Large toggle bolts for 3"x 8" split lumber


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Old 11-05-20, 10:52 AM
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Large toggle bolts for 3"x 8" split lumber

I work on a marina and some of the Walers that are split. Unfortunately, do to the length of the boards - 24' - and how the dock is constructed, we can't easily remove the piece and replace it like we can on the other parts of the dock as this particular board is on a main walkway and would require a lot of structural components to be removed.

I'm wondering if someone makes a larger version of a toggle bolt - like what is used for dry wall anchoring - but what would work in this application.

My idea is that I'd drill a vertical hole through the board - passing through the two split pieces - and then inserting this bolt. Tightening it would join the split pieces.

Alternatively I thought of just using bolts with large flat washers but there are locations where I wouldn't be able to reach to the underside of the board to thread on a nut.

Attached is a picture from the internet with a quick ink illustration of what I'm talking about. The diagram is on the outer edge of the dock but would actually be going through the board closest to the concrete - I made a little red circle indicating the location.


 
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Old 11-05-20, 11:01 AM
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Carriage bolts are my first thought. Their broad rounded head is easier on bare feet and they are commonly available and relatively inexpensive. I would get creative with ways to attach a nut on the bottom in difficult locations.

I really don't like toggle bolts especially for your application. Ones with a single barrel shaped toggle on the end would probably be the best choice. The two arm type require a huge hole in the wood to accommodate the folding wings so you really weaken the timber. Also, neither type is very strong in relation to the bolt size. The tiny pins for hinge is a real limit. And, small fussy bits and thin metal in a marine environment is the definition of corrosion and short life.
 
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Old 11-05-20, 01:40 PM
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Hey PD,

Yeah I considered the large hole needed for the wings, as you say.

There is also water pipes running underneath so I had considered carriage bolts but using the head on a large washer on the underside and the threaded portion coming up the top. Cutting off the excess thread, applying a rubber coating to offer some protection for feet and painting it Caution Yellow.
 
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Old 11-05-20, 03:20 PM
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Toggle bolts are out for sea air work. They won't last a year.

I'm not following what you are doing. I see three stacked +/- 2"x10"'s. Then I see you drew a circle on the thin edge of the board.... Are you replacing one of those boards ?

I'm trying to figure out if you drill long ways thru the wood.... what is there to catch ?
 
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Old 12-05-20, 03:28 PM
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PJ - I didn't see your reply.

The drawing is on the outer edge for illustration purposes but the bolt would actually be going through (vertically down) the board closest to the concrete - indicated with the little circle.

The reason is that that board has split horizontally around where the center holes are where the thru-rods run through.

These lengths are up to 24' and it is not that easy to replace that whole length. So my thinking was to put a bolt through the board, vertically down, so it can be tightened and joint those two separating pieces. Does that make sense?
 
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Old 12-05-20, 03:53 PM
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Drilling all the way thru width wise may encourage splitting but if do try it the only thing that I think would be effective is stainless steel threaded rod, stainless washers and stainless nuts. I know you said you can't always get to the bottom to put a nut on but that looks be the only way that will work.
 
 

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