why was this Mauser 98 guard screw seized ?
I have purchased, fired, fixed, repaired a ton of Mauser 98 sporters and milsurps in my lifetime. To date I've run across a few that had guard screws and trigger guards boogered up by previous owners, who obviously ran into a stuck guard screw on the guns. I'd see evidence of the screw heads being drilled out, or the screw itself and guard area around the hole chopped up by a struggle. I've had a few Mausers with stubborn guard screws but a good screwdriver and both hands turning it, always got them free.
Well I ran into one that finally got me. Front guard screw on a 1908 Brazilian made by Oberndorf, 7mm. I had "left it lay" there for years because the big screwdriver did not budge it and started to every so slightly booger the slot in the screw. So that one didn't get the usual complete cleaning inside/out.
Today I said enough is enough, and removed the capture screw that locks that front screw, and shot some PB Blaster automotive grade penetrant in there. Looking at another 1908 I have apart, doing that will expose the guard screw threads to the penetrant. Still would not budge.
After about 2 hours, I realized that sucker ain't comin' out, and would have to be machined out. I tried one last shot with a tiny hardened punch and hammer, hitting it at an angle on the edge, and presto, it started to turn, but very hard to turn. Still would not budge with a screwdriver, but only turned by hitting it hard with a hammer and punch at an angle. I kept tapping it until it unwound about 1/2 a turn or more, then it stuck solid again. DAMNED !
I ended up drilling it out with progressively larger drill bits, until the head was drilled completely away except for a thin shell, and the gun finally came apart. I pried the remains of the screw head out of the guard screw hole.
I removed the trigger guard, and expecting to see crusted rust in there where the cut off stud was, much to my surprise, it was CLEAN. WTH ? No rust at all on threads or threaded hole. huh ?
which led me to wonder, WTH made it seize to solid to begin with ?
the only thing I can come up with, is the stock wood swelled, and put pressure on the screw head, and would not let it turn.
the little cut off piece of stud turned out with ease using vice grips !
why the heck was it seized then, and why would it not turn with a screwdriver ? any opinions welcome.
Well I ran into one that finally got me. Front guard screw on a 1908 Brazilian made by Oberndorf, 7mm. I had "left it lay" there for years because the big screwdriver did not budge it and started to every so slightly booger the slot in the screw. So that one didn't get the usual complete cleaning inside/out.
Today I said enough is enough, and removed the capture screw that locks that front screw, and shot some PB Blaster automotive grade penetrant in there. Looking at another 1908 I have apart, doing that will expose the guard screw threads to the penetrant. Still would not budge.
After about 2 hours, I realized that sucker ain't comin' out, and would have to be machined out. I tried one last shot with a tiny hardened punch and hammer, hitting it at an angle on the edge, and presto, it started to turn, but very hard to turn. Still would not budge with a screwdriver, but only turned by hitting it hard with a hammer and punch at an angle. I kept tapping it until it unwound about 1/2 a turn or more, then it stuck solid again. DAMNED !
I ended up drilling it out with progressively larger drill bits, until the head was drilled completely away except for a thin shell, and the gun finally came apart. I pried the remains of the screw head out of the guard screw hole.
I removed the trigger guard, and expecting to see crusted rust in there where the cut off stud was, much to my surprise, it was CLEAN. WTH ? No rust at all on threads or threaded hole. huh ?
which led me to wonder, WTH made it seize to solid to begin with ?
the only thing I can come up with, is the stock wood swelled, and put pressure on the screw head, and would not let it turn.
the little cut off piece of stud turned out with ease using vice grips !
why the heck was it seized then, and why would it not turn with a screwdriver ? any opinions welcome.
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My thought is some armorer over tighened the guard screw in order to get the locking screw recess lined up. Once you drilled off the head, you released pressure.
I am not sure on your theory of wood swell creating pressure. The Mauser 98 trigger guard is recessed for the receiver front screw boss on the recoil lug, acting in effect, a front pillar bed. Should be no wood to screw contact there, right ?
Regards,
Chris0 -
Bubba used seize compound on the screw head. Be thankful he didn't use it on the threads too.
added: the fluid will crawl right in, no disassembly required.0 -
Per your description of "no rust" and ease of removing cut off guard screw with vise grip. There was misalignment causing the shank of the trigger guard screw to bind up, i.e. the tapped hole in the receiver wasn't at a precise 90 degree angle to the counter sunk hole in the trigger guard.
The wile krauts 100? years ago in Oberndorf managed to get it screwed in, with out destroying the head of the guard screw somehow?0 -
quote:Originally posted by chris8X57
My thought is some armorer over tighened the guard screw in order to get the locking screw recess lined up. Once you drilled off the head, you released pressure.
I am not sure on your theory of wood swell creating pressure. The Mauser 98 trigger guard is recessed for the receiver front screw boss on the recoil lug, acting in effect, a front pillar bed. Should be no wood to screw contact there, right ?
