how to recuve tips

[Blacktail]

just wondering what you guys use to recuve tips of bows.i got some old ply wood that is 1 1/8 thick and was wondering if it would work for a jig.and how do you go about getting a certain degree that you want.thanks john

[Justin Snyder]

If its ply wood I wouldn't use it.  When you steam the wood to wrap it around the form it will damage the back of the bow since you cannot get plywood smooth.  I use a pine 2X6 cut on the radius I want then sanded smooth.  Justin

[radius]

You can get plywood pretty smooth.  My recurve forms are made of construction grade 3/4 " plywood (3 lams thick, so 2.25 inches thick in all), and they are just fine.  Don't damage the back at all.   I like plywood better than dimension lumber because it doesn't warp over time the way lumber often will.  Just cut the forms with a jigsaw and then hit them with a smooth file.  When bending the stave or laminations into the form, you can always put a very thin strip of hardwood between the stave and the form, to protect the back, the same way you use a strip across the belly fibers to protect them from lifting up.

As for the arc:

Make your form, for explanations sake we will say it's like mine:  plywood, 6 inches deep.  make it several inches longer than the bows you plan to make in it, because you want to cut out an arc but leave a solid chunk of material on the outboard side.  This is for wedging the laminations into place. 

Now, say you want a 3 inch recurve (I mean, you want the tip of the bow 3" from the straight part of the bow).  Make a mark 3" down from the top of the form.  Square it up to the top of the form, for reference.

Now, say you want the tip to travel across 3" to get to straight.  Measure back (toward the handle of the bow) 3" from the square reference mark you just made.  Square this down and make a mark at 3". 

NOW...set the tip of your compass at the mark you just made, and align the tip of the pencil with the first mark.  Swing the arc up to the top of the form.   That is the shape of your recurve.  You need to make the opening an inch wide or so, so move the tip of your pencil 1" away from the handle region, and swing the same arc again, parallel to the first.

No problem.  IT's easier to do than to describe.

This is just an example, and I'm not exactly sure these are the numbers I used.  But you see the thinking involved, and I think you can handle it no sweat.

Scott

[radius]

you can also just use a lid from a peanut butter jar, and eye it up til you like it!

[GregB]

Radius, any chance you could post a picture of yours? 

I'll try and remember to have Pappy post pictures of the ones we have on his Life is Good thread Monday.

[Justin Snyder]

Radius, you can get edge of particle board or OSB pretty smooth, but not the edge of plywood. They are entirely different. 

[Ryano]

Justin, I have bow forms made of several pieces of plywood glued together and they work fine. Never had a problem yet.

[cowboy]

This is a simple little jig that I've seen on here before - so I made one. Just cut a 2x6 the radius ya want and notch out for a clamp up front. I screwed a peice of shipping strap to the bottom where the tip of the bow will go. Steam the part you want to bend for about 45 minutes, stick the tip between strap and form, clamp bow to strap, bend away and clamp the bow to the form and let cool - repeat other limb. Here's a pic, maybe you can see what I've just described.

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[majsnuff]

I like the shipping strap idea of Cowboy's. Think I will incorporate it into my caul.
Thanx

[adb]

I agree with Scott & Ryan. I made a recurve form from 3 layers of 3/4" plywood, glued together, and then shaped to desired curve. No problems with damage to the back of the bow. Actually, all my forms (straight, reflex, R/D) are all made from plywood, with no problems. Plywood is much more stable, and holds it's shape without warping or checking. I made all my forms from a single sheet of 3/4" plywood, so it's cheap too. I cover the face of the form with clear packing tape... to make it smoother, and to keep the glue residue off. You can change the tape, without having to sand the form.

[Dano]

I think what Justin is saying is that plywood due to it's nature, the difference in wood in the laminatons, you'll always get inconsistant density in the surface. I use a solid piece of doug fir, it works. Now if ya laminate a piece of formica or hardwood on the surface of the plywood you got a good caul, but unless your in production, I don't see the need.

[radius]

I guess the real point here is that either plywood or lumber will work:  cut the shape, give yourself room for attaching a clamp, and start making your bows.

I like the one Cowboy showed just there.  Looks like the arc is twice as long as it is deep...very graceful. 

One solid idea for making recurve forms is to get some mdf and make a template.  You can attach this template temporarily to the face of a new form and use it to guide a router with a pattern bit .  That way, if your form gets damaged somehow over time, it will be easy to replicate. 

You can also use different arcs on opposite ends of the same form, no problem, if it is long enough.

One easy way to recurve tips when gluing together laminated bows is simply to place the gluey staves on a flat form, belly down, and place a block (you can vary the heights from bow to bow, to see what you like best) under the very tips.  Then you clamp it down, approximately 8" from the tip, and presto!  Instant recurve.

[sailordad]

One easy way to recurve tips when gluing together laminated bows is simply to place the gluey staves on a flat form, belly down, and place a block (you can vary the heights from bow to bow, to see what you like best) under the very tips.  Then you clamp it down, approximately 8" from the tip, and presto!  Instant recurve.



yup radius, your onto something there,works great.  mt newest bow that i've started is  a laminated bow,not really recurved but reflex/deflex and thats how i did it

clamped the glued up mess in a form,and then cooked it in the heat box for 4 hrs and let cool,and wha la pretty looking curves,just like the wifes


                                                                            tim

[radius]

heatbox, eh?  I've never used one of those.  You're talking aout the r/d KIT your wife bought you?

[sailordad]

yup thats the one