Author Topic: Help with bracing and tillering a ~ 70 lb English style longbow (hickory/bamboo  (Read 3427 times)

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Offline Seadart

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I'm working on experiments with making English style D bows so I can eventually make a fairly heavy yew war bow.  Not so sure that is going to work out however.  I've made I think five bows in the last year: 3 flat bows (35 -45 lbs) and two English style bows out of hickory stock wood one was 45 lbs without backing and the other one was 41 lbs with fiberglass and resin backing that I made for my son.  The current bow I am working on is bamboo backed hickory and I laid it out hoping it would end up 60 -70 lbs.   It ended up being a heck of a lot stiffer than I intended.  I've got it down to where if I put it on my tiller tree with a long string  I can pull the string 10 inches at ~70 lbs.  I don't pull over the weight I want to end at.  Usually at this point I would just put it at a low brace height, and check the string alignment and check for hinges and work it a bit then brace and normal height and do some fine adjustment.  Problem is I'm only 5'8" without the longest arms,  even with a bow stringer this is a bit of beast to string.  I usually use a non stretching nylon cord for the half brace height, and had to have my wife help put the string in the knock while I pulled on the stringer.  The bow is so strong it stretched the nylon cord so there was essentially no brace height.  I have an old B50 string that should be OK for 70 lbs but I can't get the sucker slid into the knocks.  Part of the problem is that somewhere I read a 70 lb bow string would crush the bamboo, so I added very thin tip over-lays and the small ramp is making it hard to put the string on.  I don't want to weaken the bow too much more because I know once I go to full brace it will quickly get a lot easier to pull and I'll undershoot the draw weight.   I'm tempted to sand down the overlays and just weaken it a bit until I can get the string on easily by myself but I expect I'll end up with a much weaker bow.   Would appreciate any tips on dealing with making a heavier bow.

Offline bubby

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Sand off the small ramp and get some paracord for a stringer, i honestly mthink you need to scrape some weight off unless thats your intended weight and I'd still scrape some off your a long ways from full draw aren't you?
failure is an option, everyone fails, it's how you handle it that matters.
The few the proud the 27🏹

Offline Del the cat

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    • Derek Hutchison Native Wood Self Bows
Look at this blog entry...
http://bowyersdiary.blogspot.co.uk/2014/01/derbyshire-yew-on-tiller.html
It also tells you how to get over your bracing problem :laugh:
I've just watched the video ... I'd forgotten how good it is :laugh: especially the bit at the end where Sandra Bullock runs on at the and is all over me like a rash ::)
Regarding nocks. File or sand a slight angle on the back of each tip and glue on a scrap of some suitable wood (Hickory... elm etc) and file in temporary nocks and temporary stringer grooves, like in this blog entry.
http://bowyersdiary.blogspot.co.uk/2014/01/derbyshire-yew-nearly-there.html
Same bow in both blog entries.
If the tips are coming back 6-7" then you can get it to a low brace 4-5"... note:- I say how far the tips are coming back... not how far it's pulling on a long string... draw length on a long string is pretty meaningless (unless the string is only just long enough to get on the bow and isn't stretchy).
In that video, the string pulls back about 8-10" but the tips only come back about 4" so they aren't coming back far enough to brace yet.
With grooves for a stringer, you should be fine exerting enough force to get it braced... but don't try until the tips are coming back 7"
Del
« Last Edit: June 11, 2015, 01:22:06 pm by Del the cat »
Health warning, these posts may contain traces of nut.

Offline bradsmith2010

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yes putting some kind of temp nock on the bow for the long string will help,, you can pull the bow with both hands and have someone put the string on,, Badger has a great set up for heavy bow with rubber rollers,, maybe he will chime in with a pick,,

Offline Badger

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   I use a bracing jig I call it.  A 2x4 a little over 6 ft long wth 2 upright posts on either end that are adjustable. The post have a roller atop each one. You simply lay the bow on top of the rollers and push down with your hand. I have braced bows as high as 160# on my jig.

Offline Del the cat

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    • Derek Hutchison Native Wood Self Bows
Hey Badger... have you tried turning your jig up the other way, lying along the 4x2 and the "swiming" along with your arms? like a body rollerskate ::) >:D
Just wondering 'cos I wouldn't be able to resist tryin' it :laugh:
I can imagine bowing along the freeway on it with a cop car coming up behind ...."pull over"
"Now step away from the giant rollerskate"
Cheeses that home brew beer I just drank with the stir fry is pretty good stuff!! :o
Del
Health warning, these posts may contain traces of nut.

Offline Seadart

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Thanks all for the suggestions, I decided to soldier on scraping and pulling.  One limb is moving 7" and one is moving 6"; I will even it out a bit tomorrow night and offer my neighbor a beer to give me a hand bracing it up.  The long string is indeed stretching and it's still pulling 70 pounds with the limbs moving the way they are now. Very interesting blog and videos Del, will take a longer look.

Offline Badger

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      How far down is the long string when you are reading 70#?  That is pretty close to what it will read if it were braced, how far the limbs are moving doesn't mean much it is more about string angles.