Collective Wisdom ...

[GregH]

Looking for ideas (good and bad) for getting 40yr old SS bolt (slot head) out of a cast Aluminum bow plate?

Have a couple of chocks (Al as well) that need removing..

[ndutton]

Unfortunately:

• Alberg used dissimilar metals so you are metallurgically welded
• Heat is not your friend on a fiberglass boat, do not be tempted
• Alberg used slotted screws, possibly the worst screw head devised by man

I suggest starting with a hand impact tool

https://www.amazon.com/TEKTON-2905-8-Inch-Manual-7-Piece/dp/B000NPPATS/ref=asc_df_B000NPPATS/?tag=hyprod-20&linkCode=df0&hvadid=312003160272&hvpos=1o5&hvnetw=g&hvrand=12932566406063550100&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9031042&hvtargid=aud-801738734305:pla-420785539586&psc=1

and

https://itstillruns.com/use-hand-impact-driver-4809810.html

[lat 64]

Agree with Neil. Also use penetrating oil of some kind.The vibrations from the impact driver will help oil seep into the work. Time is you friend here—but, If you need to drill, remember that Stainless will get work-hardend VERY fast and only the best ($$$) drill bits will help then.
Drill very slow and keep it kool.

[GregH]

I'll get myself an Impact driver set like suggested anyways as its a good tool to have on hand I'm told. And if it does not work, then I figure I'll spend some time cutting up the alum chocks from around the bolt and then cut the bolt off flush with the top of the bow plate... which upon further pondering, I am not sure if it's Al or a cast white metal of some sort..

the job'll be done when the job is done.

[lat 64]

Wow! that's a stout plate. A step above my Columbia Clorox bottle

Perhaps you could remove the whole plate and do the removal of the chocks in a shop environment or even have a machine shop do it(?)

[tenders]

I think your time will be better spent thinking of reasons NOT to take those screws out than fancy ways of getting them out.

[Al Schober]

Go to McMaster.Com and shop for cobalt drill bits. You know what sizes you need - might even find some left hand bits, also cobalt (great things).
Stainless tapped into aluminum is trouble down the road - not that I haven't done it myself! Blocks into a boom (#8 fasteners) are one thing, bow straps into a stem fitting (1/4" fasteners) are another.
I had a SS spinnaker track attached to an Al mast with SS fasteners. Corrosion bent the track to the point that the car would no longer go up/down. Managed to remove and straighten the track. Reinstalled using new SS fasteners, but with a strip of electrical tape between the track and the mast. Problem solved.
Case #2 - jib halyard winch working hard. Standard bronze winch, aluminum mast, cast aluminum spacer (flat to curved mast). Remove screws and the winch base comes off in FIVE pieces. Corrosion between the bronze and aluminum. New winch installed with electrical tape between the bronze and aluminum. Problem gone.

[romantic comedy]

what are the screws threaded into?

You might be able to drill or grind the heads off and take them out below?
Dremel makes a great bit that makes grinding hard metal easy.

[GregH]

what are the screws threaded into?

You might be able to drill or grind the heads off and take them out below?
Dremel makes a great bit that makes grinding hard metal easy.

Haven't crawled into the chain locker to be able to see whether the bolts come all the way through. That's on the list for this coming weekend.

Popping out this evening to see if my solar panel survived after last Friday's wind storm (was away all weekend) and will put some penetrating oil on the threads for soaking this week so can see what can do this weekend.

[JOHN COOKSON]

After using the penetrating oil tap the screw heads with a hammer. It will help the penetrating goop get down into the threads. If possible do this drill daily. Gravity is working for you in this case.

TRUE GRIT

[sagem57]

just a thought. drill a small pilot hole down thru the center of the bolt, then chase it down with a large countersink to machine away the head of the bolt. and remove the chock. as for the rest of the bolt I don't know what to tell you.

[Boat]

the recomendation above, then an ez out.

[Deppard]

just a thought. drill a small pilot hole down thru the center of the bolt, then chase it down with a large countersink to machine away the head of the bolt. and remove the chock. as for the rest of the bolt I don't know what to tell you.

Can you break the bold when doing this?

[Al Schober]

Boat may like EZouts - I do not. When they break (not IF) you have a hole with a piece of hardened tool steel in it. Even a cobalt drill won't get through that!

[Al Schober]

just a thought. drill a small pilot hole down thru the center of the bolt, then chase it down with a large countersink to machine away the head of the bolt. and remove the chock. as for the rest of the bolt I don't know what to tell you.

I like this! Just get rid of the head of the bolt & free the chock. You did say you were going to move it! Don't remove the rest of the bolt - just leave it there! Drill new holes in the new location, but make them thru holes with nuts on the inside. Don't tap into the aluminum.