The tumblerThe tumbler starts as 36mm long piece of 40mm axle rod.
![](https://i.ibb.co/FsWfXcC/pic60.jpg)
The first step is to turn and thread the hammer axel. It’s threaded for a M4 screw. The diameter of the axle is 6,5mm. The blank is then reversed, jaws clamped on the hammer axle as far it will go in the chuck with the disc touching the top of all three jaws. This keeps the blank level. The bridle axle turned down to 4mm. If you try to turn the bridle axle first, it is prone to twist off while turning the larger hammer axle. Remember to leave a small, raised ring around the base of both axles. This reduces the friction between the tumbler and the lock plate + bridle.
![](https://i.ibb.co/KLpTsjZ/pic61.jpg)
You now have disc with two axels. Turn down the disc so it fits on the lock plate, keep it as large as possible. This decides the length of the tumbler arm.
![](https://i.ibb.co/Fw5j4dt/pic62.jpg)
Take a thick piece of mild steel, drill a hole for the bridle axel and soft solder the tumbler blank on it.
Mill the hammer axel square 5, 3mm.The broached square hole in the hammer is 5,2mm. This leaves the axel it a hair larger.
![](https://i.ibb.co/s30z37V/pic63.jpg)
File a short draft at the end of the square axel and swag the hammer on to it. To the rigth in this picture, you see the hollow brass punch I use to swage the hammer all the way down. This gives a perfect fit.
![](https://i.ibb.co/fSMtJCD/pic64.jpg)
File off the excess square axel. Remove the hammer by tapping out with a punch.
![](https://i.ibb.co/ZmZf0cy/pic65.jpg)
Heat and remove the tumbler blank. Clean off the solder.
![](https://i.ibb.co/HCqpNN9/pic66.jpg)
In this picture, the tumbler blank is painted with dyke and mounted on the lock plate. Notice that the blank covers the hole drilled for the sear axle. The washer mounted on the bridle axel shows what has removed to make room for the sear. Scribe around the washer.
![](https://i.ibb.co/DCYWJvT/pic67.jpg)
Mount the bridle on top of the tumbler blank using an extra-long screw in the last bridle post. Place the hammer in half cock position and scribe around the posts.
![](https://i.ibb.co/jGSZDTM/pic68.jpg)
Drill out as much of the waste material as possible. Remember to drill the post holes under sized.
![](https://i.ibb.co/yF5Pk5M/pic69.jpg)
Saw off as much of the waste as you dare, leaving ample material for the tumbler arm.
![](https://i.ibb.co/N1T7GgW/pic70.jpg)
Carefully file the “post holes” in the tumbler until the bridle slips down over the tumbler blank in half cock position. Clean up the sawn outlines
![](https://i.ibb.co/D7SBFPh/pic71.jpg)
![](https://i.ibb.co/d2tZKLJ/pic72.jpg)
File carefully at the areas pointed to with red arrows on the tumbler until the hammer can be rotated to the fired position. In this position about 1mm away from touching the bolster and further rotation stopped by the second bridle post hitting the tumbler.
![](https://i.ibb.co/HHjW0sN/pic73.jpg)
File carefully at the areas pointed to with green arrows on the tumbler until the hammer can be rotated to the full cocked position. Further rotation is stopped by the tumbler arm hitting the first bridle post.
![](https://i.ibb.co/vm0JN9n/pic75.jpg)
The tumbler arm is going to be connected to the main spring by a stirrup. The stirrup axel hole is 2,5mm and located just below the bolster with the hammer in the fired position. The “nose” of the tumbler arm is a 6mm circle and the axel hole is in the center. Punch the location of this hole on the tumbler.
![](https://i.ibb.co/cTqL6XC/pic78.jpg)
Drill the hole. Do not move the blank. Put a piece of 6mm round stock in the chuck and trace around.
![](https://i.ibb.co/YRB8hqM/pic79.jpg)
![](https://i.ibb.co/jbzGpmv/pic80.jpg)
File the nose so it’s a half circle. Next adjust the cocked position of the hammer so the nose is 2mm below the upper edge of lock plate. This done by filing the tumbler arm where the first post hits it.
![](https://i.ibb.co/0ycvr8J/pic81.jpg)
Saw out the tumbler arm. Keep bottom of the arm a straight line. This will make it easier to slot the arm for the stirrup later. Leave enough of the disc so the sear can rest on it when the hammer is fired.
![](https://i.ibb.co/6NgQmv3/pic82.jpg)
![](https://i.ibb.co/nzVNdx0/pic83.jpg)
There is still a bit to do before the tumbler is finished. The notches for the sear has to be cut, the fly installed, and the arm slotted for the stirrup. This must wait until these parts are made.
Also, there is the question where the screw for the sear spring should go. If it is placed between bridle post two and three, the tumbler must be adjusted to make room for it. It might be better to place behind bridle post three if there is room enough. Suggestions?
![](https://i.ibb.co/XVJtf8y/pic84.jpg)
Best regards
Rolf
Links
left-handed Alex Henry/Staton/Bob Roller lock. Part 1. Lock plate and Hammer
https://americanlongrifles.org/forum/index.php?topic=73225.0left-handed Alex Henry/Staton/Bob Roller lock.Part2. Four post bridle and screws
https://americanlongrifles.org/forum/index.php?topic=73497.0