Slotted underlugs for pins?

Have or do any of you use slotted under lugs for pins? The look like lugs for keys? I normally always make my own but they came with a build for a customer who feels they are right for pin/ wood expansion etc. Gotta give em what they want but...

Hi Peter,
No, I've never felt or observed a need to use lugs designed for keys or even slotted holes in lugs for pins. My holes are a little larger than the pin diameter and that has always been sufficient for any wood movement. I've also examined quite a few original guns without any slotted holes for pins. Again, the pin holes were always a tiny bit larger than the pin diameter. Slotted holes for pins are a solution looking for a problem.

dave

I have learned that unfortunately, you pretty much have to slot the tenons for the pins (though I do not know of any old guns where this is evident... of course I have seen them with busted wood around the pinholes, and with the tenons completely pulled out of the barrel...). If the wood has any cross grain or is curly AT ALL, it will expand and contract a surprising amount with varying humidity, stretching and shrinking the fore end. If the wood is STRAIGHT and level through the fore end, then, no, technically, no slots are necessary.

I learned some time ago from a gun I was making, where I had inlet the barrel during our normal swamplike humidity, and then took the barrel out to work on another part over the next day or so. During that time, the weather got nice and the humidity went down. Two days, now. I put the barrel back in and tried to put the pins in and they wouldn't go! The fore end, which had only minimal light curl, had shrunk in length nearly an eighth of an inch! The front two tenon pins simply were not going to line up, so I had to slot them. And now I slot all my barrel tenons. :wink:

I drill the bbl lug and then file a slot in the lug for wood expansion and contraction. I had a similar experience that Stophel had.....although I left the pins in. When pulling them out it was apparent that the wood had changed and once out, the pins couldn't be pushed back in.....thereafter, all the lugs are slotted......Fred

I have probably built 40+ rifles using them. That is all I use anymore & have been using them for years. I use the smallest one TOW has or a supplier that has the same one like theirs. One time everyone was out of them & I used some standard ones & put them in a drillpress & used a Carbide milling bit & made a slot in them. Small as they are, you can easily cut 3 holes & then just turn the adjustable milling vice & make a slot of it.

Keith Lisle

So for you it's easier to measure, locate and drill pin holes in the wood that accommodates the installed pre-slotted lug,, than to drill through a solid lug and slot it manually after the hole is drilled?

When I do them, I drill them and fit the pins "normally", then take the barrel out and drill a slightly smaller hole on either side of the pin hole (to make sure it's not too big or too far down away from the barrel), and cut it out with a jeweler's saw, then finish file it with a narrow file. I HATE doing it, it's a major pain. But, it's just one of those things. I do leave the rearmost barrel tenon alone and don't slot it, as it's not gonna move that much over 10" of length, but over nearly 4' it sure can, so the front three get slots. :wink:

I have built a number of rifles with either straight or tapered barrels and almost always use staples with these style barrels.

I also pin more barrels than use keys (unless keys is more correct), so many of my pins go through the staple slot.

I do try to center the pin so I can tap down the staple "relatively" snug, but they seem to work well and are still holding fine after a number of years (in some cases).

I am not advocating any advantage to using a slotted tenon or a staple, but both would/do work fine.

Seems to me, if I were to use a pre-slotted underlug I'd have to do some pretty accurate measuring and have a very accurate set up to get my drill bit to hit that slot when I drill the pin holes.

Not wanting to go thru all of this precise work, I locate the hole to the best of my ability and then drill the pin hole completely thru the stock and the underlug after clamping the barrel in place.

I then remove the barrel from the stock and elongate the newly drilled pin hole in each underlug.

I do believe elongating the hole in the underlug is an important part of building a rifle.

Although wood expands and contracts mainly in a direction across the grain, there is a little movement in the direction of the grain.
There is also the expansion of the barrel when it gets hot to be considered.

The barrel can grow or shrink depending on its temperature. If it heats up to 140 degrees F and the pin holes were drilled when the barrel was 70 degrees, pins that are located 27 inches apart will be moved by the expanded barrel .015.
Although 1/64 of an inch (.015) doesn't sound like much it is enough to cause problems. Especially if the stock has expanded or contracted because of a change in humidity.

This is why I elongate the holes thru the metal underlugs about .032 (1/32") in the forward/aft direction from the original hole.

Ok thanks guys. I always make my lugs by hand and their solid. I'm doing a build for someone so the said lugs were provided and their new to me. Ill make em work!

necchi said:

So for you it's easier to measure, locate and drill pin holes in the wood that accommodates the installed pre-slotted lug,, than to drill through a solid lug and slot it manually after the hole is drilled?

