Stuck Cam Tensioner Screw repair...

Hello Hobie sailors,
Have you ever battled with a stuck plunger adjustment screw? I get older Hobies that come into the shop for this repair all of the time. I've tried heating up the casting, digging them out with a screwdriver, and all sorts of other ways. Check out this cool tool that my friend Dan came up with for taking care of it in about 2 minutes. You can buy all of these parts at a machine shop or a good hardware store.
http://www.surfcitycatamarans.com/plungerscrew

Good Luck!

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I used a screwdriver and hammer and broke them to pieces finally getting them out with a lot of work:)
The problem now is that the thread in the rudder casting is a bit corroded and broken...even with lubrication screwing new plugers in is a nightmare
They are rock solid...
Any ideas? thanks

Go to your local machine shop and ask them to run a 3/4-10 tap in there and clean out the threads. That's your best bet. Check out the link in my original post, there are a few pictures you might find useful.

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Jeremy: I was not able to find a "reverse cutter". Perhaps you could
provide a link to a webpage with one of these.

Not having the best tool for the job, I attempted to make the repair using
alternative methods. The hot screwdriver did not work, the screw was
too brittle. Optimism turned to desparation, but I did manage to remove
the screw successfully. The method I used will probably not work in all
cases. Jeremy's method is preferable.

Very simply, I used a 1/2" drill and drilled from the top. It drilled through
the plunger, passed through the spring, and bit into the delrin screw. It
came our fairly easily.

Had the screw been wedged in there a little tighter, I probably would have
simply drilled a nice big hole in the screw and the screw would still be in
there. So Jeremy's method is better.

I'll look to see where I got it. Could you find a standard direction cutter? That works as well. The only reason that I use a reverse cutter is to hopefully back out the stuck screw. It works about 50% of the time. Usually I end up just cutting the whole thing out anyway. I'll see what I can find!

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Reverse cut drill bits are available at Sears Hardware stores as part of what is called an easy out kit. They are also available from high end tool companies such as Snap On, Matco, Cornwell, etc. I have not looked but I suspect Northern Tool and Supply probably has them as well. There is also probably hoards of them online, think automotive tools when you are looking, this is what their initial market was.

This is actually a reverse cutter head, not a drill. it makes a flat cut. I suppose a drill would work, bit it would be difficult to keep it centered, which is a critical part of the operation.

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I have done it with a wood bit. The center of a wood bit is a spike and fits right in the center of the screw. Pick one just a bit smaller than the screw itself. Usually they have long shanks too. Go slow as the bit can chatter on the screw slot, but man... that works great and fast. Pick the excess material out of the threads, tap and bang... done.

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Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

Spade bit.

Here's what my friend Dan Peake sent me today. He's the mastermind behind this awesome invention. Dan owns a business called Peake Research and put this together after hearing me gripe about it in his machine shop. I can't tell you how much time this saves. I used to turn this job down when customers would come into the shop. I worked for 2 hours on a set of castings one time. This is definitely the easiest way to deal with the situation. The initial commitment is worth it. There are many ways to do it, but hands down this is the best! Thanks again Dan.

Here's the source (I had to dig through old reciepts)

http://www.mscdirect.com

09937319 .625 X .250 reverse spot-facer
71003164 .250 X 12" Drill bit
06000160 .250 X 12" drill rod (used as an arbor)

Note that the hardened spot facer needs to be cut while kept relatively
cool (not easy, unless you have a surface grinder and a spin-jig like I
do)

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Try this one:
http://www1.mscdirect.com/CGI/N2DRVSH?P ... 0009267953

Hey Dan, if you're out there you should weigh in. I don't know what I'm talking about. I just know how to use the tool

You should put a few together and sell em to us. Who wants one?

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Matt and Karl: Yes. A wood spade bit would work well enough. I realized that yesterday when I was in Home Depot. If only I had thought of that at the time...

Jeremy: Thanks for the info. I am sure that will be helpful to our fellow Hobie-ists. When I went to specialty tool shops asking for a "reverse cutter",
I just got funny looks. Now I know what to look for. Thanks.

As for myself, I did sucessfully complete the repair using my sub-optimal
method. I feel lucky that the screw came out instead of just making a
large hole in it.

How tight should the new screw be? It seems to want to be roughly flush
with the bottom of the hole. The previous owner had this pretty deep and
very tight. The cams were almost impossible to budge!

I considered using a spade bit, but it lacked the ability to remain centered, I felt the risk to the casting was too great. If there was a spade bit with a round pilot, that would work nicely.

When Jeremy called me the other day asking for part numbers I had a heck of a time re-tracing my path to the parts I used! In other words, I agree with you that these are hard to find!

