Bow Demensions

[Badger]

        Just started working on a hickory stave a friend asked me to do for him. Going to be 70#@30" and 68" long. I roughed the bow out just to a heavy floor tiller as it still has a slightly high mc. Demensions I chose to start with are 1 7/8 near the fades, tapering to 1/2' tips from about mid limb. Tiller will be slightly elyptical. The bow still felt like a log in mass weight so I weighed it and it came in at 42 oz. According to my own projected mass theory a bow like this should come in around 26oz to 28 oz. This is a pretty comonly suggested demension for hickory. If I were to finish tillering the bow out at these demensions it would likely finish at around 36 oz and be a real sluggish bow as well as a terrible handshocker. I am going to take it back out this morning and reduce width a little and alos bring the floor tiller closer to the finsihed feel I should be feeling. At this next stage I will be looking for about 32 oz. Thats about 25% of the wood on the bow I have to remove. Will keep you posted on the progress. Steve

[Marc St Louis]

A little narrower sounds like the way to go Steve.

[michbowguy]

steve,
 i dont use the calculations as you do, but is it safe to say that if you are making a longer bow, and a heavier one , that with that length of limbs...am i assuming correctly that the handle wil be a non working one?

and if so do you figure that much weight of "non-working" bow into your figures?

jamie

[tom sawyer]

I made a hickory bow kind of like that.  Sluggish was how it shot.  I'd maybe start the width taper closer to the handle than halfway, maybe only run parallel for a third of the length.  I kind of like doing this on a lot of bows these days.  Maybe even go to a modified pyramid where you taper slightly for the first 1/3, then more on the outer 2/3.  Definitely "as skinny as possible" is the way to efficiency.  Does your model account for the longer draw?  68" isn't so long for a 30" draw, should be about right I'd think.

You should get some help mass-wise, from drying the bow out.  Hickory likes it real dry they say, and maybe its even a little wetter than you think.

[Justin Snyder]

His mass formula does account for draw and rigid handle. 
Steve, I will be watching this. I have one roughed out from dimensions I have heard over and over. It seems to me that it is rather large and bulky. I know I have seen some hickory that weren't that bulky.  Justin

[Badger]

Lenny, the way the formula works is that if you were to go right by the chart and have 8' stiff handle and fade you would need to make all bows with a arc of the circle tiller and a pyramid shaped limb. In reality we match the tiller to the front view of the bow. If a bow has paralell limbs the tiller will be elyptical, the formula is adjust by increasing the figure for stiff handle and fades, for instance on this bow I allow for 12" of handle and fades even though they are really 8", this is because 1/2 of each limb is paralell. If this same bow were a bend through the handle bow I would allow only 19 0z. Just some very basic logic goes into it, operates under the premise that the thickness of a limb determines how far the wood can bend and the width governs how far it will bend. Steve

[Rich Saffold]

Steve, the Santa Anas should drop the humidity some and shed some weight in addition to what you scrape off..I know where you live tends to be more humid than a few miles inland. This doesn't help with hickory .

Rich

[Woodland Roamer]

Steve, is this the stave that I sent Steve Quinton in trade for some snake skins? I'll be interested to see what you get out of it.

Alan

[Badger]

Alan, it probably is, sure is a nice stave, very dense wood. When did you cut it? My meter says 10% but I suspect it is a tad more than that.  I have it down to 31 oz now and as soon as it dries down to about 7% I will finish it up. Steve

[Woodland Roamer]

Steve, that was cut in June '07 if I remember correctly so it's been cut less than a year. I still have the other staves from that tree, I may have to start on one soon. Looking foward to seeing what you get from it.

Alan

[mullet]

   Steve, My first Hickory bow was almost the same demensions. It ended up at 68# at 28". It felt like a log. But shot very fast and had good cast. But when the humidity got high , it got sluggish and shot like a 55# bow. Still not bad for hunting. I've had the bow on scales with different humidity and it has run from 52# to 73#. I think, IMO, That it wouldn't hurt to leave some extra meat on a Hickory bow where the humidity fluctuates.

[Badger]

Eddie around here the mc of wood usually goes between 7% and 8% not horrible, actually pretty good for mullberry. I have it down to about 32 oz now and plan to finish it at 28 oz. If the moisture is too high it will likely take some set, when I am sure it is below 10 I may seal the back and heat the limbs up a bit to dry them out.

[Sidewinder]

Badger, I find this post very interesting. You are obviously a pretty smart guy to figure all that out. I like the hickory stick I made pretty well, my greatest concern has been what I heard about hickory and moisture. This formula you have? Is it posted somewhere? When you have time could you expound on it or put it in a format so that us "non-Einstiens" can get a grasp on it. I can see value in understanding this. I would appreciate it.    Danny

[Gordon]

1 7/8" seems a little wide for a hickory bow of that length.

[Badger]

I finished the bow up today, the guy wanted it a bit heavier so I finished it at 80#@30", came in at 29 oz, has about 1/2" string follow and goes back to even after resting. Finished width is 1 3/4".

Danny, if you have excel on your computer I will e email you the formula in the form of a calculator, you just punch in the numbers and it gives you the answer. There are a few things to know to make it work for you. I built 4 bows this week using the mass formula on all of them, I use it on every bow now.
Right now I am working on an elb, bamboo backed mora. 69" long to be 50#@28". A full arc of the circle tiller per this formula only allows 14 oz for the bow. Roughed out the bow is almost 20 oz just sitting, demensions are as narrow as I can possibly go without loosing stability so I have to use the tiller shape to allow for higher mass. In this case I will keep the center 14" semi stiff and this will allow me to use a 7" figure for stiff handle and fade raising the target mass up to about 19 oz. Ane then I take off about another 10% for backed bows so I should be able to finish it at 17 oz. Steve