First Crack at a warbow (build along)

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hunterguy1991
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First Crack at a warbow (build along)

#1 Post by hunterguy1991 » Thu Aug 14, 2014 9:05 pm

G'day all,

So I've decided to bite the bullet and get myself a nice bandsaw (pick up tomorrow) and some good quality timbers. Have developed a big interest in medieval warbows of late and a friend has ask me to make him one. Timbers I will be using are Silver Ash for the belly and a Hickory back glued with Techni-glue.

Have obtained some good templates (cheers Dennis) as a starting point and will post the process as I go with making it. First steps will be to measure and cut the timbers to length and prep the surfaces. Bow I'm aiming for is 90lbs @ 28 inches, will be 78 inches total and 76 inches n-n. As I have not used the Ash before I will be using all the timber I have in the boards ( 35mm wide and 23mm thick) and a 5mm thick hickory back so if its too heavy I can reduce it. If its too light I will introduce a core lam to add some extra thickness. May reduce the width slightly to give the 80% stack Dennis uses in his template.

Please offer any advice you think necessary through the process and I hope you enjoy. More to come!!

Colin

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Re: First Crack at a warbow (build along)

#2 Post by mikaluger » Thu Aug 14, 2014 11:03 pm

Will be watching. :biggrin:

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Re: First Crack at a warbow (build along)

#3 Post by hunterguy1991 » Fri Aug 15, 2014 7:59 am

Cheers Mick!! hope they it comes out as well as yours.


Been thinking about this for a while, would it be better to cut the rough thickness taper then glue up the backing, or mark the taper, glue the backing and then cut the taper?? I will be building in about 1.5" of reflex so if its cut first it would be easier to get the bow into reflex but wanted an opinion first.

Colin

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Re: First Crack at a warbow (build along)

#4 Post by rodlonq » Fri Aug 15, 2014 2:23 pm

hunterguy1991 wrote:Cheers Mick!! hope they it comes out as well as yours.


Been thinking about this for a while, would it be better to cut the rough thickness taper then glue up the backing, or mark the taper, glue the backing and then cut the taper?? I will be building in about 1.5" of reflex so if its cut first it would be easier to get the bow into reflex but wanted an opinion first.

Colin
Hi Colin,

I believe the former is how Dean Torges makes bamboo backed osage bows in his video. I think he floor tillers the blank before backing. The bows he makes have a fair degree of deflex/reflex put in at the backing stage, before he glues on the handle. Looking forward to seeing your progress.

If I understand correctly, you have your 80% stack when you consider your backing (23+5)/35 = 0.8 :smile:

Cheers.... Rod

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Re: First Crack at a warbow (build along)

#5 Post by hunterguy1991 » Fri Aug 15, 2014 4:43 pm

Cheers for your thoughts Rod,

I think I will cut the taper then glue the backing as I can find no disadvantage in doing it...

Have to acquire some tyre tube for binding the backing during glue up tomorrow before I can do the glue up and sort out a form for holding the reflex in as the glue dries.

I will double check and make sure the thicknesses are correct for the 80% stack, or very close, but yep that's how its calculated.

Colin

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Re: First Crack at a warbow (build along)

#6 Post by mikaluger » Fri Aug 15, 2014 5:35 pm

Hi Colin,

With the elbs I have made, I have backed the belly wood with an un tapered belly stave and still been able to form in plenty of reflex. This also helps helps stop the stave from twisting at the tips, which can happen if you taper the belly wood and dont have a form. (like me!!!)
As I said I dont have a form and clamp my stave to the bench and use blocks to achieve the reflex I require. Of course wrap the stave in tyre tube strips first!!!! I am pretty sure I have some photos on one of my posts.Here.http://www.ozbow.net/phpBB3/viewtopic.php?f=34&t=12660
OR make a form. My way you have a bit more versatility tho.

