Part two of the trigger job Clinic Will focus on the sear?
What makes a good one? What should a perfectly prepared Sear look like in a carry pistol? Once again to facilitate our talk I have attached a picture, labeled for easy reference.
A) Primary sear engagement surface (sear nose)?
B) Sear feet (?)
C) Don't know what this portion is called...
Okay, what do I do in order to get a clean letoff? I know the sear nose has critical angles, and those critical angles have to be maintained.
Why do the newer Colts have what looks like a sprue mark square in the middle of the working surface of the sear, how much does this affect the pull, and how would you go about rectifying it?
I understand that critical angles are a concern, in that you want surfaces to contact fully. But what about a proper angle and a reduced surface? I look at it as a Cartesian geometry problem... say you have an incorrect angle on a nice smooth planar contact surface, the contact will still occur on a line on that surface, so most of the surface never contacts properly its mate on the hammer notch. Wouldn't that be similar if the contact surface is reduced even at proper angle? So I guess that both proper angle and enough "meat" are required for a good mating... no pun intended...
1911 trigger pull has very little to do with springs and very much to do with geometry. Here's a summary:
The hammer hooks must be an absolutely square 90 degrees and they must be parallel to the hammer pin. Any variance will result in either trigger creep or a gritty trigger (not square) or worse yet, a partially engaged hammer if the hooks aren't straight. Additionally, the hooks should nominally be .020" high. some prefer to go down to .018; I don't think it's necessary. My hooks are exactly .020 and I have a clean, crisp trigger pull in the neighborhood of 3.5 pounds.
The sear nose should actually have two separate surfaces. The primary angle should match up exactly with the hammer hooks when placed in the gun. This means you can't just purchase a "drop-in" hammer and sear and expect them to fit perfectly. If the geometry is off even a little bit, the trigger pull suffers. Sear-to-hammer engagement must be checked on the gun itself. I have a set of pins (drill rod would work just fine) that mount the hammer and sear to the outside of the frame, and a 10x loupe that allow me to check the work. A swipe of Dykem or even a Sharpie marker across the hammer sear nose will show how the engagement surfaces mate.
The secondary surface of the sear nose should be to the inside of the hammer hook, and should be cut such that the sear engages the hooks fully but that once the nose lets off there's no sharp edge to hang up on. This will facilitate the "break" of the trigger when depressed. It is important to leave about .020", or roughly 2/3, of the sear nose at the primary angle to ensure a safe amount of engagement. For those playing along at home, make sure you stone AWAY from the primary angle so as not to place a "hair" of metal at the junction between the primary and secondary.
As you can tell, this isn't stuff you can just do by fastening the parts to a vise and grinding away with a Dremel. Proper tools and jigs are a necessity. But with the right equipment anyone can do a great trigger job for a 1911. Brownells sells an excellent kit for performing a 1911 trigger job. the kit also contains an instruction sheet that has a very well-done diagram of what proper engagement should look like, as well as some examples of bad engagement and the consequences. The instructions are downloadable here.
Thanks for your input. Those links are useful indeed and your discriptions are quite clear. I will look at those links and mull this over a bit. I may be back with questions. Stay tuned!
Breakaway Angle
Also known as the "Escape" angle. Very good post by Manevitch, by the way. Welcome to the fireside, Manevitch.
The breakaway angle does a couple of things. It reduces the area of engagement a little... fewer square inches means less resistance... and it provides a cleaner break when the sear trips.
Like barrel crowns, everybody has their own pet method, and I'm no different on that angle. Some go as heavy as 45 degrees to the primary, but I like less. I use about a 15 degree angle from vertical to the back of the sear nose to get the sear deeper into the hooks, and take care to reduce the primary angle's surface by just enough to get the entire surface IN the hooks... or, stated another way, the width of the primary angle matches the hook's length. This provides maximum engagement without having the trigger pull any heavier than necessary to be safe. The light escape angle gives a slight "rollout" break instead of the glass rod kind. A light angle on the top of the half-cock to keep the sear from tipping it as the hammer falls completes it.
