Stuck screws on bendix mag

C_Parker said:
I'm out on a long cross country flight this week, I'll be digging into this early next week.

Thanks everyone for the input! One way or another, I'm not buying a new mag unless the mag itself is shot! I'm kinda ****ed my mechanic suggested I'd have to buy one when really it's just a matter of effort.
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I wouldn't be too quick to judge your mechanic. He might see things you don't, like a lot of corrosion in various places, and he might feel that the screws are rusted in there real good. He could spend hours getting those screws out only to find that the guts are totally beyond economical repair. Now you pay for all those hours plus a new mag. He's likely been there before, as I have, and doesn't want to chance wasting your money and making you mad.

There's a time to repair and a time to replace. I've seen far too much effort (meaning money) expended on repairing some piece of junk only to have to replace it anyway.
 
flyingbrit said:
To me, the expectation of a screw extractor removing a bolt/screw whose head broke off due to the threads being corroded is the height of wishful thinking. If the head cannot apply enough torque to loosen the corroded threads there is NO WAY the screw extractor will. The only time I've seen an extractor work is when the bolt head and part of the shank break off due to either shear or tension overloading, and there is no thread corrosion so the low torque of the extractor is sufficient. This is evidence of a poor design or perhaps an accident and is relatively unusual.
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That's a different tool. Screw extractors are for screws, for bolts you need a bolt extractor. These look like demonic sockets that go over a rounded bolt head. They actually cut into the head of the bolt and give you a larger (and harder), and VERY positive wrench face.

EZ outs and Screw Extractors both break (they are made of pretty hard steel), the difference is the Extractor allows the use of a wrench instead of a t-handle and they typically grab the screw better (better fluting).

Another option for the mag is to drill/grind off the screw heads, remove the cover and then turn the screws out with pliers. OR drill out the whole screw and rethread the now smooth hole with a helicoil (kind of a last resort thing)
 
Dan Thomas said:
I wouldn't be too quick to judge your mechanic. He might see things you don't, like a lot of corrosion in various places, and he might feel that the screws are rusted in there real good. He could spend hours getting those screws out only to find that the guts are totally beyond economical repair. Now you pay for all those hours plus a new mag. He's likely been there before, as I have, and doesn't want to chance wasting your money and making you mad.

There's a time to repair and a time to replace. I've seen far too much effort (meaning money) expended on repairing some piece of junk only to have to replace it anyway.
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If that's the case, and it very well may be, the mechanic needed to communicate that to OP. Simply saying "the screws are stuck, buy a new mag" is pitifully insufficient, especially if the above reasons were true. The A&P isn't your mom that just gets to say "because I said so"; the A&P effectively works for you and needs to communicate accordingly.
 
bradg33 said:
the mechanic needed to communicate that to OP
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FWIW: or perhaps his mechanic did communicate a number of things and we only heard is "stuck screw/replace mag"??? Unless his mechanic posts here we'll never know both sides. Been there on the mx side.
 
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Betja Tom could get that screw out :)

 
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JPA said:
OR drill out the whole screw and rethread the now smooth hole with a helicoil (kind of a last resort thing)
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Notoriously hard to do to small screws that are threaded into aluminum or some other soft alloy. One has to face the stub nice and level and start a tiny drill into the very center of it, and use increasingly larger bits to remove the screw. Otherwise the bit will slide off to one side and once it finds that soft material it will drill it out instead. After a few dozen like that I just resorted to welding a piece of steel rod to the stub and backing it out that way. Less damage, and successful at least 90% of the time.
 
Bell206 said:
FWIW: or perhaps his mechanic did communicate a number of things and we only heard is "stuck screw/replace mag"??? Unless his mechanic pots here we'll never know both sides. Been there on the mx side.
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A fair and valid point for sure, but I'm just taking what OP is saying at face value.
 
Guys, my memory is precise on this matter.

There is zero corrosion on the mag, and the plane has been in arid climates it’s whole life.

I’m out on a long cross country flight and won’t be back until early next week at which time I’ll provide updates.
 
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An hour soaking in PB blaster and a little valve grinding compound on the screw head and she came right out. It was only one screw, and I could see where is was already starting to slip. I feel the valve grind compound helped the most.

thanks guys!
 
C_Parker said:
An hour soaking in PB blaster and a little valve grinding compound on the screw head and she came right out. It was only one screw, and I could see where is was already starting to slip. I feel the valve grind compound helped the most.

thanks guys!
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Cool. What does the compound do for you, never heard that one?
 
Valve grinding compound is a very fine abrasive paste. It gives a good grip for the screwdriver on the screw head.
 
C_Parker said:
An hour soaking in PB blaster and a little valve grinding compound on the screw head and she came right out. It was only one screw, and I could see where is was already starting to slip. I feel the valve grind compound helped the most.

thanks guys!
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:happydance::goofy:
 
Domenick said:
Valve grinding compound is a very fine abrasive paste. It gives a good grip for the screwdriver on the screw head.
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Yah, that is what I thought. Was wondering if there was anything else though I cannot imagine what that anything else could be...
Thanks.
 
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