How much play\clearance should there be where the recoil lug slips over the barrel tenon? As tight and precise while still allowing a "slip" fit (no tapping or driving it on)or plenty loose so that it just "rattles" into place when you tip the barrel down? Does it make a difference in your opinion and why so? Thanks
Gunsmithing Recoil Lug Fit
- Thread starter tiltonwilder
- Start date
Re: Recoil Lug Fit
Slip fit is fine.
Slip fit is fine.
Re: Recoil Lug Fit
I am with William, not sloppy nor any resistance. Any interference could affect torqueing/tightening. However, my experience's are a bit more limited then that old farts are
I am with William, not sloppy nor any resistance. Any interference could affect torqueing/tightening. However, my experience's are a bit more limited then that old farts are
Re: Recoil Lug Fit
47 and counting
47 and counting
Re: Recoil Lug Fit
I cut my tenons .002 smaller than the lug. Not tight, just slides on with no wobble. Like my girl friend tells me, snug is ok, wonder if she meant to say that to her other boyfriend? LMAO
I cut my tenons .002 smaller than the lug. Not tight, just slides on with no wobble. Like my girl friend tells me, snug is ok, wonder if she meant to say that to her other boyfriend? LMAO
Re: Recoil Lug Fit
Geez William I thought you were a bid older! Now I have the complex as I have you by almost 8.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: keydiverfla</div><div class="ubbcode-body">I cut my tenons .002 smaller than the lug. Not tight, just slides on with no wobble. Like my girl friend tells me, snug is ok, wonder if she meant to say that to her other boyfriend? LMAO </div></div>
Having had 2 of 3 wives cheat on me I am just thinking out loud...perhaps it was her 'other boyfriend' that caused her to be very comfortable with only a 'snug fit' from you??? Just sayin
Geez William I thought you were a bid older! Now I have the complex as I have you by almost 8.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: keydiverfla</div><div class="ubbcode-body">I cut my tenons .002 smaller than the lug. Not tight, just slides on with no wobble. Like my girl friend tells me, snug is ok, wonder if she meant to say that to her other boyfriend? LMAO </div></div>
Having had 2 of 3 wives cheat on me I am just thinking out loud...perhaps it was her 'other boyfriend' that caused her to be very comfortable with only a 'snug fit' from you??? Just sayin
Re: Recoil Lug Fit
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SDWhirlwind</div><div class="ubbcode-body">Geez William I thought you were a bid older! </div></div>
No worries...............I feel it if it's any consolation.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SDWhirlwind</div><div class="ubbcode-body">Geez William I thought you were a bid older! </div></div>
No worries...............I feel it if it's any consolation.
Re: Recoil Lug Fit
I have only two rifles with the washer between receiver and barrel used as a recoil lug; a Rem700 and a Sav110.
This is an unfortunate design cost shortcut for anyone who is going to screw a barrel into it in a non production setting. K98s, M70s, Arisakas, Howas, etc are better with built in recoil lugs.
I paid $180 for an old Rem700 with shot out 22-250 throat.
I put a used Krieger barrel on it and reamed a 6mmBR chamber. So I made this drawing to hang over my lathe while I worked on the project with the cheap hanging recoil lug.
My drawing may show .001" clearance between recoil lug and tenon, but I don't have a 1.0620-" pin gauge. A measurement made of inside diameter with calipers is suspect.
What does it all mean?
You keep cutting on the tenon until the recoil lug will slip on.
Later, when you screw the barrel into receiver, you wiggle and jiggle the lug to be somewhere on the bottom after the threads are torqued.
I have only two rifles with the washer between receiver and barrel used as a recoil lug; a Rem700 and a Sav110.
This is an unfortunate design cost shortcut for anyone who is going to screw a barrel into it in a non production setting. K98s, M70s, Arisakas, Howas, etc are better with built in recoil lugs.
I paid $180 for an old Rem700 with shot out 22-250 throat.
I put a used Krieger barrel on it and reamed a 6mmBR chamber. So I made this drawing to hang over my lathe while I worked on the project with the cheap hanging recoil lug.
My drawing may show .001" clearance between recoil lug and tenon, but I don't have a 1.0620-" pin gauge. A measurement made of inside diameter with calipers is suspect.
What does it all mean?
You keep cutting on the tenon until the recoil lug will slip on.
Later, when you screw the barrel into receiver, you wiggle and jiggle the lug to be somewhere on the bottom after the threads are torqued.