I taper the belly of my flatbows now, before glue up, as i like a more abrupt reflex at the tips, this defianately helps in this case.
BUT if you are not careful, you can twist the tips. I ruined a realy nice bamboo backed malas bow. It is propellered because an end twisted slightly.

Have fun,
Mick

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Re: First Crack at a warbow (build along)

#7 Post by hunterguy1991 » Fri Aug 15, 2014 6:11 pm

Thanks for the advice Mick!! Will strongly consider what you say I think.

I have not yet decided which type of form I will make as I can do either a simple block at the tips and clamp down the centre of the bow, or I can cut a full length form for the curve I want and clamp the bow to it... The later would be more time consuming and sensitive in construction but would allow for a better result and less chance of limb twist ( my first thoughts anyway). As you say though, the first way is simpler and more versatile.

Have my bandsaw now so I will play around with my options and see which looks more promising.

Colin

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Re: First Crack at a warbow (build along)

#8 Post by Dennis La Varenne » Fri Aug 15, 2014 6:55 pm

I will be watching with interest too, Colin.

For what it is worth, the Air Dried Density of Silver Ash runs around 620 - 680kg/m^3 with a Modulus of Rupture at 92 - 103MPa according to Bootle's 'Wood in Australia' compared with Spotted Gum's ADD of 950 - 1150 and MoR of 150MPa for example.

Dave Clarke's (Yeoman) bending tests seemed to indicate the elastic limit of most of the wood species he tested came out at around 65% of the MoR, after which, the test beams started to take a set.

Because you are an engineering bloke, I have attached copies of the relevant sums for calculating the fibre stress your bow will produce with the cross section you are using. They come from 'ARCHERY - THE TECHNICAL SIDE'. This particular article from that book was written by Clarence Hickman.

In reference to what Mick was saying about these bows taking a propeller twist or a cast, they can be prone to that if you have a straight taper from the handle to the tips. That is why I put in a parallel width limb mid-section for1/4 of the bow length, a slow taper out to then end of the mid-limb at which point it is kept to 75% of the handle width and the outer 1/8 sections tapering more quickly to the nock widths. These last section are not prone to taking a cast or propeller twist because of their short length.

I am a bit cautious about putting much more than 1-1.5 inches of reflex into an ELB because of the load it places on the very narrow belly, unless you apply the backing AFTER you have tillered the belly at least to brace height using the Perry reflexing method.

There are several pages which I have scanned and combined into a PDF for you to read up on. I think you will find them interesting. I can understand what it going on, but can't follow the maths. For you blokes, it is probably pretty basic.
From ARCHERY - THE TECHNICAL SIDE - pp25 -44.pdf
(2.39 MiB) Downloaded 124 times
Dennis La Varénne

Have the courage to argue your beliefs with conviction, but the humility to accept that you may be wrong.

QVIS CVSTODIET IPSOS CVSTODES (Who polices the police?) - DECIMVS IVNIVS IVVENALIS (Juvenal) - Satire VI, lines 347–8

What is the difference between free enterprise capitalism and organised crime?

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Re: First Crack at a warbow (build along)

#9 Post by hunterguy1991 » Fri Aug 15, 2014 8:01 pm

Thanks for the info Dennis!!

Will have a good read of that article tonight. I was only going to build in 1 inch of reflex into these bows in any case so it shouldn't be a problem.

I will do my best to explain the maths if your interested? As long is I get what's going on that is haha.

Cheers,

Colin

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Re: First Crack at a warbow (build along)

#10 Post by Dennis La Varenne » Fri Aug 15, 2014 10:25 pm

Colin,

You will find a section in that lot specifically to do with fibre stress in ELB cross-section bows which should help a lot. It is based on a few measurements and calculating the position of the neutral layer between back and belly and those distances from the neutral layer. As an engineer, you would probably understand about beam stresses already.

