AmericanLongRifles Forums
General discussion => Gun Building => Topic started by: davec2 on March 29, 2014, 04:25:20 AM
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I am using barrel keys on a new rifle. Four of them. Despite my best efforts, they were all too tight to start with and, after some very, very careful adjustment, all of them are looser than I would like (i.e. they push out far too easily). It seems like bending them slightly, or peening the loops tighter, will only work until they wear in and get loose again. Is there some trick to fitting barrel keys I am missing?
Thanks
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Don't bend them. Peen the loops ever so gently, trying the key often.
dp
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Yes, squash the loops gently in a vise, and use a tapered screw driver to wedge them apart if too tight. But the wood itself should be doing a lot of the work of holding the slides firmly - not just the loops. At least, that is what I strive for.
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On my last one, I burned the slot through with the actual key that I was going to use. Worked ok except was just a tad too large so next time I will try the same but with a slightly smaller sized key. I would like to know how others do the burn through method as it looks very neat when done and would like to use that method again.
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Hi Dave,
When you apply stain and finish, the slots will tighten up somewhat but pinching the loops will work and the fix will last. When fitting my keys, I inlet them very tight and then burn them in for the final fit. That seems to work well. However, I also learned another trick, which is that I now make my loops very thick (3/16-1/4") wide. The thick loop offers more metal surface area for the key to slide over and produces a firm fit that requires a light tap with a screw driver and hammer to remove. I learned that feature from looking at some better-grade British flintlock guns.
dave
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My first 4 LRs had keys and it was a learning process to get 'em right. Drilled a series of holes and then burned in the slot, but slightly lower than the final position. The top of the slot in the wood is the bearing surface that exerts force on the key and in turn, on the bbl lug. This is filed until a slight press fit is achieved. So if there's a slight gap between the bottom of the slot and the bottom of the key, this can be hidden w/ the escutcheon , the bent down head of a key. or just the head..
For tightening a key, a brass bar is used to pound the lug down or can be wedged open w/ a screwdriver......Fred
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Yes, the lugs can be easily peened shut a bit. I try to not just bow the middle, but hit the supporting sides of the loop a bit too. The fact they're easy to adjust is a great part of this set-up.
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While I have always burned my keys in I burn the hole undersized with an undersized key.This allows me to remove the charred wood with a needle file allowing for a tighter fit between the key and the hole.
Mitch Yates
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I also use this scorched wood technique to make a final fit on a butt plate.
I use a nut and screw to hold the butt plate top cap and heat it with a torch
and then set it on the wood. The scorch marks are the high spots and then
I scrape them and repeat the process.
Bob Roller
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Be careful since its is very easy to create "lumps" in the bore large enough to be felt with a tightly patched jag if pounded on enough to change the size of the opening much. The metal has to move to make the gap smaller. So if I have to do this I don't beat on the vertical legs at all or at least very lightly to assure they are really "bottomed" in the hole.
In fact almost anything one does to a barrel can and will deform the bore to some extent . As a result I make the under lug so it fits the key in the first place when in the holes in the barrel THEN I pean it tight in the holes. If its then too tight I can file a little here and there. I usually make them from piano wire.
When making the holes in the wood after drilling I file them to a close undersize than I used a key filed like a broach to cut it to exact size. First few teeth are tapered to start. Push or drive in from each side or do it when the stock is oversized enough that breaking wood out at the far side is not a factor. This is why one buys extra key blanks. If you make your own you make a broach to match the keys. Makes a nice sharp cornered hole that is just the right size and works really good for guns with no escutcheon over the key to cover "boo-boos".
Dan
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Thanks to all of you for the help and advice on fitting up barrel keys. I am trying all of them, but, in addition, I decided to modify the keys to include a fairly stout friction spring. I cut a shallow slot in each key, made a leaf spring for each one and then riveted the spring in place using a brass tack as a rivet. The keys slide in fairly easily but hold very firmly. Not HC, I expect, but I like things that are self adjusting and won't be as subject to humidity and temperature changes as I have experienced thus far with these keys. Of course, the stock isn't finished yet, but these seem to be working great so far.
(https://preview.ibb.co/n9DBUx/IMG_1619.jpg) (http://ibb.co/mcdd9x)
(https://preview.ibb.co/jr0fNH/IMG_1620.jpg) (http://ibb.co/eadBUx)
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You are SUCH a show-off Dave. :D
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Inovation is the stepchild of neccessity! Great idea Dave.
topknot
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..Make some spares right away.
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Nice job--THAT has got to be one of the more interesting solutions to the loose-key problem! Wish I was going to be around in 100 years to see if they've managed to work loose.
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I like "captured" keys. Loose one and your diddled. :o
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Depending on which side I put the spring on, these keys can still be captured by a pin.
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Hi Dave,
Just the kind of clever solution I would expect from a good engineer!! Do you think there is any risk that the spring wears away wood on the entry side of the slot. If you are using an escutcheon plate, that may not matter. The other thing is that in order for the key to clear the barrel lug when removed, the slot for the capture pin often needs to extend about 3/4 of the way down the key. That is particularly true with a slim gun. If you anchor the capture pin behind an escutcheon plate that might guarantee enough clearance without the spring rivet interfering with the pin before the key is removed far enough to release the barrel.
dave