Re: Recoil Lug Fit
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: wnroscoe</div><div class="ubbcode-body">Slip fit is fine. </div></div>
Agreed
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: wnroscoe</div><div class="ubbcode-body">Slip fit is fine. </div></div>
Agreed
Re: Recoil Lug Fit
Same subject, different tract:
When a guy buys a recoil lug the assumption (hope) is made that the two surfaces that marry up against the receiver ring face and the shoulder of the barrel are parallel to each other.
Assuming they are:
Is it then also safe to assume that the hole that the tennon goes through is exactly square to those two faces? One would hope so, but experience skewers my opinion a bit so I'm forced to say that "it's pretty good."
I'm the paranoid sort which means I tend to think the little things will bite my ass. I have the luxury of owning a surface plate and a digital height stand so checking things like parallelism between two flat surfaces like this is pretty simple and straight forward.
The hole however can be a bit more challenging as it's typically only 3/16 to 5/16 in height. Not much to go on. . .
What I've adopted as a standard practice is to ensure the hole doesn't contact the barrel tennon at all. I pin all my lugs to the receiver to index the center/clock position. The idea is to ensure that only the two parallel surfaces are contacting the barrel and the action and mitigate any potential distortion or stress induced by something being out of whack. Most importantly the fillet left by the radius of the tool that cuts the tennon. If you don't have a chamfer on the lug or virtual corner on your tennon that will clear then the lug isn't purchased against the shoulder of the barrel properly. It's being pinched by the radius and the use of brute force from installation is making up the distance.
Not exactly tension free. . .
Now, whether or not this makes a difference on paper is up to debate. I can say it certainly doesn't hurt anything to ensure you have a "no contact" bore so long as you have a means of indexing center/clock position. It's not my intention to suggest any other method is "wrong". Just sharing what I do and why.
Hope this helped. Great question!
C
Same subject, different tract:
When a guy buys a recoil lug the assumption (hope) is made that the two surfaces that marry up against the receiver ring face and the shoulder of the barrel are parallel to each other.
Assuming they are:
Is it then also safe to assume that the hole that the tennon goes through is exactly square to those two faces? One would hope so, but experience skewers my opinion a bit so I'm forced to say that "it's pretty good."
I'm the paranoid sort which means I tend to think the little things will bite my ass. I have the luxury of owning a surface plate and a digital height stand so checking things like parallelism between two flat surfaces like this is pretty simple and straight forward.
The hole however can be a bit more challenging as it's typically only 3/16 to 5/16 in height. Not much to go on. . .
What I've adopted as a standard practice is to ensure the hole doesn't contact the barrel tennon at all. I pin all my lugs to the receiver to index the center/clock position. The idea is to ensure that only the two parallel surfaces are contacting the barrel and the action and mitigate any potential distortion or stress induced by something being out of whack. Most importantly the fillet left by the radius of the tool that cuts the tennon. If you don't have a chamfer on the lug or virtual corner on your tennon that will clear then the lug isn't purchased against the shoulder of the barrel properly. It's being pinched by the radius and the use of brute force from installation is making up the distance.
Not exactly tension free. . .
Now, whether or not this makes a difference on paper is up to debate. I can say it certainly doesn't hurt anything to ensure you have a "no contact" bore so long as you have a means of indexing center/clock position. It's not my intention to suggest any other method is "wrong". Just sharing what I do and why.
Hope this helped. Great question!
C
Re: Recoil Lug Fit
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: C. Dixon</div><div class="ubbcode-body">Same subject, different tract:
When a guy buys a recoil lug the assumption (hope) is made that the two surfaces that marry up against the receiver ring face and the shoulder of the barrel are parallel to each other.
Assuming they are:
Is it then also safe to assume that the hole that the tennon goes through is exactly square to those two faces? One would hope so, but experience skewers my opinion a bit so I'm forced to say that "it's pretty good."
I'm the paranoid sort which means I tend to think the little things will bite my ass. I have the luxury of owning a surface plate and a digital height stand so checking things like parallelism between two flat surfaces like this is pretty simple and straight forward.
The hole however can be a bit more challenging as it's typically only 3/16 to 5/16 in height. Not much to go on. . .
What I've adopted as a standard practice is to ensure the hole doesn't contact the barrel tennon at all. I pin all my lugs to the receiver to index the center/clock position. The idea is to ensure that only the two parallel surfaces are contacting the barrel and the action and mitigate any potential distortion or stress induced by something being out of whack. Most importantly the fillet left by the radius of the tool that cuts the tennon. If you don't have a chamfer on the lug or virtual corner on your tennon that will clear then the lug isn't purchased against the shoulder of the barrel properly. It's being pinched by the radius and the use of brute force from installation is making up the distance.
Not exactly tension free. . .
Now, whether or not this makes a difference on paper is up to debate. I can say it certainly doesn't hurt anything to ensure you have a "no contact" bore so long as you have a means of indexing center/clock position. It's not my intention to suggest any other method is "wrong". Just sharing what I do and why.
