LOCK SCREW CLEARANCES IN THE BARREL PHOTOS ADDED 1:40 PM

[WESTbury]

Let me preface this by stating that I have absolutely no experience stocking rifles. Thus my questions below.

I have a question concerning the lock screw clearance cuts in the breechplug lower tang and in the bottom of the barrel.

If you knew the center to center distances of the lock screw holes in the lockplate to be fitted to a rifle, pistol, etc., would you pre-machine the clearances in the barrel assembly based on your experience with past rifles you have built? Or leave those operations until after the lock was inlet?

Thanks,

Kent

[RAT]

It's easier to drill the hole in the wood first and then run your bit through to mark the lug of the breech plug than to do math to "figure out" where it's "supposed" to be.

When I remove wood to prepare to inlet the lock plate, I remove the same amount from both the lock and side plate sides. I also make sure it correctly follows the taper of the barrel... or however it's supposed to be depending on the style of rifle.

With the barrel removed, I then put the plate in the mortise. I then set the side plate panel flat against the drill press table, support the length of the rifle as appropriate, line up the tap drill with the center punched mark on the plate, clamp everything in place, and drill through the plate and through the wood. This makes the hole 90 degrees to the side plate panel so the lock bolt heads lay flat against the side plate. I then re-position everything for the second hole.

Once both holes are drilled with the tap drill, I remove the plate and tap the holes.

At this point I hand drill the clearance holes through the wood. The barrel is placed back in the stock and a drill run into the hole to mark the lug on the breech plug. I mark both sides.

The barrel is removed again and hand drilled with the barrel held in a vise. If the hole is close to the rear of the lug, I file it with a round file through the edge of the lug.

The barrel and lock plate go back in the stock and I check the fit of the bolt. If there is interference, I correct as needed. Usually this means drilling a bigger clearance hole in either the wood or lug (or both).

[WESTbury]

Thanks for the reply and information Bob, appreciate it.

Kent

[WESTbury]

It's easier to drill the hole in the wood first and then run your bit through to mark the lug of the breech plug than to do math to "figure out" where it's "supposed" to be.

Bob,

What about any clearance, in the bottom flat of the barrel, for the front lock bolt?

Kent

[Eric Krewson]

Everyone has their own way of doing this; I drill the tap hole in the lock plate first, mark the side plate hole location and with barrel removed I drill the tap hole through the stock on a drilling spike on my drill press. I run a tap through the hole and tap the lock plate. Next, drill a tight clearance hole in the stock, I install the barrel and run the clearance bit through the bolt hole and mark the barrel, I pull the barrel and drill a BIG hole through the breech plug lug, I don't want any lug/lockbolt interference when I shoot the gun in and the barrel settles into its final resting place. 

I use factory side plates which don't give you any wiggle room on lockbolt location because the holes are predrilled.

My drilling spike and lock bolt drilling, yep, it is an arrow field point in my cross-slide vise;





In this case I was very close to the edge of the lug and made plenty of room for the lock bolt, probably overkill but I like BIG holes through the lug.



Early on as a rookie I tried to drill the bolt hole through the wood, through the lug and into the lock plate at the same time, BIG MISTAKE! The drill bit skated on the lug and didn't come close to hitting the lock plate in the right place. I did learn how to make an almost invisible plugged hole drilled in the bolster where it wasn't supposed to be.

[archer829]

For the front lock bolt and barrel interference:

After you've drilled your holes through the stock, replace the barrel, and then use the butt end of a properly sized drill bit to push through the front lock bolt hole from each side of the stock to mark the barrel--either with magic marker or inletting black on the leading edge of the butt end of the drill bit.

This should mark the barrel where it interferes with the bolt hole.  Then just use a properly sized round file to allow the front lock bolt to clear the barrel.  Will probably take a bit of re-marking, re-filing, and test fitting with the actual bolt before everything works.  I'm sure there are others on here with better methods, but this worked well for me.

Also you want to make sure that you're not removing an unreasonable amount of material from the barrel, leaving the barrel wall too thin....

Hope this makes sense!

Jeff

[Eric Krewson]

I hit the barrel slightly with the front lock bolt on my first build, it only took a small amount of filing to make everything right, I used a chainsaw file to notch the barrel, it was a C weight 54 and had plenty of "meat".

[WESTbury]

Eric and Jeff,

Thanks for all of your insight and photos, excellent info!

Now suppose you are stocking a half dozen of the same style rifle using the same locks, barrels and stock blanks purchased all from the same sources you have used in the past.
 
Would you feel comfortable enough to pre-machine the lower tang of the breech plug and the bottom flat of the barrel to clear the front and rear lock bolts? Of course, taking into account that there may be some slight variation in the components, so it would be prudent to make the clearance cuts large enough based on your past experience.

I realize this is a hypothetical situation, so I appreciate your indulgence.

Below are two photos of the breech area of an original "J Graeff" signed barrel showing the clearance cuts for the lock screws.

[RAT]

For the front lock bolt...

With the barrel out of the stock, I measure down to the bottom of the barrel channel and mark that onto the outside of the stock. I place a toothpick into each "feeler hole" until it bottoms out, mark the toothpick at the level of the bottom of the barrel channel, remove the toothpick and place it along the outside of the stock with the marks even, and mark the stock at the bottom of the toothpick. This tells me exactly where the ramrod hole is located. This also tells me where the web of wood is under the nose of the lock plate. I mark the plate, and drill the front hole the same as the rear hole. I can't say I've ever run into the barrel. I have run the hole into the ramrod hole. If it runs into the barrel, file a shallow groove into the bottom of the barrel with a round file. If it runs slightly into the ramrod hole, file a shallow groove around the circumference of the front lock bolt. I also use a 6-32 bolt for the front to give it a little more clearance.

