Red Oak Board Bow Layout.

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indie · #1 Post by **indie** » Tue Oct 27, 2015 9:10 pm

Hey guys. Finally making some time to make a board bow. I sourced a decent looking red oak board which is 42mm wide and 19mm thick. I've laid out a not quite full pyramid with spec's as follows;

Total length 68"
Handle 4"
Fades 2 1/2"
Parallel limb 4"
Taper to 1/2" at tips.
Backing to be linen or silk depending on what I find.

The draw weight is not critical as this is more about the learning process but somewhere around 40 pound at 28" would be good. I've already cut out the back profile based on the above but have not as yet thinned the board and this is where I'd like some advice.

I've seen most full pyramid board bows are around 2 1/2" wide at the fades and I'm suspecting that this width gives you a good tiller when combined with an even thickness along the length of the limb. So I'm wondering if my 42mm max limb width means I should taper the limbs to be a bit thicker towards the fades? I was looking at 1/2" thickness at the tips as a starting point.

I'll be adding some spotted gum for a handle so assume it is non-bending.

Thanks in advance.

hunterguy1991 · #2 Post by **hunterguy1991** » Wed Oct 28, 2015 6:21 am

Dave will be able to give you a better idea on a good thickness to start the limbs at but for a 19mm thick board you will reduce the thickness from the handle side of the fades to a thickness on the tip side, maybe 10-12mm or so for 40lbs, again Dave will hopefully give you a good figure here. This thickness will then most likely continue the majority of the limb before you begin tillering. When you start tillering you may need to reduce the thickness in the outer limbs to get a smooth bend.

hope that helps a little.

look forward to seeing your progress.

Nezwin · #3 Post by **Nezwin** » Wed Oct 28, 2015 8:49 am

Colin is right in that Dave can give a precise idea of what thickness/width/length will be needed for x-weight, but if you've already cut the width profile to those dimensions, I would probably cut nocks & radius edges ready to start tillering.

Your bow should be around 1.5" at it's widest point, which isn't wide enough to get a 'true' pyramid bow tiller, but if you start removing small amounts of material at short draws on a tillering stick or tree, your first goal will be to get the tips moving. Greybeard & others have published the 'rule of tillering' several times, but here's my understanding -

There are certain rules for tillering which ensure the bow isn’t damaged before it is finished.

• Never draw past desired weight. Doing so can cause permanent & excessive set within the bow.
• If you see a hinge (are of localised or excessive bend) forming – STOP! Hinges are a principal cause of a bow failing and must be resolved as soon as possible.
• Only draw as far as you need to ensure the limbs are bending equally & smoothly. Do not overdraw the bow at any point.
• For the purpose of this course, only remove material from the belly of the bow, never the back.

Sequentially, tillering occurs in the following order;

1. Floor tillering – bend the limbs of the bow against the floor with your hand in the centre (stiff) section. This will provide a very rough estimate of how the bow is bending and if the limbs are bending evenly.

2. Long String – fit the long string to the bow, place the bow upon the Tillering Tree and exercise the limbs just a few inches. This should give you a sense of how the limbs are moving. If there’s a stiff spot, scribble on the belly in this area with a marker then remove material appropriately. Continue with this until you are drawing to around 16” or so with the long string.

3. Short String, Low Brace – Now fit the short string (that being the string that will be used for the bow itself) but twisted to a low brace height, perhaps a 3” brace. Slowly exercise the limbs and remove material appropriately. Do this until you are drawing to around 16” or so.

4. Short String, Full Brace – Twist your string shorter until you have the bow at full brace (around 6”-7”). Repeat the exercising the limb/removing material process until you are drawing to a full 28” draw. If the bow is heavier than intended, you can now remove material and re-tiller until the desired weight is reached. If the bow is underweight, I’m very sorry – there’s no easy fix!

