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An easier way to bend wood (like Beams, etc).

Hi Tony. Let me see if I can help you out. So notice that there is one more hold in the end of the swing arm than was necessary. If I now shift to that last hole, it would extend the block by one beam thickness and I would be cutting off a piece from the shorter piece of stock that you are referring to. That shorter piece of stock is only there as a solid base to which I can glue the actual piece of correctly-dimensioned stock from which I am cutting beams. There is just a small piece of curved beam stock remaining which is just noticeable as two short points extending from both ends of the block. To make more beams I would have to remove that bit of curved stock on the table saw to get a fresh new square gluing surface, then glue on another piece of beam stock and shift the arm back to the innermost pivot hole.

There are probably several ways that this could be built, but the concept is about putting stock at right angles on the end of a swing arm with a row of accurate pivot holes at the other end, and aligning everything so as to slice off curved beams exactly as you require them.

If it still doesn't make sense, let me know and I will glue a new piece of stock on there and cut another beam or two for the camera.
 
Thank you Jimmy, all is a bit clearer, no need to glue another piece on but how many beams can you cut from the one glueing? I'm glad that I now don't have to change my name. Regards, Tony
 
Jimmy said:
Thank you Donnie for starting this interesting discussion ! It looks like you only meant to share a beam-bending technique, but it turned into an elaborate exchange of ideas. This is one of the things I really appreciate about S.O.S. So here I go with some more ideas on this topic.

Of course in any given ship's deck, the difference in elevation between the crown of a beam and the ends of the beam (at the waterways) will usually decrease toward the bow and stern of the ship. But that doesn't necessarily mean that the actual curvature of the beams is changing. The change can merely be due to the fact that the beams are becoming shorter. And another factor, as jimmy stratos has pointed out already, the curve may or may not be even throughout each individual beam. So I like to analyze the drawings to determine whether the beam curvature is a RADIUS, or an OVAL (uneven) shape. If it is a radius or so close to being a radius that I could ignore any irregularities as possible drafting errors, then I will go through my set of drawings to see whether the radius is the same in most of the deck beams, or possibly all of them within a particular deck on that ship. If enough of the beams have that same radius, I will figure out exactly what the length of that radius is. Maybe someone on this forum knows a simple way to calculate that, but I just tape my drawing down on a table top and work with a movable pivot point and a tape measure until I get it.

So why am I so interested in radii? Because then I was able to build this simple bandsaw fixture to rapidly cut identical beams.

View attachment 154851View attachment 154852View attachment 154857

The fixture can be built out of relatively rough materials. The actual accuracy is entirely based upon 2 things. First the position of the pivot pin must be precise. The pin must be exactly at right angles to the teeth in the saw blade, and at exactly the distance from the blade as your deck beam radius. Note the pencil line in the first photo which is at right angles to the teeth. The other requirement is the distance between the pivot holes at the right end of the swinging arm. That distance must equal the thickness of the finished beam + the width of one saw kerf + an allowance for the sanding (both top and bottom of beam) needed to produce a smooth finished beam. I actually used a micrometer to measure the before-and-after-sanding thickness of a simple straight-cut piece of the same type of wood. Obviously you can get as accurate as you like with this.

I will go into more detail if anyone still has questions, but I think that once you get a basic understanding of this setup, any of you guys could certainly build a much nicer looking fixture than this one.
Click to expand...
Very clever idea :cool:
 
Thanks Tony. So the number of possible beams from one gluing is really only limited by how wide your available stock is. And if you have wider stock, you have to drill more pivot holes to accommodate it. I only lightly glued my stock with white glue. It only needed to dry for maybe 15 minutes to be strong enough to cut beams. The remnant could still be broken off fairly easily, and after a little scrub with sanding block, I glued the next piece. No problem to make one or two dozen beam blanks in less than an hour.
 
So I guess what your talking about is what I would call an Ark Swing Jig.

You swing the arm into the blade to cut the set ark into the beam wood, then move in one hole on swing to cut the beam to width. You say the width stays standard from end to end and multiple beams from cutting block before changing it to new block.
 
Kkonrath said:
So I guess what your talking about is what I would call an Ark Swing Jig.

You swing the arm into the blade to cut the set ark into the beam wood, then move in one hole on swing to cut the beam to width. You say the width stays standard from end to end and multiple beams from cutting block before changing it to new block.
Click to expand...
Finally, a simple explanation
 
ken s said:
Too complicated
Click to expand...
Really? You know the width (beam) and the height (rise in centre of deck) from your plans, press go and it tells you the length of the radius.

Or you can do it the hard way:-
radius = 0.5h + w x w
(divided by) 8h

Edited because I can't overcome the formatting for the equation!
 
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