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Main Boards => The Bowyer's Bench => Topic started by: Eric Krewson on March 26, 2009, 02:15:00 PM

Title: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on March 26, 2009, 02:15:00 PM
Since I made my initial tillering gizmo there has been an input of ideas to make it work better from other bow makers. Consequently it has evolved into a differently made tool than my original design.

Here is how to make the latest version. I use a drill press, bandsaw and belt sander because I have them. This tool can be made out of any scrap wood, holes drilled by hand, out of square and work just fine.

I cut a large downed cedar looking for a bow stave. I may or may not have found a stave but I definitely found a bunch of beautifully grained gizmo material.

I start by cutting a piece of wood 1" square and 6" long. You can make the gizmo longer if you want to, length is not a critical issue

          (http://img.photobucket.com/albums/v181/ekrewson/dead%20cedar/gizmo1.jpg)

A little sanding to get rid of the saw marks.

          (http://img.photobucket.com/albums/v181/ekrewson/dead%20cedar/gizmo2.jpg)

Mark the center of the block length wise and center.

          (http://img.photobucket.com/albums/v181/ekrewson/dead%20cedar/gizmo3.jpg)

Drill a 5/16" hole on the center mark.

          (http://img.photobucket.com/albums/v181/ekrewson/dead%20cedar/gizmo4.jpg)

I use a 1/2" forstner bit to cut A 1/2' deep hole over the 5/16' hole I just cut. The forstner bit cuts a clean hole but any 1/2" bit will work just fine.

        (http://img.photobucket.com/albums/v181/ekrewson/dead%20cedar/gizmo5.jpg)

Next I mark the ends of the block with a 45 degree angle to shorten side opposite the pencil of the gizmo. This allows one to run the gizmo closer to the tips while tillering.

   (http://img.photobucket.com/albums/v181/ekrewson/dead%20cedar/45marked.jpg)

2013 update;
Here is and update for a slimmer shape for your gizmo that will go further up the limbs with out string interferance.

 
  (http://img.photobucket.com/albums/v181/ekrewson/selling%20stuff/signed%20gizmo%20001_zpslukzwdqf.jpg) (http://smg.photobucket.com/user/ekrewson/media/selling%20stuff/signed%20gizmo%20001_zpslukzwdqf.jpg.html)


I tap a 5/16" nut into the 1/2" hole and seat it all the way down with a piece of dowel.

          (http://img.photobucket.com/albums/v181/ekrewson/dead%20cedar/gizmo8.jpg)
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on March 26, 2009, 03:00:00 PM
Too many pictures for one post so here is the rest of the story.


Screw a pencil into the nut(I put the pencil in a vise and screw the gizmo on it) and you are ready to tiller. I sand the pencil a little after I cut thread on it so it will screw in and out easily. It only took me 10 minutes to make this tool, start to finish.

With a little Tru-Oil this will be a beautiful little tool, it has a wonderful grain pattern.

Older version;

   (http://img.photobucket.com/albums/v181/ekrewson/dead%20cedar/finishedgizmo.jpg)

Newest version:
  (http://img.photobucket.com/albums/v181/ekrewson/selling%20stuff/signed%20gizmo%20001_zpslukzwdqf.jpg) (http://smg.photobucket.com/user/ekrewson/media/selling%20stuff/signed%20gizmo%20001_zpslukzwdqf.jpg.html)
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: OkKeith on March 26, 2009, 03:03:00 PM
Eric,

I saw your gizzmo several years ago and have never been without one since. Great little tool. I bought a box of golf pencils to use with it 3 years ago and still have half the box left. This is the one tool I can throw when I screw a bow up and not worry about hurting it, me or someone else (hope you are not offended by that, sometimes ya gotta throw SOMETHING).

That cedar is good looking as well.

Thanks for your contribution to my bow building.

