Thread gone on screws at top of the mast..

[JollyRodgers]

Finally got around to replacing the broken masthead unit (nasa clipper) for the Windex at the top of the mast. I had to change the whole new wire because the old one was much older and didnt have the plug, but that is all taken care of now and ready to go.

I started to unscrew out the old windex and only managed to get one of the screw out, the rest were falling apart and corroding as I turned the screwdriver. I got the old windex out by unscrewing the bottom of it and pulling it out through the top, but I cant slide the new one down because it doesnt unscrew the same way on the bottom.

I have the new mount/screws ready to replace and they look very similar (but newer) to the existing ones. Exactly the same sizes.

What is the best way for me to remove the 3 remaining screws? If it was on the ground with a plug socket nearby then I wouldnt have an issue, but 40ft up and blowing around is a bit trickier.

I want to be almost 100% sure that when I next go up to the top of the mast, I will have the right tools for the job because of the effort and time it takes to go up!

I was considering using a hacksaw, cutting off the protruding screw heads, sliding off the mounts and then using a pair of pliers to twist the screws out. Then place the new windex up and screw the new mount onto it - and bobs your uncle.

Some people mentioned using a dremel with angle grinder (I dont have one) to slide a flat line into the screw and then using a flathead screwdriver to twist them out.

What do you think will be the best plan of attack?

Thanks.

pics:

 

[PaulMcC]

Is the problem that the aluminium is corroded and therefore the old screws crumble the aluminium when you turn them and don;t come out? In which case jam a wedge behind the plastic fitting to exert force away from the mast and then turn each screw a little, push the wedge in further, turn a little more, .......
Once you have the screws out you'll have a choice of either making brand new holes and tapping then to create a thread or tapping the existing holes to make a new larger thread in them and buying new screws to go with the new larger threaded holes (or figuring out an entirely different way to hold the bracket onto the mast - giant jubilee clib all the way around or whatever).

However from your proposed solutions it sounds like the screws are locked solid and you are rounding off the cross heads trying to make the screws rotate. If that's the case, I would spray with WD40, wait five mins, tap fairly gently with a hammer and respray, wait a few more mins and then again try to get a wedge in somewhere and try an impact driver.

 

[VicS]

Finally got around to replacing the broken masthead unit


What do you think will be the best plan of attack?

Unless you see one of these when you look in a mirror begin by getting it down on the ground where you can work on it porperly , taking your time, and make a good job of it.

 

[garvellachs]

Well done for getting up there first of all. Stainless screws in aluminium corrode solid. If you use force, be prepared for them to break off where they enter the mast. Assuming you can sacrifice the blocks, maybe cut them away with a hacksaw and use mole grips on the screw heads. One may come out, they all might; equally they may break. If they break, then a file can be used to flatten them off and new holes drilled with a battery drill to refit the wind sensor? Are they self tappers? Some Duralac or similar will help then not to corrode. Sort out the old screw stumps when the mast is down sometime?

It might be better to tap the holes and replace the self-tappers with screws?

 

[Lon nan Gruagach]

Heat and lots of it... if that dosnt get them out with a screwdriver then hack saw the head off the screws, remove the clamps and use moles on the nice long exposed screw (with lots of heat).
When they shear flush with the mast drill out to a larger size, tap the hole and fit 316SS with barrier cream of your chioce.

 

[JollyRodgers]

Is the problem that the aluminium is corroded and therefore the old screws crumble the aluminium when you turn them and don;t come out? In which case jam a wedge behind the plastic fitting to exert force away from the mast and then turn each screw a little, push the wedge in further, turn a little more, .......
Once you have the screws out you'll have a choice of either making brand new holes and tapping then to create a thread or tapping the existing holes to make a new larger thread in them and buying new screws to go with the new larger threaded holes (or figuring out an entirely different way to hold the bracket onto the mast - giant jubilee clib all the way around or whatever).

However from your proposed solutions it sounds like the screws are locked solid and you are rounding off the cross heads trying to make the screws rotate. If that's the case, I would spray with WD40, wait five mins, tap fairly gently with a hammer and respray, wait a few more mins and then again try to get a wedge in somewhere and try an impact driver.

