Tiller gadget???

[superdav95]

Hello gang.  I’ve had this hair brained idea for a while now of a early tiller gadget that may help take some of guess work out.  Below are a few pictures of a prototype of sorts and seems to work quite well.  It’s based on the yard stick method focusing on the arc of bend and getting it to bend evenly on both sides of mid mark of bending portion of limb.  I added a couple of cheap little metal rulers that came with little pocket clip sliders on them.  I bent those back as shown to be used as a belly contact depth indicator.  Up to this point I’ve been just using an additional ruler held up measuring depth but was a pain to do and be consistent with.  This sorts that out and is much easier to handle.  In the pics you’ll see that I have added 2 little rulers with sliders.  This is because I usually build assymetric bows with the top limb generally inch longer.  Thus the mid mark on top limb is longer by a half inch.  I made a slot on an old yard stick a few inches for some adjustability.   I’ll alternate methods depending on the build but figured I’d post this for anyone who may want to make one and try it.  Cheers. 

[superdav95]

Here it is in action! 

[Bob Barnes]

That's pretty cool Dave.  I also like the way it displays the symmetry of the bend.  A quick glance gives you lots of good information.   

[JoeC]

Looks like a great tool!

[Badger]

Looks like a handy tool!

[JW_Halverson]

I do something similar once I get the bow to low brace. I mark the end of the fade outs and measure the total distance down the limb to the nock. I divide that by 8 and mark the limb at each of the 8 divisions (I usually make one limb 1" longer than the other, so each limb is marked equally)

Then at low brace I measure the distance from the string to the belly of the limb at each of the stations. I mark with pencil the locations where the measurement on one limb is less than the other. I make light marks if they are close, dark marks if not close. Then, having measured each of the 8 stations and marked the limbs appropriately, I take the bow over to the shave horse and scrape off the pencil marks. Restring, exercise the bow 20-30 times pulling about 2/3 of the final draw weight target goal, rinse and repeat.

Once both limbs are symmetrical and have a pleasing curve, I start to shorten the string to bring it closer to full brace. Rinse and repeat the measuring, marking, scraping. By the time I hit brace height I am usually fairly close to target draw weight and have the bending profile I want in the limbs. From there, tillering is usually just taking an equal number of long strokes from fade out to tips with a card file from both limbs.

[superdav95]

I do something similar once I get the bow to low brace. I mark the end of the fade outs and measure the total distance down the limb to the nock. I divide that by 8 and mark the limb at each of the 8 divisions (I usually make one limb 1" longer than the other, so each limb is marked equally)

Then at low brace I measure the distance from the string to the belly of the limb at each of the stations. I mark with pencil the locations where the measurement on one limb is less than the other. I make light marks if they are close, dark marks if not close. Then, having measured each of the 8 stations and marked the limbs appropriately, I take the bow over to the shave horse and scrape off the pencil marks. Restring, exercise the bow 20-30 times pulling about 2/3 of the final draw weight target goal, rinse and repeat.

Once both limbs are symmetrical and have a pleasing curve, I start to shorten the string to bring it closer to full brace. Rinse and repeat the measuring, marking, scraping. By the time I hit brace height I am usually fairly close to target draw weight and have the bending profile I want in the limbs. From there, tillering is usually just taking an equal number of long strokes from fade out to tips with a card file from both limbs.

JW.  I like your approach with the 8 sections and markings. I’m gonna use that.  I’ve been using finger calipers and actual calipers and have been writing measurements down and essentially doing same thing.  I’m only Using this yard stick gadget to get to low brace and then put it up on the
Wall pull and finish up there.  I’ve been finding that this gets me very close once I get to brace to symmetrical even bend. I then so similar as you after this.  I’m gonna use your approach at low brace I think.  Thanks.  Dave

[Pappy]

Looks good Dave, guess I am still old school, I still use a tiller stick until I get it to low brace, my long string is as short as I can get it, I pull it down on the stick an inch at a time and with it on the stick I stretch a string from nock to nock just like I was stringing the bow , then look and make my measurements , make any adjustments and move down another inch, stretching the string each time from N-N , guess the string works kind of like your yard stick  by the time I am ready for low brace the limbs are usually very even bend, once low braced I go to the tiller tree from there.
 Pappy

[superdav95]

Yes this very similar to what I’m basically doin here.  I like the string idea. I may have to give that a go too.  Like you I just use this to get me to low brace  then onto the wall tiller tree.   There has been recent discussions about a careful approach to early tiller and how it can affect the overall outcome of the bow.  I believe this is the case and a lot of mistakes can happen just getting to brace.  A good tiller starts early in the build. 

