fix for worn out bolt for no4 lee enfield?

[scott585]

is there any way to salvage a worn out lee enfield bolt that allows the bolt head to turn to far past the side rib when out of the rifle? perhaps a washer or something?

 

[burnt_servo]

steel shim stock maybe ?

 

[bearhunter]

is there any way to salvage a worn out lee enfield bolt that allows the bolt head to turn to far past the side rib when out of the rifle? perhaps a washer or something?

That isn't all that unusual and as long as your headspace is OK, nothing to worry about.

These rifles and their parts were produced on a mass production basis. They had plus or minus tolerances.

The reason your bolt head turns past the sweet spot is because the bolt body itself is slightly short. Likely only a few thousandths of an inch. Even unissued rifles or lightly used rifles can have this condition.

You might be able to change this with another bolt head. MIGHT.

 

[RRCo.]

Up to 20 degrees past the main recoil lug on the bolt was permissible they say, but less is better. The more bolt head over-turn there is, the less primary extraction you have.

Swapping bolt heads was how the military addressed this.

How far over does yours turn?

 

[scott585]

That isn't all that unusual and as long as your headspace is OK, nothing to worry about.

These rifles and their parts were produced on a mass production basis. They had plus or minus tolerances.

The reason your bolt head turns past the sweet spot is because the bolt body itself is slightly short. Likely only a few thousandths of an inch. Even unissued rifles or lightly used rifles can have this condition.

You might be able to change this with another bolt head. MIGHT.

this is past tolerance, it can be unsafe because it means the threads are bearing the pressure of the cartridge thrust rather than the bolt body


its at about 45 degrees, or almost completely past the bolt rib

 

[kennymo]

Marstar has both used and unissued bolts in stock, as well as two sizes of bolt head.

 

[bigedp51]

Below is a composite photo of one bolt body that has been fitted with four different bolt heads, due to bolt thrust the bolt bodies mating surface with the bolt head has shortened. The mating surface of the bolt body to the bolt head has been peened just like a hammer hitting a metal stake. This bolt needs to be replaced and there is no fix, the bolt is now scrap junk metal. The manual calls for the bolt to be replace, and if a new bolt and a No.3 bolt head .638 in length closes on the .074 headspace gauge the rifle will be turned in for FTR overhaul. (in most cases the receiver will need to be replaced due to lug recess setback)

scott585 is absolutely correct above, once the bolt head rotates past 20 degrees the threads will start to take the full force of the bolt thrust and more damage will occur. Any time over rotation happens with several bolt heads being fitted the bolt "must" be replaced.

The inspection criteria above can be found in the manual below.

And the most accurate method for checking for stretching and thinning in the base web area is a RCBS case mastering gauge. Bent wires or paperclips are only for white collar office workers, blue collar working class people have hit their fingers so many times with hammers they have no feeling left in them to feel any thinning in the case. (I could drag a bent paper clip across Niagara Falls and not feel it)

 

[scott585]

Below is a composite photo of one bolt body that has been fitted with four different bolt heads, due to bolt thrust the bolt bodies mating surface with the bolt head has shortened. The mating surface of the bolt body to the bolt head has been peened just like a hammer hitting a metal stake. This bolt needs to be replaced and there is no fix, the bolt is now scrap junk metal. The manual calls for the bolt to be replace, and if a new bolt and a No.3 bolt head .638 in length closes on the .074 headspace gauge the rifle will be turned in for FTR overhaul. (in most cases the receiver will need to be replaced due to lug recess setback)

scott585 is absolutely correct above, once the bolt head rotates past 20 degrees the threads will start to take the full force of the bolt thrust and more damage will occur. Any time over rotation happens with several bolt heads being fitted the bolt "must" be replaced.

The inspection criteria above can be found in the manual below.

And the most accurate method for checking for stretching and thinning in the base web area is a RCBS case mastering gauge. Bent wires or paperclips are only for white collar office workers, blue collar working class people have hit their fingers so many times with hammers they have no feeling left in them to feel any thinning in the case. (I could drag a bent paper clip across Niagara Falls and not feel it)

this one looks like the second pic down.

it headspaces nicely with a new bolt and a no.1 head, but the old bolt matched the rifle

 

[bigedp51]

this one looks like the second pic down.

it headspaces nicely with a new bolt and a no.1 head, but the old bolt matched the rifle

Replace the bolt head and find one that will line up just shy of the locking lug and work the two mating surfaces together.

