First Crack at a warbow (build along)

How to make a Bow, a String or a Set of Arrows. Making equipment & tools for use in Traditional Archery and Bowhunting.

Moderator: Moderators

Message
Author
Dennis La Varenne
Posts: 1776
Joined: Sun Sep 07, 2003 10:56 pm
Location: Tocumwal, NSW. Australia

Re: First Crack at a warbow (build along)

#31 Post by Dennis La Varenne » Wed Aug 20, 2014 10:10 am

Colin,

I have a good few all-Hickory bows here made by Ben Pearson back in the 1940s and some of them have appalling grain violation and lots of rift chevrons along the bow edges, but they still hang together OK. Remarkable stuff that Hickory. I wouldn't worry too much about it.
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
Posts: 859
Joined: Mon Jul 09, 2012 10:18 am
Location: Woodford Queensland

Re: First Crack at a warbow (build along)

#32 Post by hunterguy1991 » Wed Aug 20, 2014 4:16 pm

Well, I said I was going to wait 2 days before I did anymore work on the bow... boy oh boy was I wrong!! (I'm blaming you Mick! haha)

I managed to retain 15mm of reflex having glued in 1.5 inches in the form...

I took the bow out of the form at 2 this arvo and in 2 hours have cleaned up the edges flush to the Ash belly (35mm wide), remarked the belly taper and cut that with the band saw and cleaned it up then marked out the width tapers, 25mm wide 9.75" from the tips and then in to half inch at the tips of the stave, cut those and cleaned them up...

I measured the total stack thickness at the belly and was surprised to see that it is actually 30mm thick rather than 28... so I will file or plane off 2mm of thickness when work on it resumes on Friday to get back to the 80% stack. By my calculations taking off those 2mm will lose me about 6-7lbs of draw weight.

Will say this... This thing is going to be a beast!!! I know I have not yet done the belly round and crown (belly round will drop the weight a fair bit) but it seems to be VERY stiff...

Photos of progress later tonight.

Colin

Dennis La Varenne
Posts: 1776
Joined: Sun Sep 07, 2003 10:56 pm
Location: Tocumwal, NSW. Australia

Re: First Crack at a warbow (build along)

#33 Post by Dennis La Varenne » Wed Aug 20, 2014 7:31 pm

Will say this... This thing is going to be a beast!!! I know I have not yet done the belly round and crown (belly round will drop the weight a fair bit) but it seems to be VERY stiff...
I am not surprised at that.
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
Posts: 859
Joined: Mon Jul 09, 2012 10:18 am
Location: Woodford Queensland

Re: First Crack at a warbow (build along)

#34 Post by hunterguy1991 » Wed Aug 20, 2014 7:59 pm

Here are the photos of the afternoons activities...

First shot shows the reflex that remained in the stave... measured it at 15mm at the centre.
ELB remaining reflex (640x480).jpg
ELB remaining reflex (640x480).jpg (184.69 KiB) Viewed 3677 times
Second shot shows the change in grain and colour of the hickory backing I spoke about earlier. Hopefully it will not cause a problem in the process.
ELB dark hickory (640x480).jpg
ELB dark hickory (640x480).jpg (174.61 KiB) Viewed 3677 times
Next we have the cut belly taper of one limb. Scary part cutting them for the first time!! Hard to cut straight when your hands are shaking with nerves.
ELB belly taper (480x640).jpg
ELB belly taper (480x640).jpg (140.28 KiB) Viewed 3677 times
Last, here is the stave to latest progress. Have straight cut and sanded all of the tapers.
ELB Final straight tapers (640x480).jpg
ELB Final straight tapers (640x480).jpg (198.34 KiB) Viewed 3677 times
Sorry if any of the photos are a bit fuzzy, were taken pretty quickly.

Wont be doing any more work until Friday, which will be filing the crown and belly round so more photos then.

Colin

User avatar
Stickbow Hunter
Supporter
Supporter
Posts: 11637
Joined: Sat Jul 26, 2003 8:33 pm
Location: Maryborough Queensland

Re: First Crack at a warbow (build along)

#35 Post by Stickbow Hunter » Wed Aug 20, 2014 8:15 pm

It's coming along well Colin.

Jeff

hunterguy1991
Posts: 859
Joined: Mon Jul 09, 2012 10:18 am
Location: Woodford Queensland

Re: First Crack at a warbow (build along)

#36 Post by hunterguy1991 » Wed Aug 20, 2014 8:35 pm

Thanks Jeff!

So far its been great fun to make.