OkKeith
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: razorback on March 26, 2009, 03:32:00 PM
Eric. how does the taper on the pencil side increase the usable area. I made one with the taper on teh other side so it would get closer to the tips before running into the string. I also made one with holes equidistant from the center that I can insert dowels into to give me a centering tool for staves.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: bjansen on March 26, 2009, 03:34:00 PM
Thanks for sharing that, I will be building one this weekend..Great advice!
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on March 26, 2009, 04:17:00 PM
I did a little photo editing. The pictures should be corect now. I actually cut my tapers going the wrong way in the first attempt and didn't notice it until I had already posted the pictures. I now have a 4" gizmo(by accident) and a 6" gizmo.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Leo L. on March 26, 2009, 04:44:00 PM
I'm having a hard time trying to figure out why length isn't an issue?  Wouldn't a gizmo that is too long, or too short give different readings?  Maybe I just don't understand how it's to be used...
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on March 26, 2009, 07:08:00 PM
A longer gizmo would ride higher on a bows belly and would be good while on the long string, shorter would be OK for fine tuning on the short string.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: broketooth on March 26, 2009, 07:16:00 PM
i dont understand how it works
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on March 26, 2009, 07:37:00 PM
After you floor tiller your selfbow and go to the long string. Bend your bow slightly and lock the string with your tillering tree or stick. you back the pencil off and run the gizmo up and down the limb to find where the limb is bending the most.

Adjust your pencil to be just off the limb at the deepest bend,

 (http://img.photobucket.com/albums/v181/ekrewson/bow%20making/adjustinggizmo.jpg)

Run your gizmo up and down the limb and it will mark where you need to scrape off wood to get an even bend in your limb.

 (http://img.photobucket.com/albums/v181/ekrewson/bow%20making/gizmomarkedlimb.jpg)

It won't tell you where to remove wood to get the fades moving so you have to eyeball that area.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Jack Denbow on March 26, 2009, 08:55:00 PM
Thanks Eric. I have been wanting to make one I guess now is the time. I have a nice piece of curly maple to use. Thanks again.
Jack
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Pluck Yew on March 27, 2009, 12:33:00 AM
Mr. Krewson, I'll bet if I cleaned my garage I could find another 5/16" nut...  :saywhat:  

Shawn...
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eastern Hunter 14701 on March 27, 2009, 10:41:00 PM
Neet little tool. Thanks for sharing  :)
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Shaun on March 28, 2009, 12:45:00 AM
Great tool! I often use mine (plain piece of pine with a friction fit hole and pencil). Nice tutorial Eric and lovely piece of cedar you used. I may even break down and make a pretty one with the 5/16 nut improvement.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Steve Kendrot on March 29, 2009, 02:46:00 AM
I too made one of these based on the first iteration. After using it, I thought of tapering the ends as well. I made my first several bows last year and after tillering the first one without it and coming up 30 pounds under weight because I let a hinge develop, the gizmo was the key to success with my later attempts. If you are just starting out, don't make another move until you make one of these things!
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Jack Denbow on March 29, 2009, 11:56:00 AM
I made a pretty one. I cut the angled ends back 1/8" from the end so as to not leave a sharp edge that would get banged up. Now I need to go put it to work. Thanks again Eric for giving me the motivation I needed to finally get around to making one.
Jack

 (http://i15.photobucket.com/albums/a378/jackdenbow/Tilleringgizmo0042.jpg)
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on March 31, 2009, 08:53:00 AM
What did you stain your maple with Jack? Looks like Aqufortis. I have a flintlock almost done and plan to use aqufortis on the stock when I stain it.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Jack Denbow on March 31, 2009, 09:07:00 AM
Eric I used Aqufortis like you suspected. I used a heat gun to "activate" it. I think you mentioned it a couple of years ago on a thread. I made some panels to mount some horns on and they really look nice using the curly maple. Thanks again.
Jack
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: razorback on March 31, 2009, 09:30:00 AM
Man, i hope your bows look as good as that gizmo. if you take that much pride in your tools I bet anything made with them will be just as good or better.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: buckhuck on April 03, 2009, 09:28:00 PM
Thanks for posting Eric.  I am going to have to make one of these.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: vanislebowyer on July 15, 2009, 10:08:00 PM
question:

what about using this with character bows, especially yew that has rollercoasters rather than snakes?
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on July 16, 2009, 12:15:00 PM
The gizmo won't work with a stave with a lot roller coaster. I almost always take the roller coaster out of my osage before I start a a bow because it is such a pain to tiller.