I stick the screwdriver in, twist it, and the screw stays in the exact same position, but the screw starts flaking off to bits and the screwdriver starts turning. The actual head of the screwdriver (the + shape) is starting to look more like an O.

Could try wedging it out. I also read about sticking an elastic band into the screw head and placing the screwdriver into that and twisting.

The trouble is, because of the hassle it is to get up there and the amount of people involved in getting up there safely, I only want to have to go up one more time to remove the screws and to put the new Windex up.

By the looks of things, the mounts have been replaced a few times up there - you can tell by the amount of holes up there. I don't really want to go and start drilling even more holes because the mast will start looking like a sieve.

Obviously taking down the mast would make things the easiest, but there is so much hassle (and money presumably) attached to that. I would rather pay for some marine engineers to go up there and do it all for me, even though they will probably bodge it like the previous ones have done.

Well done for getting up there first of all. Stainless screws in aluminium corrode solid. If you use force, be prepared for them to break off where they enter the mast. Assuming you can sacrifice the blocks, maybe cut them away with a hacksaw and use mole grips on the screw heads. One may come out, they all might; equally they may break. If they break, then a file can be used to flatten them off and new holes drilled with a battery drill to refit the wind sensor? Are they self tappers? Some Duralac or similar will help then not to corrode. Sort out the old screw stumps when the mast is down sometime?

It might be better to tap the holes and replace the self-tappers with screws?

Thanks, It's really not too bad. Only gets a bit funny when people on the deck start moving from one side of the boat to the other and you end up swinging all over the place.

I have 2 brand new blocks and 4 brand new screws. I don't plan on keeping the ones that are currently on there (the ones in the pictures). The mounts on there at the moment however, are made of metal - not plastic, which makes them a hell of a lot more difficult to saw out. That's why I was thinking of sawing a flat line into the protruding screw head and trying to use a flat head screwdriver, or failing that, just saw the head off and pull the mounts off and then use mole grips on the screw heads. Then stick the new blocks/screws into the old holes and tighten up - but if the screws are the same size or smaller that isn't going to work..

Heat and lots of it... if that dosnt get them out with a screwdriver then hack saw the head off the screws, remove the clamps and use moles on the nice long exposed screw (with lots of heat).
When they shear flush with the mast drill out to a larger size, tap the hole and fit 316SS with barrier cream of your chioce.

How am I going to get heat 40ft in the air? Turbo/jet lighter? and heat up the protruding screw head? What's 316SS and barrier cream?

 

[Pete7]

Had the same problem when replacing an old Stowe unit with Raymarine. Friend lent me an 18v battery angle grinder. 20 seconds later there was nothing left but a flat smooth surface and the new unit had different holes so drilled and fitted the new one easily.

 

[JollyRodgers]

Had the same problem when replacing an old Stowe unit with Raymarine. Friend lent me an 18v battery angle grinder. 20 seconds later there was nothing left but a flat smooth surface and the new unit had different holes so drilled and fitted the new one easily.

Yeah, that's what I need I think. Might get a Dremel cordless, as at least it can be used for other things too. http://www.amazon.co.uk/Dremel-Cord...id=1431451948&sr=8-4&keywords=dremel+cordless

Then I figure out how I am going to drill the new holes in for the new mount/screws.

The alternative to all of this of course, is I see how much the marine engineers at the yard will quote me to do the whole thing and I continue using my corded power tools down on deck. Seems silly to spend £70 on something just because it's cordless.

 

[garvellachs]

I stick the screwdriver in, twist it, and the screw stays in the exact same position, but the screw starts flaking off to bits and the screwdriver starts turning. The actual head of the screwdriver (the + shape) is starting to look more like an O.

Sounds like your screw driver is not a good 'un? The screws may be philips or pozi-drive; it's possible that you are trying to undo a pozidrive screw with an old cheap philips screwdriver? Worth having a new one of each from Wickes or similar?

I like the battery grinder idea as well.

Once you are at the top of the mast, a webbing belt round you and the mast helps to make you feel more secure - confident enough to use two hands etc. Also if you may need something when you are up there, take a light line up with you tied round a belt loop or something and flaked on the deck - then a helper can tie things to the end and send them up to you?

