Saved one today and learned a big lesson

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

Moderator: Moderators

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

Saved one today and learned a big lesson

#1 Post by hunterguy1991 » Tue Sep 30, 2014 12:10 pm

Morning all,

I had an order from a mate for a 90lb warbow, done in spotted gum, backed with hickory.

Settled on a bow 80 inches total length (hes a bit shorter than me) with handle dimensions 32 wide and 28 thick for a 6 inch block then following Dennis's template tapered the thickness down to 12mm at the tips, figuring that it should work out nicely.

Glued it up Sunday, out of the wrapping Monday, cut out rough dimensions, rough shaped the belly round and crowned the back (always crown the back on these now, cant explain it, it just works!!)

Measured out the thicknesses along the limbs to check how even they were, 12.4 or so on one and around 14.3 on the other. The limb that was 14.3 was somewhat thick over its entire length so I started scraping to even them out. Completed that and put a long string on... tips were coming around early, maybe even a bit much but I figured when I got the handle bending all would be ok... WRONG!!

Put the short string on and nothing but the last 8 or 10 inches of tip was bending... CRAP!!

The Problem:

Since the tips were so small compared to the handle there was no where near enough stiffness in them to make the handle bend a bit. Also, when the short string goes on and your getting a bow to brace the force vectors on the tips are different to when you pull the bow to a brace height with a long string...

Should have know about the vectors, im an engineer!!

The remedy for this bow:

Scraped out the belly around the handle to mid limb to get it bending as required to save the bow, And heres the result...
Hickory spotted gum 48@28 Brace (640x480).jpg
Hickory spotted gum 48@28 Brace (640x480).jpg (171.78 KiB) Viewed 2691 times
Brace height is around 6 inches here.
Hickory spotted gum 48@28 (640x480).jpg
Hickory spotted gum 48@28 (640x480).jpg (185.78 KiB) Viewed 2691 times
And here we are at 28 inches pulling 48 pounds.

The tiller is not quite perfect but its ok for a saved bow I think.

Let me know what you guys reckon. Any suggestions on fine tuning the tiller or just leave it as is??

The Remedy for Future bows:

Will be up-ing the tip thickness to 14mm thick and wide to give the tips a little more stiffness to get the handle bending for any bows over around 60lbs to make sure they don't end up like this one did.

Now I need a new piece of spotty for round 2.

Colin

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

Re: Saved one today and learned a big lesson

#2 Post by mikaluger » Tue Sep 30, 2014 3:01 pm

Col, you can fix that tiller, but you are going to lose weight. First third to mid limb needs work I reckon, more on the left limb than right. You could shorten it to bring the weight up again..

Next time, have a try at floor tillering each limb to where you want it, and once your happy with how the whole limb is moving, string the bow to a low brace and work from there. I dont use a long string at all now.

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

Re: Saved one today and learned a big lesson

#3 Post by hunterguy1991 » Tue Sep 30, 2014 3:14 pm

Cheers Mick,

I have looked at it again on the tiller and I think your dead on about the scraping the first third of the limbs, especially the left.

Just made a mistake on dimensions with this one and the timber is not as good as I would have normally used. This time I will be selecting the piece for it and adjust the tip size to help get it where I want.

Whats your process of floor tillering? Have seen and heard of it done a few different ways.

Colin

User avatar
yeoman
Posts: 1563
Joined: Mon Mar 08, 2004 1:32 pm
Location: Canberra

Re: Saved one today and learned a big lesson

#4 Post by yeoman » Tue Sep 30, 2014 8:28 pm

In my courses we use a long string, but it's only just long enough to get over the tips without bending the bow. At this early stage, we focus on the inner third of each limb (because of the vectors, you see). As the string shortens, we spread our attention across more of the limb. The string just gets shortened again and again each time the tips can move 8" under desired draw weight until such time as we get to full brace height.

Your bow? Easy fix. Shorten it a few inches and retiller, even to a higher draw weight. It's not as if you're low on spare limb length. You don't even have to salvage it for your mate. Just get a good shooter out of it and have it 'in stock'. Someone will want one just like it some day.

Actually, if a bow is to be exceptionally long and of a 'mortal' draw weight, then it should be whip tillered. Why? A mortal draw weight stores a mortal amount of energy, and if the long limbs (with much mass) are tillered to come fully round, the energy available to the arrow will be significantly decreased by moving the large mass of the limbs.

Making a long (very long) bow with mid-weight and normal draw length whip-tillered is essentially the same as making a normal sized bow and sticking the limbs on a long, long, looooooong rigid handle.

Onwards and upwards!

I'm jealous of all you people with hickory backing. I called Market Timber and they have no suitable hickory in stock.
https://www.instagram.com/armworks_australia/

Bow making courses, knife making courses, armour making courses and more:
http://www.tharwavalleyforge.com/

Articles to start making bows:
http://www.tharwavalleyforge.com/index. ... /tutorials

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

Re: Saved one today and learned a big lesson

#5 Post by hunterguy1991 » Tue Sep 30, 2014 8:59 pm

So you tiller from the handle outwards? I tiller from the tips in to get the handle bending late as Dennis has described to me in other posts.

Will leave it for the rest of the week as I'm going to be away from home for a few days but I think when I get back I'll take an inch or so off each limb and see how it looks then.

Its already a pretty good shooter, very smooth and pretty quick for that weight, but I'll improve it if I can.

This was just a case of the wrong starting dimensions for the desired draw weight...

I only have a couple of backing strips left myself so will need to obtain some more ASAP.

Colin

User avatar
yeoman
Posts: 1563
Joined: Mon Mar 08, 2004 1:32 pm
Location: Canberra

Re: Saved one today and learned a big lesson

#6 Post by yeoman » Tue Sep 30, 2014 9:25 pm

Yep. From the handle out.

Bear in mind though: there're many paths to a common destination.
https://www.instagram.com/armworks_australia/

Bow making courses, knife making courses, armour making courses and more:
http://www.tharwavalleyforge.com/

Articles to start making bows:
http://www.tharwavalleyforge.com/index. ... /tutorials

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

Re: Saved one today and learned a big lesson

#7 Post by mikaluger » Tue Sep 30, 2014 11:21 pm

So, Market timber have no Hickory.?
Thats where I was going to get mine from.............Hmmmmmm.
I only have a little bit left, this is not good at all.!!!!!!!!! :surprised:
Melbourne furniture timbers have closed down as well..............what to do?

User avatar
yeoman
Posts: 1563
Joined: Mon Mar 08, 2004 1:32 pm
Location: Canberra

Re: Saved one today and learned a big lesson

#8 Post by yeoman » Wed Oct 01, 2014 6:05 am

They have some, but I emailed to ask about it and apparently none of it would be suitable for our needs. He also said it was Pecan and not strictly Hickory. Not that that matters because it is in the same family and obviously makes for a good backing material.
https://www.instagram.com/armworks_australia/

Bow making courses, knife making courses, armour making courses and more:
http://www.tharwavalleyforge.com/

Articles to start making bows:
http://www.tharwavalleyforge.com/index. ... /tutorials

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

Re: Saved one today and learned a big lesson

#9 Post by hunterguy1991 » Wed Oct 01, 2014 6:59 am

Try Otto timbers in Adelaide,

I had contacted them about it a month of so ago and apparently they have quarter sawn stuff in stock most of the time.

You may have to get it courier but it will be a lot cheaper to Melbourne than to me up in Queensland.

Colin

Post Reply