I think from reading that stuff, I could probably do a fair fist of working those stresses out once I worked out the position of the neutral layer. It would be a cumbersome task for me though, because I missed out on some pretty basic maths a school upon which to build the later stuff unfortunately.
Dennis La Varénne

Have the courage to argue your beliefs with conviction, but the humility to accept that you may be wrong.

QVIS CVSTODIET IPSOS CVSTODES (Who polices the police?) - DECIMVS IVNIVS IVVENALIS (Juvenal) - Satire VI, lines 347–8

What is the difference between free enterprise capitalism and organised crime?

HOMO LVPVS HOMINIS - Man is his own predator.

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Re: First Crack at a warbow (build along)

#11 Post by hunterguy1991 » Sat Aug 16, 2014 8:09 am

Morning Dennis,

Yes I had a read through of it all, its pretty heavy maths actually!! I do understand the concepts of the neutral layer and how to calculate stresses at the surfaces of sections. Something we do a lot in structural design of bending members. They layout of the equations in that paper are difficult to follow unfortunately as how I was taught is much simpler.

From what I remember (been a few years since I did sections properties and neutral layer calculations) the neutral layer in the timber generally coincides with the centroid (exact geometric centre) of the cross section. Complex shapes like an ELB cross section would require some integration to calculate where that is due to the curved surfaces.

I will try to simplify some of it so its easier to follow with diagrams. To my understanding backed bows or laminated bows my behave slightly differently to the equations in that info, since there is a change in Young's modulus and yield stress when the timber changes... will read over it again and follow their equations on paper to make more sense of it all.

On another note, Bandsaws are time consuming to set up when purchased!! hopefully will have it all together and tuned later today and some photos of a form for my bows.

Cheers,

Colin

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Re: First Crack at a warbow (build along)

#12 Post by rodlonq » Sat Aug 16, 2014 11:39 am

hunterguy1991 wrote:Cheers for your thoughts Rod,

Have to acquire some tyre tube for binding the backing during glue up tomorrow before I can do the glue up and sort out a form for holding the reflex in as the glue dries.

Colin
Hi Colin,

I like the idea of the type of form below because it results in natural curvature of the bent laminations (not my photo - pilfered off the web). It can be used for just reflex, or you can add some deflex and the location of the deflex along the limb is adjustable as well. The amount of reflex and or deflex is simply governed by the height of the posts. I am pretty sure I have seen some pictures posted by Greybeard showing his form that is similar, just couldn't find the pictures so easily.

You can still tyre tube strips to bandage it instead of clamps (if you don't have enough clamps :smile: )

Cheers... Rod
DR BBO Form.JPG
DR BBO Form.JPG (37.81 KiB) Viewed 5267 times
Last edited by rodlonq on Sat Aug 16, 2014 12:58 pm, edited 1 time in total.

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Re: First Crack at a warbow (build along)

#13 Post by Dennis La Varenne » Sat Aug 16, 2014 12:40 pm

Colin,

Hickman finally says on page 38, that finding the neutral layer axis in an ELB can be done by us mathematically challenged bowyers by drawing the ELB section we intend to use and replicating it in large size on a sheet of stiff cardboard. Then cut it out and sit it on a pin until it balances. That point is the CoG of course, but also the position of the neutral layer.

If you measure the distances from back to pinhole and belly to pinhole, I think you can then go on to calculate the fibre stresses on the back and belly.

For practical purposes, I think you could just ignore the differences in the properties of the back and belly material. The rest of us do.
Dennis La Varénne

Have the courage to argue your beliefs with conviction, but the humility to accept that you may be wrong.

QVIS CVSTODIET IPSOS CVSTODES (Who polices the police?) - DECIMVS IVNIVS IVVENALIS (Juvenal) - Satire VI, lines 347–8

What is the difference between free enterprise capitalism and organised crime?

HOMO LVPVS HOMINIS - Man is his own predator.

