Primitive Archer
Main Discussion Area => Bows => Topic started by: Eric Krewson on September 15, 2015, 05:23:37 pm
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I was looking through and obscure picture file on my computer and found a picture of the first tillering gizmo I made. It has changed a bunch since my first attempt. A friend from Mississippi named Daniel Willoughby came up with the idea to replace the set screws that held the pencil with a 5/16th nut, a much better idea. Another guy suggested cutting the shape to a pyramid shape, another great idea.
Here is the first design;
(http://img.photobucket.com/albums/v181/ekrewson/bow%20making/limb%20marker%20side%20view_zpsxtk5hnlp.jpg) (http://smg.photobucket.com/user/ekrewson/media/bow%20making/limb%20marker%20side%20view_zpsxtk5hnlp.jpg.html)
The latest version;
(http://img.photobucket.com/albums/v181/ekrewson/bow%20making/newgizmoshape_zps216a4172.jpg) (http://smg.photobucket.com/user/ekrewson/media/bow%20making/newgizmoshape_zps216a4172.jpg.html)
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It's cool to look back over time and see how things evolve with use. That is really a handy tool to have in your bowyering tool box.
I'm not sure where my inspiration came from, but I have modified mine to be a multi tool of sorts. The body is a flat but has dowels protruding equa-distant from center point on the top side. This allows me to reverse the direction the pencil protrudes from and have a tool that defines the running center point on a stave. Now someone tell me where I saw that, cause Im pretty sure I didn't dream it up on my own.
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I have made me s a similar tool years ago. But laid it aside, for me only useful for cicular regular tiller on straight bows like ELB's.
I have made another instrument, a kinda caliper also with the nut + pencil thing, this is quite useful for me on bows with changing crowns.
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I have made me s a similar tool years ago. But laid it aside, for me only useful for cicular regular tiller on straight bows like ELB's.
I have made another instrument, a kinda caliper also with the nut + pencil thing, this is quite useful for me on bows with changing crowns.
Lets see a picture, it sounds cool.
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Strongman, did you get it from Pat Brennan? I have the same device.
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Nope I made mine, but very possibilly copied from him.
(http://i1311.photobucket.com/albums/s670/cotton7611/6F9B9A02-A030-4A07-A4F6-86AD00C236BE_zpslfolgjsc.jpg) (http://s1311.photobucket.com/user/cotton7611/media/6F9B9A02-A030-4A07-A4F6-86AD00C236BE_zpslfolgjsc.jpg.html)
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like this... Tis was te first one I made into a centering tool also. I think I gave this to Pappy.
(http://i5.photobucket.com/albums/y199/PatBNC/bowbuildingtools006.jpg) (http://s5.photobucket.com/user/PatBNC/media/bowbuildingtools006.jpg.html)
(http://i5.photobucket.com/albums/y199/PatBNC/bowbuildingtools005.jpg) (http://s5.photobucket.com/user/PatBNC/media/bowbuildingtools005.jpg.html)
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Yep you did Pat. :)Still got it and use it when the time is appropriate ,like the Gizmo, not good for everything but works very well in a lot of applications. :) Eric gave me my first Gizmo and many since to pass along. We have given a bunch away at the Classic. Thanks, I am a very blessed guy to have such good friends. ;) :)
Pappy
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Mine's made from hunk of pallet wood and a 1/4" t-nut.
(http://i884.photobucket.com/albums/ac48/knolltop314/100_3120.jpg)
(http://i884.photobucket.com/albums/ac48/knolltop314/100_3122.jpg)
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So many ideas of things to build!
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PaulnKS gave me my first Gizmo at my first MOJAM years ago. I don't use it often, but it is sometimes the BEST tool for the job. I used to use the edge of my furniture scraper for the same function, but the pencil in a Gizmo gives you a very visual queue as to EXACTLY where the issue is.
OneBow
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I know mine is a little more crude looking than yours Eric . But I don't know what I would do without it .
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The tillering gizmo (and centering tool) took my bow building to a whole new level. Thanks for sharing this fantastic little doodad with the masses, Eric!
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Do those things really work that good? Would they work on an ELB style bow? Would you need a longer one for a longer bow?
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Lots of you guys may have come up with the centering tool idea on your own, but the idea has been around for centuries. It's still a good one. Ideas similar to Eric's Gizmo have been around at least since the 1930s, but I think the earlier ideas were unnecessarily more complicate--some used a dial indicator in place of the pencil, for instance.
I think Eric's approach was unprecedented in its simplicity and utility--different from any earlier version I have seen and better.
Jim Davis
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Do those things really work that good? Would they work on an ELB style bow? Would you need a longer one for a longer bow?
Knots you should try this method I swear by it. Your belly should be flat or relatively flat you can always add or subtract for lumps and bumps. PS thats just a old photo at full draw, you make the measurements at brace height .. Lines A&B should be very close from left to right. You can make 3-4 lines but I find it does not help. I normally make the first line 8" from the tip and the second line 14-17 inches.
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When I first started using the gizmo I was getting a noticeable thumb in my bows which I didn't like. I slightly changed the way I use it now. I first get the tiller adjusted with the gizmo while it is still about 7# heavy or so, I then switch the gizmo to the outer 1/2 of the limb which I like to bend slightly more and just work that area. Any final adjustments in weight I go into the fade for. I use about 12" to 14" of handle and fade area and about 8" of stiff tips so I don't have a whole lot of working limb I need to make adjustments on. It saves me a lot of time. Past couple of years I go from floor tiller to brace to gizmo and never even fool with a long string anymore. If I am working osage I use only a scraper for adjustments on other woods I may use a rasp.
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Toomanyknots; They work great but are not "the end all be all" for various tillering configurations. My main objective in developing this tool was to allow a newbie to go from floor tillering then to long string tillering with the gizmo and have the bow hinge and stiff spot free for the final step up to the short string.
If you can have over poundage, perfectly bending limbs when you go to the short string you can adjust the tiller configuration to anything you want much like Badger stated in his post.
The gizmo works very well on ELB type bows. A longer gizmo isn't necessary as I have found from making a bunch of different lengths that 6" is the optimum length for overall tillering.