black locust build

[Yourpaldan]

I was at the lumber yard yesterday and I found a great piece of black locust for only $12. It's enough to get at least one bow from, possibly two if I'm very lucky. It's got nice straight grain but it's only 36 in Long, so I'll have to splice the billets.

The first thing I did was to split the board into billets. I figured this would be the best way to make sure that I was following the natural grain Direction along the length of the limb. Then I cut off a little piece that's 18 in long and a half inch square. I did this so I could set up an experiment that I saw from the book the Traditional Bowyer's Bible.

Basically the test involves bending a sample of your wood, and measuring how much you pull it, by weight. The important things are to know how far you bent it before it took a quarter inch of set, and also at what weight that was, and how far it would bend before breaking. With this sample of locust it had to bend 3 and 1/2 in before it took a quarter inch of set, and that was at 25 pounds. I heard a crack at 6 in of bend, but it didn't snap even went around to 7. According to the book this tells me that I should make my bow limbs an inch and a quarter wide, but maybe I'll go a little more just to be safe.

Now that I have a design for the bow, I started to chase a growth ring down the back of the bow. There were two knots on one limb that I had to be careful to work around leaving a little extra material for now at least. This is my first time chasing a ring, and my first time working with Locust. I have to say that I loved it! The locust was such a pleasure to work with. The late wood is so smooth and hard that the scraper won't go through it just glides along the surface. But the early wood is so spongy that the scraper takes it right off. Spoke shave and draw knife worked well to remove layers of late wood before coming at it with the scraper.  I was switching tools a lot.

Next thing I'll do is to draw the outline of the limb on the back of the bow oriented along the grain, and start removing belly wood. I'd like to get the two limbs floor tillered before I splice them together. I'm thinking of doing the riser in 2 parts to add strength to the splice, a  thin riser section on the back, and another on the belly of the bow, sandwiching the splice on both faces.

The sawmill specializes in exotics, and has a scrap bin with cheap cutoffs.  Was able to get some riser size cuts of koa, Gabon ebony for nocks and accents, and a plank of port orford Cedar for arrows.  3 dozen shafts worth.

[Roy from Pa]

You posted a thumbnail picture, which is fine.

After you select your picture from your PC or phone, just to the right of the little window where the picture name appears, click ( Insert Attachment 1 ). That will make the picture full size in your post.

[George Tsoukalas]

Are you making a selfbow? Are you planning to back it?

The grain is not good. It waves and runs off the face. Also the presence of a knot can be fatal because you leaving wood around is difficult on a board.

If you chase a ring how much thickness will you have left?

As I found to about 3 years into my bow making journey good wood is a must.
Jawge

[Yourpaldan]

Thanks Roy... I changed it.

George:  only 1 knot is on working part of limb.  But I've seen people build bows with knots, so just I have to learn how.  I figure if I wait for perfect wood then ill never get anything made!  But why is it more difficult to leave wood around a knot in this wood, then if I was working from a log?  The limb is 1/2" wider than I need, so can't I just cut a bulge in the edge following the grain lines, as they swerve around the knot? 

As far as the runoff... The way I split pieces off, along the grain, left billets with no runoff that I can see.  Unless I'm missing something major?  The one limb I worked has about 3/4" thickness beneath one uninterrupted growth ring.  I'm trying not to back it, but maybe I should? I have some rawhide and linen, and I just made hide glue from rawhide scraps.

[George Tsoukalas]

Dan, it is difficult to leave wood around a knot when it is in board form. It ends up getting violated.

Typically the knotted part needs to be left wider. When tillering, let the knotted portion not bend as much as the rest of the limb.

I had a little tiny pin knot in  a hickory board that ended up breaking the bow.

It is tough finding good boards but they are there.

I usually stick with red oak boards. Straight grained tip to tip with may be a run out or 2 only.

Just be careful.

Jawge

[Yourpaldan]

Spliced the billets, and added riser block to belly and back side to strengthen the splice.
I think the back growth ring is not violated.
I tillered to 40# at 28".  Still not perfect. Bottom bends too much, and both limbs appear to bend more right in the middle.

I'm going to sinew the back to add draw weight and remove the 1.5" set. Hopefully protect the back as well.  Suppose I ought to heat treat the belly first.
As the sinew dries, should I try to induce reflex with weights or backwards bracing?

[BMorv]

Yourplan,
I like your setup and your enthusiasm.  I really think you have down the basics and could be good at this with a little guidance. 
I hope you don't take this the wrong way, but I wish I would have said this on your 1st build:

-Your riser is too long.  You have a relatively long riser then long fades before you get to working limb.   Too much of your length is being taken up by that riser and fades.  You can do that with a glass bow, but not with all wood. 
-All of your bend is happening mid limb.  This puts too much stress on too small of a working area and hence the set issues.
-Your outer limbs are too stiff and carry too much mass.  Once again this is putting all of the pressure on the mid limb. 