If the roller coaster is only in one place in the limb I eyeball that section and use the gizmo on the rest.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Hermann From Bavaria on July 17, 2009, 01:45:00 AM
hello eric!

i got some spare massaranduba in my workshop and probably some spare time today. worth a try i think.

but it works only on straight grained wood i think, isnt it?
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on July 17, 2009, 08:40:00 AM
It works on any bow limb, snakey, round belly, flat belly, just doesn't work well if you have a limb with a lot of dips and humps or what we call roller coaster.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: ChristopherO on July 19, 2009, 07:03:00 PM
Eric,
Having just finished a charactor osage that won't be worth using due to a fracture in the belly I think the next project will be a clean flat belly bow.  Do you heat your osage on a caul first with clamps to clean up the roller coasters?
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on July 20, 2009, 08:53:00 AM
I start with heat and a caul and do final tweaking in my vise. Some I can get out completely, some I can't. Some raise splinters on the belly during corrections so I start with wood thick enough to rasp the belly cracks off if they appear.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: ole yeller dust on July 20, 2009, 09:29:00 AM
I used my gizmo at mojam last week works great, and also saw others,  thanks eric
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Paul/KS on July 20, 2009, 10:08:00 AM
I made a couple from some spalted maple for donating to the prize table. A great idea and a handy tool...
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Dano on July 20, 2009, 11:28:00 AM
I think it was Dean Torges that came up with something similar, he called it the "walky talky" I think, but the addition of the pencil instead of the screw is great, at least for straight staves.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Tom Leemans on July 23, 2009, 09:03:00 AM
Dean's had screws on each side at varying depths, so you could use whichever side worked best for the tillering stage you were at. The adjustable pencil feature of the tillering gizmo makes the same thing possible and easy! BTW I won a tillering gizmo in my prize package from this year's clout shoot.  :thumbsup:
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: TimTodd on September 24, 2009, 08:38:00 PM
Sorry if this sounds naive, but I'm just starting out, and I don't understand exactly what this tool does. If someone could explain it, I would really appreciate it. Thanks.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Pat B on September 24, 2009, 10:29:00 PM
Tim, as you tiller a bow you want the limb to bend evenly. This great little tool will leave a mark on the stiff areas and not on where the bend is. It allows you to see where wood needs to be removed from and where wood should stay.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: TimTodd on September 25, 2009, 12:41:00 AM
Ah, well that is an incredibly useful tool then, thank you for the explanation.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on September 25, 2009, 08:55:00 AM
I took it for granted that everyone would use the gizmo like I do but found I should have explained it's use more in depth.

One guy said when he used the gizmo it caused stiff spots to move from one place in the limb to another. Another said he works one stiff spot then uses the gizmo to find another to work on.

For the gizmo to to work at it's maximum potential, every time you put it on a limb to check for stiff spots, run it the entire length of the limb, not in one small spot.

When you start scraping off the pencil marks and removing wood, work on all the stiff spots at the same time, not just one spot at a time.

This way the whole limb will be corrected when the pencil no longer marks the limb with a gizmo swipe from fade to tip.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: AkDan on September 25, 2009, 11:44:00 PM
Eric, are you sanding down the nut side once things are finished so it's sitting flush? or is it still recessed in the finished gizmo?  Got some stuff today to build a couple of them from the home depot.  Found some 1x1" trim 6" long that'll work perfect!  now if I can only find my dang forstners LOL!
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: AkDan on September 26, 2009, 04:23:00 AM
ooops..cut my tapers backwards too LOL!  DOH!
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on September 26, 2009, 09:02:00 AM
I drill the big hole deep enough to tap the nut about 1/4" below the surface of the wood. I drilled a shallower hole on the earlier version and sanded the wood and nut flush but often lost too many threads of the nut in the process. The new version with the recessed nut works much better.  