You want a tight fitting replacement bolt head that barely lines up and must be worked into alignment. If the bolt head lines up easily after firing a few hundred rounds the bolt head may over rotate after the two parts are seated together.

 

[bearhunter]

Quote Originally Posted by bearhunter View Post

That isn't all that unusual and as long as your headspace is OK, nothing to worry about.

These rifles and their parts were produced on a mass production basis. They had plus or minus tolerances.

The reason your bolt head turns past the sweet spot is because the bolt body itself is slightly short. Likely only a few thousandths of an inch. Even unissued rifles or lightly used rifles can have this condition.

You might be able to change this with another bolt head. MIGHT.
this is past tolerance, it can be unsafe because it means the threads are bearing the pressure of the cartridge thrust rather than the bolt body


its at about 45 degrees, or almost completely past the bolt rib



You should have mentioned that it was so far out in your OP. Eking out bits of information leads to getting wrong answers.

They're right, get a new bolt if the travel is over 20 degrees.

 

[bigedp51]

People you can download your own copy of the Canadian No.4 Enfield rifle at the links below and educate yourself and be ahead of the game. The 1991 manual has bedding drawings and bedding adjustments, the 2002 manual does not.

1991 No.4 (All Marks) .303 Rifle Manuals (Complete Set)
http://www.milsurps.com/content.php?r=335-1991-No.4-%28All-Marks%29-.303-Rifle-Manuals-%28Complete-Set%29

2002 No.4 (All Marks) .303 Rifle Manuals (Complete Set)
http://www.milsurps.com/content.php?r=332-2002-No.4-%28All-Marks%29-.303-Rifle-Manuals-%28Complete-Set%29

There is a wealth of Enfield information at this site and its your own fault if you do not download it and "READ" it.

If you don't download these free manuals you should be shot with a dull bullet, be drawn and quartered, burned at the stake, have your library card revoked and your internet connection cut off. I was also going to say your scrotum should be set on fire and the flames be put out with a sledge hammer, but that might be going to extremes.

 

[supernova]

I was also going to say your scrotum should be set on fire and the flames be put out with a sledge hammer, but that might be going to extremes.

I hope you're not with any volunteer fire department... but at the same time I'd like to see just once, a man trying to put out a fire with a hammer. Do it in a clown suit with a small fire burning in the rainbow wig and I'd pay money to see it.

 

[bigedp51]

I hope you're not with any volunteer fire department... but at the same time I'd like to see just once, a man trying to put out a fire with a hammer. Do it in a clown suit with a small fire burning in the rainbow wig and I'd pay money to see it.

If you would visualize your scrotum on fire and the pain of a sledge hammer hitting this sensitive area and the fire not going out you just might see the very dark humor of this post. Then again volunteer firemen love chopping holes in your roof, smashing all your windows, ripping your ceilings down and flooding the house with water. Now who is more sadistic and how many times have you read about volunteer firemen setting fires because they love watching the flames.

Now save up and buy a sense of humor and read about forms of humor.

"Black humor, dark comedy, dark humor, adult humor, or adult comedy is a comic work that employs black humor, which, in its most basic definition, is humor that makes light of otherwise serious subject matter, or gallows humor. The definition of black humor is problematic; it has been argued that it corresponds to the earlier concept of gallows humor."

"Gallows humour is humour in the face of or about very unpleasant, serious, or painful circumstances. Any humour that treats serious matters, such as death, war, disease, crime, etc., in a light, silly or satirical fashion is considered gallows humor. Gallows humor has been described as a witticism in the face of – and in response to – a hopeless situation. It arises from stressful, traumatic, or life-threatening situations, often in circumstances such that death is perceived as impending and unavoidable."

Example #1: supernova, you would complain even if they hung you with a new rope.

Example #2: And your cat will like playing with the new rope.

 

[RRCo.]

I think I should correct my earlier comment insofar as primary extraction is concerned. The camming action of the bolt is probably sufficient for primary extraction with even an extreme amount of overturn like that shown. As Ed points out, the issue is whether the thrust of firing is transferred to the threads or the matching faces on the front of the bolt body and the rear of the bolt head.

