Screw in mast removal

[Mickeyrouse]

No doubt this has been discussed hereabouts before, so apologies in advance.
I have a storm sail track on the mast. The sheave has disintegrated and has been bent. The track is in good usable shape but the block on the slide needs to be replaced. The problem is the track stop. This track was on the boat when we became her stewards 26 years ago, and I fully imagine it was part of the original gear on this 50 year old boat. Like just about everything else on a boat accessibility is less than ideal- I’m over 6 ft and the stop is above eye-level. I realize that a blow torch may be helpful, but I’m not too crazy about using heat like that near the mainsail. Removing the main is no small task. And besides keeping a blowtorch going in the wind is problematical.
So, what is the most effective chemical for freeing up a seized stainless screw threaded into aluminum?

[neilpride]

Heat and PB blaster, impact screwdriver with a quality screwdriver head, otherwise drill and tap.

[Lee Jerry]

Originally Posted by neilpride

Heat and PB blaster, impact screwdriver with a quality screwdriver head, otherwise drill and tap.

Yeah, this. And the impact driver is the key.

However, be careful mixing the heat with the PB Blaster (or other penetrant), as it's flammable.

heat - impact driver, heat - impact driver, repeat as patience allows.

Then PB blaster - wait - impact driver, Blaster - wait - impact driver, repeat as patience allows, probably try longer than the heat (or skip the heat). Even let the penetrant work overnight.

If unsuccessful, or if the screw head gets f'd up, one additional possible attempt is with a screw or bolt extractor.

After that you'll have to resort to drilling it out. Drill carefully as centered as possible. If/when the bit wanders off the screw it takes out the soft aluminum and leaves a chunk of the SS screw. (You can get it out, but now your hole is misaligned.) Then you may want to go with a threaded insert rather than tapping.

This is all easier with the mast out and working down-hand, but it doesn't sound like you're looking to do that.

[Lee Jerry]

Oh, to be clear, I meant the hand or manual impact driver that you hit with a hammer like this one.

And buy extra bits. They break.

[Nekton73]

Personally I find it almost impossible to do effective work reaching above eye level. I think it would give you a better chance of success to come up with a work platform that lets you stand a bit higher, whatever that is. A short ladder, a sturdy chair, bench, step stool etc. lashed firmly, or perhaps a comfy bosun's chair with your feet helping you brace. Sometimes a couple of feet and a better angle make all the difference between getting something done well or mangling it.


If you do end up stripping it, an alternative to drilling it out would be to grind off the head flush so you can remove the sheave and then drill and tap a new hole for a new stop. Faster and easier than drilling out a stainless machine screw.

Or...(and I'm guessing you already thought of this but sometimes the obvious escapes me when it's staring right at me) can you just slide the sheave off the track at the other end? Remove the end cap or stop or whatever is in the way? On my boom I had an old t-track for a reefing sheave. It was capped at each end and removing either allowed me to slide it off.


p.s. When I first read the title of this thread I thought "I've never heard of a screw in mast, I wonder how you would remove one from a boat?", so I had to click on it.

[Cheechako]

A pic would help. Some will just not come out at all. There are no threads left due to the SS/aluminum interaction. They are held in by white hard oxide. When it's out all the aluminum threads are gone and buried in the corrosion. If it's been 26 years+ this is likely your case.
Usually how it looks will tell.
You may have to just drill it out, tap a new hole and put in a larger screw.

[pdx_sailing]

With a slotted head screw that was stuck and starting to strip, I used an oscillating multi tool to, re slot the head as a last ditch effort before drilling it out. The tool didn't cut much of the screw, but the vibration freed the corrosion and I could unscrew it easily. I have used this method a few times from ss screws in al.

[AKA-None]

Originally Posted by pdx_sailing

With a slotted head screw that was stuck and starting to strip, I used an oscillating multi tool to, re slot the head as a last ditch effort before drilling it out. The tool didn't cut much of the screw, but the vibration freed the corrosion and I could unscrew it easily. I have used this method a few times from ss screws in al.

Nice trick
I’ve recut slots but never used a multi tool for that purpose

[The Yacht Rigger]

Besides PB Blaster, I've had good results with 50/50 acetone and AT fluid mixed together.

Use some heat, as much as you can without risking damaging the sail if it's right there.

Then as others have said, impact, followed by drilling it out if that fails.

