Author Topic: Thick lock bolsters (Read 3054 times)

rich pierce · « **on:** March 17, 2019, 09:48:46 PM »

Seems to me that bolsters on many locks available today are quite thick compared to originals I’ve handled. Do you agree, and do you often trim them to closer to .300?

I’m not complaining. It’s easy to remove some thickness.

Eric Kettenburg · « **Reply #1 on:** March 17, 2019, 10:17:40 PM »

I believe that many were designed this way as a response to complaints that it was not possible to get proper lock panel width using a number of commercial locks, i.e. Silers and others. However, this was not the fault of the lock bolsters but rather the fault of many barrels - especially those used for earlier rifles - being not large enough at the breech. That's changed somewhat in the last 10 years or so, as barrel makers seem more apt to make barrels with breeches larger than 1 1/16 or 1 1/8, but nevertheless... I think I remember some of the L&R locks using the thick bolster as a marketing factor when they first came out.

Eric Kettenburg · « **Reply #2 on:** March 17, 2019, 10:18:09 PM »

And yes, I think a smaller barrel with a wide lock bolster just looks weird.

David R. Pennington · « **Reply #3 on:** March 18, 2019, 04:26:13 AM »

My understanding was that the lock makers did this because most modern barrels back when the muzzle loader resurgence first started were straight and the guns were too skinny across the breech. A typical original swamped barrel gave the extra thickness needed there?

rich pierce · « **Reply #4 on:** March 18, 2019, 05:13:36 AM »

Could very well be. Davis locks seem particularly thick there. I bought a Davis Contract Rifle lock and it seems quite snappy but felt I had to take some off the bolster. Their Colonial American lock has a fat bolster I trim back as well.

Curtis · « **Reply #5 on:** March 18, 2019, 06:43:36 AM »

Rich, I often thin the bolster when it is thicker than needed for the application as well.

Curtis

ron w · « **Reply #6 on:** March 18, 2019, 04:42:47 PM »

lock manufacturers don't know if the lock you purchase is going on a straight bbl. a tapered bbl, a swamped bbl., or what ATF dimension the bbl you have is. they have to make the bolster thick enough to accommodate just about any application, PC correct or not.
it's about as simple as that...….

Mr. Bubbles · « **Reply #7 on:** March 18, 2019, 10:46:18 PM »

I agree with Eric. On my latest Kuntz, with a FCI A-weight the breech is only 0.900" wide. I filed my Large Siler bolster back to .210" to avoid the "puffy cheeked" look. That made the main spring bust through both the barrel channel, and the 5/16" RR channel, so I had to put a small chamfer on the spring and RR tip to get tit to fit ok,.

Eric Kettenburg · « **Reply #8 on:** March 18, 2019, 11:00:25 PM »

Funny thing about mainsprings (probably getting slightly off topic) is that it seems guys working 200+ years ago would do anything rather than mess with a mainspring. I have had a LOT of rifles, European and American, with big hogged out chiseled areas on the lower barrel fits to accommodate the mainspring.

J. Talbert · « **Reply #9 on:** March 19, 2019, 02:32:34 AM »

I talked with one the premier lock makers about this subject years ago. He would get requests from customers to widen the bolsters on his locks to accommodate thin barrels and straight barrels commonly in use, especially back then.
His position was that the thickness of the bolsters on his locks was accurately reproduced and properly dimensioned. When matched with the appropriate sized swamped barrel would give correct wrist architecture.

Jeff

Stophel · « **Reply #10 on:** March 19, 2019, 02:58:14 AM »

Where are you gettin' Siler lock bolsters that are .210" thick?

I've never seen one that was much over an eighth of an inch thick.... and I've cursed them scrawny things for a long time. I would love a 5/32" thick lock bolster.... of course, I'd also like barrels that are 1 1/4" at the breech with a serious taper.... wish in one hand...

elkhorne · « **Reply #11 on:** March 19, 2019, 06:21:32 AM »

Several years ago in a Bowling Green, KY class, Mr. Jack Brooks had us reduce the bolster thickness on a Davis Colonial lock to 0.250 on a Bucks County build. It was a custom Rayl barrel but there were still issues with the main spring bumping into the barrel. The guys in the class that got their lock in, as I recall it, all beveled of the top of their mainsprings instead of chiseling into the lower oblique barrel flat. I talked to several well known lock makers since the class and they all said the bevel on the top of the mainspring was not a problem. Hope this helps or someone else will chime in with their experiences.

AsMs · « **Reply #12 on:** March 19, 2019, 10:30:01 AM »

If you get a little carried away and chisel into the bore you are out $250 -$300. If you file a little too much off a mainspring and it breaks you are out $25-$30.

AsMs

Eric Kettenburg · « **Reply #13 on:** March 19, 2019, 01:00:54 PM »

Sure, the bevels probably serve multiple purposes, but then mainsprings on many old locks - especially German locks - tended to be somewhat wider at the bend than what are on the majority of locks today. They were beveled too, but inevitably if you're dealing with a lock with a large, wide spring and a barrel with a large breech, there is going to be conflict. Investment cast springs can be made more narrow and yet retain strength by bulking up the cross-section of the bend, for example what you see in a Siler mainspring.

Dan Fruth · « **Reply #14 on:** March 19, 2019, 01:19:02 PM »

One thing I have noticed is the fact old locks had the top leaf of the spring closer to the bottom of the plate. The vertical section that sets against the bolster is a bit longer, and that puts the mass of the upper leaf lower in the mortice, and away from the flat of the barrel. (At least on the old English locks I have worked on)...I admit I have not had ANY 18th century guns apart to see how this issue was addressed......Hope someone will chime in on the old guns...Thanks

rich pierce · « **Reply #15 on:** March 19, 2019, 04:11:02 PM »

Good observation, Dan. I’d seen that but not put it together in my head.

little joe · « **Reply #16 on:** March 19, 2019, 04:50:46 PM »

When I developed an interest in shooting (1970 ) a swampted bbl was pretty rare. You had Douglass, Numrich and several custon makers who still made mostly straight bbls. We used a lot of 13/16 by 45 cal bbls. Made a skinny rifle however it was almost impossible to get a early gun to look right in the lock panels or wrist area. When you see a 1960 to 1970 rifle and it looks like the maker did not care about a correct bbl. profile they were using what was avaible and could afford. I can afford a nice swamped bbl easier today than I could a 33 dollar Douglass bbl then. Thick lock bolsters were not being made very much at that time.

Mr. Bubbles · « **Reply #17 on:** March 19, 2019, 06:41:02 PM »

Maybe I am misunderstanding what a lock bolster is then. I thought it was the thick part that sticks inside the lock that the pan attaches to, and that you drill through for your rear lock bolt.

D. Taylor Sapergia · « **Reply #18 on:** March 19, 2019, 07:44:57 PM »

The lock bolster, in my mind at least, is the plate's thickness, including the extra steel above the inside of the plate. In a flintlock, then, it is the inside edge of the pan to the outside of the plate. On a percussion lock, it's the part you file to seat the drum or patent breech.

I file the bolster on percussion plates to get the taper I want through the stock...wider at front than at the rear. That also helps align the hammer with the nipple. On flint plates, no tapering is required when using a swamped barrel, or a parallel barrel with historical dimensions/calibre.

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Author Topic: Thick lock bolsters (Read 3054 times)

ron w