Adding Rope Clutch to Mast

[LIsailor]

I want to make a base plate for a double rope clutch or should I just mount two.
Any recommendations on base blare material and procedure of how to create the mast profile?

[Charlie]

LIsailor it is a difficult question to answer without knowing the profile of the mast. I have single clutches on my boat and the bases are all nylon so I don't have to worry about dissimilar metal corrosion. I drill and tap the holes then mount them. A real nice tool for doing this is the self centering drill bit Drills, Drivers, & Bits | Bits-Woodworking | Self-Centering Hinge Bit (No. 8 & 10 Screws) | B249572 - GlobalIndustrial.com I tap the first hole. Then use the self centering bit to find the exact location for the second hole. It has not failed me yet. BTW I know nothing about this company it is just an example of the tool.

[LIsailor]

Thanks Charlie for the info. That bit looks great.
My question to clarify was really about the base plate. The mast is a decent size and the shape, while curved, is close to flat.
As an example, I was considering using a piece of ipe (iron wood), cutting the profile to on side using multiple passes on a table saw at different blade heights to make the profile. then sanding to cleanup the curve.
I was curious if anyone had another or better approach. Or a source for some sort of universal plate for clutches. I have found one for winches.

[pressuredrop]

i am going to make epoxy bases from the winches on my mast, i intend to do it as follows:

-wrap mast in visqueen or 1 layer of thin plastic, maybe an 18" section so i can make a big blank and cut out a few bases
-make dams out of cardboard, plastic, anything handy on the 4 sides, tape them to the mast/plastic
-mix up some epoxy, mix in cabosil, pour in the half section mold...
-pop piece off of mast and mark the templates on the flat top surface.
-cut and install pieces...

same will work for a rope clutch...

[sailnautilus]

Mount clutches directly on the mast, drill and tap holes and seal with tef-gel to prevent corrosion between mast and fasteners.

Wood is not advisable- you are inserting a softer material between two metal objects that you essentially want to weld together.
Fair winds!!!

[LIsailor]

Sailnautilus
Good point about the wood. Partly why I was considering ipe beyond it's high resistance to rot (like teak but harder)

Which brings me to:
PressureDrop
Great idea! Duh. I've recored decks, vacuum bagged, an many other glass/resin based projects. Why didn't I think of that? On top of that I presently have my mast horizontal. Perfect.
One thing I'd add or consider. Maybe add some chopped glass to the mixture to make it a little more solid. To fight the pulling stresses the screw pressure will cause against the curved surface.
Thanks!

[hpeer]

I just did this.

I got some 1/4" aluminium sheet and some 3" channel.

I cut the channel to the length of the jammers, they were 3" wide so that worked.

I cut the plate to the right length and about 8" wide then bent it to the profile of the mast using a hydraulic conduit bender.

I cut the channel down so that it sat on the crown of the bend and welded it to the plate.

This gave me a flat surface for the jammers about a 1/2" higher than normal.

I tapped the aluminum channel and plate to connect the jammers.

I used a rivet with an internal thread to put threads in the mast.

I screwed the whole shegan to the mast.

My thought is that this will reinforce the mast rather than weaken it.

No pics but I can post some next week if you are interested.

You just have to promise to not laugh at my Shreck welds.

Shreck = strong but ugly.

[Brazil]

I would consider using starbord. If the curve is not much a table belt sander is a good option to give the shape. Harbor freight has it cheap.

[osirissail]

If you can find this style tap, it is the best for tapping aluminum. Be sure to use cutting fluid, which for aluminum is cutting oil and water.
- - As "sailnautilus" posted use "Tefgel" or a similar product "Lanacote" on the threads of your machine screws (bolts) when installing them in the mast.

[CarlF]

It's usually stronger to mount directly to the mast and minimize the length of screw that is subject to a bending force.

I just drill, tap and use plenty of tef-gel. I also cut a piece of UMWH tape to the shape of the hardware base plus 1/8". This stops electrolysis (if the hardware is stainless) and also protects any mast paint from tiny scratches that give water a chance to work in.

Amazon.com: UHMW SLICK TAPE - 3" X 36" BY PEACHTREE WOODWORKING PW1117: Everything Else

Carl

[Weyalan]

If drilling and tapping the mast I'd advise using helicoil inserts to reduce the chance of stripping the threads in the (relatively soft) aluminium. Always use an appropriate anti-corrosion compound wherever you are putting stainless steel in contact with aluminium - Duralac or similar.

[LIsailor]

There is a great deal on a pair of Spinlock XAS single clutches. I have decided to go with 2 singles. I was originally looking to go with XTS but I think the XAS would be more than sufficient for my purpose. The boat is a 1985 Sabre 36. Am I wrong?

[LIsailor]

I am having trouble differentiating the difference between the XAS and XTS other than maximum working load.

[osirissail]

The load factor is the difference. The XTS series is heavier and stronger than the XAS series. If you have a small boat your line loads are normally smaller and you don't need the heavier, beefier XTS. On a larger boat the line load are considerably higher so using a XAS would be risking possible failure of the unit, which is something you don't need when out in a blow.

[LIsailor]

Just got a great deal on 2 XCS clutches. Thanks for all the input.