Re: Strength of wood pin loaded in shear, 1 inch diameter Cumaru stronger then oak No idea. Re: Strength of wood pin loaded in shear, 1 inch diameter Cumaru stronger then oak Yes, that is the general idea. The tighter the tolerance on the dowels the harder it strengtn oak dowel shear strength 08 interchangeability of the pump parts. Regarding a dowel pin joint, the glue bond at the bottom of the dowel provides 80 percent of the total holding strength, with a spiral dowel, the sides provide 15 percent of the total strength, and 5 percent oak dowel shear strength 08 from the joint between the two core materials. The carpet had 3 inches of rain dumped on it, so today with the steaming heat and humidity was lousy place to work.

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These standards give hardness values but no indication of shear strengths or load capacities. I have estimated a shear capacity using a formula for hardness vs tensile strength but am not sure how accurate this is? Someone out there correct me if I am wrong but dowel pins are not designed to carry a load. They are strictly used for locating purposes. The load should be carried by a something else in an assembly, such as bolts or studs.

While a dowel pin may be able to physically carry a load there is no reason to publish this information because it is contrary to the design intent of the part.

I am using the dowels to locate two faces which are bolted together. In order to locate, the dowel hole clearance has to be less than the bolt clearance - I think the dowels therefore have to be capable of carrying the shear load on the joint. The result is that the bolts won't "see" any shear load. If the two parts were assembled without any bolts and only dowels then the dowel would see load, but the bolts are preventing the assembly from moving and therefore carrying any side load.

Essentially, the dowel pin itself must break or the wood around the pin must crush severely to get a shear failure. That is, shear strength of a doweled joint depends on the compression strength of the pieces holding the dowel, as it is the wood around the hole that fails lets the dowel pin move. As a dowel pin gets shorter, then there is less wood that has to be crushed in order for the dowel to move.

Unless the dowel pin is very weak itself, shear failure will not occur in the pin. Fourth, when two pieces are joined using side grain not end grain and the joint is made properly, this joint without dowels will be stronger in tensile strength than the wood itself. In other words, the wood will fail first and not the glue joint. Adding a dowel to this strong joint provides only a little 1 or 5 percent extra tensile strength to the joint.

Shortening the dowel's length in half would reduce the tensile strength provided by the dowel by about one-half. As the tensile strength provided by the dowel when gluing side grain is just a few percent, the loss will be quite small. Fifth, a dowel should not be used in lieu of forming a strong joint between the two mating surfaces.

Now to your specific question. I think that the end of a dowel provides essentially no strength to the dowel. Most commonly used wood adhesives do not have any strength when they bridge a gap over 0. So, the 80 percent number you quote is zero in my way of thinking. Second, considering the gluing of side grain, such as edge gluing of staves in a panel, the sides of the dowel provide all of the tensile strength for the dowel. However, the area of the dowel sides compared to the area of the joint between the two pieces is the important ratio.

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Thread Tools Show Printable Version. Strength of wood pin loaded in shear, 1 inch diameter Cumaru stronger then oak I am going to join a 4x8 to a 4x6 by drilling a hole and epoxying in a 1" dowel made from Cumaru. Dowel is maybe going to 7 or 8 inch long. Cumaru is almost IPE in strength.

The 2 boards are at 90 degrees to each other, to go where the rear stem an upright board meets the white oak keel. Will the Cumaru dowel be sufficient in strength? Egg Harbor had use steel pins and they were Oak Dowel Edmonton wasted.

So this time around going to use another idea. I got those bolts from an old crushed work boat, wish I had been able to get more but they were buried in wood. I am also threading a bronze rod to make a bolt to reinforce the joint on the inside, that bolt to run in center of keel and go vertical to another board I will glue and screw on the interior face of the 4x6. I can post more pics later of the project. Cutting threads into bronze works very easily.