Regards,
Chris
the front upper part of the trigger guard seats onto the pillar bed, and the stock, simultaneously. There's an imprint in the stock where it was squeezed against it. If the stock swells, it will put downward pressure on the trigger guard.0 -
quote:Originally posted by rufe-snow
Per your description of "no rust" and ease of removing cut off guard screw with vise grip. There was misalignment causing the shank of the trigger guard screw to bind up, i.e. the tapped hole in the receiver wasn't at a precise 90 degree angle to the counter sunk hole in the trigger guard.
The wile krauts 100? years ago in Oberndorf managed to get it screwed in, with out destroying the head of the guard screw somehow?
a replacement screw from another Mauser I have, threaded right in though, when I just trial fit the gun last night. No binding.
there is the slight possibility the screw head itself was not perfectly round, and if even slightly oval, would jam the screw in the trigger guard countersunk hole, like a wedge or locking head.
but the hardware on early Mausers is usually top notch, it looked perfectly round before I drilled it out.0 -
quote:Originally posted by charliemeyer007
Bubba used seize compound on the screw head. Be thankful he didn't use it on the threads too.
the gun appeared to be never disassembled since imported, still had the original guard screws in it, and the slots appeared like new, they've never been turned out until I got it. The slots were still blued without a mark on them, not even one mark of deflection from being tightened/loosened- like they usually will have.0 -
Hardware stuck is usually due to one of three things. Corrosion, glued, or mis-fit.
Since you used PB blaster and it turned but then stopped suggests mis -fit.
Next time try one of the aerosol freeze spray. This causes contraction and can sometimes do the trick. These aerosol freeze sprays are designed to remove chewing
Gum by breaking it to frozen pieces.0 -
I've rebuilt a ton of engines, worked on a lot of cars, and owned my own repair shop at one time, repairing cars and trucks. I must have unstuck a thousand bolts and hardware using various techniques. I've also removed a lot of small stubborn screws from antique firearms by using some very inventive ways to get them out, such as boiling the old pistol frames in water, then use gloves to grab the frame quickly while still hot and turn the screw out. This way there's no damage to the finish from torch heat.
But this guard screw is the weirdest deal I've ever seen, the only way that screw was stuck, was with the head, not the threads. Here is a picture of the screw, exactly as it came out of the gun.
The remaining stud is in perfect condition, the threads inside the lug were perfect as well, the bluing is still on the stud, and there's not a single mark in the threads.
It wasn't the fastener, threads, "seize compound" (or did you mean locktite ?) There was no "bubba" job done- the gun was in original condition. If there was misalignment, it would misalign again with the new guard screw and it doesn't misalign.
I believe this is one of those very rare specimens anymore, where an old gun was assembled 105 years ago, and was NEVER OUT OF THE STOCK until now ! The bluing under the wood on this gun, is like new in most sections and shining- unbelieveable. The receiver, barrel, trigger, floorplate, handguard, stock, bolt stop lever are all numbers matching.
I've had one other gun, a Savage 99 takedown, that was never disassembled, and it was made in 1928, and still had the sawdust inside the stock from when a Savage employee hand fitted it to the stock, at the Savage factory- there are specimens like this out there, but they are getting fewer every year. On the Savage, the buttstock bolt was very difficult to remove.
This Mauser, having been screwed together in 1908- for 105 years- had the stock wood sandwiched between 2 pieces of metal- the receiver on top, and the trigger guard on bottom- that wood is porous, will definitely expand/contract, and must have expanded enough to put pressure on the front guard screw, and seize it.
Think about it, receiver/barrel is on top, stock in middle, trigger guard on bottom, this puts the porous wood in the position of being able to expand with weather conditions and jam the trigger guard screws.
Next time I get one like this, I'm going to very carefully use a C-clamp or vise, with wooden blocks and leather pads, to compress the gun top to bottom, i.e. squeeze the receiver down into the stock ever so slightly, and push up on the trigger guard, to relieve the pressure on the guard screws.
I'd wager that screw would have turned right out then. Have you ever tried to remove a bolt that had tension on it ? Hang a 10 pound weight from a threaded rod and try to unscrew a bolt or nut holding the weight to the rod- that's the mechanics involved. Sometimes it's nearly impossible without relieving the tension first.
Wood moves over time. The front deck on my house moves a lot when it gets very cold outside, to the point there's a big bang noise from the contraction, and it's pressure treated wood.
I welcome all the theories, thanks.0 -
CaptainCrossman,
Your theory sounds valid. What did the bottom of the screw head look like?
Another issue I see in aviation is people using the wrong grip length on a bolt or screw. They take and run the grip down into the threads. In aviation the bolt is supposed to strip first, but that's not always the case. I have had to remove bolts with two full turns of an oversize grip go into the nutplate. Each is so hard it cuts the other and makes it look like it was supposed to be that way. When referencing the numbers on the head of the bolt, I see they used 1/16th" or even 1/8th" too long of a bolt.
In your case the bolt is blued/coated and doesn't show that happening. But, I do see serious abrasion going up the side of the grip. Could well have been wedged in that way according to your theory as well.0 -
Cap'n.
With the action loose fit in the stock, & bottom metal tight in the stock inletting, heavy recoil will bend the front screw. This is prolly what jammed your screw & caused it to come free as soon as the bent portion was no longer held by the bottom metal.
Jim0
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