This nut is in a little over 1/4" deep.

  (http://img.photobucket.com/albums/v181/ekrewson/gizmonutdepth.jpg)
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Roy from Pa on May 11, 2010, 12:43:00 AM
I tapered mine even more Eric. Your Gizmo works great. Since using it, all of my bows are coming out great.

  (http://i47.photobucket.com/albums/f165/ROY-CHRIS/twin3020.jpg)
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on May 11, 2010, 08:47:00 AM
I am going to add the instruction sheet I send out with gizmos to this thread so people can see the finer points of using one. I made changes to the instruction sheet as I got feedback from the users. Some were using it incorrectly or found better ways to get the most out of it.

I will add the text first then insert pictures. I have to hunt up the pictures so adding them may take a while.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on May 11, 2010, 09:50:00 AM
USING THE TILLERING GIZMO


After floor tillering your bow, bend the bow slightly on your tillering tree or tillering stick using the long string. Retract the pencil in the Gizmo and run the wood block up the bow’s belly and find the widest gap. Screw the pencil in the block to a point it is almost touching the bow’s belly at the point where you found the widest gap. I change the angle the pencil has been sharpened to a very short angle and sand the tip of the pencil flat for the best results in marking the limb. This lets you work very slight bends.

   (http://img.photobucket.com/albums/v181/ekrewson/bow%20making/adjustinggizmo.jpg)

Initially I set my gizmo pencil about 1/8” off the limb for the first few corrections. This course setting will mark only the stiffest spots. If you set the pencil too closely for your first few passes it will mark the whole limb.

Run the Gizmo up the belly making sure it is centered on the limb. The
pencil will mark non bending areas that need wood removed. Always check the entire limb with the gizmo every time you use it and scrape wood from all the stiff spots at the same time, not one stiff spot at a time.  Start on the long string, continue at brace and up to about 20” of draw. You do need to have a way to hold your bow string while you mark the limbs with the Gizmo.  

I often set my gizmo for one limb and use this setting on the opposite limb as well. This way you will end up with two closely matched limbs.
                                               
I have holes in my tillering tree and insert a 3” piece of dowel in one of the holes to hold the string with the limbs slightly bent while I mark the limbs with the gizmo.

   (http://img.photobucket.com/albums/v181/ekrewson/bow%20making/tilleringtotheshortstring5.jpg)

Go slowly, no more than ten scrapes on the marked areas of the limb, flex the limb 30 times and recheck. I have found it usually takes 5 or more check, scrape and check sessions to get a stiff spot moving so be patient.  You can get the limb bending perfectly this way. You will still have to eyeball bending in the fades but the rest of the limb will be perfectly tillered. Hinges will be a thing of the past.

   (http://img.photobucket.com/albums/v181/ekrewson/newgizmopic2.jpg)

Make a few passes with the gizmo on your limb and the areas that need attention will be perfectly obvious. You can fine tune the tillering by closing the gap between the pencil and limb to almost nothing. At this point I like to use a cheap orbital sander to remove both wood and any tool marks that are left. With course sand paper, the sander will leave tiny swirls in the wood so I like 220 grit for my final tillering work with the sander and follow with a light hand sanding.

The gizmo doesn’t work in the fade out area of the riser so you will have to eyeball the bend in this area or put a flat board across the back of the bow in your tillering tree and watch the gap between the back of the bow and the board to see where the limb is bending.  

Tillering that once took me hours to get close  takes me about 45 minutes with the Gizmo and the end result is close to perfect.

Remember the key thing to remember for proper tillering is using a scraper or sand paper and work slowly, only scrape off your pencil marks, flex the bow and recheck. I often make a zig-zag pencil mark from one side of the limb to the other over the gizmo’s pencil mark to make sure I remove equally from one edge of the limb to the other.

