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maineguy

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Im putting a new sear in my lyman great plains, do i need to india stone the sear cause of metal to metal contact?
Thank you
 

LawrenceA

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Which sear and what part of the sear are you talking about?
If you are talking about the set trigger sear than don't bother.

If you mean the lock sear, as your title suggests, then in my less than expert opinion.....
If it is the bearing areas on the side than a swipe can ease friction but you do not need to make it shine. The fine casting pits hold oil and effectively eliminate some metal to metal contact.

If you are talking the sear contact area itself then that depends on many things.
Firstly a good grease on these points can make the world of difference.
Taking any appreciable metal off here will alter the engagement between the sear and the tumbler.
This may improve things or make them worse or even unsafe.
The fact you ask the question makes me think that you need to stay away from the engagement surfaces. I do not know how "drop in" the Lyman parts are but remember you are playing with fire. NO PUN INTENDED.
 

LawrenceA

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No worries
Surprised no one else has chimed in.
Perhaps you should consider asking Zonie to change the title to "Replacement Sear Help" and put it under "Gunsmithing".
I seriously suggest you get it installed by a professional.

If you choose to proceed:
When you get the new sear you need to check it is hardened.
Try to file it near to but not on the front edge.
If it is hard then good.
If not then it needs to be hardened.

If it is hardened then it can be fitted.
Fit it as is and see if the half cock and the full cock work.
If they work then do you use the double set trigger exclusively?
If you always use the double set trigger then you are good to go.


If the sear is soft then it cannot be final fitted until it is.
again fit it as above and check the half and full cock work.
If they do you need to polish the nose of the sear without removing the edge or changing the angles.
When this is all done get the tip red hot such that a magnet will not stick then cool it in water or oil.
Then re polish the tip.
Now slowly heat it up behind the point until the tip turns a nice blue then quench it again.
Then re polish and install the trigger.

If you use the trigger without the set than by very judiciously changing the angles and depth of the full cock notch the triggers weight and creap can be modified. BE VERY VERY CAREFUL!!!

Check everything still works.
If not then STOP and seek assistance.
 

Zonie

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Im putting a new sear in my lyman great plains, do i need to india stone the sear cause of metal to metal contact?
Thank you
IMO, if the new sear is from Lyman, you shouldn't have to do anything special. The Sear should already be hardened and machined to the point that it works just like the factory gun.
You could use a very fine oil stone to polish the nose of the sear but usually that doesn't gain much and it opens the door to you inadvertently changing the angle of the nose. That can make things worse.

Keep in mind, the sear must be capable of moving freely after it is installed. That means, the screw that goes thru the sear and holds it in place should be tightened up to a "snug" condition but no more than that. Do not overtighten it. After it is installed, use your finger to move it. There should be very little resistance except for the force on it from the sear spring.
 

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