Finished My Trigger Test Stand - Updated

[earlan357]

I made myself a poor man's Dvorak TriggerScan.  It's a bit of a chore to get the pistols mounted securely, but it's rigid enough that I can rack the slides and get repeatable results.  I threw my P320, Glock, and SP-01 (SA) to demo how easy it makes comparing triggers.







 https://www.youtube.com/watch?v=ZPE7PF7SMcA&t=3s

****Update: 9/4/2019****

Made some tweaks:
New motor no longer overheats the controller.
A slimmer "finger" with a delrin roller for a smoother trigger pull.
Doubled the capacity of the load cell to 10Kg (22 Lbs)
Stiffer load-cell mount.
Stiffer pistol mount.
Program allows me to set max weight limit.
Can measure DA, SA, and Reset.

Videos are as exiting as watching grass grow so I sped it up 3x. 

https://www.youtube.com/watch?v=DrTfWcTm4aI&feature=youtu.be

SP-01 Tactical w/ CGW Pro Kit, 11.5# Mainspring, "5" Thick Trigger.
The reason the weight is dropping is because the finger is moving straight back, but as the trigger rotates upward, the finger is in effect rolling down the trigger.  The increased leverage makes it look like the weight is dropping.

[Earl Keese]

Very cool!

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[Earl Keese]

I'd like to see a CGW graph vs the new Apex setup.  Would be an interesting comparison I think.

[Tok36]

Neat.

[Joe L]

Aw, man, you are killin' me!!  I look at those curves and think==I could shoot the 320 just fine, but would have a tough time with the SP-01 because I couldn't put any pressure on the trigger without it perhaps going off prematurely.  I might even be able to shoot the Glock but the 320 curve maybe with a weaker striker spring would be good.  I think. 

So, Earlan357, can you plot the curve for your P-10C and post it? 

So, you have a displacement measurement dpdt and a force transducer combined and then a jig to hold the gun.  Excellent!

That is a little more elegant than my method--one guy holds pistol, another operates the Lyman trigger pull gauge, another measures movement with caliper and another guy writes down the readings as they are hollered out from the caliper and pull gauge guys.  We quit when the pistol holder guy sneezed. 

Joe

[Creeker]

Neat for sure.

[Rek]

Remember the old country tv show called Hee Haw?
SaaaaaaaaaLUUUUTE!!

[earlan357]

Aw, man, you are killin' me!!  I look at those curves and think==I could shoot the 320 just fine, but would have a tough time with the SP-01 because I couldn't put any pressure on the trigger without it perhaps going off prematurely.  I might even be able to shoot the Glock but the 320 curve maybe with a weaker striker spring would be good.  I think. 

So, Earlan357, can you plot the curve for your P-10C and post it? 

So, you have a displacement measurement dpdt and a force transducer combined and then a jig to hold the gun.  Excellent!

That is a little more elegant than my method--one guy holds pistol, another operates the Lyman trigger pull gauge, another measures movement with caliper and another guy writes down the readings as they are hollered out from the caliper and pull gauge guys.  We quit when the pistol holder guy sneezed. 

Joe

I need to make some tweaks first.  I turned a smaller diameter "finger" in the lathe and added a delrin roller on the end so it won't rub against the trigger.  Also picked up a 10kg (22lb) load cell so I can measure heavy double action pulls.  The motor controller was overheating after about 10 seconds, so I'm waiting on a heat sink and a lower amp motor.  I also need to stiffen the pistol mounts a bit so I can rack the slide.  I've written a new program that takes the pull readings, then gives me 5 seconds to rack the slide before taking readings in reverse.  Should be able to map both trigger pulls and trigger reset. 

[Joe L]

Thanks for the update on your progress with the hardware.  Something tells me it won't take you long to get it all working. 
Joe

[boomenshutzen]

This is pretty awesome. Thank you for sharing.

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[earlan357]

Updated.

[Duke Nukem]

Very cool, thanks for sharing your work. 

[Joe L]

Updated.

Excellent!  Your point on the trigger peg moving down the trigger and increasing the leverage on the trigger is similar to what I have seen as the cause of different pull readings taken by hand with a hand held gauge--there are variations in how I place the roller on the trigger, as well as the pull direction.  It's a big effect on double action pull measurements, less so on single action, and not a problem on a 1911, which doesn't have a pinned trigger.

I just picked up a P-10S.  Impossible to measure the pull on that pistol, stock and new!!  It's too high! CORRECTION 0-9-19--PULL IS ACTUALLY  PRETTY GOOD FROM THE FACTORY. 

Joe   

[eastman]

Looks to be a fine creation. I've done a bit of equipment automation using LabVIEW for the programming.

[GoBlueCO1]

I'd like to see a CGW graph vs the new Apex setup.  Would be an interesting comparison I think.

I second this!