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Thread: Lug lapping

  1. #1
    1jonzmith
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    Lug lapping


    I mentioned this methode of using a brass and cutting it and inserting a spring. The brass with the spring created force on the bolt so you could then lap the lugs. Do your own research on lug contact recommendations. I recall that most lugs make contact with less than 10%....usually. You want 80% and anything beyond that was anal. I found the article about making the tool:

    http://www.snipercentral.com/forums/...ic.php?t=29357

    This is a great forum by the way and this was a superb post.

    Enjoy this guys work and generosity.

    John

    And Brownells sells the lapping kit for..... http://www.brownells.com/.aspx/pid=4...-LAPPING-TOOLS

  2. #2
    cgeorgemo
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    Re: Lug lapping

    Quote Originally Posted by 1jonzmith
    You want 80% and anything beyond that was anal.
    Tell me why I want lapped bolt lugs again?

  3. #3
    stangfish
    Guest

    Re: Lug lapping

    Quote Originally Posted by cgeorgemo
    Quote Originally Posted by 1jonzmith
    You want 80% and anything beyond that was anal.
    Tell me why I want lapped bolt lugs again?
    Because you have a Remington? ;D

  4. #4
    cgeorgemo
    Guest

    Re: Lug lapping

    Quote Originally Posted by stangfish
    Because you have a Remington? ;D
    Nope all Savages for the centerfire bolt rifles.

  5. #5
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    Re: Lug lapping

    Read this. This is what sharpshooter told me when I asked about bolt lapping. After I read it, I got down on one knee, drew my sword & saluted Sharpshooter & the knowledge he has bestowed upon me.
    So it is written, so let it be done....




    Re: Lapping in a bolt...

    « Reply #4 on: February 28, 2012, 03:13:23 AM »

    Quote


    --------------------------------------------------------------------------------

    Most bolt lugs will always look like that. The reason is the generous clearance around the bolt body raceway. When you close the bolt, it is almost always slightly cocked to one side when you start to turn the bolt down. Being slightly cocked to one side, one lug will contact the closing ramp before the other one.
    When the first lug contacts, it acts like pivot point until the other lug catches up. That's the reason for an irregular contact pattern. Believe me, when you pull the trigger, both lugs will get the same pressure.
    'Scuse me while I whip this out...!

  6. #6
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    Re: Lug lapping

    Quote Originally Posted by fgw_in_fla
    Read this. This is what sharpshooter told me when I asked about bolt lapping. After I read it, I got down on one knee, drew my sword & saluted Sharpshooter & the knowledge he has bestowed upon me.
    So it is written, so let it be done....

    Re: Lapping in a bolt...

    « Reply #4 on: February 28, 2012, 03:13:23 AM »

    Quote
    I've been taking my M10 apart and putting it together and trying to understand this lug lapping.
    I've read the quote below and wonder how he knows:"Believe me, when you pull the trigger, both lugs will get the same pressure."
    A small number of degrees of bolt handle movement, at first, operates the lugs against the action ramps and moves the bolt forward. During this rotation I think the leading EDGES of the locking lugs engage the action ramps and the bolt is cammed forward.
    Then, for a relatively lot of degrees, the bolt rotates without moving forward, engaging the locking lugs with the non-angled parts of the action ramps. I think this rotation and engagement is what "lapping" is all about.
    It seems to me that marker on the lugs and operating the bolt will tell the tale, keeping a force backward on the bolt handle if the wavy washer pressure isn't enough. For absolute assurance, marker on the locking lugs AND on the action ramp surfaces would tell the tale.
    As near as I can tell, the bolt handle ramp acting on the rear baffle ramp is where extraction force comes from. m I missing something?
    joe b.



    --------------------------------------------------------------------------------

    Most bolt lugs will always look like that. The reason is the generous clearance around the bolt body raceway. When you close the bolt, it is almost always slightly cocked to one side when you start to turn the bolt down. Being slightly cocked to one side, one lug will contact the closing ramp before the other one.
    When the first lug contacts, it acts like pivot point until the other lug catches up. That's the reason for an irregular contact pattern. Believe me, when you pull the trigger, both lugs will get the same pressure.

  7. #7
    cgeorgemo
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    Re: Lug lapping

    Quote Originally Posted by joeb33050
    I've read the quote below and wonder how he knows:"Believe me, when you pull the trigger, both lugs will get the same pressure."
    Because the bolt head on Savage 110 actions is a floating bolt head.
    In overly simple terms once you shoot the bolt head will push back and the one that contacts first will act as a pivot point until the other side also contacts and then they share the pressure.

  8. #8
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    Re: Lug lapping

    Quote Originally Posted by cgeorgemo
    Quote Originally Posted by joeb33050
    I've read the quote below and wonder how he knows:"Believe me, when you pull the trigger, both lugs will get the same pressure."
    Because the bolt head on Savage 110 actions is a floating bolt head.
    In overly simple terms once you shoot the bolt head will push back and the one that contacts first will act as a pivot point until the other side also contacts and then they share the pressure.
    There's 2 things going on here.
    1. Do both lugs engage when the gun fires? Sure, I think. Floating bolt head etc.
    2. Do both lugs engage with a lot of their surface? I don't know, and isn't this what lapping is about? If 5% of the left lug and 90% of the right lug engage, A does it matter? and B doesn't lapping fix that?

    A lot of people for a long time have lapped a lot of lugs/action ramps on Mauser-type interrupted thread actions. I've done it, and never found a problem getting a lot of engagement = marker/dykem worn off the back of the lugs. Like many things we do out of faith, I could never attribute an accuracy change to lapping.
    joe b.

  9. #9
    82boy
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    Re: Lug lapping

    Quote Originally Posted by joeb33050
    A lot of people for a long time have lapped a lot of lugs/action ramps on Mauser-type interrupted thread actions. I've done it, and never found a problem getting a lot of engagement = marker/dykem worn off the back of the lugs. Like many things we do out of faith, I could never attribute an accuracy change to lapping.
    joe b.
    Lets actualy look at what lapping is. This is my definition of what lapping is I say it is a process where you are taking two fixed objectes, and placing wear on them so that they are matted togeather. With that said can you lap something that moves?

    Here is a ddefinition from Abrading methods web site. "Lapping and fine grinding are processes used where the surface finish, flatness, or parallelism of the work piece must be held to very close tolerances." What if you dont have close tolarences? If the bolt heads is floating does the tolerances change?

    The problem with a savage is this, It is not a Remington, and it is not a Mauser, it is a complete different design. So why do we always try to make a Savage a Mauser, or a Remigton, with the gunsmithing process used for them?

    Lets think about it this way, if you lap a Savage bolt where the bolt heads is constantly moving, and floating due to its design, do we create a matting surface? If the bolt head floats and you lap it here, and the next stroke it moves to a diferent place, and the next stroke it moves to somepleace different, and never repeates the same spot, are you actualy accomplishing anything, but placing un-needed wear on the bolt head, and lugs.

    With that said you compairing apples to oranges, they just are not the same.

  10. #10
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    Re: Lug lapping

    While I cannot testify about the results, good or bad, of lapping a Savage bolt, the actions of the bolt, yes it is moving, but it is close enough and repeatable enough so that, in theory, to me, it would help. The question is, how much? On bolts like the Mauser and Rem, the bolt head do not float and if 15% of the head makes initial contact, then 85% of the head will flex into contact on firing, passing some of that flex into the cartridge base and thus moving the brass some, affecting accuracy to a degree.

    With the Savage bolt head, I would imagine a much higher percentage of bolt head actually contacts before firing. I winder is some of the bench rest shooters that compete with Savages have done this, and to what end result? I see lapping as a possible improvement that cheap and easy. Never done it but in theory it sounds like a good idea.

  11. #11
    Gmac5
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    Re: Lug lapping

    Just because savage has it pivot bolt head does not mean u should not check contact remember if the receiver locking lugs were machined off( not equal ) the sav bolt should conract both lugs it will in turn cant the fired case,which could give you harder than normal bolt lift.
    Gary

  12. #12
    1jonzmith
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    Re: Lug lapping

    Quote Originally Posted by Gmac5
    Just because savage has it pivot bolt head does not mean u should not check contact remember if the receiver locking lugs were machined off( not equal ) the sav bolt should conract both lugs it will in turn cant the fired case,which could give you harder than normal bolt lift.
    Gary

    Good point! Of course they should be even. My contact in my SS target action is a 2 or 3 thou scratch that goes half way around where another scratch picks up. 1% maybe. The other lug shows much better....maybe 4 or 5%.

    I know of nowhere that it is stated that lapping the lugs will diminish accuracy unless you are using a belt sander. Many say that it will improve it but only a small amt. I haven heard that Savage is exempt from the procedure but there are Gunsmithing accessory houses that sell lug lappers exclusively for the Savage. That is an indication but doesn't prove a darn thing, by itself.

  13. #13
    stangfish
    Guest

    Re: Lug lapping

    Quote Originally Posted by 1jonzmith
    I haven heard that Savage is exempt from the procedure but there are Gunsmithing accessory houses that sell lug lappers exclusively for the Savage. That is an indication but doesn't prove a darn thing, by itself.
    I am thinking that idealy you want the face of the bolt to be parallel to the face of the case...which should be purpendicular to the rifle bore. It Would make sense to chuck up the bolt head and skim the contact surface of the bolt head lugs and then ensure that the bolt face is parallel to that. Then minimal lapping is required and all surfaces are square to each other. Just my .02 but anything else is...as they say, pissing in the wind.

  14. #14
    82boy
    Guest

    Re: Lug lapping

    Quote Originally Posted by handirifle
    I winder is some of the bench rest shooters that compete with Savages have done this, and to what end result?
    Well to start, you will only find Benchrest shooters shooting a savage action competitivly in mid to long range matchs. (Not that it can not compete in short range.) I have shot with shooters from all over the Midwest and Eastern section of the US, and I can recall a singe person that has ever lapped a Savage bolt.

    Most of these shooters marvel over SSS's T&T job, if they are not shooting one at the time, they usualy send their actions off after the match, after feeling what one feels like. (Trust me SSS sales on T&T actions skyrocket after a match.) SSS does't lap the bolts in thier T&T job, (And they also discourage the action of lapping a bolt in a savage.) I think that is the icing on the cake.

  15. #15
    1jonzmith
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    Re: Lug lapping

    I can verify that SSS doesn't lap the lugs in a T&T service.

    John

  16. #16
    cgeorgemo
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    Re: Lug lapping

    Because the Savage floating bolt head is designed to allow a few thousandths of an inch of movement, it can adjust itself for a perfect fit only typically found with hand-lapped locking lugs.
    From the 2012 catalog.

  17. #17
    1jonzmith
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    Re: Lug lapping

    OK....I have gotten educated. SS, a much respected source doesn't lap. 82, a competitive BR shooter with years of experience, says don't lap. The Savage literature says specifically, it isn't needed. But why are people selling tools to do this to the Savage? I was conflicted.

    My best youngest Smith had the answer: The Savage, using a short bolt, can have the bolt shifted off axis and true with very little material moved. That results in the bolt face being out of true with the chamber/barrel axis. In a Remington, that is what happens at the moment of ignition. For the Rem to do that it must bend the bolt. In a Savage the small bolt head can pivot to achieve this alignment. Apparently, it is easy to over lap the Savage bolt into being out of true. It is also almost impossible to remove any metal from the bolt lugs given the bolt head is hard chromed, as is the bolt body.

    I am not sure I buy all this. And I am sure I don't buy into the theory that lug geometry doesn't matter in the Savage. Also, "every thing in a Savage, all those mass produced parts associated with the bolt body and bolt head alignment, all those parts, true up at the moment of firing ? That one needs a lot more "truing" to be in alignment for me.

    It may be that we can do little to cause any improvement in accuracy where bolt lapping is concerned but it coming down on that side of the line. Better to spend your time elsewhere????

    John

  18. #18
    82boy
    Guest

    Re: Lug lapping

    Quote Originally Posted by 1jonzmith
    But why are people selling tools to do this to the Savage? I was conflicted.
    John
    Who is selling a "Savage bolt lug lapping tools", or a kit? Just because someone makes it doesn't mean there is a need. Most tool are a carry over from Remington actions, and it may fit a Savage action, but that doesn't mean that it is needed. You see products everyday that have no need, and people buy them all the time, just stay up late one night and watch the info comericals. Another show come to mind, there use to be a show called Pitchmen on discovery channel, there was a lot of products made and people tried to market that had no need. It is called marketing, a crafty sales person can sell an air conditioner to an Eskimo in the middle of winter. If someone convences you that you need this product, then you will buy it. Another product that comes to mind is "Speedlock" system, it speeds up the lock time, they use to make it for a Savage action, but they dont anymore.

    Quote Originally Posted by 1jonzmith
    It is also almost impossible to remove any metal from the bolt lugs given the bolt head is hard chromed, as is the bolt body.
    John
    The bold bodies, and bolt heads are not hard chromed. The bolt bodies are a carbon steel in the white, that have been heat treated, (And are harder than the hubs of heck.) and the bolt bodies are made from stainless.

  19. #19
    ellobo
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    Re: Lug lapping

    My take on this is; if you feel you cant live without lapping the lugs go ahead. Its your time and money, not mine. For me its not even a thing I would consider or obsess about.

    El Lobo

  20. #20
    1jonzmith
    Guest

    Re: Lug lapping

    Quote Originally Posted by 82boy
    Quote Originally Posted by 1jonzmith
    But why are people selling tools to do this to the Savage? I was conflicted.
    John
    Who is selling a "Savage bolt lug lapping tools", or a kit?

    Well, It's Brownells, 82. http://www.brownells.com/.aspx/pid=4...-LAPPING-TOOLS I'll bet there are more ....probably. Conspicuouisly, Midway doesn't offer a lug lapper for the Savage. I thought I saw a Savage being lapped on their video but I'm not sure but that is what started it for me....that and the nifty spring laoded tool made from a empty brass..


    Just because someone makes it doesn't mean there is a need.

    I know that. I might sound like a "true believer" advocating but I really am not. I just want to know and understand some of this stuff. And certainly not to get into a peeing contest though those contests usually lead to a better common understanding.


    Most tool are a carry over from Remington actions, and it may fit a Savage action, but that doesn't mean that it is needed.

    I never disagreed with that. Never heard the Remmy angle on development but seems like it might be true.

    You see products everyday that have no need, and people buy them all the time, just stay up late one night and watch the info comericals. Another show come to mind, there use to be a show called Pitchmen on discovery channel, there was a lot of products made and people tried to market that had no need.

    I retire at 2 or 3 AM usually. More of my day is spent soaking up trons from the tube than I would like or admit to even. I agree with you on this.


    It is called marketing,

    Condescension? You are higher than that. ??? ::) ;D

    a crafty sales person can sell an air conditioner to an Eskimo in the middle of winter. If someone convences you that you need this product, then you will buy it. Another product that comes to mind is "Speedlock" system, it speeds up the lock time, they use to make it for a Savage action, but they dont anymore.

    Quote Originally Posted by 1jonzmith
    It is also almost impossible to remove any metal from the bolt lugs given the bolt head is hard chromed, as is the bolt body.
    John
    The bold bodies, and bolt heads are not hard chromed.

    My Smith told me that. He can be wrong but he tries to be correct and open. I will contact Savage and see if they remember ever doing this. I sure don't know.

    The bolt bodies are a carbon steel in the white, that have been heat treated, (And are harder than the hubs of heck.) and the bolt bodies are made from stainless.

    Not trying to be a nit picker with this....BUT.....that sentence seems, seems mind you, to contradict itself.

    I put a magnet against my SS barrel and it stuck. Same for my brilliantly polished receiver...stuck to it also. The bolt body is definitely attracted, as are the bolt head and baffle and my bolt handle that should be SS. My kitchen sink? Now there is some metal that is supposed to be SS and it could care less about magnets. And as far as my magnet is concerned......that sink might as well be made of glass. I was told a lifetime ago that there are many grades of SS and some of them are attracted to magnets. Finally, after all these years...PROOF. I solved this catchy problem professionally by only ever ordering "stuff" made from "Marine Grade SS". But I never got into the details...
    I'll post after Savage gets back to me. And, I know full well that they are selling stuff to the public and I will have to review their answer with a jaundiced eye, as should you all...still!

  21. #21
    1jonzmith
    Guest

    Re: Lug lapping

    Quote Originally Posted by ellobo
    My take on this is; if you feel you cant live without lapping the lugs go ahead. Its your time and money, not mine. For me its not even a thing I would consider or obsess about.

    El Lobo
    I knew you would understand about it being my time and my money. I don't always need help doing the "SMART" thing....but often I need help doing the "LEAST" stupid thing. I'll keep asking questions. And not take myself so seriously...that's bad for me.

    It's a hobby. Obsessing is part of the joy of the thing. I think it is still a valid procedure for guns not Savage. I'll bet you obsess about "stuff" that I wouldn't. What is your favorite sport? Home team/favorite team? Player? Religion? hoboy, don't even go there. Politics? nahauh! I could care less about all of that but they sure are popular subjects for a grand peeing contest. Right?

    Thanks for your comments,

    John


  22. #22
    Team Savage
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    Re: Lug lapping

    well said

    drybean

  23. #23
    1jonzmith
    Guest

    Re: Lug lapping

    82,

    Quote by 82
    "The bolt bodies are a carbon steel in the white, that have been heat treated, (And are harder than the hubs of heck.) and the bolt bodies are made from stainless".

    Quote by John
    "Not trying to be a nit picker with this....BUT.....that sentence seems, seems mind you, to contradict itself."

    I talked with the Savage sales rep. I have a return caLL REQUEST INTO THEIR ENGINEERING DEPT that has yet been received and I think they will have the last word. BUT, Sales informs me that my "bolt body" is SS and my bolt head and front baffle are also SS. It is supposed to be a special SS alloy and is hard as "the hubs of heck". But none of the parts are high carbon steel and heat treated. All steel has carbon in it as that is what turns iron into steel. When steel is referred to as carbon, that is redundant. The common expression, "carbon steel" usually is translated as "high" carbon steel. HCS can be made harder than the hubs of heck BUT what also follows is a brittleness that makes the metal subject to shattering and that isn't good considering the shock of firing a rifle highly stresses the action..... repeatedly. My understanding is that the steel id of exceptional quality and uniformity but not particularly hard or brittle. Mausers are particularly easy to drill for mounts but, I have read, the Brit Enfield eats drill bits in doing the scope mount task. The Enfield is the only battle rifle that is case hardened....read that once. Seems the heat treating and hardening and tempering processes are very difficult to control and quality variances make the process expensive and dangerous to the person shooting the gun. Jap Arisakas have a rep for killing the shooter due to bad steel and heat treating. All these processes are dramatically affected by the alloy content itself so all the way around tempering or hardening gun pats has been difficult. I think I have a pretty good handle on "some" of the rudiments of gun metal and I strongly suspect that hardened high carbon steel is not used in the manufacturer of Savage receivers. History: It was Krupp Industries that first learned how to cast steel canon barrels in a single pour so they didn't explode apart when fired. Iron canon was difficult to find crews to man due to their habit of exploding and brass/bronze had insufficient strength to lob shells very far. In the first battle where the krauts faced off with their arch enemy, the French, while using the Krup cannons the Krupp canon carried the day and the Krauts won their first war with the French in 200 tries. End result? The world boooo'd the Germans and labeled them war mongers and bullies. Go Figure!! And the losing-est nation the world has ever known was labeled evil and superb military minded goose-stepping etc etc. Funny world.

    There are some exotic stainless steels that are extremely hard. Dig into cutlery for that journey. V10 or D2 come to mind. D2 is attracted to magnets very well. (I just tried it) 60 RockwellC, by the way.

    I post what I learn from Engineering at Savage about action alloys if I can contact them.

  24. #24
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    Re: Lug lapping

    And I quote:
    It's a hobby. Obsessing is part of the joy of the thing. I think it is still a valid procedure for guns not Savage. I'll bet you obsess about "stuff" that I wouldn't. What is your favorite sport? Home team/favorite team? Player? Religion? hoboy, don't even go there. Politics? nahauh! I could care less about all of that but they sure are popular subjects for a grand peeing contest. Right?

    It's an addiction.... It's OCD at it's finest. Although I TRY not to be quite so obsessive about my addiction, I did read this thread with obsessive desire.
    Excellent info guys. Thanks for the "fix"... ::)

    Frank in Fla
    'Scuse me while I whip this out...!

  25. #25
    1jonzmith
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    Re: Lug lapping

    True perspective!

    Thanks

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