I don't know if this is a 'good' way to taper a limb, but it worked for me in this red oak bow with a glued-on handle, similar board thickness to your own (perhaps thinner, I can't really remember) -

: IMG_20150101_155655.jpg (200.94 KiB) Viewed 9280 times

: Red Oak w glued on recurve.jpg (117.59 KiB) Viewed 9280 times

The 6-8" dimension may have only been 4", it was a while back now. And with the thickness taper, if you go to 1/2" at the tips you should be fine (I think).

indie · #4 Post by **indie** » Wed Oct 28, 2015 1:36 pm

Thanks Hunter and Nez for the input. Some good advice there. I'm keen to start thinning but will try control myself. I'll get the handle glued on soon along with some tip overlays and hopefully Dave can chime in with his knowledge.

Cheers, Indie.

indie · #5 Post by **indie** » Fri Oct 30, 2015 4:15 pm

So I've read as far back as page 7 of Traditional Crafts so far and have found some good starting points including this one; http://www.ozbow.net/phpBB3/viewtopic.php?f=34&t=14289

Off to Masters now to look for some more boards.

indie · #6 Post by **indie** » Sat Oct 31, 2015 5:48 pm

Got a couple of bows on the way.

Small one is for my kids. 50" long, 3.5" handle, 2" fades out to 42mm. 2" parallel before tapering to 1/2" at tips. I've thinned the limbs down to around 11mm and seems to be bending well on the floor. Left the handle at 19mm and graded that down to the limb halfway into the parallel section. So far so good!

If this one comes out fine I'll be making a couple more so they can have one each.

Larger one is for mine as per specs above. No thinning of limbs at this point. Wish I hadn't cut in the handle/shelf until after thinning down the limbs. Will glue on handle soon and keep at it.

Need to make myself a tillering tree next.

Also, for tip overlays, is it necessary to use a denser wood than red oak? And where do you guys source your phenolic?

Thanks. Brad.

EDIT; Larger pic file added.

Nezwin · #7 Post by **Nezwin** » Mon Nov 02, 2015 3:53 pm

If you're using a B50 string (which is the traditional standard, by my understanding) some Red Oak trimmings will be fine. If you're using Dynaflight, you'll need horn or phenolic. No idea where to get it, I'm afraid.

Some bigger pictures of the bows would be great. For feedback, it's good to have an unbraced, a braced and a full draw picture.

indie · #8 Post by **indie** » Mon Nov 02, 2015 6:45 pm

Thanks Nezwin. I have been looking at which string material to get and it was between B50 and D97. B50 is certainly a bit cheaper (looking at ebay US supplier). Any sellers on here? AMSO?

As to the photos, the longer bow has not yet had the limbs thinned so a bit to do yet. The shorter bow has had the limbs thinned so as soon as I set up a tillering tree I'll get some pics of it on there. I'll have to make the file size bigger next time too.

yeoman · #9 Post by **yeoman** » Mon Nov 02, 2015 7:03 pm

Isn't Dacron and B-50 the same thing?

For a bow as long as you've made, Indie, I'd recommend a limb about 15 mm thick to start with. You will loose the saw marks near the handle, and will lose up to 3-4 mm at the tips to get circular tiller. Start your 15 mm thickness about 2" out from the flare. From this point, taper in a straight line to full 19 mm thickness for the same length as the handle is parallel. I sincerely hope all that makes sense. If not please sing out.

Nezwin · #10 Post by **Nezwin** » Mon Nov 02, 2015 7:37 pm

yeoman wrote:Isn't Dacron and B-50 the same thing?

Good call, getting words mixed up - Dynaflight is what what I meant. Will edit the original post.

hunterguy1991 · #11 Post by **hunterguy1991** » Mon Nov 02, 2015 7:39 pm

I've used (and still do) fast flight strings on red oak bows with a nice hardwood tip overlay. An off cut of spotty, merbau, ironbark etc will all work just fine with fast flight/Dynaflight/D97. Trick is to pack your loops with a few extra strands (I usually use 4) to thicken them up a little bit.

Dacron or B-50/B55 strings always seem to be a bit sloppy for me and my bows, even at light weights so I always use FF/Dynaflight/D-97. Tend to give your bow arm more of a touch up as well!

