[abrahamx]

I had to take (not sure what its called) the sheve at the aft end of my boom that routes the outhaul. It is connected to a plate with a four hole pattern. While taking it off two screws came out fine and one broke flush to the boom and the other I had to drill out and break the plate out. There is still some of the screw sticking out but it wont budge for nothing. Being a metal worker I am pretty familiar with working with metal but dont do alot of tapping. I will need to drill out the two screws and retap them. I am looking for the drill and tap kit to do it. I dont want to waste my money on something that wont even touch stainless. Like I just did with an extractor kit. Ended up drilling everything out with my carbide drill. Tried searching google and was not finding much so I figured I would find out more here. Anyone know of a nice drill and tap kit for stainless steel? Cant seem to find anything specifically for stainless.

 

[ReefMagnet]

You don't need anything special for stainless steel. Normal HSS drills will do. The big issue with stainless is that it work hardens. The "trick" is to drill at a slow speed with a fresh drill bit, use cutting lubricant and don't rush the drilling. Same for cutting a thread. Use a cutting lubricant and make sure you do the old back and forth business to clear the cuttings from the tap.

 

[Omatako]

I have always found when drilling stainless it is important to use a slower speed, a sharp drill (both already mentioned) but also a constant and heavy pressure.

If the drill is allowed to stop cutting even for a moment, the stainless can "gall" and then you will really struggle to get the drill to start cutting again.

Tapping is nothing special, stainless taps quite easily.

 

[H and E]

If you mess up the threads you can use a helicoil kit to restore back to original. I assume that the SS screws are in alum. You need to coat the screw with a barrier coating when installing SS in alum. I use clear finger nail polish.

helicoil thread insert kit products - Grainger Industrial Supply

 

[MarkSF]

If the design of the plate suits, I'd just drill the holes out and use ss rivets

 

[abrahamx]

I could do that. Either rivets or bolts. My main concern is getting the old bolt out. I get the drill slow and all that. I am a metal worker after all. I just thought that there might be some super strong marine bolt of something. I have not found anything yet that will even put a mark on this 3/16 bolt. Cant even put a center punch on it. only a carbide drill will seem to do. Just have to wait for a week day and fork out $25 for a carbide drill I guess. I only own a 7/16 carbide bit and that is way to big. Cant go sailing till I can get this stupid broken bolt off.

 

[MarkSF]

Personally I wouldn't give up on getting it moving. Keep spraying it regularly with PB Blaster or similar, and try working it back and forth. My experience is they normally will free up. Next time, when you feel it is seized, do the above - don't force it.

 

[hellosailor]

PBlaster is incredible.

Or a torch.

Or some dry ice slush.

Coupla tries with any of those, and almost anything will come out.

 

[fryewe]

If the fasteners are stainless and the sheave plate is aluminum and mounted to an aluminum boom and it's been there for a few years without galvanic isolation the galvanic corrosion may have locked them in place. In similar instances I have had mixed results trying to extract them.

Soaking in vinegar to dissolve the aluminum corrosion may yield some benefit. Following up with a lubricant may yield additional benefit. But in many cases the only method is destructive removal as you did with screw 3 in your description.

Drilling the fourth fastener with a small hard bit and increasing the bit size a little at a time creeping up on the hole dimension and then "breaking it out" as you did with the third screw is one option.

Another is to grind the plate and fastener away using a Dremel or other small grinding tool.

That would be my first choice I think...because I haven't ever had much success hand drilling a SS fastener...drill press - yes - but I have always had too much "walk" by the hand drill for success.

Good luck. Let us know how it turns out please.

 

[abrahamx]

I finally drilled through the one bolt that was broke off flush. Somehow on the other one I managed to slip off the bolt and drill a hole next to it. I will get the three bolts in place and try drilling out the fourth with the help of the pattern hoping it will go through. Three bolts is probably enough but I should be able to get the fourth. Heck, I'll weld the thing back on if I have to. Although it looks like some sort of casting or compost

 

[wall]

I find if you heat the screw with a soldering touch (a small one )
the screw will release .316 s/steel will drill and cut with std drills and saws
you just need to keep the pressure up .You could make a template up to stop the drill wondering at the start .
Hope this helps
Good luck