 If you ever get the urge to grab a course rasp or use a belt sander to speed things up even more, take a coffee break and come back when these thoughts have passed.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: mississippidave on May 17, 2010, 10:32:00 PM
Eric, I tillered Maggie's new hickory bow with the Gizmo you gave me at the Jerry Pierce Memorial Shoot this weekend.  I really enjoyed talking with you and the tool works great!  Cheers, Dave
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: lad on July 04, 2010, 02:14:00 AM
now this is one great tool. I have a couple tillering jobs set aside that will be back on the stick when I make one of these babies.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: FurFlyin on August 23, 2010, 07:55:00 PM
Thanks for the post.  That will be very useful.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: DEATHMASTER on August 23, 2010, 08:56:00 PM
Simple but VERY useful.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Gtownviking on September 01, 2010, 08:05:00 PM
Do you have any video of you doing this process that you care to share?
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: fish n chicks on September 01, 2010, 09:41:00 PM
Mr. K, just wanted to tell you this was the first tool I made when I started earlier this year, and will be in my arsenal FOREVER. It's the number one reason I get any kind of good tiller. Thanks again for donating it to us.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on September 02, 2010, 08:40:00 AM
No videos at the present Eric but I have thought of making one to show how well the gizmo works. I would have to do it with my digital camera because I don't have  a video camera
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: glenbo on September 02, 2010, 05:36:00 PM
Started making mine today.I will be looking foward to using it.Thanks for the sweet idea Eric.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: NTD on September 06, 2010, 01:33:00 PM
Eric,
Have you used the tool on R/D bows?  They are often flattish in the outer limbs...
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on September 07, 2010, 08:20:00 AM
Never used one on a R/D bow.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Roy from Pa on September 07, 2010, 05:52:00 PM
I have used it on r/d bows. And it is a pain in the butt to tiller a r/d bow.. But it helps a little.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: glenbo on September 12, 2010, 08:54:00 PM
I made one last week and used it for the first time,I am quite impressed at the results and ease of use.Great idea Eric
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: fish n chicks on September 13, 2010, 11:18:00 AM
Quote
Originally posted by Roy from Pa:
I have used it on r/d bows. And it is a pain in the butt to tiller a r/d bow.. But it helps a little.
This gizmo is what I use exclusively, well besides my eye, to tiller my r/d bows. From my first one in january and even now with my 6th on the bench. I made mine about 3" long tho, and when I get to the limb tips, I usually only use the gizmo to go until my deflex begins. After that I have found there is no reason (and dangerous) to reduce your limb tips too much.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Blue Tick on November 02, 2010, 10:24:00 AM
Is this for use only on the selfbows? Will it work for glass bows, recurve and long?
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on November 02, 2010, 11:13:00 PM
Never heard of anyone using one on a glass bow. I suspect they are only useful on a selfbow.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Jesse Peltan on November 20, 2010, 04:54:00 AM
To answer your question blue tick, the tool works as a gauge to measure and mark the limb, helping you obtain a tiller where the limb bends according to the arc of a circle.  If the bow's full draw is supposed to have the limbs bent according to the arc of a circle, then this tool works for that bow.  Basically it's for bows that have straight working limbs, or limbs that are curved according to a circular arc.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Red Tailed Hawk on December 01, 2010, 05:05:00 PM
will this tool work on a pyramid bow?
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on December 01, 2010, 06:16:00 PM
It will work just fine on a pyramid bow.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Red Tailed Hawk on December 03, 2010, 04:23:00 PM
Eric i have to say that this tool works wonders, such a simple tool can be so useful.    :jumper:
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: snag on December 16, 2010, 04:58:00 PM
Eric, what diameter are your pegs on the tillering tree? I used one that is 1/4" oak and it broke it off when I pulled to 18"!
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on December 17, 2010, 08:59:00 AM
My peg is a piece of 1/2" poplar dowel.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: NYArrow on February 26, 2011, 06:53:00 AM
awesome tool Eric! Where did you dream this up? I could have used this earlier in my tillering but I'm still 6" away from target perhaps it will set me straight! (or bent)
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: hova on February 26, 2011, 10:11:00 AM
i had the same issue. i use a piece of bamboo now , or a screwdriver. i had a dowel split , that wont  happen again...