Hope this helped. Great question!
C </div></div>
Chad
Now that you have thrown this tidbit out for us to ponder I have a question for your consideration.....
Your 'pinning' the lug surely makes sense so I am not argueing your technique nor theory, just asking...Read somewhere that with the diameter of tenon and diameter of action being what they are on say the 700 receiver, it has been pondered that drilling the receiver in order to pin lug actually weakens the receiver because of the diameter most use to pin lug. What are your feeling/thoughts on this theory???
Haven't discussed this really with anyone but seeing as how you are always trying to make us think and make realistic points I am going to make you the first I ask.lol
Thanks.
Respectfully,
Dennis
PS-Going to stop and see your shop/man machine toys some day if you don't mind?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: C. Dixon</div><div class="ubbcode-body">Same subject, different tract:
When a guy buys a recoil lug the assumption (hope) is made that the two surfaces that marry up against the receiver ring face and the shoulder of the barrel are parallel to each other.
Assuming they are:
Is it then also safe to assume that the hole that the tennon goes through is exactly square to those two faces? One would hope so, but experience skewers my opinion a bit so I'm forced to say that "it's pretty good."
I'm the paranoid sort which means I tend to think the little things will bite my ass. I have the luxury of owning a surface plate and a digital height stand so checking things like parallelism between two flat surfaces like this is pretty simple and straight forward.
The hole however can be a bit more challenging as it's typically only 3/16 to 5/16 in height. Not much to go on. . .
What I've adopted as a standard practice is to ensure the hole doesn't contact the barrel tennon at all. I pin all my lugs to the receiver to index the center/clock position. The idea is to ensure that only the two parallel surfaces are contacting the barrel and the action and mitigate any potential distortion or stress induced by something being out of whack. Most importantly the fillet left by the radius of the tool that cuts the tennon. If you don't have a chamfer on the lug or virtual corner on your tennon that will clear then the lug isn't purchased against the shoulder of the barrel properly. It's being pinched by the radius and the use of brute force from installation is making up the distance.
Not exactly tension free. . .
Now, whether or not this makes a difference on paper is up to debate. I can say it certainly doesn't hurt anything to ensure you have a "no contact" bore so long as you have a means of indexing center/clock position. It's not my intention to suggest any other method is "wrong". Just sharing what I do and why.
Hope this helped. Great question!
C </div></div>
Chad
Now that you have thrown this tidbit out for us to ponder I have a question for your consideration.....
Your 'pinning' the lug surely makes sense so I am not argueing your technique nor theory, just asking...Read somewhere that with the diameter of tenon and diameter of action being what they are on say the 700 receiver, it has been pondered that drilling the receiver in order to pin lug actually weakens the receiver because of the diameter most use to pin lug. What are your feeling/thoughts on this theory???
Haven't discussed this really with anyone but seeing as how you are always trying to make us think and make realistic points I am going to make you the first I ask.lol
Thanks.
Respectfully,
Dennis
PS-Going to stop and see your shop/man machine toys some day if you don't mind?
Re: Recoil Lug Fit
Dennis,
First I'll start by plainly stating I am NOT a Mechanical Engineer nor do I have any sort of formal education in the field. I do however have a small cadre of close friends that are infinitely more educated/experienced than I am who work in fields far more regulated than commercial firearms. They allow me to bounce things off of them when I'm faced with something I can't solve on my own.
That being said:
It was described to me once that a gun is nothing more than a pressure vessel. Pressure reacts to a surface at a right angle (90 degrees) This means that every square inch of the case is being exerted against when a primer lights the fire. Since the bulk of the case surface area is at (almost) a right angle to the bolt face it's surprising how little pressure is being exerted against the bolt.
What does this mean? In my mind (as it was described to me) the tennon and the cylinder portion of the barrel withstands the bulk of the abuse created when the cartridge fires. In comparison a relatively small portion is being exerted on the bolt and receiver.
I invite folks to look at high pressure fittings used in the petroleum industry. Look at the physical size/mass of a fitting designed to withstand tens of thousands of pounds. Now look at how anorexic a bolt action receiver is by comparison. How does the gun tolerate 50+ thousand copper units of pressure (this is where an engineer would be handy cause I don't know how to convert that to PSI) and be so petite yet a pressure fitting on a rig has so much more mass and is only rated to 10Kpsi?