20 degrees is pretty extreme as a tolerance and I suspect the threads are taking some of the thrust in that case. I believe the L42A1 had a 12 degree overturn limit. From some experiments with a feeler gauge and a good bolt just now, there seems to be about 4 thou of clearance, that is 2 thou on either side effectively, between the male thread of the bolt head and the female thread in the bolt body. So when pulled up tight, the male threads of the bolt head are drawn forward, off the forward faces of the female thread and onto the rearward faces, ensuring that the thrust of firing goes only through the bolt body, not the threads.

The funny thing is, the bearing surfaces of the threads taken as a whole are probably at least as large an area as the front and rear faces of the bolt and bolt head! So why does it matter?

Two reasons I suspect: the collar on the firing pin should rest against the rear face of the bolt head shank when not cocked, and if the bolt head slammed into the collar every time the rifle was fired, fatigue failure would follow inevitably. (Obviously the collar does slam into the bolt head as the firing pin reaches the end of its forward travel, but an almost simultaneous backwards thrust would add a lot to the stresses probably)

Second, the bolt head has a fair amount of lateral play in the bolt body and the "squareness" of the face of the bolt head to the chamber is critical for accuracy, so perhaps the bolt head needs to bear against the forward face of the bolt body when the bolt is closed to maintain that "squareness".

 

[supernova]

I found your post, like most others, quite hilarious as I have enjoyed them both for their insightful knowledge and often sadistic humour tossed in for fun. You quite possibly missed the humour in mine as I was making a joke about your joke.

If you would visualize your scrotum on fire and the pain of a sledge hammer hitting this sensitive area and the fire not going out you just might see the very dark humor of this post. Then again volunteer firemen love chopping holes in your roof, smashing all your windows, ripping your ceilings down and flooding the house with water. Now who is more sadistic and how many times have you read about volunteer firemen setting fires because they love watching the flames.

Now save up and buy a sense of humor and read about forms of humor.

"Black humor, dark comedy, dark humor, adult humor, or adult comedy is a comic work that employs black humor, which, in its most basic definition, is humor that makes light of otherwise serious subject matter, or gallows humor. The definition of black humor is problematic; it has been argued that it corresponds to the earlier concept of gallows humor."

"Gallows humour is humour in the face of or about very unpleasant, serious, or painful circumstances. Any humour that treats serious matters, such as death, war, disease, crime, etc., in a light, silly or satirical fashion is considered gallows humor. Gallows humor has been described as a witticism in the face of – and in response to – a hopeless situation. It arises from stressful, traumatic, or life-threatening situations, often in circumstances such that death is perceived as impending and unavoidable."

Example #1: supernova, you would complain even if they hung you with a new rope.

Example #2: And your cat will like playing with the new rope.

 

[bigedp51]

I think I should correct my earlier comment insofar as primary extraction is concerned. The camming action of the bolt is probably sufficient for primary extraction with even an extreme amount of overturn like that shown. As Ed points out, the issue is whether the thrust of firing is transferred to the threads or the matching faces on the front of the bolt body and the rear of the bolt head.

20 degrees is pretty extreme as a tolerance and I suspect the threads are taking some of the thrust in that case. I believe the L42A1 had a 12 degree overturn limit. From some experiments with a feeler gauge and a good bolt just now, there seems to be about 4 thou of clearance, that is 2 thou on either side effectively, between the male thread of the bolt head and the female thread in the bolt body. So when pulled up tight, the male threads of the bolt head are drawn forward, off the forward faces of the female thread and onto the rearward faces, ensuring that the thrust of firing goes only through the bolt body, not the threads.

The funny thing is, the bearing surfaces of the threads taken as a whole are probably at least as large an area as the front and rear faces of the bolt and bolt head! So why does it matter?

Two reasons I suspect: the collar on the firing pin should rest against the rear face of the bolt head shank when not cocked, and if the bolt head slammed into the collar every time the rifle was fired, fatigue failure would follow inevitably. (Obviously the collar does slam into the bolt head as the firing pin reaches the end of its forward travel, but an almost simultaneous backwards thrust would add a lot to the stresses probably)

Second, the bolt head has a fair amount of lateral play in the bolt body and the "squareness" of the face of the bolt head to the chamber is critical for accuracy, so perhaps the bolt head needs to bear against the forward face of the bolt body when the bolt is closed to maintain that "squareness".

The bolt head doesn't rotate the bolt does, therefore the bolt head has nothing to do with primary extraction other than the fact that the extractor is fastened to the bolt head. The Canadian manual is written differently than the British instruction for armourers to keep the Enfield rifle in service in the absence of repair and replacement parts.