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Re: First Crack at a warbow (build along)

#14 Post by hunterguy1991 » Sat Aug 16, 2014 2:18 pm

Cheers Rod. I think that is the type of form I will end up using as its much easier to make and very versatile as you and Mick have said. I do recall seeing some pic on a thread by Greybeard using that type of form also.

Got myself some bike tyre tube this morning so I will cut it to a long strip and it will be ready to go, and have a spare in case 1 is not long enough.

Slowly getting all the bits together for glue up, then will just be waiting on the weather since its raining at the moment. Unfortunately I don't have a hot box so the bow will be cured at ambient temp (will put it out in the sun under a dark piece of plastic when gluing to get the temp up a little)


Thanks for that idea Dennis, that is much simpler than the integration (and probably much faster). I have been wondering for a while now, with my engineering of beams, the max stress that can be applied at the outer most fibres (in tension or compression) of a section is what we can the Yield Stress. The Yield stress is the stress in MPa in which the material begins deforming plastically (It wont return to original position), for steel it is 500 MPa. Now I feel that the Modulus of Rupture MoR is the same thing when the material is timber... What are your thoughts? Can anyone clarify?

Colin

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Re: First Crack at a warbow (build along)

#15 Post by Dennis La Varenne » Sat Aug 16, 2014 9:15 pm

Colin,

In timber, the modulus of rupture is when the wood beam under stress actually starts to break. It is much later along the test spectrum than deformity. The term I used was taken directly from that extract I posted. It is an older American term (fiber stress at elastic limit) which I am pretty sure means the same as your Yield Stress. Bootle's 'WOOD IN AUSTRALIA' (ISBN 0071014012) goes into the relevant terminology for timber.

You will recall above that I mentioned the wood bending testing that one of our members - Yeoman (Dave Clarke) - was doing and he came up with a figure for 'yield stress' in wood samples of approximately 65% of MoR. The testing has been standardised pretty much from an idea in one of the Traditional Bowyer's Bible series where a sample of the bow wood to be used is cut to 1/2" square x 12" long, trapped at one end and bent at the middle over a fulcrum until the specimen deforms. An increasing load is applied and removed to the free end of the sample beam until it exhibits deformity. Care is taken that the orientation of the growth rings matches how the wood is to be used in the bow, ie, quarter-sawn, back-sawn or something in between.

The yield stress can be calculated in MPa or lbs/inch^2 depending upon the load units you use for the test. It is fundamentally a very simple test which can be used on any particular specimen of wood you may intend to use rather than rely on published timber industry mechanical test data which are only an average at best.

You may also find this series by Yeoman interesting - USING MATHS IN MAKING BOWS http://www.ozbow.net/phpBB3/viewtopic.php?f=34&t=5450
Dennis La Varénne

Have the courage to argue your beliefs with conviction, but the humility to accept that you may be wrong.

QVIS CVSTODIET IPSOS CVSTODES (Who polices the police?) - DECIMVS IVNIVS IVVENALIS (Juvenal) - Satire VI, lines 347–8

What is the difference between free enterprise capitalism and organised crime?

HOMO LVPVS HOMINIS - Man is his own predator.

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Re: First Crack at a warbow (build along)

#16 Post by rodlonq » Mon Aug 18, 2014 6:28 pm

Hi Colin,

I modelled a short section in Solidworks so it can calculate the location of the neutral axis for an ideal ELB profile with 80% stack. As far as I can figure, the ratio of the distance from the neutral axis to the back (44.4% of the depth) should remain constant as width changes, providing the 80% stack ratio is maintained. A couple of pictures to help explain my ramblings. Hope this is useful in some way.
Warbow80%Stack.png
Warbow80%Stack.png (20.38 KiB) Viewed 5220 times
WarbowSMoA.png
WarbowSMoA.png (64.76 KiB) Viewed 5220 times
Cheers... Rod

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Re: First Crack at a warbow (build along)

#17 Post by hunterguy1991 » Mon Aug 18, 2014 7:03 pm

Hey Rod,

That's a neat program!! Is it free to download or paid for? I had a student version of Spacegass that could do the same sort of thing but its expired and I cant afford the 10 grand for a full version license.