Click to expand...

I would rather take some precise measurements & drill to the slot, than thru a solid lug. You are drilling the same place anyway, so the initial slot just saved me the trouble of making the slot.

To me ob-longing the holes in 4 underlugs is more of a PITA than measuring accurately & hitting the slots with the drill. I drill one side, turn it over & drill the other side, slide the pin in. Now & then one will not hit the slot perfectly. You take the barrel out & take a diamond needle file & adjust the slot & put the barrel back in & pin it.

I have used many many solid underlugs & drilled & opened them up by drill & hand file, fore & aft of initial pin hole.

I just prefer to use the slotted underlug. For me it easier & I get the same results, an elongated hole for the pin.

Keith Lisle

NOTE: On a really really thin forestock & at the nosecap, slotted underlugs will not work, as the slot is not cut close enough to the barrel parallel flat. This instance requires the pin to be right against the barrel flat, thus in this case a solid underlug would be required & drilled.

Or just use rubber pins....... :haha:

Listen to the kat...

Marc n tomtom

Hi,
So do those of you concerned about stock movement also cut the barrel lug inlet bigger than the lug to allow for movement? Certainly, if the hole becomes misaligned, the wood relative to the lug also must have moved. If your lug inlet is exposed in the ramrod groove, do you see those gaps?

dave

Yes. :wink:

Yes, the inlet is cut longer than the lug. The slot is covered when the ramrod is in place so it doesn't show anyway. There are those who inlet for the lug and do not break into the ramrod groove and it makes for a clean installation, but it is difficult to get a rifle with a slender fore end this way; not impossible, but everything must be near perfect. Most original rifles have the lugs visible in the ramrod groove and the slot is longer than the lug, so it is not a new technique.

Next time you go shooting on a cool day take along a depth gauge. You can measure the distance from the muzzle of the barrel to the face of the nosecap and get quite a difference from a cold barrel to a hot one.

I leave about 1/16" gap fore & aft between the wood & underlug in the inlet. It is not visible as I seldom go thru the wood into the RR channel. Personal choice mind you......., :idunno: I don't like seeing the barrel tennons in the RR channel. Out of many dozens of rifles I have built, have only build one that showed the tennons there. I did it one time, didn't care for it showing & never let it happen again.

It is very tedious to do this & not let them go thru. Lots of times the underlug is very slight because of this & the wood covering it may be paper thin, but it is covered.

Most builders will not take the time to do this, they just got on thru & forget it because it is easier & faster. As I said, personal choice.

Keith Lisle

Hi Pete,
Actually, many of the originals that I have examined, American, British, and European do not have slotted pins or extra space for the lugs. Even those with barrel keys do not provide extra space for wood movement. None of those guns showed any problems after 200-250 years. I own a very nice English fowler made during 1760-1770. The barrel lugs protrude into the ramrod channel and even have a slight groove filed in them to match the ramrod groove. No gaps, no extra space for wood movement in the inlets or barrel key slots. No breakage or damage to the stock.

dave

If I had never seen my wood expand and contract in length, I would not slot my barrel tenons. But I have, so I do. :wink:

Dave,

mostly just thinking out loud here. But have to wonder.

"Old" rifles/guns had iron barrels that were hand formed (and beat to hell with a hammer in the process). The wood came from old growth trees etc.

Today we have machined steel barrels that were precision cut on a lathe. The wood is unlikely to be "old growth" and it was almost certainly dried in a kiln (in many cases).

Perhaps it's our modern methods which result in more movement between the wood and the metal ???

galamb said:

The wood is unlikely to be "old growth" and it was almost certainly dried in a kiln (in many cases).

Perhaps it's our modern methods which result in more movement between the wood and the metal ???

Click to expand...

I think this may be so, to at least some degree. Many old guns, like those from the Reading area, have nosecaps that are screwed to a stud dovetailed in the barrel. Definitely no room for wood shifting there! And yet they're fine (well, so far as I know...). I did one like this a few years ago, and I assume it's still ok! :haha:

I have done a walnut stocked rifle years and years ago, and did not slot the tenons, and it is fine. But the wood is straight grain in the fore end. I also have an old gun of mine that is maple stocked in fairly plain wood, no slots, and it also is fine. When you have curl though, you have stacked up cross grain, and that can definitely expand and contract.

I would just as soon not slot them, myself, as it's just a real PITA, but for me, it's a better safe than sorry thing. :wink: