Lug lapping

[1jonzmith]

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/viewtopic.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=414/Product/BOLT-LAPPING-TOOLS

[cgeorgemo]

You want 80% and anything beyond that was anal.

Tell me why I want lapped bolt lugs again?

[stangfish]

You want 80% and anything beyond that was anal.

Tell me why I want lapped bolt lugs again?


Because you have a Remington? ;D

[cgeorgemo]

Because you have a Remington? ;D

Nope all Savages for the centerfire bolt rifles.

[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


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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.

[joeb33050]

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.



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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.

[cgeorgemo]

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.

[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.

[82boy]

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.

[handirifle]

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.

[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

[1jonzmith]

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.

[stangfish]

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.

[82boy]

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.

[1jonzmith]

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

John

[cgeorgemo]

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.

[1jonzmith]

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

[82boy]

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.



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.

[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

[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=414/Product/BOLT-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.



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!