Even Tillering Tricks?

[cool_98_555]

Hi guys,

I'm at the tillering stage of another osage bow.  One issue I always have when i'm tillering (no matter what tool I use) is keeping the sides equal thickness all the time.  I can mark the whole limb at a spot where I need to remove wood, and I will remove the mark, but I always end up honoring one side over the other somehow because it ends up uneven in the end.  Do you guys always check the thickness on both sides after every wood removal with a calipers or something?  I mean how can you know for sure?  I've tried flipping the bow around on the tree several times to see where wood needs to be removed on both sides of the limbs, but I don't want to go through the trouble of doing this after every single wood removal,...know what I mean?  What do you guys do to ensure you have equal thickness on both sides of the limb? 

Maybe it's the way I'm looking down the bow when i'm removing wood.  Like I have the bow in a vise on my bench, and when I remove wood my body is on one side of the bow, not looking up the length of the bow.  Maybe I need to be at the limb tip and look up the bow lengthwise and remove wood towards me....I don't know I'm just thinking aloud now.

[tattoo dave]

Hey Cool, I can’t speak for everyone but I’m not overly worried about the thickness matching as long as the tiller is good. When I say not matching I mean you’ll never see me break out a pair of calipers to check the thickness. If they are obviously different, then the tiller is probably off as well. But if the tiller is good, I wouldn’t worry about a slight difference in the thickness.

Tattoo Dave

[DC]

I do all my scraping in a bench vice so I'm always working from one side. The side toward me gets thinner than the side away. When I do the other limb I turn the bow around and the same thing happens so I scrape propeller twist into the bow. Once I realized what was happening I compensate a bit by favouring the far side. I forced myself to actually look at both sides when I'm going between the tree and the vice. I've found that I can see a very small thickness difference. I also think that minor thickness differences are not that big a deal. I deal with high crown saplings a lot and there is really no proper way of measuring thickness differences ocross the limb on them. Sometimes you just have to go with the force

[BowEd]

Cool....It's a matter of knowing your tendencies and compensating for them working with hand tools.Learning to remove wood with a flat stroke.As said by others a good eye and finger tips can pick it all out and even it up after every material removal.Big thing is to not remove too much at one time.
Another thing is to establish tapered thickness from a line on side of limb but leaving it proud in the center of limb.Slowly flattening it out as you tiller.Pencil line marks across removal area show where you've removed material.That way your edge thickness's never change.

[youngbowyer33]

The side toward me gets thinner than the side away. When I do the other limb I turn the bow around and the same thing happens so I scrape propeller twist into the bow.

I'm pretty sure this is the issue I've had with my last 2 bows. And it feels like whatever side I remove wood from to try and correct it it doesn't change much. Gonna have to figure it out

[Hawkdancer]

Perfect is always the quest, but close counts in horseshoes, hand grenades, nuclear weapons, cow pies, and tillering!  Other than a chuckle, don't pay much mind - I am just approaching finish tiller and draw weight on my first bow!  I'm getting closer!   !
Hawkdancer

[bushboy]

i think I do it different than most because I've learned to tiller without a tree/tiller stick.i freehand some pencil lines for a somewhat heavy thickness,depending on the stave,generally 9/16ths thick .following the lines,rasping down to the marks leaves the center looking like a small pitch of a roof.then flattening it out will give even edges(best to work outside for the best lighting)!then on to floor tiller,trying to keep it flat.after getting the bend looking good,string it and finish tillering by the look of the brace

[Del the cat]

Cool....It's a matter of knowing your tendencies and compensating for them working with hand tools.Learning to remove wood with a flat stroke.As said by others a good eye and finger tips can pick it all out and even it up after every material removal.Big thing is to not remove too much at one time.
Another thing is to establish tapered thickness from a line on side of limb but leaving it proud in the center of limb.Slowly flattening it out as you tiller.Pencil line marks across removal area show where you've removed material.That way your edge thickness's never change.

+1, Yup... you nailed it.
Spend as much time looking and feeling as you do actually removing timber. That's what tea, coffee and the internet are for, keeps you thinking, stops you cutting
Del

[simk]

What do you guys do when little bumps and waves occur and grow while scraping a formerly flat back? I then regularly have to take my excenter sander and flatten the back in order to avoid further growth of these irregularities....
Suggestions?

[Greg DeJanes]

 Bushboy

You mean I'm not the only one to tiller like this ??  I do like to use a ruler to measure distances on the braced bow and picture at full draw. No tree no stick!

Thanks,

Greg

[George Tsoukalas]

As I remove wood, I look at both sides and check with my fingers as well.

I remember I was gifted a yew stave by Jim Fetrow many hears ago. Naturally, I wanted it to turn out well. I checked both sides of each limb with calipers to make sure that wood removal was even.

It didn't matter. Both limbs favored one side at brace.

In the final analysis bending wood will tell all.

Nevertheless, I do check visually with both eyes and by touch with my fingers.

Jawge

[Eric Krewson]

I lay out a bow with very precise lines drawn for the side profile, I call these lines the road map for my bow. The lines keep me from running off the road and making one side thinner than the other, you do have to pay attention to them as you remove wood.

For an osage bow in the 50# range I start at the fades with a 1/2" tall mark and drop the mark 1/16" every 6" until I get to 1/4" near the taper at to nock and l don't go any deeper. I make slightly round belly bows so even with the 1/4" side line my limb will be at least 1/2" thick at the tips.

If I have too much poundage I drop my main line another 1/16" again stopping 1/4".

My layout lines;

[Del the cat]

An experience bowyer may seem to work fast, but each stroke of the tool is considered and has a purpose. It is also constantly monitored by eye and touch.
For a newbie it's easy to sit there happily removing wood in a sort of trance without keeping a close watch on what's actually happening!
I often advocate working along each edge and then taking out the resultant raised central portion. This has a couple of benefits, it allows you to follow a line or thickness on each edge, but if you do make a slight error (and we all do) you still have wood along the centre which can compensate. Tools also cut better into a narrower edge that a big flat area.
This technique works well with everything from a scraper to an axe. (see sketch which was to show how I use an axe) for roughing down.
Final finishing may want a nice flat face of course.
Del

[bushboy]

Great model del!exactually what I was getting at!

[BowEd]

An experience bowyer may seem to work fast, but each stroke of the tool is considered and has a purpose. It is also constantly monitored by eye and touch.
For a newbie it's easy to sit there happily removing wood in a sort of trance without keeping a close watch on what's actually happening!
I often advocate working along each edge and then taking out the resultant raised central portion. This has a couple of benefits, it allows you to follow a line or thickness on each edge, but if you do make a slight error (and we all do) you still have wood along the centre which can compensate. Tools also cut better into a narrower edge that a big flat area.
This technique works well with everything from a scraper to an axe. (see sketch which was to show how I use an axe) for roughing down.
Final finishing may want a nice flat face of course.
Del
[/quote
That's it Del.Good pic drawing.