Primitive Archer

Main Discussion Area => Bows => Topic started by: smoke on March 17, 2012, 01:15:36 pm

Title: Hackberry in compression?
Post by: smoke on March 17, 2012, 01:15:36 pm
I've been thinking about trying to make a shortish (56 - 60 in.) sinewed bow out of hackberry.  Does anyone have an opinion as to whether hackberry is good in compression?  I'd like to bring the bow in at around 65# at 27.  Thanks for your thoughts,
Title: Re: Hackberry in compression?
Post by: Badger on March 17, 2012, 01:23:43 pm
  Should not be any problem, sinew is not strong in tension as is often suggested. Sinew is very elastic in tension. Strong simply means how much it resists bending and doesn't really say anything about how elastic it is.
Title: Re: Hackberry in compression?
Post by: toomanyknots on March 17, 2012, 01:41:21 pm
The first thing I would say, although this is obvious with any sinew backed bow, is to make sure the wood is very dry. Hackberry seems to me to be a wood that needs to be very dry to take little set. After the bow is ready to be floor tillered, you could use a hotbox, or you could also throw it in a hot car in the sun all day long. The second thing, although once again obvious for a sinew backed bow, is to make sure you reflex the bow a good deal before sinewing to counter set. This will end up pulling it into reflex later, even if the bow gains some set initially.
Title: Re: Hackberry in compression?
Post by: k-hat on March 17, 2012, 02:06:51 pm
Pearl highly recommends heat treating the belly to increase compressive strength of hackberry, and he's done plenty of them to know.
Title: Re: Hackberry in compression?
Post by: blackhawk on March 17, 2012, 02:18:05 pm
heres the game plan that i wood do(in laymans terms). this is what i do to my sinewed whitewoods

1. trap the back some and tiller it down to 40-45lbs at 18" in your case.

2. heat treat in 2" of reflex,and clean n sand the belly up,and then exercise it some to loosen her back up.

3. sinew two or three courses. first course full width,next course not as wide,and if a third course only a half inch wide down the top of the crown. you can either induce more reflex by a lil reverse bracing,or hanging a weight,or tie it down at that handle with a piece of sinew with the tips propped up....or let it be and it will reflex itself another inch and give you three inches of setback..up to you with how big you wanna go,and how big of balls you have..lol...USE HIDE GLUE ONLY

4.wait till dry and tiller out and enjoy shooting it ;)
Title: Re: Hackberry in compression?
Post by: Buckeye Guy on March 17, 2012, 02:26:58 pm
Sounds like Blackhawk has you covered !!
Guy
Title: Re: Hackberry in compression?
Post by: smoke on March 19, 2012, 11:05:47 am
thanks guys - helpful as always!