How can I remove giant flathead screw?

[Roswell715]

… without the proper tool, of course.

It’s one that holds the pulpit to the cockpit sole.
Think about a quarter-sized flathead. Slot is maybe 1mm wide and deep.
I have tools on boat but nothing around that seems to work.

There is a nut on bottom but it turns the screw. (Actually a big flathead bolt, I guess. Counter sunk, flush with the surface.

Another question might be: how to keep a bolt from turning with only access to the threaded side

[marcjsmith]

Any chance of adding something like butyl tape to the nut and then Putting your socket and driver on the nut. And then lash the handle to something to hold it firm while you work with the flat head....
A hand held impact driver that’s hammer operated would be a huge help.

Copious amount of your favorite penetrant

Bribe a fellow skipper with a beverage to assist...

[boatpoker]

Vice grips on the nut and braced against turning.
A $15 inventment in an impact driver will carry lifelong benefits.
I bought one on line last week for $22Cdn on Amazon.
No need to get suckered on the $75 units.

https://www.amazon.ca/TEKTON-2905-8-...785539586&th=1

[JPA Cate]

Hi, Roswell715,

You're going to have to get at the nut if you want to undo the screw. Or have a smaller, more limber friend get to it for you. It is probably a pretty big nut, too. Maybe you or he or she can fix a box end wrench on it and wedge it against turning. You can dry drizzling some weasel piss (equal parts atf* and acetone) down there first, and it might help, and you need to find a big old flat blade screw driver that will fit very well (not so tight you have to force it in, but without slop). By the way, somebody got at it to install it, so I know there's a way to do it. This is definitely a problem that will have a solution.

If you don't know the size of the nut, you'll have to get calipers on it somehow, to measure it (in order to properly size the box end wrench). You can also use a crescent wrench or a deep socket on it, but the former is likely to round the corners on the nut, and the latter may foul on the end of the screw. If you go the socket route hex head rather than 12 point will fit best, but in tight spaces sometimes it's easier to fit the 12 point ones on.

Yes, there are some new tools in your future.

Now, when it comes to re-assembly, you're going to need some good bedding compound, cause when you replace it you want to seal it up. Sikaflex will do. Turps for cleanup. May need to put some newspaper underneath, below decks, to catch drops. Put the sika on the screw in such a way that when you tighten the nut, some squeezes out around the top of the screw, so that water on it will drain off, and not run below. Wipe off any excess.

You can do this with someone helping. On our boat, I'm usually the one below, fielding drips and tightening what I can, while Jim does the screwdriver above. One other thought, sometimes people put things together using whatever they have around. If your screws are too long, you might run out and buy some the right size, for a neater fit.

Ann

[Roswell715]

Originally Posted by JPA Cate

Hi, Roswell715,

You're going to have to get at the nut if you want to undo the screw. Or have a smaller, more limber friend get to it for you. It is probably a pretty big nut, too. Maybe you or he or she can fix a box end wrench on it and wedge it against turning. You can dry drizzling some weasel piss (equal parts atf* and acetone) down there first, and it might help, and you need to find a big old flat blade screw driver that will fit very well (not so tight you have to force it in, but without slop). By the way, somebody got at it to install it, so I know there's a way to do it. This is definitely a problem that will have a solution.

If you don't know the size of the nut, you'll have to get calipers on it somehow, to measure it (in order to properly size the box end wrench). You can also use a crescent wrench or a deep socket on it, but the former is likely to round the corners on the nut, and the latter may foul on the end of the screw. If you go the socket route hex head rather than 12 point will fit best, but in tight spaces sometimes it's easier to fit the 12 point ones on.

Yes, there are some new tools in your future.

Now, when it comes to re-assembly, you're going to need some good bedding compound, cause when you replace it you want to seal it up. Sikaflex will do. Turps for cleanup. May need to put some newspaper underneath, below decks, to catch drops. Put the sika on the screw in such a way that when you tighten the nut, some squeezes out around the top of the screw, so that water on it will drain off, and not run below. Wipe off any excess.

You can do this with someone helping. On our boat, I'm usually the one below, fielding drips and tightening what I can, while Jim does the screwdriver above. One other thought, sometimes people put things together using whatever they have around. If your screws are too long, you might run out and buy some the right size, for a neater fit.

Ann

Right on. I should clarify.. I can reach both the nut below and the topside at the same time. The problem is the right “thing” to hold the flathead part from turning. A regular size screwdriver just twists in the slot. I have an impact driver but it’s just a regular size bit which just spins in the wide slot. I’m a long way from a store so I am sitting here trying to brainstorm. I filed down an inch thick paint scraper but it’s too weak and twists

[deblen]

Every boat should have a nut splitter nut splitter.

https://www.amazon.ca/Tool-Internati.../dp/B00N3YAMIA

[Rumrace]

Vise grips and a large coin.

[chris mac]

Do you have a multi tool for deck fitting removal? They come in handy for things like this, when the size lines up.
I have also used chisels or a prybar held with vice grips. Possibly a large washer.
Really anything strong that fits the slot, but can be grasped with vice grips, can work. Assuming of course that it is willing to turn, otherwise you will need a grinder[emoji854]

[HopCar]

A large slotted screw is used to fasten a lot of hurricane shutters. There is a special driver for them.
https://www.amazon.com/IVY-Classic-4...%2C109&sr=8-11

[HopCar]

I’ve also taken a spade drill and ground the end flat.

[Orion Jim]

You can buy a single slotted bit in your choice of drives, here is one example.
In addition, that pedestal guard is not original equipment nor is the bracket which holds it. The floor of your cockpit is cored with balsa. If the new penetrations weren’t done properly now is the time. You want any penetration to go through solid glass/epoxy to protect the balsa from rotting. The guard bases should have been secured with bolts and backing plates….as they were originally from the builder. The same goes for the pedestal base.

[stormalong]

Do you mean the pedestal screw? Those are aluminum and the nut might be corroded on. Try some penetrating oil to loosen it up before you try again. When re-assembling them use some anti seize compound on them.

I seem to remember Edson is no longer selling those. Check with them before drilling out what you have.

In a pinch I have made straight slot blades from sheet metal and held them in a crescent wrench.

[Roswell715]

Originally Posted by Orion Jim

You can buy a single slotted bit in your choice of drives, here is one example.
In addition, that pedestal guard is not original equipment nor is the bracket which holds it. The floor of your cockpit is cored with balsa. If the new penetrations weren’t done properly now is the time. You want any penetration to go through solid glass/epoxy to protect the balsa from rotting. The guard bases should have been secured with bolts and backing plates….as they were originally from the builder. The same goes for the pedestal base.

Yea I just bought it like that. It’s a 27. The previous owner must have thought it was a yacht lol. Going back to a tiller.
Good idea on the bit.. guess I’ll have to wait until I’m near a store

[Calif.Ted]

Drag Link Socket of appropriate size, big as will fit.

[stormalong]

Originally Posted by Roswell715

Yea I just bought it like that. It’s a 27. The previous owner must have thought it was a yacht lol. Going back to a tiller.
Good idea on the bit.. guess I’ll have to wait until I’m near a store

If you are going back to a tiller just drill them out. Aluminum drills easily. Use 1/2 inch or a little larger bit.