Help Needed- Pyramid bow build along with an oak plank

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Help Needed- Pyramid bow build along with an oak plank

Postby cachelapoudre » Mon Nov 24, 2014 9:13 am

I've posted a couple of topics in the muzzleloader section and recently became interested in bow making.

I built my first bow, a long bow in red oak; 35 pounds @ 28 inches last month.

Being a black powder shooter I wanted to make a bow more fitting to the period so I can use it at our monthly shoots and rendezvous (1840-1860).

After reading Jim Hamm's Bows and Arrows of the North American Indians I decided on a pyramid style bow as shown in the book, 48 inches long and roughly 2 inches wide. I wanted to make a short bow, one more fitting to horseback shooting

DISCLAIMER: While I've stayed at many a Holiday Inn I am in no way an expert in bow making or working with wood. Plus, I know white oak is not the best wood to use but it is what I had so I thought I would use what was available.

So here goes:

I found an oak plank on the side of the road awhile back and it dawned on me I could make a bow based on the dimensions in the book (initially I was going to use the plank for something else). The board was probably a side rail for a bed since it had 1 X 1 strips stapled along the length of the board. Originally the plank was six feet long and I cut it to four feet long before decided to make a bow. I think if I had left the plank at six feet I would have be able to make a better bow. Nonetheless, 48 inches of white oak plank or board is what I decided to go with in making a pyramid bow with a convex or elliptical profile as shown in Hamm's book.

I marked off the lines with a five inch handle and fades 2 1/5 inches wide; I had read a wide fade allows for more flex. I think this may have been one of my problems. Perhaps those of you more familiar with this can tell me more.

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My tools were a sabre saw, clamps, a rasp, drill, a straight edge board which turned out not to be straight and a cabinet scraper. I outlined the shape of the bow and proceeded to cut a blank.
image

I tillered the belly side and thought I would be able to see some bend in the wood with some initial tillering but there was not movement. It took a great deal of tillering for finally see some movement in the wood. After much tillering I was able to get a bow shaped piece of wood. I also tillered the back from the center to the edges.

With the tiller post I discovered the inner portion of both limbs were not flexing. I continued to remove wood from the edges on both the belly and back of the bow and eventually developed a hinge in both limbs. As noted earlier, the wood plank was cut for furniture so it was basically a piece of wood. There are several areas on both limbs where there is a ring of hard wood which is harder to tiller down that the rest of the wood. I chased the hinge and even tried tillering in the wood closer to the center and the wood in the center portion still does not flex.


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Being a short bow I read an arrow should be half the length of the bow so I set an arrow length of 24 inches to be ideal for this bow, 48 inches in length with a nock to nock length of 46 inches. With the tillering stick at 16 inches the bow shows hinges and despite some agressive tillering in the center of the bow, the handle portion still does not move much.


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Plus, the bow now shows a significant set. This being typical "furniture-grade" white oak as well as on the side of the road for who knows how long, would this be typical of plank wood?


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I measured the following draw amounts after my last tiller:

@ 16 inches - 22 pounds
@ 17 inches - 25 pounds
@ 18 inches - 27 pounds

Brace was roughly four inches using three strands of cotton line.

I did not measure past 18 inches since I can make a 21 inch arrow to work with the 18 inch draw and don't want to break the bow. I would like to shoot a 24 inch arrow just to keep the proportions correct.

My questions for those of you more familiar with bowmaking are the following:

1. Why would the wood hinge where it did? I know oak, especially something as old and dry as this piece, may not be the best wood to use.
2. I believe I can leave the bow as it is using 21 inch arrows not to be drawn past 18 to 19 inches. Would the wood's set change?
3. If I back the bow with silk or linen would that help draw to 19 or 20 inches without breaking the bow? I would like to be able to shoot 24 inch arrows.
4. The widest part of the wood is currently 2.5 inches. If I trim it down to 2 inches would I see more flex near or in the handle?
5. Any other thing I can do to get the center to flex more so I can draw closer to 24 inches?
6. Would scalloping the edges towards the center help give the limbs more flex? I've seen bows from the Mississippi valley which were scalloped along the entire edge of each limb.