Close to the same cross section, but I will be using a crowned back as Dennis has suggested. Bit more work to put the crown on but looks really good. Wont change the centroid location too much tho, just push it slightly more into the belly.

Colin

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Re: First Crack at a warbow (build along)

#18 Post by rodlonq » Mon Aug 18, 2014 7:27 pm

hunterguy1991 wrote:Hey Rod,

That's a neat program!! Is it free to download or paid for? I had a student version of Spacegass that could do the same sort of thing but its expired and I cant afford the 10 grand for a full version license.

Close to the same cross section, but I will be using a crowned back as Dennis has suggested. Bit more work to put the crown on but looks really good. Wont change the centroid location too much tho, just push it slightly more into the belly.

Colin
Nah... sorry mate, it's far from free, much like your expired Spacegass.

I would think if you add a crown to the back the centroid will move towards the added material. What you gain in the crown will probably be offset when you radius the corners of the back anyway.

Cheers... Rod

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Re: First Crack at a warbow (build along)

#19 Post by Dennis La Varenne » Mon Aug 18, 2014 9:28 pm

Gentlemen,

Attached is a copy of an Excel application which aforementioned Yeoman sent to me for computing bow layouts pretty accurately. I have still not used it but Dave seems to have remarkable success using it with bows coming almost fresh from the bandsaw and drawing lovely bends on his tiller. See what you think of it.
10arc.xls
(858 KiB) Downloaded 111 times
Dennis La Varénne

Have the courage to argue your beliefs with conviction, but the humility to accept that you may be wrong.

QVIS CVSTODIET IPSOS CVSTODES (Who polices the police?) - DECIMVS IVNIVS IVVENALIS (Juvenal) - Satire VI, lines 347–8

What is the difference between free enterprise capitalism and organised crime?

HOMO LVPVS HOMINIS - Man is his own predator.

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Re: First Crack at a warbow (build along)

#20 Post by hunterguy1991 » Tue Aug 19, 2014 8:02 am

Rod,

When I said I would be adding a crown, I meant that after the flat backing is glued (giving and 80% stack thickness) I would then be filing a radius into the backing thus reducing the area of the backing material. This would lead to the neutral axis moving slightly toward the belly. Sorry about the confusion with that.

Dennis,

That is an impressive program. If it was something that Yeoman wrote himself he has done extremely well!! Will take me some time to work out how to use it all tho.

You should note, the first 2 bows I posted photos of in the "Basic English longbow" thread were pretty much straight off the template you gave me and the bend in them is near perfect, so they have been a good "recipe" remember should I need to knock out a bow of lighter draw weight quickly. Simply mark the template tapers, cut, lots of filing, glue linen backing, cut nocks, sand and your done.

My younger brother and myself actually made a spotted gum bow in a single day using that template. I did vary the design slightly, making the handle full thickness section the full middle quarter long, so it is a little stiff in the tips, however if I had not changed that it would bend perfectly as the others I made do.

Colin

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Re: First Crack at a warbow (build along)

#21 Post by hunterguy1991 » Tue Aug 19, 2014 8:30 am

Ok so I said this was a build along so time for some more pictures!

Today is glue up day so I did a dry run first to make sure it would all go together smoothly (fingers crossed)
Dry run 1 (640x480).jpg
Dry run 1 (640x480).jpg (193.05 KiB) Viewed 5190 times
Dry blank and backing sitting on my reflex for to get the positioning for the end blocks.
Dry run 2 (640x480).jpg
Dry run 2 (640x480).jpg (196.58 KiB) Viewed 5190 times
Dry run of the glue up process... Glue on surfaces evenly, place backing onto blank, tape middle and ends, cling wrap entire stave, rubber tube straps on both ends from handle out to tips, set up reflex form in vice slightly off centre, position stave on form, clamp or strap middle of bow down.

