Synthetic Rigging deadeye and turnbuckle alternatives

[stormsails84]

I need to replace my stainless rigging on my 39' Colin Archer cutter sailboat. Originally I was going replace most of my rigging with galvanized but now I am really leaning towards synthetic. The only problem with synthetic is the 18 50$ deadeyes I would need to buy just to do the shrouds. I wanted to design something myself that I can build on the dock. Here's a picture of a very rough design.

You might have to use your imagination a bit. The flat bar would be bent to be the same thickness as the thimble then expand out to fit a clevis pin or bolt to wrap the seizing around. Might use some spacers or washers to keep the seizing from binding up on itself also.

My worries are that this design doesn't have enough friction to use regular seizing techniques.

[msponer]

I don't know about friction and deadeyes.

Do you have access to a table saw and a drill press? If you do, I think you could make something very similar to the commercial dead eyes out of aluminum flat bars. I don't know what dimensions you need, but I sketched a quick guess -- that the deadeyes would be about 2" thick, 4" wide, and 5" long, leads to a price of about $15/each in materials.

I can draw this for you, but if you are interested, the operations would be pretty easy, with no special tools necessary at any point. Use the table saw to make a slot down the length of the bar, wide and deep enough for your thimbles and chainplates. Then chop the bar into squares. Use the drill press to make holes for your clevis's, then for the lashings. Then use a counter sink bit and round file to make a nice radius on the lashing holes. Or maybe a router bit would be better.

If you can get a hold of a miter saw and grinder, you could even make the teardrop shape of the commercial dead eyes pretty easily. With a vise and some careful jigging to limit the cut depth, you could even use a miter saw instead of a table saw. You could buy some cheap 1/8" flat bar to use in the vise to incrementally move each piece sideways in the vice, as you cut out the 1" slot (or whatever) for the chainplates and thimbles to fit inside. But this would be a lot more work than just doing it all at once on a table saw.

I won't even pretend to do the engineering to make sure this is 'right', but I think a good place to start is with the same size and materials as the commercial ones. Then, if you are paranoid, price how much it would add to increase the thickness by 1/2" or whatever. It's not magic -- they are probably starting with the same piece of aluminum and sticking it in a CNC mill.

[msponer]

Oh, or comments on your design, I don't like the 'bending the flat bar out to expand to the size of the lashings' -- my main problem with this is how hard it will be to drill the holes so they line up in each pair of flat bars after you bend them. This could easily be a failure in my imagination, but I can't think of a way to do this so the holes line up without a jig that would be a whole lot of work. I don't know how much weaker it is if the clevis is askew in the pair of flat bars, and it doesn't feel right to have that risk in the implementation.

It's a whole lot easier to line up all the holes if the flat bar is not bent. But the problem with non-bent bars is, depending on how much you were going to bend them, is that increases the length of the clevis's through the chainplates. 9 long clevis's could be expensive, and if they are weirdly long, not as strong as shorter ones. Since the force is at the ends.

So, sorry, don't know.

[stormsails84]

Ok new design. I like your idea Msponer, is this what you mean? I did a quick rough drawing.

[msponer]

Yes! Exactly that.

Though those dimensions are smaller than I guessed, so your drawing looks to only be about ~$3/each in materials. To be conservative with aluminum, I'd make sure the area of any cross section is 1.5-2x the area in steel of the clevis or chainplate. I haven't done the math (who knew moonshine was legal in Portland?!), but it looks about right with the 1" thick piece in your drawing, but maybe consider going 1.5 or 2" thick, just to be way overboard for only $3 more per piece.

Keep in mind that if you want it to look super duper, and have the time, it's inexpensive to mail small pieces like that off somewhere to be anodized. Or even do it yourself in a bucket if you are feeling super nerdy and want to spend hours learning an obscure new skill. That will help with corrosion with the stainless pieces it touches. Read on the Internet about prepping it -- clean, nicely sanded, surfaces, and etc. Or just slather on lanocote and cut thin sheets of plastic to isolate it as much as you can.

