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Lightening Trigger Pull and Polishing Internals


jlat32

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I posted this within the BE vendor tent for EAA/Tanfo and wasn't sure if it belonged there or here.

The majority of the trigger pull weight comes from the trigger spring, sear spring and the hammer spring. You can lighten up the trigger spring by bending the two legs so that they are a little less than a 90 degree angle from one another. Be careful with bending the trigger spring though as it is very easy to go too far and either break a leg off of it or make it too light. The hammer spring needs to be replaced with a lighter one. If you are using the Henning Extra Long firing pin you can use a 13lb hammer spring and it will reliably ignight the primers. I am not sure what lb hammer spring you can go down to with the stock firing pin and still have reliable ignition. The Sear spring tension can be easily adjusted lighter by cutting a notch into the sear where the short leg of the spring rests. The deeper the notch the lighter the spring tension on the sear gets. You can use a cutoff wheel on a dremel to make a nice clean notch for the sear spring leg. Adjusting these three springs tension has a significant effect on the overall trigger pull weight but not so much the smoothness of the trigger pull.

Creating a smooth trigger pull is mainly achieved by polishing up and smoothing out the head of the trigger bar plunger and its mating surface on the under side of the trigger bar. These two mating surfaces are usually poorly finished from the factory for whatever reason. You can also cut a coil or two off of the trigger bar plunger spring to reduce the friction between the two surfaces as well. Once everything is polished up and reshaped to optimize the mating surfaces you need to use a light grease between them such as the Brian Enos Slide Glide Lite grease.

You can also polishing up the out sides of the trigger bar as it will also reduce friction between it and the frame. If you are going to use the stock sear and hammer trying to polish up anything else is a waste of time because the parts are case hardened and once you break trough the hardening the metal is very soft and it will wear out quickly. So DON'T try to polish up the sear lip or hammer hooks. If you do it will feel awesome for about 500 rounds and then quickly degrade to a point where it gets gritty and eventually causes hammer follow issues. An EGW sear and hammer are needed to make a really kick ass trigger on the EAA pistols because their metal is hard all the way through and you can modify them without fear of reducing their service life.

I hope this helps. Good luck and be safe.

Great summary! My Match had some polishing done to it by the first owner, but I had it apart a few weeks ago and noticed even the polished surfaces had gouging and other imperfections from initial machining. I was planning to go over it again and smooth things up.

What is the best way to smooth out imperfections on the plunger and trigger bar/bow? I was thinking of starting with 600 - 800 grit sandpaper and working finer and finer until I get a smooth surface, then final polishing with Flitz and wanted to know if I'm on the right track.

Can too much material be removed from the plunger and trigger bar/bow from doing the process above? I assume so long as I don't change overall shape I can smooth out the imperfections.

I'd also like to change springs to try lighten the pull. I was going to run the 13# hammer spring with Henning XL firing pin. Do they make lighter trigger springs, or am I at the mercy of tweaking my stock trigger spring?

How much will notching the sear for the sear spring affect trigger pull weight? This seems like the first part I could mess up royally and don't want to risk it if there is minimal gain.

I'd eventually like to try Henning's flat trigger, but for now want to try lighten things up with the stock trigger unless Henning's flat trigger will really make a difference.

Final question, when I had the gun disassembled, I noticed the pretravel adjustment set screw was worn to a flat that matched the surface profile of the trigger. I'd like to replace this screw. Anyone know the size or where to purchase a stock replacement?

Thanks Tanfo gurus!

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The weight of the hammer spring has a drastic effect on the DA pull of DA/SA guns, but in my experience with SAO pistols a super light hammer spring can make the break feel mushy and cause lots of frustration with light strikes, primers, etc. I have a CZ TS with a 1 1/2# trigger and an 18# hammer spring.

In a SAO gun the hammer spring can be a shortcut to a light trigger, but polishing and the other springs will do a better, more reliable job of lightening the trigger. If you have a 15# hammer spring in your Tanfo, you'll never have to worry about it and a sub 2# trigger is still attainable.

It sounds like you're using the stock Match trigger at the moment right? The set screws are M3x0.5 your local Home Depot probably won't carry them so try to find a specialty hardware store.

I'm not a big fan of bending or clipping springs to reduce power and I think you can get where you want to be without it. First off, with the stock trigger (the Henning trigger uses a different style TRS) you can use the reduced power trigger return spring Cajun Gun Works sells for CZs; that alone will lower the SA pull weight by 8oz. Next is the CZ sear spring, the coils are a smaller diameter than the Tanfo sear spring. The trigger plunger spring can be really light and still work, a lot of guys here use the springs from click style ball point pens.

Polishing is just that, not sanding. Deep machine marks will not come out until you remove all the metal around them; it's easy to get obsessed with shiny parts inside the gun, but trust me, I've ruined a few internal parts getting carried away. I don't generally use sand paper with a grit lower than 1000 and I finish parts off with 3000 grit. Don't forget to sand the inside of the frame as well where it contacts the moving parts. My CZ tuning thread will give you some ideas for areas you missed: http://www.brianenos.com/forums/index.php?showtopic=191773

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Thanks kneelingatlas! I ordered the CGW reduced power TRS and the CZ sear spring, now to raid the stash of pens at my desk to find a new plunger spring. I'm going to swap these springs and give it a good polish and see where it ends up with the stock hammer spring. Maybe try some lighter hammer springs in the future. That CZ tuning thread you posted is awesome! Thanks for sharing your experience in such detail. Makes me want to get a CZ or two!

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Thanks Nealio.

