Looking for some info on temps or advice about doing this, is it neccessary. I have recently polished the sear face on a trigger, this involved filing smooth, then plolishing with ceramic stones and buffing with a dremel tool. Should I heat treat the trigger sear face, and if so, what temp should it be before quenching. Any advice is apprieciated.
Thanks
P.S. I did use the search function and could not find anything on this, though I remember seeing some posts on this subject.
It looks like your searching for a fix on something that isnt broken
Unless you heated the metal enough to ruin it’s tempering, you shouldn’t have to worry about re-heat treating it. I’m not sure if the parts were heat treated to begin with or not. I don’t think so…
Those parts, at least the USGI ones, are surface heat treated. I have seen a few guys “trigger job” their parts into unreliable hunks. Good for a couple hundred rds & then…
I took vary little metal off. Just enough for a smooth trigger pull. It worked great, smooth with a crisp break. I am just concered about long term reliability(more than a few hundred rounds). The trigger sear face did appear to be surfaced hardend before I started.
I´m not sure if I took enough metal off to have removed all of the surface hardening.
Brownells sells a paste(for want of a better term) that you can apply to a surface that you are going to heat treat. It melts when you have reached the correct temp. The thing is that it comes in varying temps. 400F to 1400F in 50F increments.
What I envision is heating the searface to the correct temp, then quenching it in oil. I just don´t know what temp I should heat it to.
I do have a few extra triggers lying around, this is a case of fixing something that isn´t broken. Just thought I´d try my hand at improving a stock trigger.
Thanks for the responce´s
You should have left it alone and it would have broken in by itself.
87 degrees.
There’s a how to thread on rimfireforums explaining the process. There’s some material used there which I don’t remember. Thi sis from the trigger jobs on the 10-22’s which removes the surface hardening and the process restores it.
Lessons learned, leave them triggers alone.
Thank´s for the responces. It is one of 4 spare triggers I have, had a little spare time and thought I´d see what I could do to improve trigger feel. I remember seeing a post that had a Brownell´s product that surface hardened metal. I´ll keep looking.
They do, it’s called casenite. I would recommend having a professional re-harden them if you want to keep them.
The trigger is manufactured from a 4140 steel casting (yes all those who are screaming from the pulpit about the use of cast front sight towers are running cast FCGs). These are machined and then case hardened to a depth of 0.010 to 0.015".The final process is to grind the engagement surfaces so you should have typically 0.007" of case hardened steel. Pull is set at 9-12 lbs and the sear has a positive engagament. Typical surface hardness is 60 HRC.
I do not think you have done any damage to this trigger unit. Given the hardness that should exist, being able to file it smooth indicates that the unit was out of spec before you started.
My suggestion would be to replace the trigger with a reputable aftermarket one and if in doubt have the installation checked by a good gunsmith.
The hardening product is Kasenit. It is indespensable for rehardening parts that have been ground but it can provide a brittle edge. Given the potential consequenses of a sear collapsing, not worth it.
Bill Alexander
Use to be the case, but not necessarily so with today’s quality parts manufacturers like LMT, and Colt.
I have a trigger job that has 1500 Rounds on it and is still going strong. The same Gun Smith (Bill Springfield) has done other triggers for guys on this site and TOS, and some are reporting >5000 rounds without fail.
I waited for 3,000 rounds for this on my Colt Trigger, and it didn’t get notceably better. I had Bill Springfield do a Trigger Job on it. Now it’s 4# and breaks like a glass rod with over 1500 rounds and no problem. Some report 5000 rounds with no issues.
LMFAO…You’re killing me!!!
Thank´s Bill, really appriciate the information. It did take about 2 hours infront of the TV with ceramic stones to get a mirror finish on it. I have a Colt trigger from SAW, guess I´ll leave that one installed and call it good. Thanks for all the feedback.
Guys,
Nobody needs to be adjusting or doing a trigger job on a GI trigger setup.
It is a combat weapon and a reliable trigger when in spec. If you don’t like the trigger pull, you just need to deal with it.
Todd read the post… USGI = Colt, FN, or LMT
“and some are reporting >5000 rounds without fail.”
WOW… :rolleyes: 7 days training time…
Combat weapon blah blah blah.
If a person with male genitals doesn’t try something that he thinks will or might improve his rifle then he isn’t a man.
There are only a few triggers you should be considering for a good AR.
The factory GI trigger and the KAC trigger.
The GI is for fighting guns and the KAC is for precision guns but still durable enough to go into the field.
Every other trigger is too delicate or not in spec.
Thats the bottom line.
I build a single stage dedicated precision rifle trigger. It is machined out of billet S7 tool steel, heat treated to 54 HRC and then hard chromed so that you do not loose the sear edges after years in aggressive enviroments. The unit runs stock GI springs for reliability and floats the disconnector on a stainless steel bushing.
The base line steel exceeds the strength of the GI stock by at least a factor of two and I run this off some of the best grinding equipment in the industry today. Typically this stuff can split tolerances to 0.00005" although this is certainly not required for trigger work.
I do not want to cause an argument but the best thing about this site is that it mostly provides sensible and well directed advice for people who ask, without being condecending even if the question is elementary. There are some fine triggers out there including the KAC unit but your answer does a lot of them a disservice.
Bill Alexander