As an example there is a reference to bending the trigger guard for trigger pull adjustments. Capt Peter Laidler sent a PM to me once asking why this was done, the answer is simple, there are no more replacement fore stocks. The British would replace the fore stock when the wood was compressed over .010 below the receiver and trigger guard because the lobes on the trigger could not be adjusted for proper trigger pull.

Another example is the British used bolt head timing when fitting a bolt head and this is nothing more than "when" the rear of the bolt head is to contact the collar of the firing pin as the bolt head makes its last turn before stopping. The British used the 3:00 position for contact or 90 degrees before lining up with the locking lug. The Canadian manual tells you to replace the bolt head if it does not push the firing pin and cocking piece 1/16 to 1/64 to the rear. Meaning the Canadian manual uses a wider tolerance and a "air gap" between the rear of the bolt and cocking piece for adjustment. What this means is bolt head timing is from 5:00 to 2;00 and makes more use of worn parts.

Bottom line the Canadian manual is the perfect manual for anyone owning a No.4 Enfield rifle and wants to keep the rifle servicable. Anything else would be a myth and borderline hammer and chisel maintenance.

 

[RRCo.]

The bolt head doesn't rotate the bolt does, therefore the bolt head has nothing to do with primary extraction other than the fact that the extractor is fastened to the bolt head. The Canadian manual is written differently than the British instruction for armourers to keep the Enfield rifle in service in the absence of repair and replacement parts.

Yes, we know the bolt head doesn't rotate once inserted into the guide rail and the body of the bolt does, but what I was referring to was the play in the threads which allows the bolt head to remain stationary through a greater part of the bolt handle's upward movement, before the bolt and bolt head is pulled rearward and the respective threads make contact as the small recoil lug on the bolt body is forced rearward by the slot or groove it runs in. But as I already said above, this was a misstatement, or at least an overstatement on my part, as the camming action of the small recoil lug would generate sufficient primary extraction (I believe) with even the most worn bolt head threads, just a bit later in its travel than with a bolt head with no or little overturn.

As an example there is a reference to bending the trigger guard for trigger pull adjustments. Capt Peter Laidler sent a PM to me once asking why this was done, the answer is simple, there are no more replacement fore stocks. The British would replace the fore stock when the wood was compressed over .010 below the receiver and trigger guard because the lobes on the trigger could not be adjusted for proper trigger pull.

One reason the L42 had a steel plate inserted around the guard screw to spread the load. Of course the collar on the guard screw was supposed to prevent over-compression of the wood, if properly adjusted. Bending the trigger guard is all very well, but then the sides of the guard either don't sit flat on the shoulder around the mag well or else they project too far down and wood has to be relieved. The Mk2 trigger hung on the receiver was long overdue.

Another example is the British used bolt head timing when fitting a bolt head and this is nothing more than "when" the rear of the bolt head is to contact the collar of the firing pin as the bolt head makes its last turn before stopping. The British used the 3:00 position for contact or 90 degrees before lining up with the locking lug. The Canadian manual tells you to replace the bolt head if it does not push the firing pin and cocking piece 1/16 to 1/64 to the rear. Meaning the Canadian manual uses a wider tolerance and a "air gap" between the rear of the bolt and cocking piece for adjustment. What this means is bolt head timing is from 5:00 to 2;00 and makes more use of worn parts.

Makes sense to measure the "air gap" rather than the degree of rotation since it is visual and measurable rather than by "feeling" when the bolt head touches the collar of the firing pin. After all, keeping the cocking piece from hitting the rear face of the bolt is just as important as keeping the firing pin cone from striking the cone inside the bolt head that it passes through.

Bottom line the Canadian manual is the perfect manual for anyone owning a No.4 Enfield rifle and wants to keep the rifle servicable. Anything else would be a myth and borderline hammer and chisel maintenance.

I have both, and while it's been a while since I looked at them, I felt the British EMER's were much more comprehensive in gauging, dimensions and tolerances. The graphics in the CF manual and indeed the whole presentation is more "dumbed down", which probably reflected a lack of continuity in the training and skill sets to maintain the No.4. Not to mention the equipment to do so. It would be interesting to know what the CF manuals looked like before the 1984 version, and the subsequent revisions of it.