Looking forward to seeing these on a tiller mate

Colin

indie · #12 Post by **indie** » Tue Nov 03, 2015 6:28 am

Yeoman, thanks for the input. I think I understood that. Essentially you're saying to keep full 19mm depth to the end of the 4" handle, then taper to 15mm halfway into my 4" parallel limb section, then taper to 11 to 12mm at the tips. Is that right? I was thinking I'd glue on an extra section for the handle maybe to around 38mm total depth and then taper that down to the mid-parallel section.

Thanks for the tips on the string Colin.

yeoman · #13 Post by **yeoman** » Tue Nov 03, 2015 7:15 am

indie wrote:Yeoman, thanks for the input. I think I understood that. Essentially you're saying to keep full 19mm depth to the end of the 4" handle, then taper to 15mm halfway into my 4" parallel limb section, then taper to 11 to 12mm at the tips. Is that right? I was thinking I'd glue on an extra section for the handle maybe to around 38mm total depth and then taper that down to the mid-parallel section.

Thanks for the tips on the string Colin.

You've got the emboldened bit exactly right. However I meant for you to initially cut the thickness a full 15 mm for the whole length, and let the tillering process dictate how thin the tips end up. It's really difficult/annoying to put wood back on once you've taken it on.

If you want to build up the riser a bit, there really is no need to go more than 3-6 mm. This will increase the stiffness far more than you might at first anticipate, and makes for a much safer transition from limb to fade to handle. Making the handle too thick with glued on honking great lumps of wood is a common way beginners break bows, I think.

yeoman · #14 Post by **yeoman** » Tue Nov 03, 2015 7:17 am

Also, if you make your riser lamination from some other timber, spotted gum or such, and make the tip overlays of the same wood of the same thickness, the bow will have a simple sophistication to its look.

indie · #15 Post by **indie** » Tue Nov 03, 2015 8:56 am

Thanks Yeoman. I've already cut a section of spotted gum which is about 11mm thick. I'll glue that on and then plane down to suit. Will also be good for tip overlays.

indie · #16 Post by **indie** » Sun Nov 08, 2015 5:41 pm

Handle is glued onto the larger bow and shaped and things are roughed out. All starting to bend with some floor tillering. Tomorrow I'll knock up a tillering tree. As yet I don't have any string material so will use some paracord for a long string.

What do you guys do for tillering nocks? Do you file the side grooves in but not on the back, and then add overlays and finish off? I wondered about putting in a small groove on the back of the bow and then sanding that off before adding angled tip overlays.

hunterguy1991 · #17 Post by **hunterguy1991** » Sun Nov 08, 2015 7:11 pm

Just some nocks cut in the side should do fine for tillering, just don't make the loops in the strings too big and they wont slip. You could even just add the overlays and leave them rough for the time being.

greybeard · #18 Post by **greybeard** » Sun Nov 08, 2015 8:01 pm

Indie,

I use a double pocket bow stringer.

Daryl.

yeoman · #19 Post by **yeoman** » Mon Nov 09, 2015 4:22 pm

My own practice mirrors Colin's.

There's no reason your tillering nocks have to be anything separate from your final nocks.

indie · #20 Post by **indie** » Tue Nov 10, 2015 9:24 pm

Got the limbs bending to about brace height pulling about 35lbs. So a fair way to go to get it to 45 at 28.

Next job is to put the backing on. I bought linen but that was before I learnt that linen ain't linen. All I know is it was expensive linen. Also since learnt that linen shrinks when wet and stretches when dry. Worth sticking with the linen? Note it was bad enough going to Spotlight to buy linen and there's no way I'm going back to buy silk.

Thanks for the input on how you do your nocks. I like Daryl's idea but ended up filing in side nocks.

Lastly, the bow is currently around 24.5oz. Is it worth shaving a bit off the sides at this time? I'll weigh it again after I back it.

indie · #21 Post by **indie** » Thu Nov 12, 2015 6:05 pm

Pic of where I'm up to. Currently around 40lb as shown. Need a better background to cut down some visual distortion. Top limb is on the left. It's probably a tad stiffer than the other at present. Bow as yet is unbacked.