User avatar
mikaluger
Posts: 410
Joined: Sun Aug 28, 2011 10:08 pm
Location: Melbourne Towne

Re: First Crack at a warbow (build along)

#37 Post by mikaluger » Wed Aug 20, 2014 8:48 pm

That dark wood is common in Hickory Colin, it has never been a problem for me.......... it looks great in contrast with a coat of finish. My bow is the same at one end. All good. :biggrin:

hunterguy1991
Posts: 859
Joined: Mon Jul 09, 2012 10:18 am
Location: Woodford Queensland

Re: First Crack at a warbow (build along)

#38 Post by hunterguy1991 » Wed Aug 20, 2014 8:53 pm

ok, that's good to hear :biggrin: At least mine is the same both ends :wink: haha.

So looking forward to getting a bend in this sucker!!

Would you be willing to make another and do a trade? Doubt you'll want to part with that one.

Colin

Dennis La Varenne
Posts: 1776
Joined: Sun Sep 07, 2003 10:56 pm
Location: Tocumwal, NSW. Australia

Re: First Crack at a warbow (build along)

#39 Post by Dennis La Varenne » Thu Aug 21, 2014 11:43 pm

Colin,

Here is a very nice picture of a whip-ended ELB I sourced on the internet (I forget where now). It has all the most desireable features I look for in a mediaeval ELB as described by Ascham.

I did some lines on the bow and there were some minor surprises. I would have called that an almost perfect circular ELB bend. However, all is not as it seems. The eye deceives.
$_57-10 copy2.jpg
$_57-10 copy2.jpg (585.06 KiB) Viewed 3671 times
Each red chord has a blue bar standing at 90 degrees from its exact centre. Chord 1 is on the left. Its blue bar measures the distance from the chord to the belly of the bow.

Duplicating and flipping chord 1 horizontally, then positioning it so that it (chord 2) runs from the centre of the tiller stand where the belly of the bow would be, shows that the right hand end of the chord is longer than the distance from the tiller centre to the horn of the right hand limb. This means that the right hand limb has a greater bend in it than the left hand limb, especially in the outer part. You can also see that the blue line just goes inside the limb instead of just touching the belly as with chord 1, proving that there is more bend in the right hand limb.

Creating a chord 3 which is horizontal, and positioning it so that its blue line is dead centre on the tiller stand, and moving that chord up until its termini contact the belly of the bow, you can see that the vertical distance from chord 3 to the bow's belly is much shallower than on either of the other two chords meaning that the centre of the bow is much stiffer than the outer limbs. The right hand terminus of chord 3 also runs past the belly of the right hand limb instead of just contacting it, verifying again that the right hand limb is bending much more than the left hand limb.

However, because this bow is a typical ELB which does not have a dedicated handle section (which is correct), the difference between the curvatures of the two limbs can be equalised by the simple matter of shifting the shooter's bow-hand a little toward the left-hand limb which will rock the whole bow sightly forward in the upper limb and even out the tiller during shooting.

If both horns are shaped identically so that there is no upper or lower horn, you can shoot this kind of bow any way up and it would still shoot well. Perhaps this was an advantage under battle conditions in mediaeval England – you could just grab a bow from the waggon, brace it and just shoot it without having to determine which end needed to be up.

This bow also has a very stiff centre section, but this is the only way in which you can create Ascham's whip-ended limbs to give high limb-tip speed. Note also how much slenderer are the tips below the horns compared to the middle of the bow. That is a lot of taper.
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
Posts: 859
Joined: Mon Jul 09, 2012 10:18 am
Location: Woodford Queensland

Re: First Crack at a warbow (build along)

#40 Post by hunterguy1991 » Fri Aug 22, 2014 12:58 pm

Thanks for the photo and description Dennis.

Will set my aim on some thing very similar when I tiller my bow. Still got a bit of work yet before it will be getting any bend. Have to hand file the crown and belly round today and will look at tillering tomorrow. Im hoping I can get fairly lucky with the tiller like I have done with the lighter ELB's in my other thread but we will see in time.

I have the belly thickness at 30mm for the middle quarter and that straight tapers to the tips which are 12mm, which happens over about 30 inches of limb so the taper is pretty steep!! Tips look very fine compared to the handle at this stage.

Colin

hunterguy1991
Posts: 859
Joined: Mon Jul 09, 2012 10:18 am
Location: Woodford Queensland

Re: First Crack at a warbow (build along)

#41 Post by hunterguy1991 » Fri Aug 22, 2014 5:41 pm

Well, I'm pretty sure all my effort on this one has just gone to ****...

Rounded out the belly and crowned the back this arvo, stuck a long string her and discovered I had created an absolute monster. Scales said 65lbs with the tips back about 2 inches maybe 3, so I started to reduce the weight and exercise the limbs each time I took some timber off (as ive heard your meant to do). Used the spoke shave for the first time on the belly and man does that thing make it easy!!

