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Removing Stainless Screws from Aluminium Rig?


Clipper

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I am missing the sheeve from the fractional kite exit block on my mast. It appears to be tapped into the mast with 6 stainless screws/bolts. But of course, they have been there for eternity, and are now seized in their pretty tightly (read impossible to undo).

 

Any suggestion on how to remove the bolts/screws? I tried breifly, only to start twisting the slots open, as can be seen on a couple of the screws.

Fractional Sheeve.JPG

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You are up the mast in that shot aren't you?

There was probably no corrosion inhibitor put on the threads before assembly, so there will be a mass of white powder jamming the screws.

WD40 or CRC may help if left a couple of days to soak if it can be got onto the threads.

You are probably going to end up grinding the heads off, drilling out, then retapping for a bigger size screw. :thumbdown:

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Heat. If you can get a hot gas flame on the screw head, heat it up real hot and let it cool again. The expansion and contraction breaks the white powder. Then a little WD40 and try the screw driver. If still no go, you will have to cut and drill them out, then re-tap and go the next bigger thread size. Use a really good anti-seize...Lanocote or Nickle. Do not use Copper.

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Heat. If you can get a hot gas flame on the screw head, heat it up real hot and let it cool again. The expansion and contraction breaks the white powder. Then a little WD40 and try the screw driver. If still no go, you will have to cut and drill them out, then re-tap and go the next bigger thread size. Use a really good anti-seize...Lanocote or Nickle. Do not use Copper.

 

Sounds fun....Need a calm day for that!

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Use a hammer, make sure your screw driver is old. Put the screw driver in the slot like you were going do undo them and give the top a good wack, this loosens the crud most times. But heat is good too.

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Guest Dry Reach
Use a hammer, make sure your screw driver is old. Put the screw driver in the slot like you were going do undo them and give the top a good wack, this loosens the crud most times. .

 

? :roll: thats why professionals use a impact driver.

 

just make sure the slot in the screw head matches the driver attachment perfectly.

 

or, grind of the heads and punch the threaded bit through!

 

or, hacksaw of the heads of the screws and punch thru.

 

also instead of going to oversize rivets or screws for replacement fitting ... just make a curved (old mast section) oversize backing plate (with holes pre drilled to original fittings screw/rivet size) that slides into the mast (tape or blu tak in place) then put in new fitting and re fasten (rivet preferred)

 

if you want to go to a new smaller fitting just make a adapter plate and use the existing hole (and screw holes) :thumbup:

 

Pity you not reading this though :|

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my past experience says try everything before brute force. heat/lube/hit with hammer without twisting.

 

impact driver could quite easily snap the heads off if its very corroded. iv done it by hand before, then end up having to grind flat then drill out old screws.

 

insulate between ali and stainless, could be as simple as some sparky tape but using some sticky poo from a tube is better.

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I suppose that did sound a tad gash, BUT, if you use an impact driver you have no control over the turning moment. If you use a screw driver you wont burr over the head of the screw (well push the burrs that have already been made from the bit slipping into the slot making more work for your self), it transfers the shock straight to the shank of the screw, not over the head on into the structure. AND you can control how much turning force applied, thus not ripping the head off and having more work for yourself.

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Thats what I like about an impact driver, you can start gentle, by using it as a screw driver, then a couple of light taps. Gradually increasing pressure as required.

 

I recently removed a couple of screws from a gate in my main track, I would guess they hadn't been removed since Spellbounds rebuild in the 80's! I had to wire brush the oxidation away to find the grove of the screw's.

 

Soaking the screws in CRC as often and as long as possible is definitely a good idea.

 

SHANE

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If it's well corroded the alloy should give way before the screws bust but Col does have a point even though I'm knot sure I would have used the word 'easily'. Often you'll find one good smack will loosen it enough to undo with ease, you are only trying to beak the death grip between the 2.

 

Once you have the screws out it is possible the fitting is stuck down with sillycone. Take a big screw driver as you may have to lever it off, that sillycone can stick like you wouldn't believe sometimes. Looking at the pic it could be sillyconed down.

 

The soaking with CRC type stuff was a good call and may just have done the trick by the time you get back to it. Make sure you clean that off before sillyconing the new fitting in.

 

And if the halyard has been damaged, if the core is still good look at recovering that rather than buying new, heaps cheaper. It's a Donaghys Superbraid so the cover is only pretty rather than structural.

 

I didn't realise you were up the mast in that pic, I was distracted by your fat looking thumb :lol:

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FYI, every mast i have rigged from new where i have to put a stainless fitting against the alloy mast section i have Chromate etched / Epoxied a curved sacrificial alloy plate to the mast and cut the fitting into it.

 

then i have sillyconned (neutral cure) or mastic'd the fitting to this and used either Alloy rivets (low load) or Monel (for high loads).

 

i have one mast that is over twenty years old and the alloy (mast) was "as new" as! when i took the plate of last year. and the sacrificial plate was slightly corroded.

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It would be a helluva lot easier and safer to pull the mast off and do the job at waist level with the mast on a couple of saw horses. You will get a much better job of the new install as well.

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I agree with TimB.

 

Further if those screws are stuck / corroded in, then what about the other screws?

 

What about some grease on the mast head sheeves, which may have similar amounts of corrosion?

 

Definately use an impact drive, but also use a decent small sledge hammer. One GOOD whack is better than many piddley tap tap tappings.

 

From the picture, the screw heads show that it was probably installed by a lowly under paid, under nourished apprentice, because the screw heads are KNOT aligned.

 

Take KM's advice, and PM Squid as you should visit his manicurist, who can do wonders after you've smashed your thumb really well :thumbup:

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Mast needs to come out anyway I reckon.

 

Heat to get rid of the old screws. In conjunction often with Impact Driver.

 

New fastenings go in with tefgel or duralac.

 

BTW there aren't many off the shelf exit boxes capable of taking the loads of a GBE

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