Need to drill vent hole help

[messer454]

A buddy just got a flintlock pistol from military heritage and they come without a vent hole. Anyone have any pictures of the best location to drill this and what size? I am not sure where to start. Thanks I will try to get some more info this PM.

 

[biliff]

1/16" to 5/64" diameter for the touch hole. Draw a line across the top of the pan and center it there. Do NOT put it toward the bottom of the pan.

 

[Rebel]

Center it front to back in the pan and then draw the line across the top of the pan and if anything, get the Bottom of the vent hole at the TOP of the line. High is good, low is Bad. Start with 1/16", you can always make it bigger.

 

Be sure you find the face of the breech before you drill the hole. A buddy a mine tried to drill the hole by measuring the center of the pan as described above and ran right into the edge of the breech face. Snapped the drill bit right off. What a mess. Stick a wood dowel down the barrel and take a sharp pencil and mark the rod at the muzzle. Pull the rod out and line it up on the outside of the barrel and put the pencil line at the muzzle. Where is the breech end of the rod? That is where your breech face is and now you know how much space you have to play with. Good luck on yer project.

 

[Allan Gray]

That's a good tip!

Depending on how far to the front or back the lock was set, the center of the pan could put into the breech plug. If it does, there are ways to remedy the situation.

Other than that, centered on the top of the pan, or slightly higher is best. Some refer to it as the "rising sun" position. Go slow and easy so you don't snap off the delicate drill bit. :v

 

[Birddog6]

My rule is you Never drill for a vent hole or for a vent liner hole with the breechplug in place. If you drill thru the barrel & hit the plug with the drill, it could snap the bit off or it will push the drill forward towards the muzzle as the bit will cut towards the least resistance, thus you end up with a oblong hole. End result is a vent liner hole with threads on just 2 sides & this is NOT safe.

This is a photo of a "in the white" rifle that was sent to me years ago & the builder was well known & look at the threads in this vent liner hole. It is a prime example of a vent liner hole drilled & the bit hit the face of the breechplug, walked the bit over & end result is a oblong hole. Thread it & you have a accident looking for a place to happen. :shake:

I redrilled to the next size vent liner & installed another one properly, with full threads.

 

You are right, of course. Take the plug out first. BUT, some of these guys are afeard ta take a breech plug out so I figgered I would suggest another option.

 

[jimmy82]

I'm curious! So you take the breach plug out and drill your hole. What if your vent liner hole cuts into your plug threads? And if this happens what if your plug protrudes into the space normally taken up by the plug? Even if it is just one thread into it lets say. I know you have to go in and file any extra metal that sticks into the bore but what about metal that only sticks into the threads for the plug?

Or do you drill your vent liner hole with plug out then put the plug back in before screwing in your vent liner. Then you put the vent liner in until it bottoms out on the plug (if it bottoms out) and file the rest flat?

Don't know if I'm barking up an empty tree or what but that is my biggest fear when it comes to working on the barrel, making sure that I don't mess it up. You can sand and shave and hide minor mistakes on wood, but there isn't much you can do with a misaligned hole in metal.

 

[DrTimboone]

As Cooner said :applause: measure where the face of the plug is and be sure to drill just in front of that line...with the plug removed. If that doesn't work, :cursing: move the lock forward or cut a slanted notch in the face of the plug that allows for clearance of the vent hole... sort of a poor man's patent breech :thumbsup:

 

[Ian Pratt]

1. Locate where the vent liner goes

2. Remove fitted and index marked breech plug

3. Drill hole for liner

4. Install plug to index mark

5. Through vent hole mark area of plug that will block vent

6. Remove plug, using a round file remove a cone shaped notch of metal, widest from the marked area and tapering to nothing toward the center of the plug face.
The liner does not enter this notch, you still install your liner so it ends up flush inside the bore. This little channel you cut in simply removes steel that was blocking the flame path

7. Replace plug, look through the liner hole and see if you need to remove some more from the notch

8. Remove plug, finish installing your liner

9. Polish the notch you cut in the plug face and replace the plug

10. Put the barrel back in the gun. Go outside and kill animals.

 

[jimmy82]

Makes sense I guess. This would be one of the parts of gun building that I went really slowly on and measure multiple times. :surrender:

 

Ian did a fine job of laying it out for you. Measuring more than once is always a good idea. My old pappy used to say,"Measure thrice and cut once." :wink:

For Ian's Step #6,... I use a chain saw sharpening file.

 

[DrTimboone]

Great description Ian!!

 

[Birddog6]

I'm curious! So you take the breach plug out and drill your hole. What if your vent liner hole cuts into your plug threads?

I position the barrel back far enough so the breechplug threads & the vent liner threads will not intersect. I don't like one thread cutting into the other, but that is just me, I want full threads on the vent liner & on the breechplug.

 

[Old40Rod]

A related question... where does one install the vent liner on this type of plug -

In the center of the octagon section or at the face of the breech forward of the threads? The description of this breech indicates there is a powder chamber drilled about 1 inch downward from the face.

 

[tg]

"I position the barrel back far enough so the breechplug threads & the vent liner threads will not intersect'

A plain hole is nice to and it reduces the intrusion into the plug, but that is probably to 18th century for most these days.

 

[jimmy82]

I'm not ruling out a straight hole without liner, but in the event of poor performance or hole erosion and a liner need be installed I would hate to muck it up and ruin a barrel. But then that would be a major step in the lessons learned category, just don't want to go there is all.

 

[Birddog6]

A plain hole is nice to and it reduces the intrusion into the plug, but that is probably to 18th century for most these days.

It is for me. To me PC means simply how it was done at the time (era), definately not the best way it could have been done.

:thumbsup:

 

[tg]

"It is for me. To me PC means simply how it was done at the time (era), definately not the best way it could have been done."

True, I can't understand why anyone uses round balls when a gun can be rifled for a long jacketed bullet and increase the range and ballistic efficincy.(VBG)

 

tg, the 18th century way was to place the fence at the breech end of the barrel and any breech threads that were in the way of the flash hole were removed by the "V" groove or "U" groove cut into the face of the breechplug as described above. I have seen them.

Old40Rod, again...put the fence of the lock at the back of the tang and drill the hole located where the flash hole ought to be in relation to the pan center.