Hobie Cat Forums

One of my rudders is popping up too easily. Along with new cam plungers and springs I would like to replace the plastic screw that adjusts the rudder release tension. Neither one of these screws on my old boat will budge. What is the best way to get them out to replace? Drill and tap? If so, what size can I use without hogging out the aluminum or screwing up the threads?

And a related question, under certain sailing conditions I am getting some pretty good weather helm. The set screws for rake adjustment on my boat are also frozen. Anyone know what these are made of? Best way to get them out? If drill and tap, what size?

I got this boat last Spring and kinda rushed it into service. Everything worked pretty okay last year but now, during the off season, I would like to take care of some of these little irritants.

Jeremy at Surf City did a video of the casting repair...

http://www.surfcitycatamarans.com/video.html

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Matt Miller
Director of Parts and Accessory Sales
Hobie Cat USA

Both screws that you refer to are plastic. I'm fairly certain the rake adjuster screw is 1/4-20. Best bet for that one would probably be an easy out, or if that doesn't work, drill it out and tap.

I don't know what size the plunger screw is, but it shouldn't be too hard to figure out. One method I've always heard in the past for removing a frozen one is to use a hand drill with a spade bit and insert the bit into the slot in the plunger screw to try to unscrew it. The other trick is to heat up a large screwdriver and melt it into the screw, then unscrew. I can't tell you if either of these works because I guess I've always been lucky enough to get the screw free by using a screwdriver.

Put some grease on the screw when you re-install.

sm

That guy has some pretty unique tools. I did a Google search on reverse cutter drill bits and came up with nothing (not sure why one needs to drill in reverse...ever). I guess I was looking for a way to do this with ordinary tools. Maybe I'll just replace the springs and shim them up with nylon or fiber washers to get a little more tension.

Sunvista a few years ago I replaced those plastic screws on the "81" boat I had. I too had one of the screws that would not budge. I found an article somewhere on the internet about a guy who heated the blade end of a standard screwdriver with a propane torch, then inserted and pushed into the plastice screw letting it melt its way in. Let it set for a bit and try to unscrew it. I tried it and it worked like a champ! You have nothting to loose if it doesn't work as you will be replacing the plastic screw no matter what. Good luck.

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07 H16
Sail No. 110387

Melting the Delrin creates a poisonous gas, so do this only in a well ventilated space.

I found that a flat wood drill bit, that is a bit smaller than the screw size, works very well. The center of the bit fits nicely in the hole down the middle of the screw. You drill and then chip the plastic out of the casting threads.

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Matt Miller
Director of Parts and Accessory Sales
Hobie Cat USA

That guy's crazy too...

The reason I use a reverse cutter is that sometimes a little cutting and the rest of the screw backs out. Saves time on the tapping end of things. The more screw you unscrew, the better off you are. Forward cutter will work, just dont damage the casting.

I melted them out one time and it took 3 hours. This method takes about 5 minutes. I highly recommend drilling them out by some means if possible.

You should see the pics of the new cutter my friend Dan showed up with today. Pics soon.

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Sail Revolution
Join us on our new FB Page!

Five minutes sounds too good to be true, but I'll testify to the truthfulness of the claim after watching Jeremy do it on my castings.

Well the Delrin screws wouldn't budge with 25 years of petrified salt in them. I used a 5/8" wood bore which worked nicely to cut most of the Delrin screw out without damaging the threads. The remaining plastic spiraled right out with an ice pick. Needless to say the threads are in really poor shape. I think I can obtain a 3/4 x 10 tap no problem but not sure what kind of extension is used in the video since the tap needs to be around 8 inches long to reach up inside the casting. Also it looks like I need to find a hone or something to clean up the bore surface for the plunger to move freely. The surface is pretty crusty.

I welded a 1/2" ratchet extension to the end of the tap. The extension should fit over the end of the tap no problem, so no welding is really required. 3/4" 10 tap should be readily available. You're almost there. Don't forget to lube it all up when you're done. I use Lanocote, but pretty much any grease will work.

J

This might be easier to see than the video:
http://www.surfcitycatamarans.com/plungerscrew




Hope that helps!

J

Edit:
The new tool made by DanP on the forums. It's pretty sweet. It eliminates the need of having both a drill and a reverse cutter. It's all in one! Thanks again Dan.

Here's my $3 solution:

I used a wood bit to rout out most of the screw, then bought a 3/4 inch continuous thread rod...cheap at any hardware store. I filed one side smooth , and then just used a pair of vice grips to screw it into the casting. cut it to a proper lenght (about 12 incles long) then screw it in and out to clean the threads......you coul weld a "T" handle to it for easier handling but the vice grips worked fine.

The galvanized 3/4 inch rod has standard threads that match perfectly with the thread pattern of the casting....dont go looking for expensive taps that are long enough to reach the casting threads ..... I did spray sailcoat onto the threads, but I don't know if that helped or not.

take the casting to the hardware store and check for youreself for the correct thread rod size....

Grease the casting threads and put new derlin screw in and your done.

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Raced extensively as a kid (against Matt Bounds!!), just bought a 20 year old 16 and am refurbishing it.

Sail # 21888

A section of 3/4" stainless all-thread would be a good idea but I found a used tap on eBay for ten bucks. (there is one more available if anyone else wants to do this). I have plenty of sockets and extensions. I'm sure I can find one to fit the shank of the tap. I'm thinking of wrapping the Delrin screw with teflon tape rather than using grease or anti-seize. I don't think grease lasts that long in salt water and anti-seize might eat into the plastic. Thanks for all the suggestions!!

Anti-seize will not eat the plastic, but I recommend silicone brake grease. It is designed to say put under very harsh conditions as it was designed to keep the sliders on your disk brakes moving.

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06 getaway -- always remember, man with both feet in mouth have no leg to stand on.

There was a good article with pictures by Gary Wilcox on "Rebuilding the Hobie Rudder Cam Assembly" in "On The Wire" April 1997 issue.

http://www.thebeachcats.com/OnTheWire/h ... ature2.htm

There also was a good article with pictures by Bill Mattson on "Raking Rudders" also in "On The Wire" May/June 1989 issue.

http://www.thebeachcats.com/OnTheWire/w ... ature3.htm

Another good article with pictures by David Hall on "Towards The "No Slop" Rudder" also in "On The Wire" March 1997 issue.

http://www.thebeachcats.com/OnTheWire/h ... ature1.htm


I used all three of these to rebuild my 1982 rudders last year and what a difference.

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Tim
82' H16
Sail # 88863
Panama City Beach, FL