Trigger Q's

[Warthaug]

I've been thinking of making my own speargun for a long time now, and I think I'm ready to start. But I have a Q about triggers before I jump in.

I've noticed that many plans for guns don't include a trigger mechanism. I assume this is because they have bought their mechanism from a commertial source. Is it really that hard to make a safe mechanism?

If it is possible to make a safe mechanism, would anyone have a design they would recommend? I'm very much a do-it-yourself kindof guy, so I would prefer to make my own mechanism if it can be safely done.

Thanx in advance

Bryan

[Fish Tale]

I've built two triggers of the same simple design that I call the"butter knife trigger". The stainless steel trigger is cut from the handle of a solid sst butter knife which can be purchased for about a quarter from a local thrift stores collection of misc stainless flatware.


Here's a link to a web page that talks about these guns: http://flshoredives.nexuswebs.net/biggun.html

The simple design makes it relatively easy to get the geometric and spatial relationships between the parts right. A safety can be incorporated into the design.

Is it safe? I'm one of those people that will never assume any trigger is absolutely safe. I do trust the two I've built. They've never failed to do what I expected them to do.

[StretchArmStron]

" They've never failed to do what I expected them to do."


I think you answered your own question? lol.

[Warthaug]

Thanx for that design - I cam across one of your older designs in my initial seach, and if you don't mind me saying this one seems to be much better. I've already collected about 1/2 of what I need to make your new one. I'll see if I can get it rigged up!

I wonder if SWMBO will miss one butter knife. . .

Bryan

[Fish Tale]

Originally Posted by Warthaug

Thanx for that design - I cam across one of your older designs in my initial seach, and if you don't mind me saying this one seems to be much better.
Bryan

That old design, the "junkyard speargun" is very simple.

Not something I'd feel comfortable putting a lot of power on.

[Warthaug]

Fish Tale.

Thanx for the plans and help. I have put togeather a stand-alone trigger and am testing it (on land, using a static line in place of a spear/bands), and I have one last quick question.

In your instructions you mention that the stiffness of the trigger pull can be adjusted by altering the angle of the trigger surface. I need to make this change (it's way too stiff, I almost need two hands to pull), but am unsure exactly what you mean. Do you mean:

a) the surface is filed to alter it's angle?
b) the pivot point is moved forwards or backwards on the gun to angle the whole trigger?
c) the length of the pushrod is adjusted to alter the angle of the whole trigger?
d) something I'm missing entierly?

Thanx

Bryan

[rigdvr]

I wouldnt want to swim around with anyone with a homemade trigger. Sorry if offend anyone but thats just silly.

[milhouse]

Why?

I understand your point of view; a trigger has to be 120% safe, but commercial triggers are made by humans too. I make triggers and I trust more mines than commercial ones. The trick is to be well equipped and to be carefull. I made an extra tough one based on the old Kitto' two part trigger. It's as tough as hell, and I'm sure it can handle 1000 pnds of pressure. 1/4" SS pins, 1/8" SS box sides, and 3/16" SS gears. Commercials are lazer cut, but I do it with milling, grinder, and finish it with different shaped files (with a caliper) It take a lot of time, but it gives the same result, and the satisfaction in bonus. And my "homemade guns are entirely "homemade". (the only part I have to buy is shaft. These can be made too, but it's really, really hard and cost as much as a buying one)

I recently made another one with Riffe's gears pattern (1/4" SS), in a U shape SS box (1/16"), with 3/16 SS pins.This on is for euro style wood gun. Haven't tried this one in water, but tested it ouside.

I am confident in my abilities and if someone else can do it, why not me?
I use the same materials, use the same systems, and am carefull. Try it too, the satisfaction that comes with it is good.

[ajwaverider]

Originally Posted by milhouse

I am confident in my abilities and if someone else can do it, why not me?
I use the same materials, use the same systems, and am carefull. Try it too, the satisfaction that comes with it is good.

Right on. If you look at a few massed produced triggers it will make you feel
alot better about the ones you've made.I've got two trigger mechs and one is supposed to be a copy of the other.but the copy is built with a lot closer tolerances than the original.I guess that is the price to pay for mass production.

[Fish Tale]

Originally Posted by Warthaug

Fish Tale.

In your instructions you mention that the stiffness of the trigger pull can be adjusted by altering the angle of the trigger surface. I need to make this change (it's way too stiff, I almost need two hands to pull), but am unsure exactly what you mean. Do you mean:

a) the surface is filed to alter it's angle?
b) the pivot point is moved forwards or backwards on the gun to angle the whole trigger?
c) the length of the pushrod is adjusted to alter the angle of the whole trigger?
d) something I'm missing entierly?

Thanx

a) the surface is filed to alter it's angle

If the trigger you made works on the same principle as the the one shown above then the problem your having is probably caused by the profile of the trigger face being slightly off.

With a spear loaded (NO bands or tension) slowly pull the trigger to the firing position while examining the movements of the mechanism from the side. You will probably see the seer move up towards the spear if the profile of your trigger face is lifting the seer. That's very bad. That's what causes your trigger to lock up. It's like trying to open a door that's been wedged shut with a door stop. It's much easier to see what's going on in your mechanism if you take the cap nut off the end of the seer bolt before you do this.

When the trigger face profile is correct the seer will never be lifted upwards and into the trigger notch in the spear as the trigger is moved to the firing position. The trigger will fire the spear when the seer drops off the face of the trigger and falls behind the trigger. Another thing to mention: A good smooth surface finish on the trigger face will minimize wear, make the trigger pull easier, and help the trigger feel the same every time you fire it.

The only other possibility I can think of would be that the leverage of your trigger has been reversed by having the trigger's pivot pin hole closer to the pushrod connection point than to the trigger face end of the trigger. I doubt that's it.

I hope that helps. Let us know what you find.

[rigdvr]

Originally Posted by milhouse

Why?

I understand your point of view; a trigger has to be 120% safe, but commercial triggers are made by humans too. I make triggers and I trust more mines than commercial ones.... I made an extra tough one based on the old Kitto' two part trigger. It's as tough as hell, and I'm sure it can handle 1000 pnds of pressure....

How often do you test a trigger to failure? I know one company that does on a regular basis. Ive been in the shop and pumped it up to 1000 pounds of pressure and squeezed the trigger. There is only one company that does this but it makes me feel better that they do. Kudos to you for building your own and while you are pretty sure in its cqapability to hold I KNOW mine will.

I understand the reasoning but I think I would get just as much satisfaction from building a gun without having to build my own trigger. I dont need to build my car to appreciate it or my firearms or my house

[rigdvr]

AJ, what triggers are you talking about?

[milhouse]

But there's a difference in a car and a trigger

[rigdvr]

they'll both kill if something goes bad...

[milhouse]

I won't argue about my triggers safety, but anyway, commercial or homemade, isn't safer to never point in unsafe direction?