Brown Bess Lock Kit

[jmf]

Im going to attempt this lock project after deer hunting, so maybe 3 weeks or so. Asking a coule questions now would give me things to ponder while sitting in a tree.
Most things look straight forward, but I am certainly unsure on a few things.
1) the plate is warped pretty good, is a vise the best tool or an arbor press? Is heat needed?
2) How do you get the round tenons to actually be true?

[T*O*F]

is a vise the best tool or an arbor press?

No heat is needed.  Both the above will work by supporting the plate and applying pressure at the high spot.  Personally, I would lay the plate across the vise jaws and hit the high spot with a dead blow hammer until it was straight.  They all work.

[smart dog]

Hi,
Yes heat is needed very badly because castings from TRS may be somewhat hard on the surface.  I write this having extensive experience with building their locks and in particular, Bess locks.

dave

[jmf]

Thanks to both Dave’s for your replies. I sort of thought it’d take some warming up. I will put some heat to it and press it flat then.
I was looking at the tumbler and assume Id chuck up the round right behind the square and then the other end should be concentric with the first round that goes through the pkate? Its not when I tried that in a drill. How small would that opposite round dare become to be concentric?

[44-henry]

You really should use a lathe to true up the tumbler shafts. Ideally a collet, or a four jaw chuck to hold the tumbler while you true up the other side, than do the reverse. There is not much chance the two shafts are concentric in their cast form.

[smart dog]

Hi,
Generally, they will true up nicely.  I do this job with a simple wood lathe, fliles and stones.  A metal lathe would be better but I achieve all the precision I need for a good working lock.  I place the large spindle in my lathe chuck first.  Rest a file with safed edges on edge on a tool rest, I spin the tumbler and true up the side.  Then I place the safed edge against the side of the tumbler to clean up the big spindle. Usually, it takes very little filing to true up the sides ad spindles.  Use a medium or fine cut file and be careful the spinning toe of the tumbler does not catch the file. Next turn the tumbler around and do the same on the other side. The bridle spindles on Bess locks are large so don't take off much diameter.  Next, I repeat the process using stones and oil.  Keep in mind JMF, you are not building a jet engine with spindles that turn thousands of revolutions a minute.  You want the best precision you can do but you don't really need a CNC milling machine to build a fine lock.  I urge you to buy a copy of Goldstein and Mowbray's "Brown Bess", which is an invaluable asset for building the locks and the guns.  The only thing better is an original in your hands.  Another tip, if you can, heat soak the cast parts at about 800 degrees for 15-30 minutes and let air cool before working on them.  Sometimes, TRS parts can be really tough on the surface after the molding process and they can ruin your files.  The preliminary heat soak will remove any risk of encountering surface hardening.  Finally, do not completely trust the witness marks on the lock plate.  Usually the tumbler hole is marked accurately and you should establish that hole first before drilling any other holes.  The position of the tumbler will determine all else internally including the position of the main spring.

dave

[jmf]

I do have an old Fay & Egan wood lathe, and a 4 jaw chuck, but the chuck isnt geared, but rather independently adjustable. I only use it for offset turnings, so Im thinking I need to use my geared 3 jaw for this, chucking above the square on the larger journal, then truing the smaller journal. That smaller journal is at .200” as cast. Just by observing it spinning in a hand drill, it appears tome that I would be fortunate to get .125” diameter after truing. Is that sufficient, or should I build it up a bit before turning?
Ido have a copy of The Brown Bess by Goldstein and Mowbray. It’s the next best thing to your advice.

[45-110]

The tumbler shaft(s) need to be co-axial, along with concentric. Working with on a lathe with a collet set up offers the best machining solution.

[smart dog]

Hi JMF,
The spindle on my Delta lathe is hollow and takes a Morse tapered chuck inside as well as 3 or 4-jawed chucks screwed on the outside. I simply have several Jacobs chucks that slip into the spindle and automatically center the work. On all of the TRS cast Bess tumblers I've trued, none needed much metal removed from the spindles and both sides were concentric when checked with a point inserted into the tail stock.

dave 

[jmf]

Yes, there is a #2 mt as well as the 1-1/4” threads on my lathe spindle. I can get that chucked up. This morning I decided to look at the hammer and cap. I did some rough filing to fit things up. That notch for the cap took an hour of filing andI still need to work it into the dead end some more. Is it normal for the hammer shelf to be at such an angle? Its off about .180 from one side to the other. I filed the slot straight with the hammer, not perpendicular to the shelf. The boss on the cap is not centered is why its slightly off center. Should I grind the shelf to be perpendicular to the hammer or is it cast correctly?

[smart dog]

Hi JMF,
No the jaw should be level and perpendicular to the vertical axis of the cock.  It just may need filing. 

dave

[Clark Badgett]

I do have an old Fay & Egan wood lathe, and a 4 jaw chuck, but the chuck isnt geared, but rather independently adjustable. I only use it for offset turnings, so Im thinking I need to use my geared 3 jaw for this, chucking above the square on the larger journal, then truing the smaller journal. That smaller journal is at .200” as cast. Just by observing it spinning in a hand drill, it appears tome that I would be fortunate to get .125” diameter after truing. Is that sufficient, or should I build it up a bit before turning?
Ido have a copy of The Brown Bess by Goldstein and Mowbray. It’s the next best thing to your advice.

That 4 jaw independent chuck will be the most precise, IF you have an indicator. I love a 4 jaw chuck.

[Clint]

Dave's advice on stress relieving (800 - 900 degrees) is pretty important, it saves drills and minimizes broken taps. If you get a hard spot while drilling, it is worth it to stop and stress relieve again. The castings from TRS and Chris Hirsch are taken from original locks and you are working from a hand forged and filed pattern. Things like a slightly canted bottom jaw will not affect the function or appearance of the finished lock. On most casting sets that I have built, the round peg on the bridal is just that. They put a plug in the tumbler hole and used it as a casting gate. Don't cut it off, but use it in your lathe as a drilling guide.  I use an electric kiln for all of my low temperature heating and a coal forge for everything over 1000 degrees. Without a kiln I have used a big propane burner and an old piece of insulated stove pipe for low temp heating. 900 degrees is just barely red hot in a dark place. The big musket locks are great for first lock builds because of their size and relative low tolerance. Good luck and speak out if you get stuck.

[Gary Ruxton]

Red heat the flat twist and hammer down the jaw high edge to square it up. Filing would thin it down too much and it would be narrower than the top jaw. I've had to fix a few bent hammers along the way. Good luck!

[Craig Wilcox]

It looks to me as tho that cock is bent just below the bottom jaw,  The top of the cock is about the same angle as the jaw.

[jmf]

I did some more checking and I think Craig is right. Its below the jaw, but not really bent. Its as cast. I cobbed a square from the lower end if the cock and its really not far off at all, just looks wonky. The top jaw seems to be parallel with the lower, just holding it in place and moving up and down the slot. Im thinking as Clint said, its not really an issue. I sure do appreciate all your good advice.