Original holster pistol single set trigger

[keweenaw]

I have a holster pistol, probably Dutch, maybe German, that dates from the 1720's. It has a neat, compact single set trigger in it.  It will work set or unset. I pulled the trigger out and have taken some photos and dimensions in case anyone want to try building one.  The view of the mainspring is from the bottom to show the clearance cut for the catch spring.  There are some dimensions to help go with the photos at the bottom of this page:















Trigger length from front of tension hook to end of trigger bar - 1.060", 27.0 mm

Trigger bar and catch thickness 0.082", 2.06 mm

Trigger and catch pin diameters 0.081"

length of top of catch 0.292", 7.50mm

O/A length of catch 0.570", 14.5mm

O/A height of catch 0.280", 7.26mm

Mainspring length  1.912", 48.5 mm

Mainspring width 0.462", 11.72mm

Mainspring slot length to rear square corners 1.234", 31.4mm

Mainspring slot width 0.265"

Mainspring thickness at front 0.076"

Mainspring thickness at rear 0.10"

Mainspring arch 0.062"

Catch spring O/A length 0.682", 17.1mm

Catch spring body thickness 0.046", 1.2mm

Catch spring working arm thickness at tip 0.018", 0.44mm

Trigger plate hole to hole center distance 0.854"

Trigger plate slot length through plate .517", 13.2mm

Trigger plate ears above base of plate 0.272"

[Dave B]

Snyder,
this is great! I love seeing how these old triggers looked when apart. I have several times had triggers apart to see how they were made. I like the Germans the best. I was able to restor a set triggers from a rifle that looked like one of the gizmos that you drop a marble through to make all the leavers interact. It had  five different springs for little levers and was bulit  like a Swiss watch. Thanks for sharing

[Acer Saccharum]

Snyder, thanks for posting this material. This is the next best thing to having the actual triggers on my bench!

Thanks for taking the time.

Tom

[Benedict]

Snyder, I want to add my thanks for posting these pictures.  Pictures like this are about the only way I get to see details of original guns.

Ever since you posted the pictures, I have been trying to figure out how the trigger works.  I realize that pushing the trigger forward sets it and that it works set or unset.  But when I look at the parts, I am having trouble understanding the details of how it works.  It looks to me like it either won't release or will release on its own so I realize I am missing something.

Thanks,
Bruce

[Acer Saccharum]

It looks to me that this little pivoting cam at the end of the trigger bar, the little catch piece, is what catches the trigger when you push the trigger forward to set position. It relies entirely on the spring pressure from underneath in order to snap over the end of the trigger bar. Without the feather spring, it would never catch, nor ever hold the end of the trigger.  To get the set trigger to trip, you have to squeeze enough to overcome the little feather spring that holds the catch engaged. Trigger travel, or creep, is adjusted out with the set screw. Lightness of pull is controlled by how strong that little feather spring is.



Should you have this trigger set, and the spring fail, the gun will go off. Probably true of many set triggers.

[keweenaw]

Bruce,

When you push the trigger forward, the end of the trigger bar latches under the pivoting catch at the back.  The catch, in turn, is held in the forward position by the catch spring pushing up under the notch at its back.  When you pull the trigger the upward movement of the trigger bar pivots the catch to the rear against the catch spring tension until the trigger bar clears the catch and it snaps up.   The amount of engagement is regulated by the adjusting screw pushing on the forward extension of the catch.  With a lot of engagement the pull can be quite heavy but it can be adjusted down to a relatively light pull.  The old guy who built this used a relatively coarse thread on the adjusting screw so that a very small percentage turn of the screw makes a big difference in the weight of the pull.  It would have been much better with a fine thread adjusting screw.  

Tom

[Rolf]

Thanks Tom for the pictures. I've started drafting plans for copy of the trigger.
I'll try to build a mock up in brass and see if I can get it to work.
I've done some calulations based on the pictures , scaled to your measurments, but I'm not sure if they are correct. Could you check these?

Total length of triggerplate 72mm
Width of triggerplate 12mm
Length from front of triggerplate to begining of triggerslot 20.5mm
Length from front of triggerplate to the front of triggerplate ears 15.5mm
Higth of triggerplate ears at the front end 3mm
Overall length of triggerplate ears 37mm.