See the pdf I wrote for Jeremey when I donated cutter to Fleet 240 and Surf City Catamarans (my local fleet & dealer). Jeremey, I'll have a 2nd copy ready for you next week.

http://www.peakeresearch.com/misc/CAMEX3.PDF

Building this thing was a simple affair, except for clearing the hole through the center of the cutter. The cutter comes with an obstructing keyed arbor-retaining detail inside the .250 thru hole which can not be drilled out, so you need to cut off the section of the cutter that has the key detail in it. If you have a way to spin the 5/8" cutter, while using a dremel with a cut-off disc, you might be able to do it. Once that is done, you can silver-solder, or heliarc the cutter to the 12" drill blank.

Everything else is self explanatory. Tip: use a 12 inch long 1/2" drive socket extention to extend the 3/4 10 tap to allow room to get a tap handle on it. I felt that trying to turn the tap using a wrench inside the casting "D" was a recipe for cross threading.

If you do not have the ability to cut the cutter, and/or weld the cutter to the 12" drill blank, there is another route which will probably work just as well, but does require that you remove the cam, plunger and spring. Using the same cutter, and it's mating arbor 00428151 (which has the coresponding key detail to mate to the cutter): prep the cam screw by drilling the .250 pilot hole through the Cam screw; assemble the cutter and arbor; feed the arbor (long end) through the cam screw from the BOTTOM until the cutter is in contact with the bottom of the cam screw; Apply the drill motor to the end of the arbor that is sticking up out of the casting; run the drill in reverse pulling the reverse spot facing cutter up as it cuts through the cam screw; clear remaining cam screw remnants with the 3/4-10 tap.

I much prefer my original way; it literally takes less than 7 minutes per side, requiring no disassembly of the rudder system.

Peace,

Dan Peake
2003 H17 SE
Campbell, CA

It might help to look for a left hand end mill instead of a reverse cutter. You may find the prices in http://www.mcmaster.com (McMaster-Carr) a bit better. Same thing and you usually don't have to pay tax either. You will be able to find all of the machining tools you need there too.

Be careful with easy out kits. I have had to do more repairs to engine blocks and other large parts that someone tried to use easy outs on. Your best bet is to drill out (slightly undersized) the delrin screw with a regular old drill bit, a spade bit, or an end mill - whichever you prefer. The run a 3/4"-10 tap through it. Get a taper type tap as it will be easier to cut with and will definitely remove the screw. These will have a point on the end and not be flat. When you drill the hole out make sure the drill is no larger than a 41/64". A 20/32" will give you more room so you have less of a change of hitting the threads.

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Nick

Current Boat
In the market
Previous boats owned
'74 Pearson 30
'84 H16
'82 H18 Magnum
St. Louis, MO

McMaster Carr is wonderful, but it generally has higher prices than MSC. MSC is a machine tool catalog, where Mcmaster has everything from drill-bits to tampon dispensers. BTW, Cheapest, by far is is www.use-enco.com

Using an endmill is NOT a workable solution.

Financially:
A 5/8" forward cutting endmill will cost more than the reverse spot-facer I specified and used. A reverse 5/8" endmill will cost more yet. And a 5/8" endmill with a 12" shank is simply not made.

Mechanically:
There is no practical way to chuck the 5/8" endmill on an extension in order to apply it to the surface being cut. Typical hand drill chucks accept a shank of upto .375", some .500, but the bore needed to allow tapping is .625, which requires a .625 end-mill, which has a .625 shank. To grab and spin a .625 end mill, you will need to spend a lot of money on a large chuck, and then find a way to adapt and extend it to your Dewalt or Makita.

Have you ever tried to use an endmill on a hand drill? There is no way to keep it centered - try it, and you will destroy the casting. My bet is that you will seriously injure yourself in an attempt to keep it centered.

Why did I design it with reverse cutting? You don't want to screw IN the old cam-screw if it comes loose during the boring process. If that happens it might screw it deeper into the casting than the 3/4-10 tap can reach, so you've made your problem worse (possibly unable to tap out the remnant).

News:
This project just became MUCH more DIY. Yesterday, in making a replacement cutter for Jeremy / Surf City Catamarans, I eliminated the difficult cutting of the hardened spot facer. I went to Home Depot and picked up a 3/16" diameter chain-saw blade sharpening/grinding bit for my dremel, spent about 5 minutes grinding; completely clearing the bore detail of the spot facer! (before, I had used my $15k surface grinder to cut off the end of the spot facer.) This leaves the DIY'er with one final challenge; welding the spot facer to the drill rod (metal welding solder from HD might work, but I haven't tried it. I tig welded mine)

Best,

Dan Peake
2003 H17 SE
Campbell, CA