OK, gotta get this off...

[brackish]

...to make the modified piece that will hopefully end my rudder problems.

I need to remove the two PH screws holding the SS tab and Delrin plate on the top.  The aft screw comes right out, the forward screw won't budge.  It is a stainless steel machine screw that goes through a countersunk hole in the SS tab, then through a clearance hole in a piece of Delrin, then into an aluminum casting which is threaded.  I suspect never seize was not used on the original assembly and now, after nine years it is locked up tight. 

So I'm thinking maybe a little penetrating oil although I'm not sure it will get through, then maybe wrap the casting top with a heating pad, then put a chunk of ice on the screw head, let it soak for a while, then give it a shot.  Any and all suggestions welcome.  Really don't want to end up moving on to an easy out which has never been "easy" for me.

[cas206]

SOP for me on stuck nuts/bolts is to apply heat with torch.  I suppose the Delrin prevents that as a solution in this case.   Not sure what else to suggest.   I've also resorted to a cutting disk on Dremel tool to cut a some off.

[BruceW]

I"m no help at all on your question, but I'm very interested in your approach to solving the problem.

Curious what the actual fix is.

What about extending the aluminum pieces that hold the tiller on?

[guync5]

HEAT! is the only thing that will do it.

[Salty19]

An impact driver should do the job extremely nicely after a little shot of PB blaster, or as skip has reported, a mix of auto tranny fluid and acetone. Some heat on it first, then let it cool..then smack hard with a hammer on the impact driver. Make sure it's set for removal if it's adjustable.  I usually use this tool if I predict any problems with stripping the threads from a traditional screwdriver, rendering it more difficult later to remove.

You can rent them at auto parts stores if you or a friend doesn't have one.

You could also clamp some large vice grips on the screwdriver, hammer down on it from the top while twisting the vice grip. If you do it this way, bang on it hard a few times before twisting.  Heat it up first, then cool down beforehand.

[capt_nemo]

brackish,

I may be badly mistaken but I don't think that SS Handle Assist Mechanism has been available and galling in the cast aluminum for 9 years.

Regardless of whether or not I am correct, I would suggest starting with methods that are SIMPLE and/or do the least damage to surrounding components, and move progressively to methods more COMPLEX and/or damaging to surrounding components.

Over the years I have often (not always) successfully loosened dissimilar metals by combining a good penetrating liquid treatment with PRESSURE and INDUCED VIBRATION in one or both components. The vibration tends to break, crack, or loosen the grip enough to allow the penetrating liquid to be effective.

RECOMMENDATION: (as if it were My problem!)

I would try using a good TIGHT-FITTING (not worn) Phillips screw driver with a pair of vice grips attached high on the shaft under the handle and lot of downward pressure. Have a helper apply penetrating oil and tap repeatedly on the screwdriver top with a small hammer while you apply as much downward pressure as you can with one hand on the screwdriver handle and the other on the tightened vicegrips. Then, using the vicegrips for grip and leverage, try working the screw, alternating clockwise and counterclockwise while tapping for vibration. Hopefully the screw will start to give!

Good luck and do let us know what happens.

capt_nemo

[Salty19]

LOL...I edited my post without reading Nemo's response with the vice grip suggestion, and by god, we both like the vice grip method.  

If it was my problem, I would use the impact driver first if you have one. Usually by 2-3 hits it turns it enough to break the seal so to speak.

[Bob23]

   Long periods of regular soaking with PB Blaster before you try anything. Sometimes I'll heat the area first then apply the PB. Either way, patience is a nice tool to have in this case, too. I like the vice grips on the screwdriver approach although my old Snap-on screwdrivers have a hex just beneath the handle which is sized to fit a common wrench. Really handy.
   I suppose the last resort is to drill it out, retap the next bigger size and use marine Never-Seeze on the threads. Just my 2 cents...keep the change.
Bob23

[Eagleye]

Brakish,
I am in the agreement with the hand impact driver school of thought.  If you don't have one now would be the time to make the investment. I bought one similar to this 35 years ago and I would not be without one now. ($20 to $40 Sears, Amazon, ect...)

http://www.amazon.com/Pro-Grade-19620-2-Inch-Driver-Impact/dp/B002O16UPM/ref=sr_1_2?ie=UTF8&qid=1393157815&sr=8-2&keywords=manual+impact+driver

IF ALL ELSE FAILS......Remove the one screw. Sacrifice the delrin and cut it away with a Dremel type tool leaving the screw exposed to grab with a vise grip.  Then heat up the surrounding aluminum and ease the screw out with continuous and gentle back and forth motions.

I have had mine off on my Eclipse and if I recall that is a ¼- 20 screw.  Trying to drill and easy-out that would be a surgical feat.  At that point I would drill and tap a new hole even if it meant acquiring a piece of delrin a bit longer.

Good Luck,
-Allen

[Harrier]

Assuming all else has failed...
Remove the one screw, split/crack/gouge/chisel/pry the delrin from the aft side such that you can remove it.  (Delrin is cheap and easily replaceable) With the delrin piece removed, you will have accomplished two things.  One, you will have removed any preload on the screw.  Now all you are fighting is whatever corrosion has the threads bound up.  Two, you have given yourself more access to the screw and the ability to get more penetrating oil onto the threads as well as more leverage on the screw.  

