Touch hole size ??

[pretty]

I just bought a 50 caliber Flinter and some one told me the touch hole was to small, could some one tell me what size I should drill it out to?

 

[Larry (Omaha)]

I just bought a 50 caliber Flinter and some one told me the touch hole was to small, could some one tell me what size I should drill it out to?

Don't drill it, check the ignition first!!! 1/16" can work well, but will depend on the lock and touch hole configuration. You do not want to go any larger than needed to accomplish decent ignition.
Larry

 

[TreeMan]

Every rifle I own is drilled to 1/16. I’ve not found going any bigger gets better results.

 

[Musketeer]

1/16" (~1.6mm) is pretty standard. Some go up to 5/64" (~2mm), which is what the factory vent on my Pedersoli Brown Bess appears to be. Like Larry says, make sure you shoot it before you do anything (if you haven't already), as it may shoot fine as is.

 

[Bighorserider]

When I built my first flinter I drilled a 1/16 hole. It seldom went bang the first time. I opened it up to 5/64 and it worked good. I didn't have any number sized drills. A touch hole liner may work better with 1/16, but I don't have one of those either.

 

[Art Caputo]

I think judging the size of the flash hole visually can be deceiving. I agree with testing the rifle first, and would measure your current flash hole size before any drilling , particularly if the measured diameter is greater then 050”. While my flash holes have ranged from .047-.078”, given a chosen starting point, my preferred size is .0595”(#53 drill bit) to .0625”(1/16”), my experience has been that starting at .059”(#53), with the coned style liner, you can do a whole lot of shooting before the flash hole erodes much beyond 1/16” and maintain consistently fast ignition. IMO.

 

[Grenadier1758]

It is worthwhile to have a set of number drills from 60 to 1. @Art Caputo is quite correct in suggesting a starting point for the touch hole to be the #53 drill bit with a tiny chamfer on the exterior side of the touch hole. What the chamfer does is to smooth the flow of the hot gas from the flash through the touch hole.

There are 5 number drill sizes between 1/16" to 5/64" on the fractional drill set. It may not be machinist quality, but the Harbor Freight set is cheap enough and will perform as we need.

Search Results For "Number Drill Set" (harborfreight.com)

 

[Jakeytoo]

Ever since I started using socket head set screws for touch hole liners back in ‘79 or ‘80, I drilled to 1/16. That is bigger than originally used in my Dixie TMR, and I used 1/16 because that’s the smallest bit I had.

 

[rafterob]

I concur that there is no need to mess with anything if it touches off fine now. If you are currently having issues start at 1/16th.

 

[flntlokr]

Ever since I started using socket head set screws for touch hole liners back in ‘79 or ‘80, I drilled to 1/16. That is bigger than originally used in my Dixie TMR, and I used 1/16 because that’s the smallest bit I had.

Same here, and they work well for me. I also put a countersink into the hole on the inner end, and thus reduce the length of the parallel-sided part, thus creating a venturi which should (according to Physics) cause the flash to expand and accelerate as it passes into the charge. No way for me to measure that, but that is how it should work.

 

[Packrat]

I have a Baker Rifle, my touch hole was worn and oversized, I had many misfires and had to pull numerous balls because I was losing pressure through the touch hole. I finally drilled and tapped a touch hole liner , diameter about 1/16" and all was fine

 

[XVIIc Wheelock]

I put a slight countersink in the outer (pan) side of the the 1/16th hole. This helps directs pan flash into the hole rather than directing chamber ignition out to pan. Makes sense. For me, It is counter intuitive to countersink on the inner side. However what works for the shooter is the name of the game.

 

[French Colonial]

Whatever works is exactly right.
I use Jim Chamber's white lightning liners that are countersunk on the inside, I believe that it positions the charge closer to the pan when you load.
It seems they are standard with 1/16" holes and I am very happy with them.

I think countersunk on the inside or outside would work as it keeps from having a long "tunnel" if you will that would act like a fuse.

 

[hanshi]

What TreeMan said. All mine 1/16".