Thimbles For Galvanized Rig

[trofast]

After reading "The Complete Rigger's Apprentice", I decided to splice 1/4" 7x7 galvanized wire for most of the rig on my Cape Dory 28. My knowledge is limited, so I thought I would turn to the community with a couple questions:

It has been suggested to increase the thimble size 1/16" over the wire size. i.e. 1/4" wire = 5/16" thimble. Is this common or good practice?

With galvanized wire, it is my understanding that I will need either galvanized or stainless thimbles. I found these cast, closed end 304 stainless thimbles online. Has anyone used these and will the square bottom be a problem?
http://www.uscargocontrol.com/Riggin...himbles-SS-304

Thanks,
Jonathan Hilbert
Baltimore, MD

[Brion Toss]

Happy Every Holiday,
You can use stainless, bronze, or galvanized thimbles. The only limitation is that the thimble fits into the turnbuckle jaws, and most modern turnbuckles have narrow jaws, which means you need solid bronze thimbles if you hope to have service (thus a thicker thimble), especially on 7x7, which is bigger than the 1x19 that the turnbuckles are designed around. I hope that makes some sense. Anyway, the extra 1/16" or so is to make room for the service. Blue Wave has the widest jaws that I know of in stainless.
The square bottom is a very important, very good thing. It makes for a stronger thimble, and one that you can serve/seize up to cleanly.
Fair Leads,
Brion Toss

[trofast]

Brion, thank you for answering my questions. I will use 1/4" thimbles with 1/4" wire, as I do not plan on having service and I'll try treating the rigging and turnbuckles periodically with Lanocote or anhydrous lanolin and see how it goes.

As you suggested in your great book, I will use jaw-and-eye turnbuckles (galvanized) that can accommodate the thimbles. I have already replaced the internal chainplates with 3/8" x 1.5" external bars, that I hope will hold up to the wear of a shackle pin. I still need to upgrade the hardware on the mast to tangs with pins.

Jonathan

[Brion Toss]

Hi again,
You might consider going up on the thimble size anyway, just to get a stronger thimble; unless they are solid thimbles they will tend to deform otherwise...
Fair leads,
Brion Toss