Here are the various bolts. Corroding SS bolts, that was a waste of money, they are still usable for something that wont be so wet all the time with salt water. From 15 years use. Re: Strength of wood pin loaded in shear, 1 inch diameter Cumaru stronger then oak No idea. Re: Strength of wood pin loaded in shear, 1 inch diameter Cumaru stronger then oak I am cutting a roundish shaped piece from a board on the table saw. I will cut off the corner edges and grind it roundish, so will have room for glue.

It wont be perfect but will be functional The other idea is simply use the bronze carriage bolts as pins. Seems like a waste of good bolts if a piece of Cumaru wood can work instead. The current end hole in the keel will need to be drilled bigger to use a wood pin. I actually made it wrong, so it did not really drop in use, but it is going to be much stronger and lined up properly now.

The board and vertical through bolt I am adding will serve as additional support. I just finished threading 2 inches on the bronze rod. For the head end, I plan to heat with my oxy torch and squash it down. Those two pins are like indexing pins to keep the boards aligned. They are like huge nails, they dont offer any holding in power. The basic construction of the boat holds the two boards next to each other.

Re: Strength of wood pin loaded in shear, 1 inch diameter Cumaru stronger then oak On a boat it's a trennel. I am not familiar with the wood you propose but not all very strong woods are suitable.

For example, oak is not good here because the cell structure allows so much water uptake through the endgrain. You must have a wood that's strong and has a closed endgrain.

Best made of black locust and numerous trennel threads you can look up easily banged out. The standard rule is one inch diameter for every ' of waterline. The trennel and the hole need to be a tight fit.

The trennel hold by fit and friction, not glue. I use a bit of epoxy on the trennel banging it in because epoxy while wet is a terrific lubricant and that makes driving it home easier. Also, the epoxy seals the end grain exposed by the hole through the planking and frame. For that reason, I make my trennels with a little 'blood groove' to let both air and epoxy being compressed by hammering the trennel home escape. I would not use the furniture dowls illustrated at 2 because they are likely the wrong wood, the fit is problematic, and their design is glue dependent.

Also they are expensive. If you can't find how to very easily and quickly make trennels of whatever size you want with hand tools you no doubt have right at hand on one of the several existing threads, let me know and I'll go over it again. Re: Strength of wood pin loaded in shear, 1 inch diameter Cumaru stronger then oak Thanks. Cumaru is really strong and basically does not rot so it is like Locust.

These are functioning more like indexing pins side to side locators, not doing any holding in power. There is a lot of wood all around this that holds it in, the keel to rear upright stem boards together.

This is some wood left over from my worm shoe replacement. Re: Strength of wood pin loaded in shear, 1 inch diameter Cumaru stronger then oak Guy I know used cumaru to make a cockpit sole grating for his sailboat.

IIRC it was hard, and splintered a lot. He found it a bugger to work with, but it looked nice when finished. Re: Strength of wood pin loaded in shear, 1 inch diameter Cumaru stronger then oak You are joining a 4x8 to a 4x6 at a 90 degree angle? I think that is what knees are for.

Re: Strength of wood pin loaded in shear, 1 inch diameter Cumaru stronger then oak I recall Egg Harbor had used plywood as an angled brace on each side and had used two 2x8 nailed together for the upright board. Most of their transom work when I got the boat was rotten. So I redid it Oak Dowel Shear Strength Valve my own way, and it has mostly been fine, except for this area with those SS bolts. They also used plywood under thin Mahogany planks for the transom.

The things they did which I discovered when I rebuilt my boat, awful stuff designed for a short life. I am making a knee like design on the inside using that bronze bolt I am making and another piece of white oak on the inside of the upright.

Like a brace, will be screwed and glued to the upright stem board and the new bronze bolt pass through it and the keel. So will have the two wood pins and the interior brace.

Re: Strength of wood pin loaded in shear, 1 inch diameter Cumaru stronger then oak Okay , just an alignment thingy. Consider putting a square peg in a round hole , which allows lots of epoxy to lock it up.

This is the opposite thinking to Ian's trunnel , but this is not a trunnel , more of a corrosion free drift , if I understand it right.

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