How do I remove big flathead screws in the main??

[basssears]

Originally Posted by Scorpius

work-harden the stainless, ruin your bits, your sanity, quite possibly your marriage, and NEVER get the damn things out.

Come on Scorpius, stop sugar coating boat work

[basssears]

Welding stainless is not the easiest thing in the world. As a hack welder, just saying... I'm ok enough to do decent mild steel welds (they're ugly but they don't fail) but stainless and aluminum are a whole higher level of skill.

+1 for MAPP gas, the numbers seem to make it not much hotter than propane but seems a lot more effective really.

Should have added before, something I didn't focus on until recently, the whole point of heat is to move different metals at different speeds to break them loose... once you've heated the stainless screw but not the aluminum spar (heat differential = good) hit everything with ice water from a jug / cup / spray bottle / towel (heat differential = good... again)... emphasizes the heat differential and can help break things loose.

EDIT: As far as cooling, Celestialsailor says don't cheat by cooling, I take that to mean don't rush the process by cooling with a bit of room temp water just to move to next step (this will take awhile), I still believe in the shock value of a towel soaked in a bucket of icy icy water applied to the screw right after heat, not to try to speed the process but just to accentuate the shock to break the disparate metals' bonds.

Free advice, worth less than you paid for it ;-)

[JOHNMARDALL]

Originally Posted by Gary Mc

My mast spent 22 years in salt water before I purchased the boat. I stripped the mast down to bare metal to paint it. The manual impact driver took every SS screw out of the aluminum.

I was amazed, thought I would be doing a fair bit of drilling. All screw heads were Philips which would be easier than flat head.
Good luck!

I'm a convert to Torx head screws when I can get them in the siz required. Better grip on the screew than phillips and more foregivng than square drive.

Good luck
John Mardall

[lifeofreilly57]

Just one note, when your reinstalling use Lanocote on the screw threads. I use it any time I'm putting stainless fasteners into dissimilar metals, like my mast.
Sure wish the past technicians had used it.

[Cheechako]

Originally Posted by robert sailor

It really comes down to whoever installed those screws in the first place. If they were installed with antisieze then you will probably get them out with some heat and an impact driver but if they were installed dry then it's going to be tough going.
One fellow suggested heat and a punch in the direction of travel which I would agree with as well. This usually gets the real tough ones moving. If that fails your going to have to drill them out.

That's really the question. many I have taken out were not extractable, they were simply a "slug of SS sitting a hard white powder" which used to be threads. Even drilling these out you had to go to a larger replacement screw as the threads were gone and the powder was larger diameter than a new screw.

[P3sailor]

Flathead screws can be the worse. When all else fails you may want to purchase a few EZ-Outs. They're relatively easy to use and shouldn't damage the piece the screw is fastened to. Don't worry about damaging the screw you're trying to remove it's most likely beyond that at this point. Use quality EZ-Outs, a cheap one could break off leaving part of the device in the screw you're trying to remove. If that happens then you're in deep do-do.

[C420sailor]

For these purposes, welding to stainless with mild steel rod/electrode/wire is fine and actually preferable if the nut isn’t also stainless. It’ll be plenty strong. The bolt will be junked once removed, anyway.

[jpendoley]

I bought a cordless Ryobi impact driver to remove thirty 3/8 stainless bolts holding an old spinnaker pole track in the front of the fifty year old mast on my old Vanguard. Before the impact driver everything else failed-heat, cold, kroil, freeze out etc. I have no doubt they had been there for 45 years. The impact driver pulses impacts many dozens of times in a minute. It backed out all of them. You can dial the intensity up or down minimizing/eliminating risk of snapping a bolt. It is a great tool for corroded fitting removal.

[Makr0]

Quick update! I have two slotted bolts left, I have also learned their proper name.

I used a combo of Penetrating oil heat and a manual impact driver. Half of the bolts came out without much fuss, the other three heads stripped.

One of the folks who said don’t buy the impact driver from the local hardware store was bang on. The cheap bits wrapped and eventually blew apart. I think the warpping bits created the problem with the slots. I decided to go destructive, and grind the heads off.

I’ll post pics when I’m done.

[hzcruiser]

Well done!

[Scorpius]

Originally Posted by Makr0

Quick update! I have two slotted bolts left, I have also learned their proper name.

I used a combo of Penetrating oil heat and a manual impact driver. Half of the bolts came out without much fuss, the other three heads stripped.

One of the folks who said don’t buy the impact driver from the local hardware store was bang on. The cheap bits wrapped and eventually blew apart. I think the warpping bits created the problem with the slots. I decided to go destructive, and grind the heads off.

I’ll post pics when I’m done.

Excellent! Keep up the great work!

[Makr0]

All in all I’ve put in about 8 hours on the project I’m in the home stretch now. I managed to remove the last 2 bolts, and only had to grind one off. I figured out if I pulsed my impact drill I was able to get the same result as the manual driver.

With the unused gooseneck in hand I turned my attention to removing what was left of the old gooseneck. It had bigger slotted bolts, the first 2 zipped out but the other 2 would budge.... I blew up 7 bits. So finally had a good long look at old broken gooseneck, who ever installed it. Epoxied the crap out it. The bolts would budge so I demel’d them off.

Not I’m all set to installed the new gooseneck with means I get to driller and tap 6 holes into my mast.... I have maybe used my die set 3 times, so I’m a bit nervous I’ll just take it slow.

A couple of notes, I’m upgrading my hardware to philips head bolts, i looked fore hex and torx at the marine shop but had no luck. Second this may be my inexperience speaking but I could have saved a ton of time drilling the bolts that wouldn’t move out, but I worried that part of the bolts would fall into my mast and rattle around on anchor. So I ground do flush.

Thanks for all the support!

[Cheechako]

Originally Posted by Makr0

All in all I’ve put in about 8 hours on the project I’m in the home stretch now. I managed to remove the last 2 bolts, and only had to grind one off. I figured out if I pulsed my impact drill I was able to get the same result as the manual driver.

With the unused gooseneck in hand I turned my attention to removing what was left of the old gooseneck. It had bigger slotted bolts, the first 2 zipped out but the other 2 would budge.... I blew up 7 bits. So finally had a good long look at old broken gooseneck, who ever installed it. Epoxied the crap out it. The bolts would budge so I demel’d them off.

Not I’m all set to installed the new gooseneck with means I get to driller and tap 6 holes into my mast.... I have maybe used my die set 3 times, so I’m a bit nervous I’ll just take it slow.

A couple of notes, I’m upgrading my hardware to philips head bolts, i looked fore hex and torx at the marine shop but had no luck. Second this may be my inexperience speaking but I could have saved a ton of time drilling the bolts that wouldn’t move out, but I worried that part of the bolts would fall into my mast and rattle around on anchor. So I ground do flush.

Thanks for all the support!

Yes take it slow, when tapping, reverse direction occasionally (that will get the chip out rather than drag it through the new threads)
Use only coarse threads in aluminum.
A 2 flute tap works better than a 4 flute in aluminum .
Use some lube when tapping.

[AKA-None]

Originally Posted by Cheechako

Yes take it slow, when tapping, reverse direction occasionally (that will get the chip out rather than drag it through the new threads)

Use only coarse threads in aluminum.

A 2 flute tap works better than a 4 flute in aluminum .

Use Lots of lube when tapping.

There fixed it for you

[MicHughV]

I'm no expert on the matter....but I would have thought a fine thread would be better than a course thread in an aluminum mast, as the mast typically has marginal wall thickness.
A fine thread would have more "threads" in the mast section, whereas a course thread might have only a single thread...
I might be totally wrong about this, and if so, please educate me....