I will only be trying for 1.5 inches of reflex in this bow and I think it will lose 1/4 to 1/2 inch once its taken off the reflex form.

Glue up will be at 9am since its still a bit cool here.

Colin

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Re: First Crack at a warbow (build along)

#22 Post by hunterguy1991 » Tue Aug 19, 2014 9:40 am

Glue up complete without a problem... Glad it looks like all the ones I've seen on here haha! I will be using a stiffer mixer and spreader next time!! The make shift one I had didn't work the best. Techni-glue CA was used for this bow, hopefully it will hold well. Considering ordering some Smooth On to be like everyone else.
Glue up 1 (640x480).jpg
Glue up 1 (640x480).jpg (195.52 KiB) Viewed 5182 times
Placed the form outside in the sun, hopefully will elevate the temperature a little and help the glue cure a little bit stronger. I may even throw a sheet of black plastic over it to create a bit of an "oven" effect.
Glue up 2 (640x480).jpg
Glue up 2 (640x480).jpg (197.43 KiB) Viewed 5182 times
Will leave it 2 days to ensure the glue is fully cured before I do anymore to it. Next step will be sanding the back lamination flush with the sides of the Ash and then cutting belly and limb width tapers on the band saw... Better get some practice with the saw in over the next 2 days as I really don't want to bugger this one up!!

Colin

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Re: First Crack at a warbow (build along)

#23 Post by mikaluger » Tue Aug 19, 2014 7:05 pm

Oh that looks familiar!!!!!!!!!!
Cut your tapers just away from the line, and then finish off with your hand plane. When you do your edges, make sure you check which way the grain is running on the hickory. It can chip really easily!!!!!!!
The techniglue will be fine, I have never used a hot box and I have never had a bow delaminate.
Looking great buddy.
Mick.

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Re: First Crack at a warbow (build along)

#24 Post by hunterguy1991 » Tue Aug 19, 2014 7:28 pm

Thanks for the tips Mick,

I think I will do the crown in the Hickory with a file and scraper and very slowly and the sides flush with the Ash as well. I think the belly round will cut nicely with a small hand plane and scraper but I may use a rasp to do the bulk removal.

Think I'll leave it 2 days before I do any more work on it. I know 1 should be sufficient but I don't want to rush anything.

Looking forward to getting it on the tiller later in the week.

Colin

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Re: First Crack at a warbow (build along)

#25 Post by Dennis La Varenne » Tue Aug 19, 2014 8:16 pm

Simon,

That Excel app was from somebody else I believe - a bloke on PaleoPlanet I think. It will take some ferreting around, but I reckon you will sort it out OK.

I am glad you understand about the centre quarter of the stave now. It should start out full thickness over its whole length and gradually you bring your taper in from the tips in past where the centre section depending up how the limbs are bending. Leaving it full thickness ensures you have wood to remove as necessary as you have found. If it is left that way, as you also found, much of your bending will occur in that area because of the full thickness and little in the outer limbs leaving a staffish ended bow.

I am looking forward to this bow coming out.
Dennis La Varénne

Have the courage to argue your beliefs with conviction, but the humility to accept that you may be wrong.

QVIS CVSTODIET IPSOS CVSTODES (Who polices the police?) - DECIMVS IVNIVS IVVENALIS (Juvenal) - Satire VI, lines 347–8

What is the difference between free enterprise capitalism and organised crime?

HOMO LVPVS HOMINIS - Man is his own predator.

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Re: First Crack at a warbow (build along)

#26 Post by hunterguy1991 » Tue Aug 19, 2014 8:28 pm

Hi Dennis,

No-one called Simon here haha, must have got mixed up. Not to worry.

I will play around with the excel sheet over the next few days and see how well I can get it working for me.

