body diameter is around 1/8". If I drill with the center drill just about out to its full diameter, then finish the hole with a 1/16" drill, seem to work great. Locating the hole about 1/64" above the bolster/pan centerline works better sometimes.....

[Jim Kibler]

I wonder how common this heavy tapered treatment was originally used?  I can't recall seeing any original guns like this, but I haven't been looking specifically for it either.  It seems that a 1/8" hole on the side of the barrel would be noticable though.  Jack mentions seeing it on an original fowling piece I beleive.  Have any others come across this treatment?

[Curtis]

I made a reamer from a file as Jack Brooks described in his article, and used it on this gun when I built it a couple of years back.  I have never timed the ignition, but it is quite fast and reliable.  I would recommend trying it, like the article says you can always drill it out and use a liner if you aren't happy.



Reamer in use by Micheal on his trade gun:



I highly recommend turning the reamer by hand and NOT in an electric drill, if you don't get the heat treatment just right the reamer could snap off in your touch hole causing you to figure out how to remove it, and of course then make another reamer.  Don't ask me how I know this......  

Curtis

[James Wilson Everett]

Guys,

I surely looks like the reamer Curtis used is very similar to an 18th c square reamer!  The only difference I see is the the reamer Curtis used has a more pronounced or sharper taper than originals.  Maybe the wheel has been reinvented, again?  I may surprise modern craftsmen to find out how quickly a square reamer will cut metal.  Here is a small reamer I use to size my lockplate screw holes to about 0.15 diameter.



Here are some larger original square reamers, you can see the much more gradual taper.



My original contention was not that flash holes were tapered on purpose to make better ignition, but that all such holes were slightly tapered as necessitated by the existing tooling of the 18th c.  I have never seen any original 18th c. tooling that would result in straight diameter, smooth, straight holes.  Twist drills and chucking reamers simply did not exist in the time period.  If anyone out there has seen any original tooling that would result in the type of straight flash holes we use today, it would be wonderful to see the research.

Jim

[tallbear]

Jim
I understand the point you are trying to make but your pics are a little misleading.While I have had no real problem drilling parallel hole using a bow drill set up similar to the one in Dederoit's plates found here http://artflx.uchicago.edu/images/encyclopedie/V21/plate_21_19_34.jpeg even if you followed up with a reamer like the one pictured below, the difference in the size of the hole in the barrel wall thickness is less than .001.Hardly enough to worry about in the grand scheme of things.

Mitch