Author Topic: Ash ELB measurements?  (Read 1034 times)

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Offline Bootthrower

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Ash ELB measurements?
« on: April 01, 2018, 08:48:05 am »
Hi!
I'd love to get some measurements for an ash ELB! I'm aiming for around 100#@32" but anything is appreciated..
I've honestly never made a bow before, so a hundred pound ELB might be a bit ambitious, but I'm very keen on trying!

I've cut down a european ash with a diameter of roughly 25cm and cut it into around 10 decent staves. I'm going to reduce them down into a more bow-like size so they dry quicker, but I'm unsure about what the finished measurements are going to be, so I'm too afraid to actually cut in them..

Thanks in advance!

Offline WillS

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Re: Ash ELB measurements?
« Reply #1 on: April 01, 2018, 09:16:42 am »
Ash varies a lot, so the same dimensions can give very different weights depending on the timber, but if you don't want to go down the route of doing bending tests / density tests and just jump in and get making I'd start with 38mm wide by 30mm deep in the handle.  You'll end up taking the depth down to around 26mm most likely, and usually I wouldn't personally suggest starting oversize and working down but ash needs to be tillered very well to support heavy weights so that gives you time and timber to tweak the tiller.

Don't fall into the trap of making it rectangular, ash does better with a round back and slightly round belly (but not as round as the common perception of Victorian English longbows) and you'll want to heat treat at around 20" and 30" as you tiller.  Again, that will vary depending on the quality of the timber but I'd start there.  With so many staves you can do a lot of learning on the first couple and start homing in on the best method for your timber as you proceed. 

As an example on the difference, I've got an old 115lb ash bow I just measured and it's 36.9mm wide and 29mm deep in the handle, but yet a 150lb ash bow that I made a few years ago was 38mm by 29mm deep.  The 150lb was made of the best ash I've ever come across however, I've still never found another tree quite like it.

Offline FilipT

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Re: Ash ELB measurements?
« Reply #2 on: April 02, 2018, 12:05:38 am »
Does ideal ash cross section resemble yew warbows / MR bows or is somewhere between squashed rectangle and them? I am also making tomorrow ash warbow so I ask for future reference.

Offline Strichev

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Re: Ash ELB measurements?
« Reply #3 on: April 02, 2018, 02:29:05 am »
I, too, wonder that the optimal cross section might be.

Anyway, to add some data for the OP; I've had an intentionally under-built, unfinished bow of around 100 pounds that measured 30x30 mm in the center with a perfectly rectangular cross section and only slightly rounded corners. It took no set but failed in tension around 29, 30 inches, I presume due to the corners on the back not being rounded enough and a botched heat-treatment that weakened the back.

Regarding the belly cross sections I think that the flatter the belly the more durable the bow and thus you should make it as flat as possible without having a terribly uncomfortable bow and (this is important, I think) creating abrupt transitions, "steps" in thickness taper due to the earlywood being soft/spongy. I've had this problem with my two rectangular ash bows.

On top of that they were ugly, the rectangles.

I think that the cross section should allow for easier thickness tapering and wood removal as well as a more comfortable grip. I plan to make my next bow fairly rounded - a bit less than your stereotypical MR bow.

« Last Edit: April 02, 2018, 11:59:43 am by Strichev »

Offline Bootthrower

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Re: Ash ELB measurements?
« Reply #4 on: April 07, 2018, 06:02:10 am »
Thanks for the wonderful tips and sorry for my late reply..
I'll be sure to test them out and see what works!

Offline Bootthrower

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Re: Ash ELB measurements?
« Reply #5 on: April 07, 2018, 06:11:10 am »
Is this similiar to the cross section that you suggested?

Offline WillS

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Re: Ash ELB measurements?
« Reply #6 on: April 10, 2018, 02:21:36 am »
Close.  That would be a very safe section, I'd personally go for something quite a bit deeper than the drawing.

This is the MR cross section, and adjusting this for ash would be a case of leaving more wood in the bottom corners - not enough to make it square, but just enough to widen the belly crown slightly.



If you wanted to avoid the hassle of heat treating, then you could leave the belly much flatter, but although ash doesn't *need* to be tempered, it does make a marked improvement on performance.  If you temper at the right stage, it also reduces the chance of seeing chrysals as it improves the compression properties of the belly.  Ash will still chrysal at the slightest error though, around the heavier weights so you have to get that tiller shape spot on nice and early.

Offline Bootthrower

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Re: Ash ELB measurements?
« Reply #7 on: April 10, 2018, 07:37:02 am »
By making the belly flatter you mean a less prominent crown? (Totally beginner so I don't know all the terms)

I don't mind going through the trouble of heat treating, but I don't think I have the equipment! I don't have a heat-gun or a blow torch, so I don't know what I should do.. I have heard of people using just a campfire for treating, but I don't know if that works with a longbow, or if it yields decent results if done by a total beginner like myself..

Offline WillS

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Re: Ash ELB measurements?
« Reply #8 on: April 10, 2018, 09:31:27 am »
Yep - the flatter the belly, the better it resists compression before folding up and getting chrysals.  Lots of people who don't push whitewoods much think you need a flat belly to make a heavy bow, but you just need to tiller more carefully.  A flat belly is possibly more suitable for a beginner as it gives you that little bit extra breathing room before it all goes horribly wrong, but if you've got wood spare and want to do it properly, you may as well just do it properly  ;)

Here's a great tutorial by one of the best heavy meanewood bowyers around, Jaro Petrina.  Follow his cross section and in particular follow his tiller shape and you'll be fine.

http://www.theenglishwarbowsociety.com/Making_a_whitewood_longbow2015.html

Campfire will work fine for heat treating - let it burn down first though!  One popular method is to arrange the hot coals in a long line or trench and hang the bow above it, clamped to a 2x4 or similar.  You can add reflex, remove any set etc at this stage too, and even correct sideways bend if you have any.  When you're tempering a bow you don't want to see scorch marks or really any dramatic colour change - just a gentle golden shade is plenty and the heat should be penetrating right through to the back of the bow so that it's too hot to touch.  Takes a while, but is well worth it.

Offline Bootthrower

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Re: Ash ELB measurements?
« Reply #9 on: April 10, 2018, 11:55:40 am »
This is just what I needed to know! Thanks a lot for the fantastic help!

Offline FilipT

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Re: Ash ELB measurements?
« Reply #10 on: April 10, 2018, 12:43:02 pm »
Too bad I can't see at Jaro's page close shot of belly. I did on my hazel warbow just rectangle shape with big radii and I think this one is easiest to make.