Current mass is 24.3 Oz and need to remove around 5 of those. I've decided to leave the tips a little stiff and thin the width a bit which should knock off some mass. I've also got a few saw marks on the sides so will sand them off once I get closer as I don't wish to lose my layout marks just yet. Doing a fair bit of work with a cabinet scraper so it's slow going. Might have to invest in a spokeshave soon.

: Red Oak Bow 1.jpg (298.45 KiB) Viewed 9012 times

yeoman · #22 Post by **yeoman** » Fri Nov 13, 2015 5:44 am

If this is your first, or even your fifth bow, I strongly recommend against worrying about the mass of the bow.

As a beginner, there are already a lot of variables to keep across:

- Right draw force
- Right draw length
- Right tiller shape
- Not breaking it

If you then add in the variable of trying to control the mass, you might become a bit overwhelmed, and you could well end up with a broken bow or one massively underweight.

The goal in your early bows should be simply to make one that shoots, and is intelligently tillered. So don't worry about the physical mass of the bow for now, and just enjoy the journey of making shavings.

indie · #23 Post by **indie** » Sun Nov 15, 2015 9:15 am

Thanks for the advice Yeoman. I won't get too hung up on the mass but for a first timer I'm finding it's not a bad guide as to whether I've still got way more wood to remove or not.

Tillering with a cabinet scraper is a slooooooow process. At least I am not making mistakes quickly.

indie · #24 Post by **indie** » Thu Nov 19, 2015 5:20 pm

Not a lot of progress but did get the linen backing on the kid's bow. I think I'm more excited about that one than I am about my own. Here's a pic of it at 20lb. Still a bit to go. Any thoughts on how to tiller from this point on greatly appreciated. Not sure if the camera was perfectly level for the shot but pretty close.

Indie.

cmoore · #25 Post by **cmoore** » Thu Nov 19, 2015 8:19 pm

Looks nice so far indie, the left limb looks a tad stiff around the mid limb area but it looks like it's coming around nicely, ...I would also make a long string for the bow and string it up to a low brace height, say 3 or 4 inches then put her on the tiller & observe how she looks....slow and steady

indie · #26 Post by **indie** » Fri Nov 20, 2015 7:59 am

Thanks cmoore. The left limb seems to bend more quickly straight off the handle. Will scraping mid-limb on the left release some tension in that area so the bend at the fades will even up?

cmoore · #27 Post by **cmoore** » Fri Nov 20, 2015 8:41 am

You're on the money indie

if you get that mid limb working more it will relieve that hinge that you're seeing at the fade

greybeard · #28 Post by **greybeard** » Fri Nov 20, 2015 8:57 am

I have found it beneficial to gently exercise the bow limbs after each scraping session before putting the bow back on the tiller.This I believe helps the reworked limbs settle in.

If the bow can be drawn safely to brace height I would make a string to the correct length and use it to finish the tillering.

The short string will give a different braced profile because the forces are pulling in towards the handle whereas the long string is pulling downwards and away from the handle.

Daryl.

yeoman · #29 Post by **yeoman** » Fri Nov 20, 2015 11:26 am

I would shorten the tillering string. Short enough that you need to stretch it a little to get it into the nocks. This will change the leverage and the bent shape will be closer to what you would expect with a final string.

indie · #30 Post by **indie** » Sat Nov 21, 2015 10:37 am

Thanks for the input guys. I don't have any string material so far so still using paracord. I've shortened it to get maybe a 1" brace off the handle. Did a bit of scraping as suggested and put it back on the tree. Pic of outcome as below.

: DSC_0034.JPG (277.88 KiB) Viewed 8882 times

Since that photo I did a touch more scraping on the left mid limb. What I noticed when putting it back on the tree was the right limb is twisting clockwise when viewed from the tip. Bugger. I will check to see the limb thickness is even across the entire width. Twist seems to develop early in the limb so maybe needs some light scraping on the front side (viewed from the front as per pic) or left side when viewed from tip to get that side of the limb bending as per the rear side. Make sense?

Ozbow

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