Started to get some decent bend going, maybe close to brace height... And then found a couple of chrysals out near the limb tip of one limb after exercising the limbs. They are maybe 10-12 inches from the tips.

Now, I put it down to 2 possible scenarios:

1. I cocked up when exercising the limbs and pushed them a little too far (probably :cry: )

2. The Ash just isn't strong enough to handle the compression, and the stave should be very much smaller for a lower draw weight or longer for that draw weight.

Hate to say it, but I think this one is fire wood now. Cant imagine chrysals in a warbow are a good thing.

Will try to get some photos up later of the problems, bit to annoyed at myself and in general at the moment.

Colin

User avatar
mikaluger
Posts: 410
Joined: Sun Aug 28, 2011 10:08 pm
Location: Melbourne Towne

Re: First Crack at a warbow (build along)

#42 Post by mikaluger » Fri Aug 22, 2014 8:09 pm

Hmmmmm......... not good Colin. By the sound of it I dont think you have done anything wrong.
I tend to not use the long string now and floor tiller the stave to a low brace height, say 3 or 4 inches. Then even out the limbs, THEN put it on the tiller and wind her down. Then adjust the brace height as I tiller to the first 20", then I apply the hornnocks and continue.

IMHO the longstring can put alot of stress exactly where you have problems on the limbs. On heavy bows like this, the long string will bring the tips around way before the belly starts to move thus putting stress right where you have had a drama. I too, learnt this the hard way my friend.

Having said that, timber selection can come into play here. Maybe Silver ash is just not right in a d section belly! Maybe a flatter section is more suitable for Silver ash. Elm did exactly the same for me.

Malas has worked fine in one D section bow, and chrysalis the next. It is much better suited for Flatbows.

I have made a nice Hickory backed (masters)Red oak bow, perfect tiller, low poundage though. And it was a fair chunk of timber.

Some people would say the same for American ash, but I use that stuff for both types and never had a problem either way. I love American ash, it works well, is easy to get, not to expensive and you can find pieces with exceptional straight grain! NOTE it needs to be Backed!!!!!!!(IMHO)

With this bow, maybe just take the dimensions back, and go for a smaller bow with a lower poundage and try and get the tiller spot on. Great practice, and take it on the chin as a lesson learned. Dont cut it up mate, get something from your hard work. Poo happens.

You still have more hickory and plenty of time! :smile:

hunterguy1991
Posts: 859
Joined: Mon Jul 09, 2012 10:18 am
Location: Woodford Queensland

Re: First Crack at a warbow (build along)

#43 Post by hunterguy1991 » Fri Aug 22, 2014 8:57 pm

Cheers Mick,

I think before I have a crack at another warbow I'll make up a straight laid stave and shoot for 50-60lbs or so and see how the Ash holds up.

Originally I had wanted American Ash but the timber yard didn't have any. I picked the silver ash because it has very similar properties to American Ash and Red Ash, both of which I've been assured make D section bows.

I think the next Warbow I will also alter the belly taper slightly so that the full thickness section is not quite as long. That will help with getting it bending a little to start with. Also, I will glue it flat rather than reflexed. I really don't think there is a need for it in a bow that heavy and it makes getting the bow to brace pretty tricky.

Learned a few things on this one that I'll take to the next so all is not lost, and I'm certainly not discouraged that's for sure. I will make a Warbow yet!!!

Colin

Dennis La Varenne
Posts: 1776
Joined: Sun Sep 07, 2003 10:56 pm
Location: Tocumwal, NSW. Australia

Re: First Crack at a warbow (build along)

#44 Post by Dennis La Varenne » Fri Aug 22, 2014 11:13 pm

Colin,

Frets are not fatal if they are treated properly. Ascham writes about 'pricking' the frets. Frets can happen irregardless of your tillering because essentially they arise where a short section of wood is softer than the wood on either side of it. It is not a sign of poor tillering necessary.

Here is how I have quite successfully treated mine. it does not look pretty, but is has worked so far.
Pricking on Lower-limb.jpg
Pricking on Lower-limb.jpg (68.21 KiB) Viewed 3646 times
This pic shows a line of pricks parallelling the line of the fret and some distance away from the fret. The bow is an Eastern Woodland Indian long flatbow style of the Cherokee pattern made a good few years ago and still shoots fine, showing no inclination to worsen.

The purpose of the prick holes is to allow the harder wood on either side of the fret to compress into the holes where there is a sort of controlled 'give' section which prevents the harder wood from compressing against the actual fret and cause the wood fibres to rupture more and pinch up into a ridge across the bow's belly.