I think the issue that caused stiff limb tips on the spotted gum bow was that the was not enough "meat" and stiffness in the middle of the handle to make the tips bend first. That shouldn't be a problem on the hickory backed ash bow since the tips are tapered down to 12mm and the handle quarter is 28mm... I should be able to get that "slightly whip ended" circular tiller that we spoke about without too much trouble. It is possible that it could go the other way and be very whip ended but I have wood there in the handle that can be removed to allow the handle to bend late like a true ELB should.

Great to have people interested in how a bow is going and giving advice along the way so thank you everyone!!

More progress shots later in the week.

Colin

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Re: First Crack at a warbow (build along)

#27 Post by Dennis La Varenne » Tue Aug 19, 2014 9:01 pm

:oops: Er, ummmmm, Oh dear! I think I will go and have tea now.

Colin,

Here is a post I just did on Mick's thread on his American Ash ELB. http://www.ozbow.net/phpBB3/viewtopic.php?f=34&t=15013
Dennis La Varénne

Have the courage to argue your beliefs with conviction, but the humility to accept that you may be wrong.

QVIS CVSTODIET IPSOS CVSTODES (Who polices the police?) - DECIMVS IVNIVS IVVENALIS (Juvenal) - Satire VI, lines 347–8

What is the difference between free enterprise capitalism and organised crime?

HOMO LVPVS HOMINIS - Man is his own predator.

hunterguy1991
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Re: First Crack at a warbow (build along)

#28 Post by hunterguy1991 » Tue Aug 19, 2014 9:33 pm

Cheers Dennis :biggrin:

Read the post and will take not of it all in my bow. One slight difference between mine and Micks is that his was glued flat where as mine has some reflex, so it will take a bit of time to know if the tips are going to come round like his have. With the straight laid bow the tips are forced to start bending early as there is so little mass and stiffness there compared to the handle... that is my experience so far anyhow. My bow will have to first overcome the reflex early in the tiller.

Possibly an incentive to leave more meat in the handle to 'make' the tips bend...

Will aim for a similar braced profile which should indicate the proper tiller. Of all the warbows I've been watching on youtube in the last few weeks (may have gotten a little obsessed), the best ones seem to have a fairly straight middle third at brace and then bend in the tips, producing a late bend in the handle when drawn. Look at the Italian Yew bows in Joe Gibbs and Jake Fenwick's videos to get what I mean.

Colin

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rodlonq
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Re: First Crack at a warbow (build along)

#29 Post by rodlonq » Wed Aug 20, 2014 7:54 am

hunterguy1991 wrote:Rod,

When I said I would be adding a crown, I meant that after the flat backing is glued (giving and 80% stack thickness) I would then be filing a radius into the backing thus reducing the area of the backing material. This would lead to the neutral axis moving slightly toward the belly. Sorry about the confusion with that.

Colin
I should have known what you meant instead of taking it so literally, of course you would be removing material to "add the crown". For some reason I visualised you would use a thicker backing and then crown that..... Reading and responding to fast without engaging the grey matter :oops:

Your layup looks very good. I hope I see some plastic wrap in there to stop your rubber tubes sticking to your blank :smile: . Is you hickory back sawn or quarter sawn?

Cheers... Rod
Last edited by rodlonq on Sat Aug 23, 2014 8:13 am, edited 1 time in total.

hunterguy1991
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Re: First Crack at a warbow (build along)

#30 Post by hunterguy1991 » Wed Aug 20, 2014 9:57 am

Morning Rod,

All good mate. Guilty of that myself a fair bit.

Yes it has been cling wrapped before the rubber tube was wrapped on. Wouldn't want to waste a $6 bike tube! haha I have no idea how the hickory was originally cut. Mick was kind enough to send me 6 strips that he milled for me!! The grain on that particular piece and 3 others like it was fairly straight and fine in the middle of the length but dark and very irregular at the ends... Hoping that doesn't cause an issue but will find out in due course. Will post photos when it comes off the form later today of what I mean.

Colin

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