View Full Version : Sear lubrication??
June 4, 2010, 07:20 AM
I have read in several places that any lubrication of a hammer / sear's engagement surfaces is a no no. Some folks recommend the use of lighter fluid, Acetone etc to de-grease the engagement surfaces.
Is degreasing and no lubrication of these surfaces in fact a good and proper practice?
Why is it a good (or not so good) practice?
June 4, 2010, 07:55 AM
Frankly, it depends how the engagement is set up? The Frank White trigger on my AR comes with moly grease all over it, and the recommendation to use more of the same. Works great. I set up my 1911's with a slight overhang of the hammer hook so they are mechanically safe whether oil gets in them or not. It will do so accidentally in most any semi-auto, as they tend to blow lube and smoke and graphite and all the rest all throughout the gun. Many other guns will get lube creep or accidental distribution, so it is best to have a trigger that can tolerate some lube.
If you like a crisp trigger, most mechanisms depend on rapid slip of the engagement going from a static to a kinetic coefficient of friction, the latter being usually about half the former. But if you put a lube film there or let Teflon or other dry lubes accumulate in the engagement, the difference in the friction coefficients will be reduced and the trigger can lose crispness, engagement weight, and even start to creep in some instances.
An example of a mechanism that would not like lubrication is the older Savage pre-Accutrigger still in use on the Stevens models. I replaced that factory trigger on my 10FP with a Rifle Basix trigger and set it up a bit lighter than the factory trigger was out of the box. The result was one incident of discharge on closing the bolt (gun pointing downrange at the berm). I increased the trigger release weight a half a pound and gave it some jostle testing and it was fine after that. I later replaced the trigger again with the Sharpshooter Supply trigger, which has allowed safe lighter engagement. A friend with that same rifle and the factory trigger also had one discharge on closing the bolt. I think he messed with the springs or some such thing, so it also had to go back to original condition. But the bottom line is that trigger mechanism is not one you want to lube. It runs too close to the edge of safe to begin with.
On the 1911, I've also had occasion to clean one out for a fellow competitor whose wad gun had doubled on her. She never tore the the down, I guess, and over a period of years it had built up so much powder residue that it was caked with graphite/carbon mix. The trigger broke without creep, but felt slightly mushy and the hammer followed the slide on closing. The graphite/carbon mix had actually accumulated at the corner of the hammer hook to the point it was reducing the engagement depth, and it was actually lubricating it. I didn't have a trigger weight with me, but suspect it was too light. So, I gave it a good de-caking during the match lunch break. The trigger crisped right up and the hammer stopped following the slide on closure.
In her case, additional lubricant might have made the hazardous situation worse or it might have cleaned out some of the carbon? I don't know which would have happened?
June 4, 2010, 08:02 AM
Had the same thing happen to a cheap semi-auto and an 870 one time. I cent believe how long people go without fully cleaning their guns. Years and years of crap in the actions will make them fail no matter how good the design is.
June 4, 2010, 08:12 AM
I admit that as a tinkerer I probably tear my guns down a lot more frequently than I need to. In one week of intensive practice, though, with barely enough time to eat and sleep and every spare minute spent reloading, I did once run close to 3000 rounds of dirty ammo through my fixed-sight 1911 without cleaning. The friend who hosted the event had bought cast bullets with moly lube on them so it really blew the black muck around. By the end it was expelling in small quantities around the edges of the grip panels, so my hands would come away looking like I'd been loading charcoal into the Bar-B-Q. It finally got packed up enough that the slide was feeling draggy, so I had to make time to clean it that evening before the shooting continued. But the gun never actually failed. I've got good confidence in its reliability, as a result.
June 4, 2010, 10:32 AM
The sear interface is subject to high pressure. A few pounds over a tiny fraction of a square inch contact surface = lots of PSI. There are a few exceptions, but most sears should be lubricated with grease. If you hunt in sandstorms, use a dry lube.
June 4, 2010, 11:12 AM
I guess I agree with unclenick, it really depends on the set up. The words always and never can get you into trouble with guns.
June 4, 2010, 07:10 PM
Years ago, people would get a less than great pistolsmith to do a trigger job on a 1911 and would have "hammer follows the slide" problems.
In many cases the "gunsmith" would claim that "my trigger jobs are designed to be run dry of lube".
This was of course a load of BS to try to cover an improperly done trigger job.
The fact is, in most firearms it's impossible to keep lube off the trigger assembly.
Lubricants are designed to creep and spread, and the operating action and recoil will quickly sling lube into the trigger.
My thought is, if the trigger "has to be run dry" something is wrong, and since it's GOING to get lube on it, you might was well insure it's the right lube and in the right places.
This usually means a thick oil or an actual grease.
The laws of friction causing increased effort to work and increased wear are not repealed just because it's a trigger.
All moving parts need lubrication.
June 4, 2010, 08:31 PM
Thank you to all that passed on their knowledge and experience about sear / hammer lubrication.
I have been using Brownell's moly action grease on all of my firearms sear / hammer (striker) surface for many years. I wondered about the advice to not lubricate them many times.
Now I have a better understanding and will continue to do as I have in the past.
Roger aka velocette
June 5, 2010, 12:00 PM
My thoughts are that you fit engagement either with or without a lubricant and maintain that situation.
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