Sorry to say but I think you should work on getting your inner and outer limbs working and practice your tiller on this one without worrying about the weight.  Heat treating is usually done at floor tiller or around 20".  It doesn't fix set either, those fibers are broken for good.  It just strengthens the good fibers around it.  I wouldn't spend time with all of that until your tiller comes around more. 

Can you post un-braced pics and a pic of the width profile?   

-Ben
 
 

[Yourpaldan]

Thanks Ben,

I think that's just what I needed to hear.  I tend to run into things head first.
So here's the pics u asked for.  Its 1.5" wide throughout all of the working limbs.  There's a little curve at each tip, but they cancel each other out and the string is centered at the handle.

Its 66" long, and 11" of that is riser, so I guess I can remove some riser and lengthen the working inner limbs? And should i narrow the limbs more on the outer section to remove mass? Or should I tiller them to get them bending more?
Ill take your advise, and if it becomes too low weight, ill give it to my cat to shoot some mice.  She's a better archer than me anyway.

[BMorv]

The unbraced profile gives you an indication of where the bow is taking set, and as suspected, it's taking all of the set in the mid limbs right after your long fades end.  Your bottom limb is hinged right past that knot on the back.  Can you see how much the thickness changes right there?  It's a challenge to get even thickness with a wavy piece like that. 
I would try and get more of that area right after your riser to start working some ie the area between your glued on riser and that knot (while not touching the mid limbs where the set is taking place).  That's a good 2" of working area on both sides that you aren't really using.  So you have around a 15" dead spot although your riser is only 11".   
Are you using a tillering gizmo?  I would use that as your guide on the outers to get more of that working too.  The gizmo would have picked up those heavy bends mid limb too early in the game.  Eric Krewson just posted a new video on it's use, if you haven't checked it out. 
I wouldn't mess with the width right now. 
     
 

[Yourpaldan]

Okay yes I see what you're talking about. So I was able to get another 3 in of Bend on each inner limb. But I'm having trouble on the outer limbs yes, because it seems like they're really thin and I can bend them with my hands, but when I put it on this tree they look completely straight? And I can't believe I didn't know about the tillering Gizmo... This thing would have been so helpful!

[BMorv]

Yeah the Gizmo is great. 
Since you added reflex to the tips that area will look flat, and you can't use the gizmo in the traditional sense there.  You are more looking for a gradual change in the gap.  I usually leave my tips stiff, about 6-7".  Reflexed tips can be hard to judge.  I normally trust that my thickness taper is correct and I don't mess with that area.  Or you have to rely on experience and knowing how much that area should flex.  Anyway, it adds an extra level of complexity for someone just starting out.   

[BMorv]

Even saying that about the reflexed tips, you have some area before the reflex that is stiff that you can work with the gizmo.  Around these areas....
 

[Yourpaldan]

Ok here's what I've got now.  I may have gone too fast, again!  Its better than before, but now are the inner limbs too weak? This is messing with my brain!

At 30" (I'm pretty tall) it pulls 35 lbs.
I'm looking at the string angle now, and realizing that this bow is way too short, and its probably stacking. Also the right limb is the upper, and it looks stronger than the left to me. So now I'm wondering if I can get it to an acceptable tiller, it may be around 30 lb. If I sinew back it that may give me some weight back. Or is this this bow too far gone to be worth it?

  I've already glued up my next bow. Bamboo locust tri lam, with a tapered walnut core.

[BMorv]

It does look better than before.  The area right past the fade is a little tricky too.  You can't use the gizmo there.  You more or less have to develop an eye for how much it needs to bend.  It's probably bending more than it should but you really needed to get more working limb, so I think you did the best you could.

I didn't realize you had a 30" draw! You REALLY need to maximize your working limbs especially when your design is based off of a 28" draw.  When you read about designs, you should automatically add +2" to the length and about 1/4" to the width.  If you want to push the limits and make shorter bows, make sure you thickness taper and material selection is near perfect.  Even then if they call for a 12" riser, I would make mine 10" to get more working limb.  I learned all of this the hard way.  I too have a long draw and all of my 1st bows took 2"+ inches of set, mostly because they were designed for a 28" draw (and because my tiller wasn't good). 

Draw a vertical line on your tiller tree where you intend to pull your string from.  Your pull hook will sway toward the stronger limb.  Very easy to read.  Make the hook tote the line and your bow is balanced.  Read some of Bowjunkie's post on his tiller method if you are more interested. 

I have never used sinew so I can't help you there. 

That should be an interesting tri lam.  Just eyeing it, your belly looks much too thick to start with.  Depending on layout and other details, I can normally get any weight I want out of a total thickness of .550"

I'm not an expert.  I've been doing this for 3 years.  I'm just trying to help you avoid the mistakes I've made.  I've made a lot!