[Jim Davis]

I floor tiller until normal brace, then eyeball the bends and adjust as needed.

When the bends look as good as I can guess I go to my tillering post and pull with a scale and rope.

I don't do any measuring. Measuring is of no use unless you are working with a flawless stave. Any kinks or curves make numbers worthless.

People have made tillering tools for a long time, but tillered without them far longer.

https://www.archerylibrary.com/books/hickman/archery-the-technical-side/klopsteg/a-bend-meter-and-a-bow-weigher-using-the-same-indicator/

[superdav95]

I floor tiller until normal brace, then eyeball the bends and adjust as needed.

When the bends look as good as I can guess I go to my tillering post and pull with a scale and rope.

I don't do any measuring. Measuring is of no use unless you are working with a flawless stave. Any kinks or curves make numbers worthless.

People have made tillering tools for a long time, but tillered without them far longer.

https://www.archerylibrary.com/books/hickman/archery-the-technical-side/klopsteg/a-bend-meter-and-a-bow-weigher-using-the-same-indicator/

I wish I was good enough to not need tools to assist me in tillering.  I’m sure it will get better over time and be less reliant on them and still get good results.  This curvometer is a good reminder that it’s all been done to some extent.  Cool idea!   

[Dances with squirrels]

"I don't do any measuring. Measuring is of no use unless you are working with a flawless stave. Any kinks or curves make numbers worthless."

I'm with Jim on this, to include, lumps, bumps, small deflex or reflex areas, and more, but...

It's ok to use 'some' measuring instruments or thickness or bend indicators if we apply them appropriately and not give them more value than they deserve, always keeping in mind that a selfbow's limbs, and/or areas of the same limb are unique and shouldn't necessarily be made to look or flex like the other limb, or other areas of the same limb. Doing so might make the limb look more pleasing to the eye, or like the perfect limb or arc in our mind's eye, but isn't necessarily the best thing for the bow.

[superdav95]

"I don't do any measuring. Measuring is of no use unless you are working with a flawless stave. Any kinks or curves make numbers worthless."

I'm with Jim on this, to include, lumps, bumps, small deflex or reflex areas, and more, but...

It's ok to use 'some' measuring instruments or thickness or bend indicators if we apply them appropriately and not give them more value than they deserve, always keeping in mind that a selfbow's limbs, and/or areas of the same limb are unique and shouldn't necessarily be made to look or flex like the other limb, or other areas of the same limb. Doing so might make the limb look more pleasing to the eye, or like the perfect limb or arc in our mind's eye, but isn't necessarily the best thing for the bow.

Thanks for your thoughts on this.  I only would use this to get to low brace.  I’ve also used a floor tiller method lots too and still will.  I have found that using a method like this however helps me get to low brace little quicker with less adjustment then if I floor tiller.   That’s just me.   I still incorporate all the principles of good taper and or narrowing needed including humps and bumps on belly and back.  I use my fingers as calipers for this going by feel and by eye.  On more intricate builds and multiple laminated layer bows I’ll use actual calipers.  This little gadget is just a convenient tool for me to get close.  The real job of tillering keeps going from there.  My theory is that it may be possible to avoid some over stressing the limbs that may occur during floor tiller by the use of a tool like this to get to low brace instead.  I know that for me getting a bow to brace with floor tiller sometimes results in uneven limbs when braced.  Not a big deal I suppose but when I’ve used this method I rarely get that if at all.  I also find that doing so makes the rest of the tiller easier.  When I floor tiller I will typically get my inners bending as well as I can and as evenly as I can with slightly less bending on the outers.  I’ll then work the outers and mids to get bend looking good.  This works for me just fine to a good shooting bow.  I’ve often wondered if more stresses are placed on the inners floor tillering this way.  Now some will say well why not just get the bend looking good the entire length of the limb before brace?  I’ve tried this and found I get a little more set poss as result of the stresses are put on the outers.  I may be overthinking this and the difference may be negligible.  Going by feel is great for persons who have the experience to do it correctly.  For those that are still getting there a tool like this or anything like it (pappys string measure method) to assist is a good option till then.  My first several bows were all floor tillered.  I know that getting to brace with some of those was likley done too early and stressed the wood prematurely putting way more pull in lbs draw weight target to get to brace.  They still shot ok but difference was noticeable.  I guess my thinking with this little gadget is that a new bowyer can use something like this or the like and be able to stay below target draw weight safely limiting over stresses until they get a good feel for floor tillering.  A good strategy for progress for newer bowyers may be a combination of both a measuring gadget and floor tiller to get experience and feel for how much force one should apply when floor tillering.  I hope someone out there can get some use for it possibly especially those just starting out.