What are the possible causes of set.

[Don Drake]

I have been learning on osage staves that are not completely cured and assumed that this is the reason for the set in my bows.  I was just reading Jawge's web site and he mentioned humidity could give a bow a permanent set.  I live on the Outer Banks of North Carolina and the humidity is very high (like 90%).  Could the climate here be a contributing factor.

The stave for my current project was cut in 2009.

[PEARL DRUMS]

If they arent dry you will get excessive set. Too short, too narrow, poor tiller, too much early weight during tillering, high humidity on unsealed bows and of course set happens some no matter who ya' is. If it was cut in 2009 your in good shape. Get the bow floor tillered well before you even bend the limbs on the tree, that always helps.

[Shaun]

In order of most likely:

1. Wood not dry.

2. Pulled past visible flaw during tillering.

3. Pulled past final draw weight/length during tillering.

It takes about one year per inch of thickness to dry a stave. A roughed out bow blank can dry in a few months. "Seeing" a flaw in tiller is a learned skill and becomes much more obvious with practice. The last one is easier to avoid.

All wood will take some set while tillering. If you want a straight or reflex profile to your finished bow you need to induce some backset before going past floor tiller stage - about 1.5" backset for osage = straight finished.

[razorback]

I got 2" of set on a recent oak board bow. Good tiller and real careful pulling to weight and length. No reflex induced so I puting mine done to the wood and my humid basement. Could also have been me, but I doubt it  

[Don Drake]

To induce some backset, do I heat the bow and bend the limbs backward?  Should I use a form for that?

[PEARL DRUMS]

Don do you have the Bowyers Bibles by chance? The second one shows a simple "press" that is used to induce reflex after steaming. I use a 72" caul that has 3" of reflex. The shorter the bow the lesser the reflex. I reflex every single bow I build unless it has enough naturally. Most end up straight, or with an inch of set at most.

[Don Drake]

Pearl,  yes I do have that book.  I will take a look at it.  Thanks.

[SEMO_HUNTER]

Don, it depends on if your using a single stave or a bow with a backing like bamboo on osage. Just like the other guys have said already wood that's not completely dry (osage in particular) will take set. Just from my experience with the bamboo backed bows I've made so far I have glued in reflex to all of them and when it's all said and done, I'm lucky if it retains half the amount I put into it. That just seems to be par for the course, so I guess you could call it taking set, or tillering out the reflex I put into it.......6 of one, half dozen of another? At least by inducing some reflex to begin with, if you lose half of it after tillering your still ahead of the game and haven't gone past the zero point. Just don't get carried away with trying to reflex it too much or it's a bugger to tiller.

[Don Drake]

So far, I have made only osage self-bows, no backing, no laminations.  I am really impressed however with bowyers who do that.

If I understand correctly, aside from the pride factor   :D , the only real problem with set is a reduction in bow weight, maybe arrow speed?  My third bow is for a nine-year old who has a draw length of 19".  The bow is 44" ntn, has a 4" set when unbraced and shoots 30# @ 20".  Its actually going to be easier for him to string since the bow is nearly at brace height when unbraced   :eek:   !!!

Both of the bows I shoot are at 65# and 75#, so I don't mind if they get a little weaker.

I would love to able to get this next bow fairly straight though.  So we'll see.

[PEARL DRUMS]

A 65# bow with excessive set CAN be slower than a 50# bow that stays straight, or close to it. Draw weight doesnt make up for set. Let that osage stash dry out Don. You will be glad you did.

[Art B]

Like Shaun mentioned, you're wood isn't dry enough. Or more specifically, it's moisture content is to high. Around 8% is good for most woods in my opinion. Hickory a little drier of course.

Jumping right in from a stave/board to a working bow is seldom a good idea. A good course of action is to rough the bow out, store horizontally for a week or two in the proper condintions that'll produce the 8% M/C you want. This could be in a hot box or in your house. Around 70-75 degrees and between 40-45 R/H will assure proper M/C. Work on your bow sparing during these hot and humid conditions......Art

[Don Drake]

The current project is roughed out and standing on its end in the TV room.  I guess I should move it into the attic and lay it flat.

[PEARL DRUMS]

Lay it flat for certain. Art turned me on to something that never crossed my mind. If its left standing up the moisture "runs" to one end. It makes sense to me. If your house has AC you could also lay it under your bed to dry. It wont take long.

[Art B]

Attics get too hot Don. And due to the nature of osage, not a good idea. By using a cheap and simple temp/humidity monitor you can achieve proper M/C in you house in a week or two for a roughed out bow. Like Pearly mentioned, it won't take long, especially for wood that's been cut for a while. For example, and from experience, I know that a  fresh cut/roughed-out hickory bow will dry enough to heat treat without any drying checks in 30 days under the conditions mentioned above......Art

[Don Drake]

I just bought a moisture meter from a national dig store for a Lowe price of $30.  I tested it on two staves which were cut and pollied around march.  It says 7.2%.  Can that be correct?

[Art B]

For that price it's got to be a prong/pin type. Good for checking the moisture on the outside of your bow/stave Don. But little else IMO! I've got one that's been in my drawer for years now. Never use it. Monitoring R/H and temperature is a much better method......Art