-hov
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: inksoup on July 22, 2011, 01:19:00 PM
after i read the second time, now i understand how it works. i mean the logic behind it.
it is really brilliant idea. so simple yet so useful. like fire!
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: oneraindog on August 04, 2011, 07:03:00 PM
hoping to revive this for an answer:

i assume this thing will not work so god on limbs with reflex/recurve?
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: SEMO_HUNTER on August 05, 2011, 06:39:00 AM
It doesn't work on R/D hybrid type profile bows raindog, that's the only draw back. I sure wish it did, cause the R/D bows are a bugger to tiller!
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: DVSHUNTER on August 05, 2011, 09:07:00 PM
I think the tool is very useful as a learning tool. it teaches perfect tiller. IT doesnt work as well imo for d/r bows, but i hear it does work. I tiller by eye now, after learning with a tool similar, but without a pencil. I always though abouto having one here in the shop to help/show others what i see, but have never made one yet.  Kudos to Mr. Krewson for sharing his idea free for all to use. Not to mention all the free ones he's sent out.  Lota guys building real nice bows because of him.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: SEMO_HUNTER on August 05, 2011, 09:56:00 PM
I got one of those free ones myself, Eric is a fine fella.  :thumbsup:
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Blackie76 on September 12, 2011, 10:35:00 PM
This is amazing. Needs a better name though.  I hereby propose we refer to it as a Krewson Hinge Stopper. Before long, 3 Rivers will be carrying them in stock!  :)

Simply ingenious tool. Great work!
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on September 13, 2011, 08:58:00 AM
I thought about marketing them but I am retired and don't want a job, I guess I will keep giving them away.

Gave two away at an ASTB tournament this weekend and am completely out of them at the present. When I get caught up on other projects I will spend the day making them to restock my supply.

I have changed the way I hand them out. Used to be, I would give them to anybody who expressed an interest. Now I only give them to someone who is actually making a wood bow. I have given away dozens to people who were thinking about making a bow but I  found out thinking about making a bow seldom translated into actually making one.

Lots of the gizmos I handed out were never were put to use and probably ended up in the trash.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: eflanders on September 13, 2011, 09:41:00 AM
With all due respect to Mr. Krewson, I modified his version to make it even more useful.  What I did was add a 1" long wooden dowel on each end of the tillering gizmo.  I also countersunk and glued in the nut so it is secured in halfway through the thickness of the wood.  

Now the jig can do two functions:  1) Mark/find the center of the stave.  2) Tillering jig.

To use as a centering jig, have the pencil mounted on the opposite side of the dowels.  Twist the jig so that the dowels constantly touch the side of the stave and run the jig down the entire stave.  A pencil mark will be left right down the middle of the stave no matter how snakey the stave is.

Eric has already described very well how to use the tillering gizmo.  All you have to do with my version is to mount the pencil so that it is on the same side as the the dowels.

Two useful jigs in one simple to make package!
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: vanillabear? on September 13, 2011, 02:10:00 PM
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: **DONOTDELETE** on September 17, 2011, 11:25:00 AM
Quote
Originally posted by Eric Krewson:
I took it for granted that everyone would use the gizmo like I do but found I should have explained it's use more in depth.

One guy said when he used the gizmo it caused stiff spots to move from one place in the limb to another. Another said he works one stiff spot then uses the gizmo to find another to work on.

For the gizmo to to work at it's maximum potential, every time you put it on a limb to check for stiff spots, run it the entire length of the limb, not in one small spot.

When you start scraping off the pencil marks and removing wood, work on all the stiff spots at the same time, not just one spot at a time.

This way the whole limb will be corrected when the pencil no longer marks the limb with a gizmo swipe from fade to tip.
This is a great gizmo Eric.  This is one aspect of fine tuning limbs that a lot of glass bow builders overlook completely. they just assume that the limbs bend evenly because of the glass backing.

i know there are a lot of self bow procedures that just don't apply to composite building. But this isn't one of them.  i don't use a pencil in mine like you have, but use a block and a ruler or tape to check the consistency of my working limbs, and it makes a HUGE difference in performance and hand shock issues.

this is a perfect example how a limb can measure perfectly on tiller measurements and still be out of whack.

of course on a hybrid long bow the whole limb is not going to bend the same... But!  the location of the working portion can easily shift, or be shifted to time the limbs properly on both a wood bow and glass bows alike.