[Mickeyrouse]

Thanks to all. A new mast may be easier.��

[Celestialsailor]

Originally Posted by neilpride

Heat and PB blaster, impact screwdriver with a quality screwdriver head, otherwise drill and tap.

Oh oh...you have just opened up Pandora's box! As a Toolmaker of 44 years and remove fasteners for a living, I suggested the same in another thread and received the wrath of Jedi for such a statement.
All joking aside, yes heat is your friend. Aluminum starts to loose it's temper at 300F but the aluminum oxide is compromised at 200+F I usually heat to where I get a water sizzle on the area I am heating. I like to heat and cool with Kroil and do that a few times. I have used pneumatic impact drivers, hammer-impact drivers and occasionally a square shanked screw driver with a crescent wrench.

[neilpride]

Originally Posted by Celestialsailor

Oh oh...you have just opened up Pandora's box! As a Toolmaker of 44 years and remove fasteners for a living, I suggested the same in another thread and received the wrath of Jedi for such a statement.
All joking aside, yes heat is your friend. Aluminum starts to loose it's temper at 300F but the aluminum oxide is compromised at 200+F I usually heat to where I get a water sizzle on the area I am heating. I like to heat and cool with Kroil and do that a few times. I have used pneumatic impact drivers, hammer-impact drivers and occasionally a square shanked screw driver with a crescent wrench.

Hahaha ok, good, but what Jedi may not know is that I have loosened hundreds of screws on masts with this method, sometimes it works sometimes it doesn't.

I usually apply PB first or another brand, not necessarily PB blaster, leave it overnight, next day apply torch, very small blue flame and heat the head of the screw.

Pb again, wait a bit, torch again, maybe 3 times and give it a sharp blow with the impact screwdriver, make a mark on the screw to see if there is any progress, if it moves, continue with the Pb and try to move back and forth ,if the head breaks, drill and tap, not big deal.

[Celestialsailor]

Originally Posted by neilpride

Hahaha ok, good, but what Jedi may not know is that I have loosened hundreds of screws on masts with this method, sometimes it works sometimes it doesn't.

I usually apply PB first or another brand, not necessarily PB blaster, leave it overnight, next day apply torch, very small blue flame and heat the head of the screw.

Pb again, wait a bit, torch again, maybe 3 times and give it a sharp blow with the impact screwdriver, make a mark on the screw to see if there is any progress, if it moves, continue with the Pb and try to move back and forth ,if the head breaks, drill and tap, not big deal.

Yes...I do the same. And heavens forbid, I sometimes use my smallest Oxy/Ace brazing torch to heat the head of the fastener to a blue color. If you only do it for 5 seconds or so, the aluminum dissipates the heat before the aluminum gets too hot.

As I'm sure you are aware, when all else fails and you get that occasional one whose head strips, I dill the head out, starting with a center drill to get a good starting point, then drill the head off. This gives me the opportunity to get some vise grips on it and again, with heat, get that sucker out. Only once out of hundreds of fasteners, have I had to (very carefully) drill the center of the fastener out and use a thread insert.

[neilpride]

Exactly, vice grips work if it is not a flush head screw for example on a spinnaker pole track.

I always use TiAlN or high quality cobalt drill bits, when there is a thin sheet of SS left then I tap it with something sharp and remove the remains , if the aluminum thread is in poor condition, I pass a threaded tap of the same size to clean it , if not, I enlarge to the next size.

Another thing, nothing will happen to aluminum with heat, not in T6000 series, if the heat is focused on the head of the screw, no problem, if the torch has a wide flame the anodized finish can be damaged.

And also, always apply heat before applying Pb or another penetrating oil, when is hot Pb begins to boil and work by capillary action, the other way around is flammable, it already scared me a bit in my beginnings.

[rls8r]

Hmmm ... you obviously have a different storm track setup than mine. The bottom of my storm track starts about a foot above the mast boot and doesn't have a cap (or a slide with a sheave).

My topping lift track does have caps like I think you're talking about (and a slide with a sheave). I removed the caps by heating them with a heat gun and applying PB Blaster (several times) - and then using a cordless (Ryobi) impact tool.

Most of the screws in my masts were threaded using some kind of corrosion inhibitor that must also have been an adhesive. I first thought that they had 'frozen' but after wringing a few off I discovered that heat and an impact tool worked wonders.