Best regards

Rolfkt

[Benedict]

Thanks guys for the explanations on how it works.  Basically your explanation was what I thought but it seemed quite scary relying on that little spring to keep your gun from going off.  Obviously the balance of the springs is critical to the operation of the trigger.

Thanks, again,
Bruce

[Acer Saccharum]

Tom Snyder, doe s the let off get lighter as you adjust the screw, or does it just make the trigger pull shorter?

Cool stuff. Thanks again.

Acer.

[Tim Crosby]

 Really neat, great pics and measurements. Thanks for posting them.

Tim C.

PS: What holds the front of the plate in, the trigger guard? Maybe I missed something?TC

[Ken G]

Thanks for posting the wonderful pictures!  They are great and you did a fantastic job with the measurements.  The information will get stored in my "Keep trigger info" file. 
Ken

[Pete G.]

That is pretty much the same trigger that Susie sells from MBS. I tried one, but don't like it at all. I use it only in the unset mode so now I have a $12.00 trigger that cost me $47.00. It just feels awkward to try and set it, plus it takes both hands to do so. Might be better if I got more familiar with it, but it works fine for me as a simple trigger.

[keweenaw]

Acer,
The pull gets lighter as the engagement is cut down.  With a lot of engagement the pull can be quite heavy.

Rolf,

I don't have all those measurements here right now as the length of the plate isn't critical to the working of the trigger. The length of the slot through the plate for the trigger is .517", 13.2 mm.  The only way you can get the trigger though the slot is to feed the bar up and then slide it to the rear in that rounded notch so that you can pivot the front hook up through the plate.  The distance from the front of the standing ears to the center of the screw spring hole is 1.75", 44.5 mm.  The distance from the front of the ears to the top corner of their rear shoulder is 1.325", 34.2 mm.  I'll measure this evening to see what the distance is to from the front of the plate to the front of the ears and from the front of the plate to the front of the slot.  The island with the ears on it is about .270", 6.80 mm wide at the base against the plate but tapers up to .244", 6.24 mm at the top.  The distance from the top front of the trigger bar to the bottom of the bar/plate against the back of the trigger is 6.25", 16.0 mm, and the distance to the bottom of the rounded island that fills the trigger slot is .443", 11.18 mm.  Rearward movement of the trigger is determined by the bottom of the hook on the front of the trigger bar hitting the inside top of the trigger plate.

There is a wood screw which hold up the back end of the trigger, the front is held up by the trigger guard.

[keweenaw]

Pete,

You can hold this trigger plate in the fingers of one hand and easily set it with a light push.  Not at all bad for something hand built about 280 years ago.  This one was well designed and well built.  If yours is that hard to set, you might try reducing the tension on the mainspring by loosening the screw a bit or putting a washer between the mainspring and the catch spring to do the same thing while keeping up the catch spring tension.

[Pete G.]

I probably didn't express myself properly. Mine is not that hard to set, but what I meant was that it takes one hand to hold the gun and the other to set the trigger. It just is awkward to me, whereas with a double set you are already in firing position and the set seems a more natural motion. I didn't mean to imply that there was anything wrong with the design, just the shooter.

[Acer Saccharum]

But you gotta admit, Pete, this is a pretty dandy set for a pistol. I wouldn't want a clunky double set in a fine pistol. Gotta hold onto it with both hands anyway. 

On a rifle, I'd not be happy with this arrangement.

[keweenaw]

Canjar made quite a business for himself making single set triggers for modern rifles and they are commonly used for the rifle barrel on German combination guns.  Once you get used to using them, they are no less bothersome than a double set, and unlike double sets you can't accidentally set the triggers when you mean to be pulling the front one on that big buck.  (Been there, done that and a loud click is not desirable with a close deer) If the trigger is working correctly you can push it forward with your trigger finger w/o removing your hand from the grip.

Going back to Acer's question, unlike most double sets where increasing the engagement increases the length of the pull, on this one changing the engagement functionally results in only an increase in the weight of the pull as the trigger bar clears the catch after exactly the  same amount of movement regardless of how the weight is set.  This gives a very wide range of weights of pull that can be set from less than an ounce to a couple of pounds.

Tom