[brackish]

I"m no help at all on your question, but I'm very interested in your approach to solving the problem.

Curious what the actual fix is.

What about extending the aluminum pieces that hold the tiller on?

You will notice that there is a gap between the Delrin plate that extends past the rudder casting and the SS tab that is welded to the lift assist handle.  In the picture it looks like something is in there, but that is reflection, the gap is about 1/4".  That shouldn't be.  It is designed so that when the rudder is down and locked in the operating position, there is a very snug fit between those two surfaces.  Without it, it doesn't work.  The shock cord can hold it fore and aft but the rudder still kicks up until that 1/4" is filled which is just a couple of degrees but still not at optimal position.  However the real problem is that the shock cord cannot hold the arm/tab laterally.  It tends to slide to port or starboard and when it clears the delrin piece, the rudder kicks up about 20 degrees and the handle flops around.  That is the problem.

Hutchins suggestion is to rebend the arm.  I've worked with metal all my life, and to hit the material yield point on a piece that thick to a vague projected dimension with a cold bend is dicey at best.  Too many issues and I'm not currently equipped for a hot bend.

I considered:  Cutting off the tab and welding it back at the right spot, but that still doesn't solve the lateral slide problem, plus most invasive of cures.  I considered extending the aluminum tiller yoke pieces as you have suggested and even bought some aluminum to make some screw on extenders.  But I decided to replace the piece of Delrin with one that curves down the back of the rudder casting and will have a slot at the bottom.  It will curve down and then leave a flat that will make up the 1/4" gap but will be a channel with sides that will extend another 1/8" or so to lock the handle tab in laterally.  I think this will be the easiest cure (if I can get the screw out) give the best operating outcome and will be the most cosmetically pleasing.


I may be badly mistaken but I don't think that SS Handle Assist Mechanism has been available and galling in the cast aluminum for 9 years.

Don, the boat is a 23 IV commissioned in 2005.  The rudder assembly is OEM.  I'm the second owner.  I don't think the previous owner ever had this thing apart.

Thanks for all the suggestions, I'll start with least invasive first and move on until I have it out.  I'll let you know how it comes out.

[kickingbug1]

im with bob on this one----soak it and wait---and wait----and wait some more   then attack it with the impact driver

[skip1930]

Delrin ... what is that 1/4 or 3/8 thick?

Delrin melts at 336 deg F. so I'd sacrifice that by softening it up with a paint stripping gun and try one of those hand held impacts that twist about 5  degrees when stuck with a hammer. That will either kill and snap off the screws or loosen them. Baring that...

You could grind the Delrin out of the way from under the two screws with a 4-1/2 inch angle grinder or Dremel and a stone or cut it with a hack saw blade.

It's no big deal to find another piece of Delrin or UHMW and cut or grind to shape a new piece of plastic.

Anyway with the plastic out of the way the two screws would be standing up above the aluminum casting. Dribble some Kroll or another brand of penetrating oil [auto tranny fluid and acetone] into heated screws and let it sit overnight. [Make a little PVC tape dam around the casting and flood the area like a lake.]

You want to make some space between the stainless steel [rate of heat expansion .12] screws and the aluminum [rate of heat expansion .24] so what dissolves aluminum? Any chemical that leans toward a base pH ... something about 11-12-or 13 pH ought to do that. We are talking about microscopic movement of aluminum molecules to make space. So time, chemicals, and heat. [Check our Naval jelly for steel and Aluminum Jelly for aluminum. I buy mine from ACE Hardware.]

By the time I responded to this the screws are probably out. BTW. "I suppose the last resort is to drill it out" Your not going to be able to drill out stainless steel with out a lot of blue laungauge.

It should be noted that when it comes to 'twisting' [not drilling] stainless steel is no stronger and just as soft as regular black iron [steel] screws.

Side Bar: I had a 80 year old Ford Model 'A' 275 lb block with four aluminum pistons frozen into the grey iron block. With the oil pan and head off I filled the bores with Marvelous Mystery Oil and let her sit a week. With three flat bars set on cement blocks holding the block off the ground and a bag of charcoal brickets afire under the block I waited for the oil to boil. With my 1 inch breaker bar and a five foot steel tube as a cheater bar and my 216 lb jumping on the bar things budged. Eventually it was rebuilt with new poured babbit and ran fine.

skip.  

[MacGyver]

Brack,

2 things: First off, more pictures please of how this works...... I might need to mod mine and make something similar, not to mention I like what this possibly does, looks interesting.....

Also, If that rod goes port or starboard, couldnt you just get 2 plates for the tiller handle that are longer and install them so that it keeps that piece in there? That is my sketch up plan to avoid lateral movements on a mock up I have..... I just havent made a solid test device yet since at that time I was going to sell the boat.

Mac

[capt_nemo]

Mac,

Two (2) whatevers, mounted wherever, to "capture" the rod is the first (design) thought I had also to prevent uncontrolled athwartships movement.

I have the same Factory Rod controlling my Com-Pac Foiled Rudder (on a Sun Cat) and haven't got around to addressing the rod movement - too busy with other things. Use a ball bungee as a temporary fix.

Soooo, I'll just wait and see what great minds come up with before jumping in with my Engineering Drawing Board!

I'm either blessed or cursed to be an Engineer, haven't quite decided which yet.

capt_nemo