 

[PetiteFleur]

Yeah, that's what I need I think. Might get a Dremel cordless, as at least it can be used for other things too. http://www.amazon.co.uk/Dremel-Cord...id=1431451948&sr=8-4&keywords=dremel+cordless

Then I figure out how I am going to drill the new holes in for the new mount/screws.

The alternative to all of this of course, is I see how much the marine engineers at the yard will quote me to do the whole thing and I continue using my corded power tools down on deck. Seems silly to spend £70 on something just because it's cordless.

Aldi are doing a cordless Li-ion drill at the moment for £25 - the guy in front of me bought one this afternoon, it looked fine and you'll find lots of jobs to do with it - I rarely use my corded drill after I got an 18v Ryobi when B&Q had them on special (+10%discount on wed.!)

 

[wklein]

The best way would be to cut a slot with a cordless grinder in the head and unscrew with a big flathead, the heat from the cut will often result in it coming out fairly easily. As you don't have access to one we'll gloss over that.

First I would try mole grips on the side of the head. The added leverage will probably get two of the three out cleanly. If that fails you'll probably need to drill out what's left of it. I would not move it as you have a lot of holes in that area already, I would drill out the holes in the new brackedsfto m6 and tap the mast.

 

[ianat182]

As you already have replacement brackets and screws would it not be easier,,if able,to fit on the starboard side of the mast head,leaving the originals until a mast down operation is arranged. I would also take up a pop rivet gun and fill any unused holes with stainless or alloy rivets and primocon.



ianat182

 

[William_H]

To reiterate 2 points. You should have a screw driver with decent hard replaceable tips. Right size right type. Clearly the screw driver you are using is worn out.
The idea of using mole grips on the outside of the screw head has merit. Try the molegrips on something similar before you go up. It can be difficult to get a grip that hangs on. You may want to grind down the end of the mole grips to give a good flat surface end on. Or perhaps try side on.
Take these up with you plus a hack saw to cut a slot for a blade screw driver. Again the hardened replaceable tip type screw drivers are best. If an ordinary screw driver at least dress the tip for better grip. good luck olewill

 

[Scotty_Tradewind]

https://www.google.co.uk/search?q=w...SEgPgC&ved=0CCEQsxg&biw=1506&bih=994&dpr=0.85

Wera make extremely good quality screwdrivers and other accessories for sensible prices.

Great photos but they play havoc when trying to read the postings so I gave up!

S,

 

[Strolls]

You should have a screw driver with decent hard replaceable tips. Right size right type. Clearly the screw driver you are using is worn out.

How do you determine that the screwdriver is to blame, and it's not just that the screw is so severely seized?

 

[vyv_cox]

A few days ago I replaced my masthead wind instruments from a cherry-picker. It cost me €100 per hour, which enabled me to drill holes for the new attachment and fit it, replace the cable, try unsuccessfully to remove the old fitting. This was all done in total comfort and safety with all my tools up there with me. A lot cheaper than removing the mast would be. If you can get your boat alongside a quay somewhere it could be worth considering.

My windex, on the same mast type, is on a bracket that is bolted to the top plate, extending aft. This is a better design, easily removed if necessary, and in the best place when viewed from the cockpit.

 

[J Neeves]

Applying heat to fittings at mast head.

I fail to understand any yacht incapable of making Creme Brûlée and Baked Alaska - the key ingredient of which is a little blow torch.

Go to your nearest kitchen utensil store and buy one (they are quite cheap), you can always use it to impress your guests. Its also useful for shrink covers for cabling and, a bit clumsy, sealing the ends of synthetic cordage. I actually have a disposable blow torch on the lines of a cigarette lighter, but it was a gift and bought here, so I cannot suggest where one buys them.

Working at the masthead is all about comfort and security. A decent seat, a decent harness (I use a climbing harness) 'stirrups' attached to the crane for your feet etc will make it much easier and allow you stay there for hours and do a decent job. If its a big job I spend quite a bit of time getting comfortable and secure and then passing hoons are not an issue.

Excellent pictures of the masthead.

Jonathan