Hobie Cat Forums

I found another relatively cheap gadget I am going to use to set the rudder release tension. Over the holidays I was in a luggage store and saw a product used for picking up and weighing suitcases prior to check in at the airport to avoid excess baggage charges. It is a dial tension meter calibrated zero to 50 lbs. It has a handle on top and a big hook on the bottom of the dial. You hook the suitcase handle, lift and read the dial. I'll just clip the hook onto the rudder leading edge, pull and adjust the delrin screw for proper kick up.

...I'd think you'd want at least 20 to 25 pounds, or else they'd be kicking up in a big blow?

_________________
Sheet In...Max Out
www.fleet297.org
sailflatlands at gmail dot com

From "Hobie Trailing and sail guide":

Hobie Cat rudder blades
are preset to break away
from the locked down
position at 17-26 pounds by
testing with a line around the
rudder blade seven inches
above the lowest tip of the
blade. Once the rake is
changed, the breakaway
tension should be
rechecked. The tension may
be adjusted by turning the
3/4" internal screw in the
housing. The screw tensions
an internal spring. Turn it
clockwise to increase
and counter clockwise
to decrease the tension.

17 to 26lbs @ 7" from tip....I'm on it. ':D'

The two methods here for removing the Delrin screw seem a bit risky. Drilling a 3/8" hole and chiseling the remains out with a hammer or threading a coping saw through the screw (although very clever) might damage the threads of the casting. Having just completed this I can say for certain that using the 5/8" wood bore and drilling slowly was ideal for removing 95% of the plastic screw and none of the metal. The remaining plastic threads virtually fell out of the casting with no sawing or chipping.

I, too had the same issue. I used a combination of the heated screw driver method and drilling the old screw out to remove mine. It was not fun.

HOWEVER...Once you have the screws out, I used the same method that is described in the link sunvista posted to keep them operating with no issues.

I purchased a 1/2 in bolt with the same thread pattern. The bolt, made of hardened steel, is much harder than the aluminum castings. Rather than WD-40, I put a bit of grease on it and threaded it into the slot where the delrin screws go. I think the grease will last longer than WD-40. Only after this, I put in thew delrin screws. This accomlished three things.

1. It cleaned out any junk left over in the threads.
2. It helped correct any damage I did to the threads. Little nicks and bent edges that might catch on the delrin screws. The bolt's thread are stronger and this seems to clean them up nicely.
3. The grease got into the threads and helped keep them lubricated making it easier the next time I needed to remove them

Since doing this, I have not had any issues. When winterizing my boat or setting it up in the spring, I now will remove the screw, insert the bolt with a spot of new grease and replace the screw. Never had an issue since!

I hope that helps folks.

Andrej

I'm sure this will work in some cases but I don't think I would have tried it. I received my 3/4" x 10 tap today. My 1982 salt water threads were SEVERELY oxidized to the point where the original thread cuts were barely visible. It took me twenty minutes of working the tap back and forth with cutting oil to do each casting. A steel bolt might have easily cross threaded in and ruined the castings.

Hey sunvista,

Sounds like yours were in much worse shape than my 1982 and later 1984 boats, so the tap is probably a better option for you.

I did make a mistake, I typed that I used a 1/2" bolt, when in actuality, it was a 3/4" x 10 bolt.

The bolt still does a good job maintaining those threads and might serve you well now that you have cut your new threads.

60's this weekend in Virginia! Is spring just around the corner???? (wishing so, but not so naive!)

Yeah, I hope so. The 40 degree Bay water temperature is not exactly inviting. Death by pitch pole.

I've got to fix a stuck tension screw too. This doesn't look too difficult, but I've never used a tap before, in fact, I don't even know what one's for. I'd appreciate it if someone can clue me in as to what the tap's function is regarding delrin screw removal.

Thanks,

_________________
Mark Van Doren
Division 9 Chairman
H20 #647
H14 #47787
H16 #112205

A Tap is a tool that's used to cut female threads into a piece of material (as opposed to a Die which is used to cut male threads onto a piece of material).

So you would use a drill to drill out the frozen screw from your rudder casting. The drill diameter needs to be less than the inside diameter of the threads inside the casting (ie., you don't want to drill out the threads). Then you use the tap to clean the remaining plastic screw material from the casting threads.

To properly use a tap, you want to go slowly and back the tap out frequently. As a general rule of thumb, turn the tap one full turn then back out 1/2 turn and repeat. This is the case when cutting new threads, for just cleaning out threads, you may be able to do more than one turn. Lubrication helps too.

sm

Some good ideas in this thread. It should be made a "sticky".

_________________
'88 Nationals Blue
Hobie Alter Signature Model
Sail #11

Hobie Mirage Classic

I always just melted them with a propane torch. You're going to change the cam anyway, so leave that off so it won't deform. Heat the casting outside-fumes are deadly, when there is a little breeze. Have the hole vertical so some plastic can drip out. Move the torch and don't try to heat it too fast. You can coke the anodizing before the screw gets hot if you dont' move it around and let the heat get to the screw by conduction. Once anything at all drips out the screw will be soft enough to jam a big junk screwdriver in it and it will come right out. I'd never put a drill bit in there.

I made a low tech tap out of a long grade 5 bolt. With a 6" fine cut flat file, cut the cutting notches into the threads from fairly deep at the tip to nothing 2 or 3 inches up the bolt. Cut two "taps". One on one side with the cutting edge perpendicular to the circumference for cutting on the way in and the other one to cut on the way back out. Push a little pressure on the way in, and pull a little pressure on the way out. Mine is probably still around here somewhere but I used it for a decade without having to redo the cutting threads. I could probably make a new one quicker than I can find the original. You're just cutting aluminum, so I never saw the need to buy a dedicated tap.

Never-Sieze on the new screw and it will always come back out.

Better yet... vise the casting and heat a long (big) blade screw driver. Melt it into the screw like a branding iron. Then turn with a vise grip on the driver shaft.

But, I like drilling them out... its easier and no fumes.

_________________
Matt Miller
Director of Parts and Accessory Sales
Hobie Cat USA

When you replace make sure to use a good lubricant on all threads and Cam/plunger.
http://beachcatsaustralia.ning.com/