If I were making 6 of the same rifle, I'd do them the same way I normally do. If I were doing 600... that would be a different story. IF I were doing production... I guess I wouldn't... unless I had the proper machines to machine the parts with precision. Most of us aren't going to have access to that kind of equipment.

I've tried making 2 sets of the same parts before. It seemed to take too long. I was going to stock them at the same time... doing one step on one... then the other... then moving on to the next step. It didn't seem practical so I gave up the idea. At the time I mentioned it to a friend, who said he tried that before. He said it works better just working on one at a time. Otherwise it seems like you never move forward and you loose momentum.

[WESTbury]

Bob,

Thank-you for all of your information and comments.

As you may be able to see in the photos I attached of an original barrel from a rifle I have, Graeff made the front lock bolt clearance close to 3/8" at its widest and approx. 3/32" deep. The lock bolts for this original rifle are a little smaller than a #10 machine screw.

Incidentally, the barrel is 47-1/4" OAL.

Kent

[archer829]

I’m not sure.  I guess if you oversized the hole in the tang and the groove in the barrel enough you’d be fine, but there might be enough variability in the holes’ location that you might run into trouble.  Depends on your equipment.  I used a hand drill.  Lot of variability.  If you use CNC…not much variability.

[Eric Kettenburg]

Just my opinion but I strongly doubt that he or anyone would cut the notches first, even if using similar locks and barrels.  It's been my experience in taking apart a whole lot of antiques that those notches, as well as the drilled holes for the bolts themselves, tend to run larger - sometimes considerably larger - than the diameter of the screw shanks.  I think its more a situation of playing it fast and loose than worrying about precision.  When stocking up these rifles, I want the barrel out of the stock as little as possible and sticking it in and pulling it back out repeatedly (dear lord  ) to cut a "precise" notch or groove is a pain in the rear, not to mention an invitation to breakage (forearm) or buggering inletting.  Better to cut the notches if needed once allowing some wiggle room and be done with it.

[WESTbury]

When stocking up these rifles, I want the barrel out of the stock as little as possible and sticking it in and pulling it back out repeatedly (dear lord  ) to cut a "precise" notch or groove is a pain in the rear, not to mention an invitation to breakage (forearm) or buggering inletting.  Better to cut the notches if needed once allowing some wiggle room and be done with it.

Eric,

Appreciate your input and opinions very much based on your experiences with these old rifles.
I've looked at many posts in the Rifle Building section of the Forum and from what I can see, the barrels are fully inletted before the lock is inlet and the touchhole is drilled. That makes sense. Am I correct in my observation?

Kent

[Eric Kettenburg]

Yes.  On any planet or plane of existence, the barrel needs to be fully inlet first - barrel, tang, lugs and pinned.  Everything else flows from there.

Something I should add, which I'm sure I have mentioned here at times.  We hold these guys up on a pedestal now because we appreciate antiques, and we appreciate what they were able to accomplish with simple shops, and we appreciate what we view as a "art" form.  I can't speak to European work or philosophy where things were much more specialized, but here a lot of these guys were building guns and farming at the same time, and I strongly doubt they considered themselves "artists."  Over the years, after both handling and restoring and working upon many of these old guns, I think I can say with a fair degree of certainty that the men making them were not thinking 100 years down the road.  Most probably anticipated maybe a 25 year life span at most and I would feel very confident in saying that most hobbyists today - who may only build a gun or two a year - probably execute more precise work than many of the 'old makers.'  I have seen many pieces that even when brand spanking new would not hold up to what we now view as quality work; we, however, are basically dilettantes and have the luxury to "play" with these antiquated guns whether it be because of a sense of nostalgia for the past, or an appreciation of antique style, or whatever. 

I would hazard a guess (trying not to broach forum rules here) that most of us being 'gun people' do not rely on black powder guns for home defense or personal defense or whatever might be a critical situation.  So I guess what I'm saying is that we look at these things and our way of building them now through a very overthought and myopic lens, and from this perspective, things like 'judging' rifles or picking apart every little detail is not conducive toward a better understanding or what was expected 200+ years ago.

I doubt anyone in 1780 was using a micrometer to measure whether or not a groove across the underside of the barrel or a notch in the breech plug was excessively sized for the required purpose!

[WESTbury]

I doubt anyone in 1780 was using a micrometer to measure whether or not a groove across the underside of the barrel or a notch in the breech plug was excessively sized for the required purpose!

Exactly! The more clearance the better, within reason of course. That is precisely on of my points with some of my questions. The clearance cuts in the barrel assembly were put in with the thought in mind to do it once so as to not be taking the barrel in and out to "tweak" things.

I spent 39 years in the machine tool industry both as a fixture designer and a machine designer. I was told early on to "make things beefy" and give things plenty of clearance where possible. Re-machining components is time consuming and expensive.

As you say Eric, the old rifle stockers were practical men and did what was necessary to get functioning rifles into the hands of their customers as fast as possible. I would imagine that most of the time they had a customer order backlog to satisfy, so time was of the essence. That is why I believe that if practical, those men bought finished or semi-finished components whenever they could. We know that locks and barrels were specialties of other vendors and I imagine that brass furniture was also available particularly after the Rev War as businesses were started during the War to supply musket components to some of our favorite rifle builders who were "drafted" into musket building.

Anyway thanks to all who have responded so far to this thread.

Kent