I was wondering what in your opinion is the best lapping compound. And correct if i am wrong but dont you just put some on the locking lugs and work the bolt a few times?
Gunsmithing Lapping Compound
- Thread starter deadly0311
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Re: Lapping Compound
Shoes is right.
However, there are those young, headstrong folks who wanna do it anyway.
So, let's deal with a few of the issues.
When to do it? Only after wear patterns on the bolt locking surfaces reveal that large portions of those faces are not engaging. Even then, if the distribution of those wear patterns shows parity between the two lugs, leave it be. The point here is that unless there is evidence of a large disparity in contact, there is no evidence of potential bolt head flex. Unless there's such evidence, there's no reason to lap; normal wear will procede evenly and there is no problem to fix.
What abrasive value is good or bad? In truth the abrasive value only determines how fast the process occurs. Regardless of the abrasive value, the important issue is to keep careful track of the progress. As long as you do this, the faster the better, and no need to finish polish it, normal wear will do this anyway. The other important thing here is to stop when the wear patterns show parity. It's not about getting it all, it's about getting it even.
About honing the lugs and headspace. Yes, headspace will grow. Honestly, even if you abrade the lugs down to where the wear patterns cover 90% of the lug face, we're still only talking about a few thousandths of additional headspace. Handloaded ammo will accomodate this, and probably, commercial ammo will never really be able to tell the difference. Personally, unless one goes hog wild with the abrasion, I think it's a smaller issue.
Still, because of the considerations regarding the ideal way of applying pressure while doing the process, and other issues that make it less than optimal to do without removing the barrel; it's really wisest to leave it to a properly trained and equipped gunsmith.
Greg
Shoes is right.
However, there are those young, headstrong folks who wanna do it anyway.
So, let's deal with a few of the issues.
When to do it? Only after wear patterns on the bolt locking surfaces reveal that large portions of those faces are not engaging. Even then, if the distribution of those wear patterns shows parity between the two lugs, leave it be. The point here is that unless there is evidence of a large disparity in contact, there is no evidence of potential bolt head flex. Unless there's such evidence, there's no reason to lap; normal wear will procede evenly and there is no problem to fix.
What abrasive value is good or bad? In truth the abrasive value only determines how fast the process occurs. Regardless of the abrasive value, the important issue is to keep careful track of the progress. As long as you do this, the faster the better, and no need to finish polish it, normal wear will do this anyway. The other important thing here is to stop when the wear patterns show parity. It's not about getting it all, it's about getting it even.
About honing the lugs and headspace. Yes, headspace will grow. Honestly, even if you abrade the lugs down to where the wear patterns cover 90% of the lug face, we're still only talking about a few thousandths of additional headspace. Handloaded ammo will accomodate this, and probably, commercial ammo will never really be able to tell the difference. Personally, unless one goes hog wild with the abrasion, I think it's a smaller issue.
Still, because of the considerations regarding the ideal way of applying pressure while doing the process, and other issues that make it less than optimal to do without removing the barrel; it's really wisest to leave it to a properly trained and equipped gunsmith.
Greg
Re: Lapping Compound
read here...
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=1094157#Post1094157
read here...
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=1094157#Post1094157
Re: Lapping Compound
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Greg Langelius *</div><div class="ubbcode-body">
Honestly, even if you abrade the lugs down to where the wear patterns cover 90% of the lug face, we're still only talking about a few thousandths of additional headspace. </div></div>
You do realize the difference between a Go and a No-Go gauge is 3 thousandths right??
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Greg Langelius *</div><div class="ubbcode-body">
Honestly, even if you abrade the lugs down to where the wear patterns cover 90% of the lug face, we're still only talking about a few thousandths of additional headspace. </div></div>
You do realize the difference between a Go and a No-Go gauge is 3 thousandths right??
Re: Lapping Compound
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: PFCSkoug</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Greg Langelius *</div><div class="ubbcode-body">
Honestly, even if you abrade the lugs down to where the wear patterns cover 90% of the lug face, we're still only talking about a few thousandths of additional headspace. </div></div>
You do realize the difference between a Go and a No-Go gauge is 3 thousandths right?? </div></div>
.003??? what?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: PFCSkoug</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Greg Langelius *</div><div class="ubbcode-body">
Honestly, even if you abrade the lugs down to where the wear patterns cover 90% of the lug face, we're still only talking about a few thousandths of additional headspace. </div></div>
You do realize the difference between a Go and a No-Go gauge is 3 thousandths right?? </div></div>
.003??? what?
Re: Lapping Compound
the only difference between a go and no-go gauge is .003 in length
the only difference between a go and no-go gauge is .003 in length
Re: Lapping Compound
Depends on who makes them but that last time i checked it was .005
Depends on who makes them but that last time i checked it was .005
Re: Lapping Compound
well at least through dave kiff and everything i have been being taught they are .003 for a no-go and .010 for a field gauge and i sure hope you aren't passing that one
well at least through dave kiff and everything i have been being taught they are .003 for a no-go and .010 for a field gauge and i sure hope you aren't passing that one
Re: Lapping Compound
I guess it depends on calibers then. I havent checked very many of them. Usually only get a go gauge. .003 seems a little tight for a no-go in a cheytac.
I guess it depends on calibers then. I havent checked very many of them. Usually only get a go gauge. .003 seems a little tight for a no-go in a cheytac.
Re: Lapping Compound
An to continue on greg's post it doesnt matter how far your headspace is set back if you form the case to your chamber the first firing and them bump your shoudlers back about .002 in your die the gun will work just fine...
An to continue on greg's post it doesnt matter how far your headspace is set back if you form the case to your chamber the first firing and them bump your shoudlers back about .002 in your die the gun will work just fine...
Re: Lapping Compound
The degree of wear is significant; but I don't think it's prohibitive, especially if the rifle is being fed with matched handloads.
But it is still significant. This is one key reason why I favor the Savage barrel nut system, which allows headspace to be recalibrated independent of lug wear.
The point I alluded to about doing the lapping with the barrel removed is because the proper way to begin the process is to lap the engagement face of the receiver perfectly perpendicular, before lapping the bolt lugs to match.
I'm not a gunsmith, and I don't allude to being one. I wouldn't do this operation myself. So I'll make the emphasis again; I'd leave it to someone who has the proper resources and experience. Quick and dirty Rube Goldberg fixes can be made to work, but nothing beats the real thing.
Greg
The degree of wear is significant; but I don't think it's prohibitive, especially if the rifle is being fed with matched handloads.
But it is still significant. This is one key reason why I favor the Savage barrel nut system, which allows headspace to be recalibrated independent of lug wear.
The point I alluded to about doing the lapping with the barrel removed is because the proper way to begin the process is to lap the engagement face of the receiver perfectly perpendicular, before lapping the bolt lugs to match.
I'm not a gunsmith, and I don't allude to being one. I wouldn't do this operation myself. So I'll make the emphasis again; I'd leave it to someone who has the proper resources and experience. Quick and dirty Rube Goldberg fixes can be made to work, but nothing beats the real thing.
Greg
