Author Topic: Putting a slope to the trikker bar!  (Read 4465 times)

Offline Roger Fisher

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Putting a slope to the trikker bar!
« on: December 18, 2008, 06:31:58 PM »
Ol Pete Alexander suggests to file an angle on the trikker bar making the axle higher than the contact with the sear for much better trigger pull.  (I am doing just that now) And attempting a bout a 3/8 inch distance from said contact point to the axle.  This be on a single trikker smoothy!

Do any of you do this as common practice and how successful is it?

I do know that trade secrets are rarely kept 'secret' here so that is why I'm asking. ;)

George F.

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Re: Putting a slope to the trikker bar!
« Reply #1 on: December 18, 2008, 06:41:52 PM »
I 'm guessing you mean trigger bar on a simple trigger?  If so, yes is does help to have a higher pivot point, with the trigger bar slopping down engaging the sear bar. It's best to have no slop between the trigger bar and sear bar. Polish the contact points between the sear and trigger bar.   ...Geo.

Offline Jim Kibler

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Re: Putting a slope to the trikker bar!
« Reply #2 on: December 18, 2008, 07:08:14 PM »
As a few others have mentioned previously, draw a line between the sear pivot and the trigger contact point on the sear bar.  Pin the trigger on this line and shape the top of the trigger bar to this line as well.  This is the ideal mechanical geometry of the trigger bar sear relationship.  In practice it doesn't have to be perfect however.  Get somewhere close and you will be just fine.

Offline P.Bigham

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Re: Putting a slope to the trikker bar!
« Reply #3 on: December 19, 2008, 12:32:04 AM »
 It also helps to pin the trigger as close as possible to the sear contact. closer better leverage, farther less leverage.
" not all who wander are lost"

Offline Jim Kibler

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Re: Putting a slope to the trikker bar!
« Reply #4 on: December 19, 2008, 01:19:28 AM »
It also helps to pin the trigger as close as possible to the sear contact. closer better leverage, farther less leverage.

Keep in mind, there is a trade off between leverage and amount of travel.  The closer the sear contact is to the pivot, the better the leverage, but as you approach the pivot, the amount of trigger travel required to disengage the sear increases.  Everybody has there preferences here, but I find somewhere in the neighborhood of 3/8" to work well.

Offline volatpluvia

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Re: Putting a slope to the trikker bar!
« Reply #5 on: December 19, 2008, 05:08:04 AM »
I like the extra travel.  I like the feel of it in that there is no build up of pressure.  The extra leverage causes the sear to break very smoothly, which aids in not flinching.  It gives a very light trigger pull and the length of pull makes the light pull safer.
One can go too far, pin the trigger too high, make the slope on the bar too steep.  At that point the pull becomes harder and it just doesn't work well.  Ask me how I know this!  Hee Hee!
volatpluvis
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Offline Long John

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Re: Putting a slope to the trikker bar!
« Reply #6 on: December 19, 2008, 05:27:47 PM »
Roger,

Triggers are something I make myself and have gotten some fairly nice results, in my opinion.  I want the top surface of the trigger bar to be parallel to a line drawn from the bottom surface of the sear bar to the center of the sear screw and just a hair's-breadth of space between the two at 1/2 cock.  (On the Chambers locks I have used recently the position of the sear bar at 1/2 cock and ful cock have been the same.)  I locate the trigger pivot on that line, about 5/16ths of an inch beyond  the sear screw location.  With careful cut and try filing I have been able to adjust the lash to almost zero.  Once the top surface of the trigger is filed to the proper height I round it over a little, polish it with 1200 grit crocus cloth and case harden.

Best Regards,

John Cholin

 

Offline Dphariss

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Re: Putting a slope to the trikker bar!
« Reply #7 on: December 19, 2008, 06:19:43 PM »
If the pivot point is too close to the sear the movement of the trigger increases.
Too close makes for possible creep since it takes a lot of movement to move the sear.
Too far and leverage is lost. Its a trade off.
I tend to make trigger plates with a "tower" like this one
http://trackofthewolf.com/(S(4puaibignkd0j255ccxjd245))/categories/PARTDETAIL.ASPX?CATID=14&SUBID=156&STYLEID=709&PARTNUM=TR-ENG-P

This gives a high pivot point and better leverage. You can fold a piece of 1/16" or thinner steel and silver solder to the plate to make the "tower".
Low pivots can be made to work but its harder.
Triggers need to have some slack to make sure everything works properly.
If the sear surface that contacts the sear is rounded the trigger can be flat where if contacts the sear. Both surfaces need polish of course.
Getting within 1/2-5/8" is close enough for the sear contact/trigger pivot distance. Somewhat longer will work fine if the lock is right in sear spring pressure and sear nose/tumbler notch geometry and depth.
Needing a close sear contact/trigger pivot distance, less than 1/2" to get a decent pull,  2-4 pounds means the lock needs to be tuned.
Its all a matter of trade off. Greater distance will produce a crisper let off, one that "breaks". Closer can make it lighter all else being equal, but less crisp. Closer gives more leverage greater gives less. Its always a balancing act.
And like many things people here have their pet ways of doing things that work best for them.

Dan

He who dares not offend cannot be honest. Thomas Paine