There's a lot about this on the Internet, but if you haven't cut aluminum before -- it works great with normal wood blades. Use plenty of lube (wax, WD-40, etc) and take shallow enough cuts that the piece doesn't get too hot. If it gets warm to the touch, let it cool down before taking the next pas. With aluminum, when it gets hot it tends to stick to the blade and gum it up. The special (expensive) aluminum blades are slightly better since they have a more aggressive angle and resist getting gummed up, but they aren't necessary for low volume parts runs like this, where you can just take your time with a wood blade. Drilling it is no problem, easier than stainless since it is softer and doesn't work harden.

I'm interested in how it goes for you, what you decide and what it looks like in the end, so please keep in touch.

[phstol]

I like your workaround to the expensive parts. I see that you have an aluminum hull so presumably you have looked at the issue of work hardening of your fabricated turnbuckles?
I believe that this would lead to failure = breaking, in time, with no warning or visible precursor to the failure.
Would be interested your thoughts on this, maybe I'm wrong.
Other than broken turnbuckles, may you always sail with fair winds and empty holding tanks .... .

[Delancey]

Why reinvent the wheel? Not sure where the OP is located. In the states Black Locust has been traditionally used for deadeyes. Very, very hard wood with excellent rot resistance. Fairly inexpensive. Just a thought.

[Delancey]

http://www.cruisersforum.com/forums/...yes-41461.html

[msponer]

Originally Posted by phstol

... presumably you have looked at the issue of work hardening of your fabricated turnbuckles?

Nope! I am not a mechanical engineer and haven't touched a calculator in weeks. I was just throwing out some papers from college and can't even read the funny symbols.

So yes, these could easily be missing a critical design detail, a carefully engineered radius or little nub of metal in just the right spot, that the $50 aluminum dead eyes have.

[mikereed100]

$900 for terminals on a 39' boat doesn't sound like all that much in boat terms. After all, this is what keeps the mast up. I don't think you will be able to come up will a workable alternative that will be as functional as the commercial offerings and save you money at the same time. The deadeye in your drawing would work, but leaves sharp corners at all the holes. When you factor in all the work you will have to do to do it right (18 times) $50 per starts to sound pretty economical. I think the wooden ones suggested by Delancey would look awesome on your boat!

[stormsails84]

So I've had some more time to think about the last drawing for deadeyes. Comparing my drawing to the commercially available ones, the biggest flaw I see is the fact that the line isn't wrapped around the deadeye, so if the aluminum breaks the splice doesn't still hold your shrouds together. So I'm pretty much building one of these and using it everywhere instead of just the chainplates.


Chainplate Distributor, 3/4", Black; CSS62.5 - Colligo Marine - Synthetic Rigging

[msponer]

Yes -- I think your second drawing is better (and less expensive) than the 1st. But not as good for the top as the commercial ones with an integrated thimble.

I can't think of a good way to make the integrated thimble kind with tools typically in a garage or on a dock. I think the teardrop shape is probably the best, which would be easy on a mill (a manual one with a rotary table or a CNC mill). So all you need is $2k for a small CNC mill and you can start saving money.

You could price having a water jet cutting shop cut the teardrops out for you. Then drill the holes for the lashings yourself (or have the water jet folks cut these for you, for more cost), round out the lashing holes, and use a router to cut the channel around the outside edge to be the thimble.

I've never used a router this way and don't know how well it would work, to cut a deep U shaped channel into ~3/4 or 1" aluminum. Maybe it would smoothly cut a beautiful groove like butter, and maybe it would kick back and make a ragged mess. I don't know.

Oh -- the waterjet place may charge less (or even be more willing to give you a quote) if you can give them a 2D CAD file (DXF) of the shape you want cut. Since this is such a small job and most places software can just eat a DXF, nest it, and make a job or estimate. It looks like your using SketchUp, and when I last used it (~4 years ago), it was actually raster, and not vector, which doesn't work for machining. There are open source CAD programs, or even some vector drawing programs work well (my wife has drawn complicated things in InkScape that then load pretty effortlessly into our CNC mill).