After I have pricked the fret line, I then use a short piece of steel rod and quite heavily press it down onto the pinched up fibres of the fret, pushing them down level with the wood surface, burnishing over the fret, then dribbling super glue over the fret line bit NOT into the prick holes. That seems to fix up the frets.

If you don't notice the frets until they have extended right around the curve of the belly, then you do have a problem. But if they are concentrated only on the highest part of the convexity of the bow's belly, the bow is far from lost.

You should also take note of how level is the surface of the bow on all sides. using scapers incorrectly will often cause slow corrugations to form on the surface of the bow. The hollows of these corrugations are where the softer wood is because the scraper will always gouge deeper into the softer wood with the same pressure from the scraper. Unless the stave is from a log, it is beneficial to use a tool something like a cabinet maker's float in long strokes which leave the areas of softer wood at the same surface height as that of the harder wood along the bowstave.

When I use a scraper, I always hold it at an agle of about 45 degrees to the long axis of the bowstave so that there is more chance of the scraper blade riding across the peaks of the harder wood and missing the softer wood between.

Does that make any sense?
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
Posts: 859
Joined: Mon Jul 09, 2012 10:18 am
Location: Woodford Queensland

Re: First Crack at a warbow (build along)

#45 Post by hunterguy1991 » Sat Aug 23, 2014 10:06 am

Right, an update.

I woke this morning determined to see how far I could get this bow to go.

I thinned down the width of the stave about 2.5mm on either side and then the thickness down 4mm (to keep the 80 % stack) and then evened out the belly round again to make a smooth half circle.

Put the long string back on and evened out the limbs to bend evenly. Currently pulling about 60lbs to make it to a 4-5 inch brace height with the long string.

BUT this is progress!! I will try to get a "long" short sting on it later today and continue to tiller it to see how far it will go. If it breaks, it breaks, lessons learned.

Heres a shot of the bow now.
ELB thinned on tiller (640x480).jpg
ELB thinned on tiller (640x480).jpg (179.36 KiB) Viewed 3643 times
Colin

User avatar
mikaluger
Posts: 410
Joined: Sun Aug 28, 2011 10:08 pm
Location: Melbourne Towne

Re: First Crack at a warbow (build along)

#46 Post by mikaluger » Sat Aug 23, 2014 6:39 pm

Good stuff Colin!

hunterguy1991
Posts: 859
Joined: Mon Jul 09, 2012 10:18 am
Location: Woodford Queensland

Re: First Crack at a warbow (build along)

#47 Post by hunterguy1991 » Sat Aug 23, 2014 7:14 pm

Ok time for an update!!

After being out all day and doing nothing but think about this bow, I decided to see how far it would go, chrysals and all.

I present "The Ugly Duckling"!!...
ELB The Ugly Duckling (640x480).jpg
ELB The Ugly Duckling (640x480).jpg (178.97 KiB) Viewed 3635 times
This shot is at 28 inches, pulling 55lbs. Not quite the 90lbs that I wanted but it has given me some hope with the timber. The belly looks like a road map with the fractures in it, but it didn't break and it shoots!! Throws a Heritage 250 Carbon with a 125grain point like a small missile.

Dennis, I would really appreciate it if you could assess the tiller with your Chord magic on this one. I feel like it does bend early in the tips then later in the handle, as is my experience from shooting it this evening. You can feel it start to bend late in your hand!! very cool I must say.

I think with careful thought, design and crafting good bows can be made with the Silver Ash as a belly.

My next attempt will be using the smaller template I have, for a 45lb bow to see if I can make one chrysal free. Since there are so many compression cracks in it it has lost some performance and draw weight, so I figure if I can find the right stack and dimensions I may be able to make a smaller dimension bow pull just as much as this sucker.

As for the heavier ones, it may just be that the stave needs to be longer so that the timber must deform (bend) a bit less to reach full draw. This stave was 78 inches long, maybe I need one that is 82 or 84 to prevent too much deformation.

User avatar
mikaluger
Posts: 410
Joined: Sun Aug 28, 2011 10:08 pm
Location: Melbourne Towne

Re: First Crack at a warbow (build along)

#48 Post by mikaluger » Sat Aug 23, 2014 8:57 pm

Good work Colin,
Left limb is fine, Right limb slight hinge starting 2/3 of the way round.( Right where it is adjacent to the plaster patch in the background).
Having said that, The fractures in the limb may change the tiller if they get worse.

If you make a bow 82" or 84", you will be able to take up pole vaulting! :lol: Holy Crap thats huge!!!!!!!

hunterguy1991
Posts: 859
Joined: Mon Jul 09, 2012 10:18 am
Location: Woodford Queensland

Re: First Crack at a warbow (build along)

#49 Post by hunterguy1991 » Sat Aug 23, 2014 9:29 pm

Cheers Mick,

Yes I see the spot your referring to now. I may try to relieve it, might just leave it alone since the bow is far from perfect anyhow...