I like .021-.023 hooks, as that seems to offer the best trigger without compromising the built-in "safe" zone that keeps everything engaged in the event of a weakened sear or mainspring. As I've stated before, I get nervous when hammer hooks fall below .020 inch. I'm not a trigger man, though, and I know that there are some smiths who can do a perfectly safe trigger with .018 or even shorter hooks. I'm just not one of them, and if one of my trigger tweaks results in a pull weight of less than 5 pounds, you'll find me bending sear spring legs forward to get it up to that level.
Your link goes to a page that shows a Kit and 7 items for sale.
I can not tell if the "kit" for 200 plus dollars ( very reasonable ) includes everything or just some of it.
I think I am interested in trying this kit and I have maybe learned enough in these clinic threads and some off -line conversation to give this items a try.
If I order them I will start another thread about my adventures with that kit. Complete with pictures and questions!
I have to say I am really enjoying these threads. I hope they expand and we get input from a larger group of people. To that end I went over to the 1911forum and invited folks from the gunsmithing section there.
The kit is all inclusive, consisting of the jig, hammer squaring file with handle, 3 stones, alignment pins, pillar file, shim stock, and stirrup die, plus a box to put it all into.
Quite honestly I think I could have done without the stirrup die - I use McCormick triggers, which have a slight radius at the rear end. That radius keeps it from forming on the die well, so I just fit it on as best I can, square up the trigger pad, then take it off and check visually that the two sides of the bow are straight. Everything else is entirely worth it.
One tip: if you get the jig, pull the pin out - the one that's (somewhat) glued in to hold the dear in place - and refasten it with some Loctite. Otherwise you'll pull the pin out before it locks the sear in tight enough.
Oops - one more tip: invest in a decent loupe. I have a 10x that's great. Also, a bench vise with plastic jaws is pretty much mandatory. Picked mine up at Harbor Freight for about $6, with a suction base for use on the kitchen table - er, I mean my gunsmithing room...
I learned all this by reading a ton, and tearing down my 1911. It's not really that difficult; there's just a lot of critical steps in working on the trigger group.
The deeper you dig into your 1911, and the more work you do on it, the more you'll respect and admire the simplicity and effectiveness of the design.
So if your Gun comes with a sear that has no secondary angle from the factory would it be wrong to add a secondary?
Wouldn't a secondary angle be benifical to limiting damage if by chance your sear tip bumps the half cock notch?
Secondary Angle
quote:
So if your Gun comes with a sear that has no secondary angle from the
factory would it be wrong to add a secondary?
If you mean a breakaway or escape angle...Probably not on a stock Colt with .028 inch hammer hooks.
quote:
Wouldn't a secondary angle be benefical to limiting damage if by chance
your sear tip bumps the half cock notch?
Probably not, unless the half-cock passed by the sear close enough to barely tip it. The breakaway might be just enough to cause it to miss, or cam it farther open as it made contact. If the half-cock gets that close, there's something else wrong. I normally file a light angle on the end of the half- cock as a matter of course. Not enough to actually do anything, but just to break the corner 'cause, well... I like broke corners.
I just recently bought the Brownells trigger kit that Manevitch mentions. I also bought some expendable hammers and sears to practice with (strongly recommended.) It's very good, although the large spur hammers that I prefer will not fit in the stoning fixture properly - I may have to take my mill to it.
The real trick to working on the sear seems to be matching the sear primary angle to the hammer. The dissasembly pins that come in the kit are very handy for testing the angle without having to put the entire trigger group back together.
Also, just like on the hammer, it's important to make sure that the pin holes are parallel to the sear engagement surfaces. I don't know how much of a problem this is on modern parts, though.
Does anyone have an opinion on the Powers Series I fixture? I have been using it and I like it. It seems to be a lot of tool for the money - also from Brownells.