That answer should clue you into something. It's an engineering fact that the Remington 700 is really only rated to about 3500lbs per square inch. That was relayed to me by a gent who's close friends with the man (who is a very good ME) who originally designed the thing. (A name that I can't seem to recall at the moment-sorry)
How this applies to your question is, I have no doubt that drilling a pair of .094" holes does remove some degree of strength from a receiver. Common sense says it has to because we are removing material. I will say though that there are too many pinned recoil lugs out there in circulation that function every day just fine.
Nesika Bay actions are done this way and they use an 18 pitch thread which has a larger root diameter than a 16 pitch. (meaning the hole in the action where the barrel goes is bigger resulting even less wall thickness as they are built to 1.35"-same as the Remmy (1.47's are offered too, but that doesn't count for this discussion).
I think it gets to a point of being so far "in the mud" that while it certainly can be shown on paper, it has no real relevance in the world we live in.
I invite you or anyone to come by and visit anytime. Glad to have you.
All the best,
Chad
Dennis,
First I'll start by plainly stating I am NOT a Mechanical Engineer nor do I have any sort of formal education in the field. I do however have a small cadre of close friends that are infinitely more educated/experienced than I am who work in fields far more regulated than commercial firearms. They allow me to bounce things off of them when I'm faced with something I can't solve on my own.
That being said:
It was described to me once that a gun is nothing more than a pressure vessel. Pressure reacts to a surface at a right angle (90 degrees) This means that every square inch of the case is being exerted against when a primer lights the fire. Since the bulk of the case surface area is at (almost) a right angle to the bolt face it's surprising how little pressure is being exerted against the bolt.
What does this mean? In my mind (as it was described to me) the tennon and the cylinder portion of the barrel withstands the bulk of the abuse created when the cartridge fires. In comparison a relatively small portion is being exerted on the bolt and receiver.
I invite folks to look at high pressure fittings used in the petroleum industry. Look at the physical size/mass of a fitting designed to withstand tens of thousands of pounds. Now look at how anorexic a bolt action receiver is by comparison. How does the gun tolerate 50+ thousand copper units of pressure (this is where an engineer would be handy cause I don't know how to convert that to PSI) and be so petite yet a pressure fitting on a rig has so much more mass and is only rated to 10Kpsi?
That answer should clue you into something. It's an engineering fact that the Remington 700 is really only rated to about 3500lbs per square inch. That was relayed to me by a gent who's close friends with the man (who is a very good ME) who originally designed the thing. (A name that I can't seem to recall at the moment-sorry)
How this applies to your question is, I have no doubt that drilling a pair of .094" holes does remove some degree of strength from a receiver. Common sense says it has to because we are removing material. I will say though that there are too many pinned recoil lugs out there in circulation that function every day just fine.
Nesika Bay actions are done this way and they use an 18 pitch thread which has a larger root diameter than a 16 pitch. (meaning the hole in the action where the barrel goes is bigger resulting even less wall thickness as they are built to 1.35"-same as the Remmy (1.47's are offered too, but that doesn't count for this discussion).
I think it gets to a point of being so far "in the mud" that while it certainly can be shown on paper, it has no real relevance in the world we live in.
I invite you or anyone to come by and visit anytime. Glad to have you.
All the best,
Chad
Re: Recoil Lug Fit
i have a similar opinion as chad on this matter. i don't want a press fit or even a tight slip fit due to me not knowing if the hole is absolutely perpendicular to the parallel surfaces of the lug. unless it is out by a lot, since it is such a short distance i doubt it really makes much of a difference on target but giving about a thousandth or two of clearance between the lug and tennon is something that makes me feel better. i also chamfer the inside of the lug hole to make sure it clears the radius left from my turning tool when creating the tennon. i prefer to have a small radius between the tennon and shoulder instead of plunging my turning tool into it like i have seen others do.
i have a similar opinion as chad on this matter. i don't want a press fit or even a tight slip fit due to me not knowing if the hole is absolutely perpendicular to the parallel surfaces of the lug. unless it is out by a lot, since it is such a short distance i doubt it really makes much of a difference on target but giving about a thousandth or two of clearance between the lug and tennon is something that makes me feel better. i also chamfer the inside of the lug hole to make sure it clears the radius left from my turning tool when creating the tennon. i prefer to have a small radius between the tennon and shoulder instead of plunging my turning tool into it like i have seen others do.
Re: Recoil Lug Fit
I took apart a factory built HS precision Pro 2000 that had over 1/16" total clearance between the barrel tennon and the lug.
I had to locate the lug carefully before I put it back together.
I've watched that gun shoot a bunch of sub 1/2 moa groups.
I took apart a factory built HS precision Pro 2000 that had over 1/16" total clearance between the barrel tennon and the lug.
I had to locate the lug carefully before I put it back together.
I've watched that gun shoot a bunch of sub 1/2 moa groups.
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