From what I can see, they are bad but aren't getting any worse with shooting it 40 or so times.

A lot of the Yew warbows on youtube that are over 120lbs are 82 inches long. Particularly warbows by Joe Gibbs and the Polleti bows (sorry about the spelling, I think its wrong).

Increased length lessens the tip deflection and so the chance of chrysals...

Food for thought when your Yew turns up anyway.

Colin

Dennis La Varenne
Posts: 1776
Joined: Sun Sep 07, 2003 10:56 pm
Location: Tocumwal, NSW. Australia

Re: First Crack at a warbow (build along)

#50 Post by Dennis La Varenne » Sun Aug 24, 2014 12:47 am

Colin,

Mick picked up on that potential hinge well. However, before you remove any wood inboard of that, just try sitting the bow further to the left on your tiller cradle and see if it disappears.

Because these bows don't have a dedicated handle, they are very tolerant of being held and drawn in slightly different places than that where they sit on the tiller. When you shoot it, mark where it seems to sit in a balanced position in your hand. Open your fingers from the grip and just pull it into your hand. If it wants to rock toward or away from you, move your bow hand up and down the handle area until it balances. The place where the ball of your thumb sits is where you should sit it on your tiller cradle.

It is still shows early hinging, you will have to do a little bit of scraping. Here is my usual analysis. As you can see from the edges of the picture, I have rotated it so that the tiller is exactly vertical.
Colin's-bow.gif
Colin's-bow.gif (372.5 KiB) Viewed 3623 times
All 3 chords are the same length and their vertical blue bars also the same length and exactly at mid-point along the chord. All are copies of the left limb chord serving as a datum. Note how the early hinge is developing just outboard of the vertical blue bar on the RH limb. I have shown where I would remove wood to relieve it. Remember also that what you remove from the RH limb also affects the left limb as well.

Next, note also that because of the developing hinge, the RH tip is bending more, well past where it should sit at the end of the red chord as with the LH limb. The centre chord is right. You have the correct amount of mid-bow stiffness to ensure that the tips whip properly. The hinge may be an issue with a local softness of the wood in that area.

Never mind about lesser draw weight. If it shoots and doesn't break, you have done well indeed. The kind of bend you have there is classic in my opinion. The tips are whipping nicely a la Ascham.
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
Posts: 859
Joined: Mon Jul 09, 2012 10:18 am
Location: Woodford Queensland

Re: First Crack at a warbow (build along)

#51 Post by hunterguy1991 » Sun Aug 24, 2014 9:51 am

Morning Dennis,

I put some light scraping into the area you suggested and it seems to have relieved the hinge pretty well. There is a fairly large chrysal close to the hinge are so id say that's why it was bending like it was.

Thanks for doing the Chord diagram for me, it helps a lot so see where and how the bow is bending.

Shot it again this morning after scraping the hinge and she still hasn't come apart so I will be hanging onto it. Will try for a full draw shot later today and post that up for you all.

I posted it to an archery group on Facebook and suggestions that came back were that the handle was far too stiff... These guys obviously don't know how a longbow is meant to bend!! This is the tiller I will be aiming for with all of the ELB's that I make from now (minus the hinge of coarse!! haha )

Something I did notice is that the string to limb angle is very close to 90 degrees, suggesting that the 28 inch draw is pretty close to as far as this length bow will go with that tiller... unless the handle bends more at longer draw lengths.

Cheers,

Colin

Dennis La Varenne
Posts: 1776
Joined: Sun Sep 07, 2003 10:56 pm
Location: Tocumwal, NSW. Australia

Re: First Crack at a warbow (build along)

#52 Post by Dennis La Varenne » Sun Aug 24, 2014 12:09 pm

Colin,

A bow of this length certainly will bend more in the middle as it draws longer. That is what it is meant to do. The inner part of the bow is supposed to work like the shorter leaves of a leaf spring on a 4WD. With smaller bumps, the outer ends of the long leaves take the jolt, but as the bumps get bigger, the inner shorter leaves do more work. As I understand it, this is how the ELB is supposed to work.

I think you will find that your bow will outshoot a comparative ELB from the same wood which bends more in the handle and has heavier outer limbs like most of them are.

Below are pictures of a genuine Mary Rose ELB on a tiller. The picture is from Robert Hardy's book LONGBOW - A SOCIAL AND MILITARY HISTORY (pp218). Have you recently seen a bow which has a tiller very similar to this one??? I have!

