Primitive Archer
Main Discussion Area => Bows => Topic started by: Sidewinder on April 11, 2009, 09:26:52 pm
-
Being a novice bowyer I have not graduated to characeter staves and ones with twist. I have only worked with fairly easy ones in terms of knots and none with twist. I have a good thick and long piece of 3-4 yr old cured osage that has some twist but is straight vertically and no knots. My question is, " when I lay it out, how do I compensate for the twist in layout and how does it efffect my approach to tiller?
Thanks in advance. Danny
-
Lay out the centerline following the longitudal grain...wherever it goes.
Then measure the width from that line, ignoring the twist. I would lay it out around 1/4" wider than I intend for the bow to be to allow for scraping shaping, and finishing the sides down to final width. Once the bow is layed out and floor tillered a little, straighten the twist out with dry heat and tiller as usual.
-
Excellent advice from Saw-Filer. This may help you.
http://georgeandjoni.home.comcast.net/~georgeandjoni/layout.html
Also see Aerobow.
Jawge
-
Thanks you guys, thats what I needed to hear.
I will check that out George, thanks for sharing. Danny
-
all excellent advice, when i finaly understood the longitudenal grain, was when i read TBB-4's cha
pter on character bows. it tells how to identify said grain. it helped me alot when i built this bow
(http://i528.photobucket.com/albums/dd326/evldwrf/bow010-1.jpg)
-
Nice bow evldwrf, what is the length? it looks like a shorty. I may have to go back and read that chapter. Danny
-
Great timing for this question...as I too am struggling with the same issue. I hope that adding another question isn't hijacking - if so, mods please delete this.
I've got a freshly cut stave, still green. I want to reduce it to 2.5" wide and general bow shapes to set it up to dry. It's species is yet to be confirmed, but I think it's an ash Brandon Elm - yet another victim from a car-tree collision on a boulevard here in the city.
Peeled all the bark last night and was trying to locate the grain. I can see very small striations in the surface of the wood, but they twist all over the place. Is this really the grain, or just an "imprint" of the bark? does that make sense? When I split the log, it really didn't snake all over the place....
...any suggestions?
D
-
D,
Feel free to post the pic so we can look at it. The mods will not care if I don't. Its all a big happy family around here.
Danny
-
Danny,
I just tried to take a few photos to show the 'striations' but it just doesn't show up that well....in fact, it's even harder to see the lines now then it was a couple of days ago.
I guess my question really is, for those of you whom have worked with elm, is the growth of the bark (ie twisty) indicative of the grain of the underlying stave? If so, then I have a stave with almost a 90 twist to it.
I will try to rough out a bow, let it dry, tiller it and will then shape the handle to point at the string, per TBB. Either way, fail or pass, it's a good exercise in learning.
thanks.
D
-
(http://home.comcast.net/~dcm4/pwpimages/we5.JPG)
Winged elm.
Yes, generally if the bark is spiral so will be the tree. But you can do a great deal with green wet elm. Reduce it carefully, you want consistant thickness throughout so it won't have stiff spots which hold shape easier. Then put the reverse twist on that mother. You got about 3 days after you reduce where you can really make some shape. After a week you can take it down. After another week you can start to force dry, seal the thick spots in the handle. Get it down to about 50% Rh sustained and it stops loosing mass weight and you can take the heat to it.
Elm is wonderful wood and a little remaining twist won't be to much trouble. Just remember to check both sides when tillering, as one will always end appear stiffer than it really is.
-
you know the saying - a picture is worth a thousand words.....I'm inspired. In fact, between diaper changes I managed to cut a bit off with my bandsaw today, and it's really starting to twist now that some extra bulk has been removed.
I'll try to reduce it some more and figure out a way to impart some reverse twist during drying.....all I need to do now is buy a garden tractor to park on it. LOL.
Thanks DCM..
D