Wanna Make a Straight (Hill?) Longbow

[arachnid]

Hi Guys.

I want to make a straight longbow and need some directions. I`ve only built R/D bows until now, so I have a few questions:

1) What should I use as the form (I`m using inner tubes)? I guess a straight board would be enough as a form?

2) I`m planning to make it 66" long (I`m a short guy). I`ve seen hill bows go up to 72" long. So, is 66" too short?

3) How long should I make the riser? I`ve read that it`s between 15-16" but I want to be sure.

4) Stack..... is there a list of stacks for a straight longbow? I need a starting point (I`m planning to go light... 30#)

That`s all folks...
Thanks in advance

Dor

[skeaterbait]

I can only speak from my own experience.  

To date a straight bow is the only glass bow I have made and I did it on a rubberband form that was nothing more than a 2x8 that I ran over a jointer and drilled for dowels.

As far as stack, you can down load the Bingham Kits sheet for stack thickness' on their kits. It's a good starting point.

[Forwardhandle]

Get a hold of a book called the American long bow by Stephen Graff  it has all the info you asked and then some great book easy to read strait forward covers stack thickness , form building , Etc . and its only $17  There are some chapters on save the earth type stuff, but the meat of bow building is there and then some !

[Forwardhandle]

[jsweka]

My answers to your questions:

1.  A straight board could work, but I'd be afraid of it warping with repeated heating and cooling in a hot box.  A plywood form would be better.

2.  66" is not too short - especially if you have < 28" draw length.

3.  15 - 16" will work.  I make mine 16", but that is on the long side for this style of bow.

4.  Lot's of variables here.  If I wanted to make a 30# 66" bow, here's what I would do.
- 16" riser
- 0.410 total stack with 0.050 glass and 0.005 total taper rate in the laminations
- Width of the bow would be 1 1/8" for 14" from the center of the bow out each limb, then it tapers to 1/2" at the string grooves.

[mikkekeswick]

I agree with jsweka a plain board is likely to warp. Birch ply is the best but make sure it is dry before gluing it up. I cut my ply to size then let it sit in the hotbox for a few days. It won't move then.

[arachnid]

Thanks guys.

A few more:

1) Should I use a tip wedge? if so, how thick/long? if not- why?

2) should I use a power lam? if so, how thick/long? if not- why?

3) Whould a 0.003" taper work for a straight longbow?

Thanks

[Forwardhandle]

I have never made a glass long bow but Im curently reading Graf's book on HH style long bows  for a 66 in. bow he recomends a 3 lam core total taper 0.006 with a 17 in. riser no power lam but uses tip wedges & adds about 2 in. of form reflex !

[arachnid]

Does he explain why such a high taper rate?

[kennym]

I’m not a hill bow guy but with narrower bows you need more taper in the lams be cause you have less side taper in limbs

Just think 1 3/4” down to 1/2 inch compared to 1 1/8 “ down to 1/2” at tips .

[monterey]

.004 to .006 is typical of Hill style.  It's apparently what he has found to work with his overall design parameters.

[Forwardhandle]

Graf says that he has experimented with different tapers and found it best for his design with the lower limb being 2 in. shorter then the top his tiller pics in the book look spot on ,  I'm going to make a  R/D bow for my first but this book is a really good source for HH style bows and a easer read then Jack Harrison's book  it has most of the answers your asking !

[arachnid]

Originally posted by kennym:
I’m not a hill bow guy but with narrower bows you need more taper in the lams be cause you have less side taper in limbs

Just think 1 3/4” down to 1/2 inch compared to 1 1/8 “ down to 1/2” at tips .

Makes sense.... So 2 0.003 tapered lams should give me a 0.006 taper, right?

[kennym]

Yep, one thing to consider tho if your riser back is straight and you put the .003s in=der it on the form, glue a couple .003s to the form with thin end to center so your riser fits right.

Or I guess you could parallel the tapers out to riser ends, but I think the first option would be easier.

the .003 tapers may be stiff enough to give trouble upo the riser ramps if you run them on the belly.

[monterey]

Heed Kenny's advice reference the tapers on the form under the stack.  You can get away with taping them if your form will retain them in position.

Not using them and shaping the riser back is also a good option but will require some fine tuning to the riser.

The use of tapers that match the flat back might be a bit formidable if you don't have the necessary experience grinding the tapers but I'll wager that Kenny could grind them!  

[Forwardhandle]

I dont want to put out the wrong info ,but in graffs book he does use a power lams he didnt state it tell later in the book he didnt list the wedges or power lams tell deep in the book he also uses non standard lams for the upper limbs grinding them by hand using sanding stix from standard lams , he also uses pine boards for the form saying there more stable then ply wood  I never herd that before !

[monterey]

JMO, but with such a steep taper a power lam probably isn't necessary.  I started one out to build 1.5 at the fades and 5/16 at the tips with total .002 taper but the lay up squirmmed so much in the form that it ended up at 1.125 at the fades.  That bow has taken some set at the fades.  Still a shootable bow but it could have been better!

And again, JMO, but with that much taper a tip wedge might keep it from being more whip tipped than desired.

[Forwardhandle]

He had another recepe in there for a Hill style follow bow strait limb 1.25 fade to 0.75in. ,10 in. out from the tips then to 3/8 , that one had a total taper of 0.002  said it took 5/8 in. set. One fade made longer & the riser set 1 in. off center said it had little shock !

[arachnid]

So I went ahead and built a straight longbow. 66" long, 1 1/8" wide, drawing 34#@28", 15" riser, 0.006" total taper. BUT, I didn`t even got to shoot it once. I made a string and pulled the bow a few times and then CRACK- I got a little de-lam under the lower fade (between the first and second lams):

   

other side
 https://scontent.fsdv2-1.fna.fbcdn.net/v/t1.0-9/26804393_10210711589016817_3493276792687846925_n.jpg?oh=e3d76d8c5cde3bfa2ceccc79f5ebdbad&oe=5AEAB23A

I used enough glue, had good glue lines. My guess is that it`s a design flaw since it`s probably bending too much near the fade. Might be too short of a fade OR I should have used a power lam.

I`ll be greatful if you guys give me some input and opinions on what do you think went wrong.
If it`s fixable- I`d like to save it.
And at any case- what to do differently the next time around.

Thanks
Dor

[Bvas]

I would say fade thickness was definitely a contributing factor. I try to follow close to kenny’s rule.
1/16”@1” and 1/8”@2”. And the the ends of your fades should be THINNER THAN PAPER. You should be able to hold the riser up to a light and see daylight thru the tips of the fades.