Keep in mind I started this exercise to see if I could make a pyramid bow with simple tools and practise my tillering. That part I am happy with. I am going to make some 21 inch arrows and see how they shoot with the bow.

At this point I have a bow that has not broken and that will shoot an 18 inch arrow and hit the target board. That, for me, is an accomplishment.

Suggestions are appreciated.

I believe the wood would benefit greatly from oiling; I don't want to stain or oil until I either lay a backing or do some final tillering, based on suggestions. Recommendation for better wood stock to make a pyramid bow are also appreciated.
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Re: Help Needed- Pyramid bow build along with an oak plank

Postby KsBow » Thu Nov 27, 2014 12:38 pm

I'll try to give some points for you to consider.
First thing right off. If you're going to make a short bow like this you want as much limb working as possible. I never make the handle more that 4" long on any bow I make. You have short fades which is good, but you lost a possible inch to the limbs by going with a 5 inch handle.
On to your questions. 1. Probably more stress out there because of less movement near handle.
2. Shouldn't
3. The materials mentioned would help, I don't know if they would do a lot to prevent failure.
Sinew or an 1/8th inch edge grain hickory backing would help and you could take some of the
follow out of the outer limbs.
4.Yes down to two inches would help. You've got a lot of wood near handle
5. Thinner near fades.
6. Maybe, I'm not sure on this one.
On future "short bow" projects, think about a bends in the handle design. I've made 48 inch bows by laminating bamboo and hickory, that bend in the handle. They shoot well, I'm pulling them to 24 inches. I have a picture of one with a turkey I killed. I'll try to find it.
Having a prob adding, will try in a separate post.
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Re: Help Needed- Pyramid bow build along with an oak plank

Postby Poggins » Sat Nov 29, 2014 7:14 am

One thing to consider on a pyramid style bow is the width taper down the limb is the tiller , any place in the limb that is thicker will be a stiff spot and any place that is thinner will be a hinge .
You are putting a lot of stress on one that short so backing it is wise .
As short as this is a bend through the handle would have given you more weight and less stress on the short limbs .
On your next pyramid keep the limbs the same thickness thier full length from fade to tip and that should help on the tiller .
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Re: Help Needed- Pyramid bow build along with an oak plank

Postby cachelapoudre » Sat Dec 13, 2014 5:14 pm

Thanks for the suggestions. Unfortunately I broke one of the limbs in the hinge area when I placed the bow on a table and put some pressure on the limb from the belly side. Given that I now have a very short bow with no flex in the handle I am still going to work the handle area to see if I can get some movement. That will help me understand how close to go to the handle.

KSBow, thanks for telling me the handle is too long. Next time I'll go four inches.

Poggins, I am going to see if I can get a bend in the handle.

I still have the center part and am going to glue two rectangular pieces of the same stock and see if I can get a low poundage Mollegabet out of this. If not, it's been a good exercise for me in cutting and shaping wood and I will try a flat bow first and then another pyramid, although I'll make it a bit longer first.

Thanks you all for your suggestions.
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Re: Help Needed- Pyramid bow build along with an oak plank

Postby George Tsoukalas » Sat Feb 28, 2015 9:54 am

Basically, it is hinging there or bending too much because that's the thinnest part of the limb. Too much wood removed there.
There are also a lot of grain run outs on one of the limbs (right). Not a good piece of wood.
You need straight grained stock.
There is a red oak buildalong on my site. I suggest a bend in the handle design you can change the dimensions I gave to 1 3/8" wide for 45-50# potentially. No glued on handle. No narrowing of the handle.
Same width of the handle out to a little mid limb narrowing to 1/2 in. nocks.
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