The second picture has my usual chords drawn on it. Note that this bow has a lot more bend in the RH limb. The central chord shows that the bend is circular essentially, but much closer to your bow than what you commonly see. This bow has been drawn to 30 inches. What would happen to your bow if you drew it to 30 inches do you think? This MR bow has spent a few hundred years underwater. It is remarkable that it holds its tiller this well.

Your bow is doing fine. Take no notice of rubbish. Time's wasted what's spent educatin' fools.
Actual-MR-bow-on-tiller-from-LONGBOW.gif
Actual-MR-bow-on-tiller-from-LONGBOW.gif (604.64 KiB) Viewed 3615 times
Actual-MR-bow-on-tiller-with-chords---from-LONGBOW.gif
Actual-MR-bow-on-tiller-with-chords---from-LONGBOW.gif (513.75 KiB) Viewed 3615 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.

hunterguy1991
Posts: 859
Joined: Mon Jul 09, 2012 10:18 am
Location: Woodford Queensland

Re: First Crack at a warbow (build along)

#53 Post by hunterguy1991 » Sun Aug 24, 2014 12:44 pm

Cant believe they actually put on of those on a tiller!!! That's crazy.

I think if I pushed mine to 30 she'd most likely fail, so I'm not going to haha. Had it been made better and not developed Chrysals everywhere in the limbs it would most definitely have continued to 30 and maybe further (my goal eventually is proper MR draw, 30 inches at least).

As happy as I am that the bow I made shoots and bends as is supposed to, with a slight whip tiller, I cant help be a little disappointed that its chrysaled so badly. but I shall take what I've learned on this one and apply it to the next and hopefully it will be even better.

Dennis, could you make some recommendations of timbers that will hold up to the ELB shape and are relatively easily obtained. I know that Mick's American Ash is holding up well, so that's one I will attempt to get my hands on, but are there many others?

Eventually I will place an order for a full length Yew stave, but not till the confidence is a bit higher with my skills.

Cheers,

Colin

Dennis La Varenne
Posts: 1776
Joined: Sun Sep 07, 2003 10:56 pm
Location: Tocumwal, NSW. Australia

Re: First Crack at a warbow (build along)

#54 Post by Dennis La Varenne » Sun Aug 24, 2014 3:35 pm

Yes they did, Colin. But there were plenty more to play with out of 134 recovered as I recall.

With regard to your bow and the frets, can you post some pics of them please? Frets are not necessarily fatal. There is always the possiblity of a dutchman to remedy that problem quite apart from pricking. Have you got any left over American Ash?

Suitable Australian timbers would be Red Ironbark (Eucalyptus sideroxylon) and Spotted gum (Eucalyptus maculata). Both of them would make a much heavier bow than your presently for the same dimensions because they are both pretty close to 1000kg/m^3. American White Ash (Fraxinus americana) rates at around 770 kg/m^3.

Another American hardwood I would recommend, and I think Mick has used it before, is American Red Oak. It is a very open grained wood and can resemble Hickory in appearance. I have it on a few little ELB style bows I have here and it seems to hold up very well in that design. One thing about it is that it is delightfully light in the hand, almost too light and surprisingly quick for an ELB.

On consulting the US Forests Products Laboratory which is part of their Dept of Ag., I found that there are 9 species of Red Oak (Quercus spp.) but I presume the commonest is Quercus coccinea or Scarlet Oak with a dry density of 753kg/m^3, about the same as White Ash, but there are another 2 species of Red Oak with the same density as Scarlet Oak anyway. Heaven only knows which ones are imported here. The Americans certainly do not know which one they use either, but I would still give it a go. Back it with Hickory too.

Here are some more pics from LONGBOW (facing page 213) showing Simon Stanley shooting two Mary Rose approximations as they called them made from Oregon Yew. Have a look at the distinctly stiffer centre section of these two bows which were made by the notable British bowyer, Roy King.
MRA1-and-MRA2-from-LONGBOW-pp-212.gif
MRA1-and-MRA2-from-LONGBOW-pp-212.gif (382.51 KiB) Viewed 3611 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.

hunterguy1991
Posts: 859
Joined: Mon Jul 09, 2012 10:18 am
Location: Woodford Queensland

Re: First Crack at a warbow (build along)

#55 Post by hunterguy1991 » Sun Aug 24, 2014 4:48 pm

Dennis,

I will try to get some photos of the frets tonight if the camera will play the game for me. My bow is Silver Ash not American Ash like Micks and yes I do have a fair bit more here which I will be making more bows with, but changing dimensions and design slightly to try and stop the frets occurring.

