Custom 3D Printed SAO Trigger

[tdogg]

I've got big hands and shoot USPSA Limited with a TSO.  I've tried a number of different profile grip's to try and improve the trigger reach (lengthen it) but nothing really improved it.   I'm running LOK palm swell bogies as I like the grip they offer but with them I still don't have an ideal trigger finger placement.

Awhile ago I purchased a 3D printer and have been playing with it fine tuning it to produce really great prints.   As an engineer it's a perfect toy,  you get to create things and it requires learning the process to produce functional "good" parts (read it needs a tinkerer).  It's paid for itself 10 times over by now.

The first thing I printed was a custom designed magwell for the TSO.  While it worked,  the way CZ mounts magwells is not ideal and it came out of position during a match.  It was really a material issue as the polymer isn't rigid enough to prevent flexing out of position.   I since went back to the stock for now.

My latest print was a custom designed SAO trigger.   It shows real promise to improve ergonomics with my rig.   I went through a couple of iterations getting to the final design (two on left are my design):



I'm printing with a carbon fiber infused nylon that is tough,  chemical resistant,  and rigid.



My design increases the trigger reach by about 0.25 inch which gives me a much better feel.  It has both over and post travel set screws, same as the stock trigger.




I'm running it at my local match this weekend to see how I like it.   I hope I can retrain my muscle memory to the longer reach and don't go home early due to an AD.

Here is a close up of the trigger:


Cheers,
Toby

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[newageroman]

Wow, that is cool! I love seeing people make better stuff than the paid engineers.
Sometimes I run a 3D printed mag/grip, but yeah it is delicate and flexy. more for a range grip, but it it a cool design. A guy off FB made it based on the S2 frame but it works on the SP01.

Rock on, and thanks for sharing.

[tdogg]

Well I dry fired it tonight and I did have some premature launches.  By the end of dry fire, it felt normal.  I think it is going to be a winner. 

I have spent some time figuring out how to print the trigger with a better surface finish.  I can but it is at the cost of play in the trigger pin hole.  If I rotate it 90 degrees and print it with both sides of the trigger perpendicular to the build plate it gives a great surface finish on all sides but the rear of the trigger (which you can't really see).  Unfortunately I can't figure out how to make vertical holes (the trigger pin hole) from being oval when printed in the vertical axis.  This will lead to trigger slop.  I guess I could just make the holes undersized and then drill them out post print.  I will need to get the right size drill bit.

It might be a tad too long of reach with my current design.  I may make a slightly shorter reach variant and see if it feels any better.  After I run it at this weekends match, I need some more trigger time before I make any tweaks.

I have a handful of triggers that are all functional but may not have perfectly round trigger pin holes or will have different surface finishes on either side if anyone wants to try one.  Send me a PM.  I accept no responsibility for their use in or failure to function in your firearm.

Cheers,
Toby

[Tok36]

Very cool. It looks like you have done some nice work there. I think i might like to tinker with one of those, ill send you a PM.

I look forward to seeing how the testing progresses. Thank you for the post.

[Steve Menegon]

The trigger looks good!

I am not knowledgeable in 3D printing, but have a question about the holes distorting. Is it due to heat and they sag during cooling? If you change position of the printing to get the holes to cooperate, could you sand the finished product on a machinist stone or any flat surface to attain the finish you want?

How about printing an extension to fit the "shorter" original trigger?

[tdogg]

Thanks!

The distortion is a combination of things (I think).  There is some thermal distortion due to the print temperature.  You want a higher temp to ensure all the layers "bond" together and make a strong part.  But the real culprit is the fact that the there are finite layers printed vertically and you can only make a psuedo circle with the layers.  The thinner the layers, the smoother the circle will look but I can go so thin on the layers practically.  There ends up being a larger gap at top and bottom of the circle because the slope of the circle is nearly flat there.  I picture here would be best.  I will have to pull up the slicer software and take a screenshot.

My first thought was to print a trigger "shoe" that slipped over the stock trigger.  I may still try that.  It will just make the trigger wider than it already is which may not be a bad thing?  I'm afraid of it moving/dislodging during use though.  It would have to be a bomber attachment and fit.

With regard to refinishing, I'm printing with Nylon which is far more durable than other standard filaments but it is also mostly chemical resistant (which is why I'm using it for this application).  With PLA you can smooth out the surface with an acetone fog and I'm not sure you can with Nylon.  You absolutely could sand and refinish the trigger.  Folks paint 3D parts all the time.  I'm just not sure what would work with Nylon or how durable it will be?

The easiest solution is to print it with smaller holes and just drill them out to the right size.  That would result in excellent fit and appearance.

Here are some close ups of the two different print orientations (left better appearance,  right better trigger pin holes).  The surface finish is rough with this material due to the fact it has carbon fiber in it.  It is just how it prints.  It doesn't look bad and actually hides the layers better than most materials.







Cheers,
Toby

[Steve Menegon]

I see what you are saying with the holes. I'd want to try as you said, make them smaller and drill them, or don't put any in them and utilize original as a guide to drill them out.

I'm sure you'll figure out the best method.

The trigger shoe might work as long as a good bonding agent possibly coupled with attaching screws, but the use of screws may cause discomfort. Carbon trigger shoe? I can see that.

Good luck in any case!

[tdogg]

Ran it at my local match today.  Worked great.  I did have a couple of times where I didn't reset the trigger properly.  I didn't expect that to happen but it makes complete sense given the increase in reach.   I will keep running it for now and get more trigger time on it.  I'm sure I will retrain my brain soon enough.

I took one of the prototype triggers and soaked it in Acetone, Brake Cleaner, and Bore cleaner (independently).  It didn't phase it.  I was sure one of those would soften it but I couldn't get it to show any signs of degrading.  It's living up to it's rep and is chemical resistant thus far.

Cheers,
Toby

[Steve Menegon]

Glad to hear it worked out for you!

[Stuart]

Looks great Toby!!
Bet that feels great for the trigger placement

[tdogg]

Looks great Toby!!
Bet that feels great for the trigger placement

Thanks!  It does feel much more natural for my large hands.

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[tdogg]

I updated the profile a little and made it a little longer.  I think I like this look better:
Updated profile:

Old profile:


Cheers,
Toby

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[MoRivera]

You used to be able to find these SAO triggers for 'larger hands' at like ArmoryTech, but they don't seem to carry them anymore.  Other places overseas don't seem to have then in stock either.

[tdogg]

Yeah, I almost purchased one of those a while back but didn't like the curved profile of the trigger face.

My trigger is flat and is farther forward.  Thus far it is a winner.  Numerous dry fire and live fire with it now and it's starting to feel normal.  I have no concerns about longevity/durability at this point.  This material is bomber.  I might actually install this another trigger on my other TSO.  I will probably wait a and test a little longer before fully committing both rigs.

I can't wait too long because shooting season is getting into full swing and I will be shooting majors soon.  I don't want to be switching it up right before any major matches.  It does take a bit of reprogramming to feel normal.

Cheers,
Toby

[tdogg]

Just thought I'd update this thread.

I've been running these printed triggers for some time.  I've cleaned the guns numerous times now without issue.  The triggers show no signs of wear or degradation.  The material seems to be fully chemical resistant. 

I've run them at local competitions and a major with no issues.  I'm headed to nationals in Oct and will run them there as well.  They feel completely normal now.

Cheers,
Toby