Originally posted by LittleBen:
Originally posted by macbow:
Very nice Ben.
Would like to see a formula for the bow. Like the design.
I can give you the basic rundown of what I do. If you want stack thicknesses I will have to go measure later.
3 lams, 1.5" wide, all lams are tapered at .002"; always hickory back, almost always Ipe belly, core of whatever I've got, I'm not picky although I like walnut. Use a lot of hickory core because I have a ton of it not suitable for backing and I've been too lazy to grind new walnut lams.
12" riser block sandwiched between the backing and the core lam. So from back to belly it goes backing, riser, core, belly. Then a glued on handle block maybe 10" or whatever looks right.
Typically I keep the limbs nearly parallel to ~2/3 then taper to tips. Typically a hair under 1/2" wide. You can obviously go as narrow as you dare. I use the side taper as the first means for tillering. I only belly tiller if I need to after side tilllering. I find the .006" total taper gets me close enough that side tillering, trapping the back, and rounding the corners usually gets the tiller done. It's pretty cool to get a wood bow off the form, cut a front profile, round the corners, quick floor tiller check, and go basically right to a low brace. It's very very quick to tiller a bow glued up like this. The work is all upfront making good lams.
Stack thickness at the fades runs from around .400" for around 35#@28" to .500" at the fades for 60#@28".
The downsides: little bit of handshock. These bows are definately wider than need be, but I do that purposely so that they are not likely to be damaged from overdrawing. I have used this design at 67" long for 65# @ 31" without failure or too much set. Walnut core helps with the handshock too.
Tend not to be the absolute fastest for my shorter draw. The longer bows don't typically top 150fps @ 10gpp and my short draw of under 26". Shorter versions have hit 160, but I prefer longer.
Tend to be a little loud for a wood bow, they end up with a relatively wide flat limb, and it resonates a lot like a glass bow limb does, but I also shoot 3 under which seems to always be louder.
I don't have a printout of the form, but it's nothing special, just a typical R/D form with some blocks for flipping the tips.
I hope that gets at some of what you were looking for. If not just ask specifically, I have no secrets left to keep about my approaches. [/b]
Thanks for posting your details! The profile looks pretty good on your bows, but it would be nice (as Kenny pointed out) to see full draw pictures.
I was about to make another trilam and I was thinking about a "forward handle" design with a bit of wood on the belly as a means to make the handle "fuller"... what I had in mind is exactly what you posted, so I'm glad someone else has done it before me! It'll be a hickory-osage-ipe trilam with a purpleheart riser and a figured maple belly handle extension.
As for your tapers, while I'll still be following a more "standard" thickness design (probably 1 1/8" wide, with the hickory being 1/8" throughout, the osage tapering from 1/8" at the fade to 1/16" at the tip, and starting with 1/4" of ipe throughout and tillering the ipe), it's neat to see your formula work. I might try it in the future, but instead of using a narrower starting point (as an attempt to get a little more performance/less hand shock from the bow), I think I will try using the same dimensions but using a belly material that's not as dense as ipe (maybe yellowheart/satinwood or yew).
Besides all that, nice work and great work space! Best wishes to you with juggling bow making with work and being a father. Also, I hope you are able to make a serious attempt out of those yew billets you posted!
Topic: Quick shop tour, and some bows ... (Read 1175 times)