Red Iron Bark and Spotty hey, hmm... will have to track down some suitable sized pieces for some heavy bows. I really want to crack the 90lb mark but with good tiller like this last one! I think it would say a lot about my skill level to have made a bow that heavy with a perfect, slight "whip" tiller... time and practise tho I think.

The only red oak I have seen is that which is available at Masters and it is limited in thickness to 19mm I think. American White Ash is one timber I originally wanted but could not get up here in Queensland with much ease.

Beautiful bow in the photos!! Again I notice the string angle which is far from 90 degrees, so its got plenty left in it yet. Also the flat-ish centre section you spoke about...could easily go to 32 inches with no problems I reckon.

I will be starting a new one tomorrow with slightly smaller dimensions than what I started with in this one so I think I should get a nice bow with no frets. if it does fret again, I think that will indicate that the Silver Ash belly is just too soft, but we will see what happens.

Will post photos of my progress with it.

Colin

Dennis La Varenne
Posts: 1776
Joined: Sun Sep 07, 2003 10:56 pm
Location: Tocumwal, NSW. Australia

Re: First Crack at a warbow (build along)

#56 Post by Dennis La Varenne » Sun Aug 24, 2014 10:24 pm

Colin,

I have never really understood how the string angle is measured. It seems to be some kind of straight linear projection from the bow tips measured against the angle of the string to that projection. What I cannot understand is how can you obtain that kind of linear projection from a bowlimb which is curved???

I would have thought is more sensible and accurate to measure the string angle at the arrow nock point at full draw if there is any truth to the string angle/stack hypothesis. I have done my line thing on the MRA 1 showing the limb tip angle in red versus how far the tip would have to bend further to make something approaching 90 degrees.
String-angles-on-ELB.gif
String-angles-on-ELB.gif (449.83 KiB) Viewed 3603 times
If it were possible, even with that length of bow, gorilla length arms would not come into it. If stacking is supposed to start at the 90 degree angle, this bow has a very very long way to go and I don't believe there would be a human being in existence with arms that long.

The angle of the string between top and bottom is 127 degrees. If it were to be drawn so far that that angle were also 90 degrees, the actual draw length would likewise be prodigious. The fluoro green lines show a string angle of 90 degrees measured in line with the plane of the arrow for a string angle at the arrow nock.

So, I am curious as to what your engineering brain thinks of the 90 degree thing.
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
Posts: 859
Joined: Mon Jul 09, 2012 10:18 am
Location: Woodford Queensland

Re: First Crack at a warbow (build along)

#57 Post by hunterguy1991 » Mon Aug 25, 2014 7:51 am

Morning Dennis,

Everything you have said there is spot on as far as I'm concerned!! Diagrams are flawless as well.

The 90 degree string projection is exactly as you have shown it, the line which is 90 degrees from a tangent at the nock or "normal" to the nock.

I my opinion making big bows like that is about pushing the timber to its limits to obtain the heaviest draw possible from a stave and the "limit" in my opinion is reaching a 90 degree string angle. I know it is possible to go past that but it gives no real advantage in terms of performance since you start stretching the limb rather than bending it.

I have no idea what the draw weight of this bow is (probably around 80 or 90lbs going off thickness) but since this particular bow is showing a less that 90 degree string angle it would be possible to shorten the stave and get more draw weight from it.. Now correct me if I am wrong but shortening the stave would produce a greater stress in the handle section of the bow, forcing that area to bend more so it would not be as straight as in the photo, and, it would also bring the string angle closer to the 90 degrees. Since the draw length would not have changed the tips would have to come around further to cope with that length of pull, thus creating a greater angle.

As I said, it is about pushing timber to the limit.


Now compare that to the bow which I made... the string angle is close to 90 degrees, suggesting that that is the shortest possible length in which that timber will allow a 28 inch draw with that thickness of bow. This is where things start to merge... To make a heavier bow, it would have to be longer to decrease the deflection (curvature of bend or amount of bend), which in turn would decrease the likelihood of getting chrysals... I feel that the development of chrysals is a combination of both the stress in the timber and the amount of deflection it is under at that stress.

BUT!!

The bow would also need to be thicker give more stiffness thus creating the larger draw weight.

My engineering thoughts at least... there may very well be some problems with my thought process but to me it all seems logical.

