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Adjusting sear


alecmc
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I'm going to attempt my amateur attempt at installing an apex hammer in my new n frame.

I know the sear needs to be adjusted and I have the *basic* idea on what needs to be done, but I'm having trouble finding any decent information / tutorials on what I should be concerned about and procedure.

Wanted to reach out to the experienced folks here for some advice, I'd really like to try to get this done myself , I'm really starting to enjoy putzing around with revolvers and would take pride and getting this done on my own.

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The 3 main things you have to achieve are -

(1) It is short enough to reset every time when the trigger returns. This is partly a function of how tall the hammer rest pad is on the rebound slide. If it's factory height you're good to go. You may have to shorten the sear a little.

(2) Make sure the sear doesn't hit on the trigger as it goes forward after being cocked single action and the trigger pulled.

Sometimes a little chamfer on the bottom front corner will facilitate both.

(3) Make sure that the sear slides forward over the top of the trigger as the trigger is first starting to be pulled. In some cases it will tend to go backwards at first if the sear starts too far back on the trigger. This can be caused by too much radius on the top rear edge of the trigger or the sear not sticking out far enough forward.

You have to observe all these and if there is a problem, figure out the cause and then what remedy will be the best fix. Normally everything goes fine, but if someone has been in there and worked on it that is usually when problems arise. In some cases you have to replace parts to get the geometry back to original specs.

Edited by Toolguy
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The 3 main things you have to achieve are -

(1) It is short enough to reset every time when the trigger returns. This is partly a function of how tall the hammer rest pad is on the rebound slide. If it's factory height you're good to go. You may have to shorten the sear a little.

(2) Make sure the sear doesn't hit on the trigger as it goes forward after being cocked single action and the trigger pulled.

Sometimes a little chamfer on the bottom front corner will facilitate both.

(3) Make sure that the sear slides forward over the top of the trigger as the trigger is first starting to be pulled. In some cases it will tend to go backwards at first if the sear starts too far back on the trigger. This can be caused by too much radius on the top rear edge of the trigger or the sear not sticking out far enough forward.

You have to observe all these and if there is a problem, figure out the cause and then what remedy will be the best fix. Normally everything goes fine, but if someone has been in there and worked on it that is usually when problems arise. In some cases you have to replace parts to get the geometry back to original specs.

sw.jpg

Page 50 of "The S&W Revolver A Shop Manual" by Jerry Kuhnhausen.

Edited by toothguy
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Attempt 1 for sear.... thought maybe I had it right?

Installed everything on the apex hammer, using a jerry m main spring kit as well

having issues setting primers off below like 7.5 - 8 lbs though, I have another 327 that was professionally done and it will fire off primers at 4.5-5lbs consistently,

I think maybe my issue is that the sear is letting the hammer go to early??? Causing the hammer to lose some of it's full energy potential? Also think I may of took too much off, has a bit of wiggle before contacting the sear, while my professionally done 327 does as well, mine is a bit more

Did I screw up the angle on this sear? I want to keep the same angle on the sear the way it is on the bottom, just shorten it a bit?

8418693442_9cc1ea9949_b.jpg

quick video:

http://www.youtube.com/watch?v=SaoZDrGs1nA

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Looks like the bottom of the hammer is hitting on the raised area on the rebound slide and stopping hammer from going all the way forward. I would clear this on the hammer. Hard to tell from video.

The Sear doesn't control the distance the hammer travels. The last part of the DA stroke is handled by the trigger as it picks up the hammer from the sear.

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Looks like the bottom of the hammer is hitting on the raised area on the rebound slide and stopping hammer from going all the way forward. I would clear this on the hammer. Hard to tell from video.

The Sear doesn't control the distance the hammer travels. The last part of the DA stroke is handled by the trigger as it picks up the hammer from the sear.

ah, i think i see what you mean... when the hammer strikes all the way the rebound hump should sit flush in the groove of the hammer right?

Edited by alecmc
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Take it off the hammer, the spot that is hitting does nothing. the hump on the rebound slide and similiar hump on hammer should NOT be altered, just polished and radiused.

it actually isnt hitting that part and coming to a stop, it has enough clearence all around to make it in to the slot, but it just wont go that far..

the hammer is fully falling on to the firing pin and bottoming out on the frame.

video explains better then I do.

http://www.youtube.com/watch?v=CvrAt1HIc6E

Edited by alecmc
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thought.... if the bottom front " point / edge " of the sear was a bit longer ( length wise ) would it not bring the hammer back just a tad farther before it let it go? giving more momentum during it's travel to the firing pin?

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If you look closely the sear disengages the hammer toward the end of the DA stroke and the lower ledge on the TRIGGER finishes the DA stroke. Randy does weld a little on some on the triggers on his really light trigger jobs. This increases the DA stroke and hammer travel.

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If you look closely the sear disengages the hammer toward the end of the DA stroke and the lower ledge on the TRIGGER finishes the DA stroke. Randy does weld a little on some on the triggers on his really light trigger jobs. This increases the DA stroke and hammer travel.

I'll have to go and look closer, but to me it looks like once it disengages from the sear its just flying past everything and not even touching the lower ledge of the trigger to complete DA pull

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From Jerry Kuhnhausen's shop manual pictured in my previous post "(E) Sear tries to lever off to the trigger cam early and the cam hits the bottom of the hammer's cocking notch. Again this is to much let-out and/or too much clearance. This can produce misfires."

Edited by toothguy
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Thanks, I ordered the book once you mentioned it, had a hard time reading the text in my screen.

So it looks like I took to much off the bottom ( clearance ) since I didn't touch the let out at all

Sorry couldn't find anything larger. In the book on page 51 he checks the preclearance (trigger at rest) and finds it to be .008" at the front edge of the sear and .010" at the back. I checked my 625 and that's about right. When you pull the trigger it contacts the sear almost immediately.

I can see if it were possible to add a little metal to the trigger cam, it would push the hammer back a little more like Bosshoss was saying.

Edited by toothguy
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And another quick question, what would be the purpose of " let out " ... At what point or reason do I want to stone the top left of the sear so it sticks outward more ?

And thanks for helping me out fellas, this newbie appreciates it

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If you look closely the sear disengages the hammer toward the end of the DA stroke and the lower ledge on the TRIGGER finishes the DA stroke. Randy does weld a little on some on the triggers on his really light trigger jobs. This increases the DA stroke and hammer travel.

You're right, examized it just now, the DA stroke does finish on the DA ledge of the trigger, right at the end of the stroke, disengages sear, sits on trigger da ledge for just a split second and then falls.

still dont understand what my issue is though

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