Touched up the polishing on the trigger bar and plunger, and also polished the inside of the frame where the trigger bar slides, which hadn't been done before. Replaced the trigger return spring with a CZ reduced power TRS from Cajun Gun Works, replaced plunger spring with a click ball point pen spring, and replaced the sear spring with a CZ sear spring (fewer coils than Tanfo stock spring). Pull weight went from a little under 3.5# to a little under 3#, and perhaps closer to 2.75#. Reset is noticeably softer after I changed the sear spring. Not sure yet how I feel about that, but I haven't fired it yet so I'll keep an open mind.

I don't have a pull weigh gauge, so I looped a bucket handle over the trigger and filled with water incrementally until the hammer fell, then weighed the bucket.

I have 13, 14, and 15 pound hammer springs on order and will post another update when I find which one I like best. Hoping for the final pull weight to be around 2# or a little under.

Kudos to all the guys who have posted how-to videos to YouTube. Very helpful. Thanks for sharing your experience with novices like myself. These guns are relatively simple to work on!

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Not exactly sure how to describe it, but it doesn't seem to reset as "positively" as before. Mushy could be a way to describe it.

I first replaced the TRS and plunger spring and dry fired a few times and the reset seemed similar to the original springs. Then I did the sear spring and noticed a change. I'll swap the sear spring tomorrow morning and see if it seems closer to original reset. If not, I'll try the plunger spring. Stand by and I'll report back.

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Not exactly sure how to describe it, but it doesn't seem to reset as "positively" as before. Mushy could be a way to describe it.

I first replaced the TRS and plunger spring and dry fired a few times and the reset seemed similar to the original springs. Then I did the sear spring and noticed a change. I'll swap the sear spring tomorrow morning and see if it seems closer to original reset. If not, I'll try the plunger spring. Stand by and I'll report back.

If the ballpoint pen spring is too soft u can nest 2 springs together. OR : What i do now is i increase the inside diameter of the factory tbl spring. First i weigh the spring, then i reduce the weight by 20 to 30 % until i get what i want. I use a small round diamond chainsaw sharpening file chucked in a dremel. I do this with clipped firing pin springs too. With a little patience u can get exactly what u want with this method.

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Not exactly sure how to describe it, but it doesn't seem to reset as "positively" as before. Mushy could be a way to describe it.

I first replaced the TRS and plunger spring and dry fired a few times and the reset seemed similar to the original springs. Then I did the sear spring and noticed a change. I'll swap the sear spring tomorrow morning and see if it seems closer to original reset. If not, I'll try the plunger spring. Stand by and I'll report back.

It was definitely the plunger spring. Swapped sear spring back and it felt the same. I guess I didn't realize it the first time I tried it. I put the CZ sear spring back in. I raided the pen drawer and found one that felt in-between stock and what I had. It was a bit longer but didn't bind when fully compressed, so I'll try it for a while.

Attaching sear and plunger spring comparisons pics.

post-44766-0-61128900-1398102270_thumb.j

post-44766-0-29900700-1398102284_thumb.j

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I also started playing around with hammer springs. Didn't have much time to try multiple springs over the weekend, but put in the 13# spring and the pull came in a bit over 2#. Has enough of a wall that I can feel it, but kinda rolls through it. Assuming it sets primers off, I'm going to run it like this for a while. I'll try a 14# and 15# hammer spring just to compare feel.

I'm running Henning's XL firing pin, which I've read is pretty much required to run a 13# hammer spring, and even then not everyone gets reliable ignition. If anyone can share experience, both good and bad, with a 13# hammer spring that would be great.

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Kneelingatlas, I actually tried that recently and if anything it made matters worse! I use a 16lbs hammer spring and an Xtreme firing pin - the one that works with the FPB! I use Magtech primers and usually do not have ignition problems but that changed last weekend! Had many failures and first changed the hammer spring to a new 16lb which did not help! I took the FPB out and as that did not help I started cutting off coils on the FP spring. To my surprise it did not change anything and it wasnt until I took the firing pinn from my Limited, that works without the FPB, I started getting reliable ignition!

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I just did a polish job on my new Stock 3. The trigger bar had nasty chatter, requiring an emery wheel prior to polishing. The firing pin had burrs on both sides of the FPB slot. Significant improvement after the pin and fpb got shiny.

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Hey guys, I am looking for some punches to take down my Tanfo. I have one but it is a little big for all the jobs. Can y'all recommend where to get some and what kind/brand that has the appropriate punches needed? Thanks in advance.

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Hey guys, I am looking for some punches to take down my Tanfo. I have one but it is a little big for all the jobs. Can y'all recommend where to get some and what kind/brand that has the appropriate punches needed? Thanks in advance.

I have found that the Grace roll pin punches are absolutely worth the money. I've screwed around with cheaper, hardware store model punches and have some scars on guns to prove it. They don't damage the pins as much, are nice and long, and have a ball end to center the punch on the pin. Good luck.

http://www.brownells.com/gunsmith-tools-supplies/general-gunsmith-tools/punches/roll-pin-punches-prod38883.aspx

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Just learned this from a friend.

Take old drill bit that has a shank the size you need in a punch.

Drill into the handle material of your choice...I have a bit of aluminum rod scraps. friend uses brass.

Leave the drill bit in he rod and squish the material around it so it grabs into the flutes.

Presto, instant pin punch.

Cost me pretty much nothing as the dull drill bit and scrap rod pieces had no real use any more.

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Does anyone else have an ambi-safety on a Stock II? Mine works but the one on the right side is very loose and wiggling. The safety mechanism still works but just the right side is loose. Anyone know how that can be fixed? I believe I had heard that a new roll pin may be the solution but any advice would help. Thanks in advance

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That's just a part of the design, some are looser than others, but they all wiggle a little. A new roll pin will likely not help, but if you were so inclined you could dill out the holes in the right hand safety to match the one in the left hand safety more exactly and use a bigger pin.

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