Colin

User avatar
rodlonq
Posts: 2096
Joined: Wed May 06, 2009 3:02 pm
Location: Ingham NQ

Re: First Crack at a warbow (build along)

#58 Post by rodlonq » Mon Aug 25, 2014 12:15 pm

Hello Dennis,

Perhaps the draw length in your diagram is a little exaggerated. It seems the green lines are much longer than the string. Predicting the draw length when the string angle reaches 90 degrees (to a line tangent to the nock) is difficult because the limb tips will move towards the archer and inwards towards each other as the draw continues, all the while the string length needs to remain consistent. I have tried to predict the tips movement in an elliptical arc (orange line) and the location of the string (light blue line) when the string angle at the tangent to the nock is 90 degrees. Not quite as long as your prediction, and probably not accurate either, but a prodigious draw length all the same. For some reason I couldn't re-post the picture as large as you did, I had to down size it before I could attach it?
String-angles-on-ELB2.gif
String-angles-on-ELB2.gif (146.29 KiB) Viewed 3593 times
Edit: I had the following drafted before Colin replied, so what the heck, leave it here. It basically says the same thing in a little more detail.

This is just my take on the issue after studying the mechanics of bow design. I don't think the string angle at the middle of the string (SAM) is as important as the string angle to the tangent (SAT) to the limb at the nock (I just made up those acronyms :lol: ) If SAM exceeds 90 degrees before SAT, you still have potential to bend the bow further without stack (albeit with a lot of finger pinch).

When SAT is less than 90 degrees there is still a small component of force acting on the limb towards the grip (i.e. the tangential component of the force is compression). This tangential component does work by storing energy in the limb in a buckling type of load. When SAT equals 90 degrees, the force applied by the string is purely perpendicular the the tangent at the nock, with zero tangential component. As SAT exceeds 90 degrees the force is now acting on the limb away from the grip (i.e. the tangential component of the force is tension) which is counteracting the perpendicular bending force and resulting in stack. This tangential component undoes work by stretching the limb.

Cheers... Rod

Dennis La Varenne
Posts: 1776
Joined: Sun Sep 07, 2003 10:56 pm
Location: Tocumwal, NSW. Australia

Re: First Crack at a warbow (build along)

#59 Post by Dennis La Varenne » Mon Aug 25, 2014 4:07 pm

Rod,
I can follow your reasoning and I think you are correct. I did not consider the string length. My green line is incorrect because it is based on the current position of the bow tips rather than where they would be if the tips were pulled down to a 90 degree angle as you realised. I like your SATs and SAMs. But in essence, at a SAT angle of 90 degrees, one would still need gorilla arms to get such a long bow back to the stack level. That particular MRA would need a draw length of around a metre long if that arrow is 30" long.

I can see where you have those dotted lines to get a right angle between the string nock and the arrow pass, but were would the focus for the curve be relative to that right angle?

I have always had a fascination with the geometry of bow limbs from my tillering experience and tried reading up on the relevant geometry of circles and so forth. I thought I had a reasonably good handle on it, but I can learn lots more too. I still have trouble getting my head around the maths, but I am not going to give up on the subject. I will just keep pushing my brain until it understands it.

Colin,
If you shortened your bow to get a higher draw weight, the bend would certainly move toward the middle of the bow, but barely noticable on a tiller. You would problably feel it before you saw it on a tiller. You would need to remove more than 2 inches from each tip to start to notice anything. I would do it, but before that, I would like to have a look at the frets to make an assessment of whether it is practicable or not.

Your idea about pushing the wood to the limits of what it will stand is correct. It is just that in such long longbows, most of the time, they are under-drawn even with their cross-sectional geometry. Underdrawn is obviously safer against breakage.
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.

User avatar
rodlonq
Posts: 2096
Joined: Wed May 06, 2009 3:02 pm
Location: Ingham NQ

Re: First Crack at a warbow (build along)

#60 Post by rodlonq » Tue Aug 26, 2014 9:10 am

Dennis La Varenne wrote:Rod,
I can see where you have those dotted lines to get a right angle between the string nock and the arrow pass, but were would the focus for the curve be relative to that right angle?
Dennis,

I initially drew the arc as a circular segment then realising that as the limb bends more, the radius from the arrow pass to the nock will shorten, so I simply squashed the circle to a guestimated ellipse. As stated it is probably not accurate, just trying to develop a concept. The focus of the ellipse will change depending on whereabouts the limb bends. If it was hinged at the arrow pass then the arc would be circular. The more the bend moves toward being whip ended the flatter the ellipse will get. I note that I only needed a short segment of the curve to describe the arc, but a full quadrant was all I could manage with my drawing tool (MacDraw).

EDIT: I didn't really answer the question. The focus is somewhere along the major axis between the arrow pass and the nock. In the case of my estimated orange ellipse (minor axis ~ 0.75*major axis), the focal point is at about 66% of the length of the major axis. It may have been more accurate to assume an ellipse that begins with a straight unstrung bow (yellow ellipse), however the result is much the same for these purposes.
String-angles-on-ELB4.png
String-angles-on-ELB4.png (174.06 KiB) Viewed 3579 times
Cheers... Rod

Post Reply