Well, thanks to these fine threads, I have my Government, Combat Commander, Officers Model and my Gold Cup Trophy all torn apart on the dining room table and I'm looking at at the sears! Hey-it keeps me off the street!
As all the pistols are Series 80, all the sears look the same. Except for the Trophy sear. It has a square notch right in the middle of the sear engagement surface, and the hammer has a knob, roughly triangular in profile and looks as if this knob passes through the notch on the sear.
The trigger press on the Trophy is much lighter and feels cleaner-maybe due to the design of the sear (?) and probably because the National Match series uses a wider trigger which tends to make it feel lighter.
What is this protrusion on the hammer for and why do I have a cutout on the sear?
Delmar's Sear and Hammer
Delmar, as near as I can figure by your description, the square area on your sear engagement angle is the unworn portion. The center isn't touched by anything at full cock/sear trip, while the hammer hooks bear on the ends. Simply put, it sounds like a wear pattern. All my hard-use pistols show the same pattern. No way to tell if it's excessive without looking at it.
The triangular thingie on your hammer... from your description... is a modified half-cock. Only the center portion is left so that in the event of a followdown to half-cock, the only part of the sear that gets hit is the part that doesn't engage the hammer hooks, thus protecting the trigger job. Simply put... it sounds like your trigger has been tuned, and if I'm not mistaken, that's a McCormick hammer, or somebody has copied the modification. It's actually one of the few deviations from original that I like.
quote:
Also, just like on the hammer, it's important to make sure that the pin
holes are parallel to the sear engagement surfaces. I don't know how much of a
problem this is on modern parts, though.
Can anybody tell me if this applies to Norincos? I had it apart, and the wear pattern is disturbingly skewed, almost oblique... also the hooks look like they were cut crabwise, and polished with a garden rake...
Norinco Skewered Sear
Yep romulus. It applies to all of'em. There's a possibility that the holes were catty wampus and some sharp factory tweaker just cut the sear at an angle to get the gun out the door.
Check it by coloring the primary angle with a chisel point felt-tip marker... preferably blue, and dry firing the pistol a few times. If both hammer hooks hit the sear, and the sear is cut at an angle, it's been "smithed". It'll work. It just ain't right, and swapping sears will require that the new one is likewise modified.
I really botched up the description on the GCT. You are of course correct in the sear bearing on the hammer hooks which are on the ends
Upon looking further at this, that lump is indeed the half cock shelf, and the notch in the sear nose apparently provides clearance for it in normal operation. BTW-this particular pistol is bone stock. I bought it NIB from a good friend who had it sitting on his shelf for a couple of years unfired, and I asked him today if he had made any mods to it at all. Not a thing was touched according to him. So it looks as if Colt either farmed out the hammer and sear or they have copied it.
It really does make a lot of sense to me having this half cock shelf as you describe-if the hammer does follow to half cock, its not going to bear on the ends of the sear nose and possibly damage the working surface.
I would suppose that if someone were to choose a hammer design like this that they would also have to use this type of sear as well?
Odd Half-Cock
Delmar said:
So it looks as if Colt either farmed out the hammer and sear or they
have copied it.
That, or somebody modified and refinished it.
Sear type? Though I haven't used a hammer with that type of half-cock, it's my understanding that the conventional sears will work with it. I could be wrong. I need to get offa these old GI pistols and get cozy with some of the modern stuff.
Tuner-just to see if it would work, I put one of these new fangled hammers in my old Government model and it does work with the conventional styled sears.
Cylinder and Slide were dumping some "Colt National Match" hammers out of their inventory last spring so I bought 3 of them. What the heck says Delmar, they're only $17.50 a piece. They are different from the GCT hammer in that they use a spur rather than the abomination enlongated commander types you see now. It has the same little triangle thingy for a half cock notch above the hooks.
Quote:
I need to get offa these old GI pistols and get cozy with some of the
modern stuff.
I'm looking to get back to GI stuff. Tuner is right, some of these new hammer designs are just abominable to look at. Are old fashioned spur and rowels still available, in tool steel, machined to final form?
Rowell Hammers
romulus said:
I'm looking to get back to GI stuff. Tuner is right, some of these new
hammer designs are just abominable to look at. Are old fashioned spur and
rowels still available, in tool steel, machined to final form?
Yep. I think STI has a good spur hammer, and the standard configuration rowells are available too, though I'm not exactly sure who makes'em. I do know that Brownells lists those, and I'm pretty sure they're steel.
Thank Chip McCormick for the ugly rowell hammers. I think they're kinda neat, but beauty is in the eye of the beholder. The elongated hole isn't just for trick looks, though. There's a perfectly sound reason for it. It lightens the hammer a little. This not only reduces the inertial mass of the hammer for less chance of hammer bounce... it speeds up locktime. Ugly is as ugly does, HEY!
Cylinder and Slide sells a spur hammer, as does Kings Gun Works. Have used both and they seem to be made well. Kings is one of the few which carries the old wide spur hammer.
I have seen some of the traditional rowel hammers in Brownells, but I haven't been able to find the old style Commander grip safeties.
Seems these days, you're supposed to be happy with the ducks arse style or the upswept, which to me feels comfortable but does nothing for the looks, or you can still find the scorpion tail Colts which look so-so, but I do not find them so comfortable to shoot with. Too square in cross section and they tend to dig into my hand.
Hammers and safeties and ducktail.Oh MY!
Delmar said:
I have seen some of the traditional rowel hammers in Brownells, but I
haven't been able to find the old style Commander grip safeties.
Delmar, I hear ya, and the answer is to take a standard grip safety from a Government Model and get out your dnady-Danyd Dremel and make one.
It works, though it does take a little time. Colt MIGHT send one... but I wouldn't hold my breath. Call the Customer Service folks and ask for Cindy. She seems to be the most accomodating, and a nice lady too.
Wish I could post some pictures of the ones that I've reshaped. A little cold blue paste from Brownells, and you're golden.
Seems these days, you're supposed to be happy with the ducks arse style or the upswept, which to me feels comfortable but does nothing for the looks, or you can still find the scorpion tail Colts which look so-so, but I do not find them so comfortable to shoot with. Too square in cross section and they tend to dig into my hand.
Ah, Grasshopper... Your file is your friend. Become one with your file, and you can achieve grip safety happiness with patience and perseverance.
What's a rowel?
What's different about a Commander grip?
What's a scorpion style?
What the are you guys talking about?
I'm going to be replacing the grip safety on my Loaded model soon, and if I understand correctly, I'm going to have to think about all this stuff, and you guys are making my hair hurt.
A rowel hammer is the old fashioned Commander hammer, basically rounded, not spurred. Basically the hammers used on beavertail setups but with a round lil' hole, not the elongated hole that's in vogue these days...
The "scorpion" I think refers to an older style grip-safety that's not a beavertail, more like the GI safety but scalloped out so it looks like a scorpion tail...
Spur hammers RULE!
But sadly Kings doesn't make them anymore, and I found out too late and C&S cost too much IMO.
STI, while nowhere near conventional in my eyes, does look good on custom guns.
Once Caspian had a Spur hammer catalogued, however there vendor never made an acceptable blank for them so they never went into production... poor Gary, I bugged him endlessly "spur hammers available yet?" finally I came to terms and stopped bothering him.
I hear LesBaer makes spur hammers too... have to keep them in mind.
Jammer, if you happen to look at an older Commander with the "rowel" or round hammer, you'll notice the grip safety is shorter front to back-doesn't stick out from the frame as far. That is to give enough clearance for the round hammer to cycle.
Can anyone help me find an origanal Tom Wilson #1 hammer Jig and instructions, also instructions for #1 sear jig. e-mail or post
The reason for need is theft, The hammer jig and inst. sheets were in box I use for them and sear jig was on bench, box disappeared?
I know there is better jigs, but I'e used them for years and like them. I don't really need instructions but like to have them with tools.