 (http://i171.photobucket.com/albums/u301/kirkll/Bow%20building/Tiller%20Tree%20stuff/PaulsBow006-16.jpg)
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Dennis La Varenne on September 25, 2011, 10:00:00 AM
Eric,

Very impressed with your simple device. Did you know that a very similar tool was in use waaaaay back in the pre-WWII days? It is described at length in Robert Elmer's book "Target Archery" and there are pictures of it being used by Russ Wilcox on one of his duoflex bows, the precursor of the modern recurved bow.

Yours has the advantage of the pencil to mark as it goes, whereas those in Elmer's book use a dial micrometer gauge to actually measure the amount of curvature in the limb surface.

Your design has the advantage of actually marking high spots when the pencil is set to contact any wood above a certain level. You can even keep screwing the pencil down until it contacts and use that level as the datum level until the limb bends evenly.

However, I do not see that it will work on other than circularly bending limbs. Elliptical limbs where there is either increasing (whip-ended) or decreasing bending (stiff-ended) toward the tips will be difficult to cater for.

Have you worked out any way around this at all? I would be particularly interested.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on September 25, 2011, 11:18:00 AM
For stiff tips I ignore the pencil marks within about 4" of the tips, don't make any whip ended bows so I don't have any experience with such.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: 30coupe on January 22, 2012, 02:36:00 PM
No offense, Mr. Krewson, but unless your nuts are bigger than mine, you will need a 3/8" forstner bit for the larger hole. A 5/16" nut will drop right into a 1/2" hole.

Here's another tip on installing the nut into the block. Instead of using a dowel, screw a 5/16" bolt into the nut, and then use the bolt to drive the nut into the block. The threads will be undamaged and you can use the bolt to make sure the nut is squared to the hole. I use a long enough bolt to to through the block. Then I screw the bolt all the way through the block. This will align the nut with the hole in the block.

The gizmo does work pretty slick and is really simple to make. Thanks for the tip!
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on January 22, 2012, 06:15:00 PM
Always a smarty pants in the crowd. You are wrong Russ you must not have taught shop class.

I have just about used up my second box of 100 5/16" brass nuts so I have made almost 200 gizmos. A 5/16th brass nut has an inside hole diameter of 5/16".

My 1/2" forstner cuts a hole this diameter.

   (http://img.photobucket.com/albums/v181/ekrewson/bow%20making/gizmoholediameter.jpg)

A 5/16" nut has an maximum outside measurement of this;

   (http://img.photobucket.com/albums/v181/ekrewson/bow%20making/gizmonutdiameter.jpg)

A 5/16" nut taps right in a 1/2" hole in soft wood by expanding the wood slightly for a tight fit. The best way to tap the nut in is with a slightly smaller bolt, 1/4" in this case(thats bolt diameter Russ not head diameter).

   (http://img.photobucket.com/albums/v181/ekrewson/bow%20making/gizmotapin.jpg)
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: KellyG on January 22, 2012, 07:23:00 PM
All I know is if you are trying to make a self bow you need to make one of these.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: 30coupe on January 22, 2012, 08:29:00 PM
Quote
Originally posted by Eric Krewson:
Always a smarty pants in the crowd. You are wrong Russ you must not have taught shop class.
 
Yup, you got me!    :knothead:

My bits are a mix of old and new in a plastic box. The shaft for the 1/2" and 3/8" bits are the same size, but the slot for the original 1/2" is too big for the one I have now, so I shifted them over one and forgot that I had done that. I also find that I have two 5/8" bits in that box; one of which I used instead of the correct 1/2" bit.

Nope, I didn't teach shop class, but I should have used my brain anyway!

Anyway, this is how I put the nut into the (1/2") hole.

I thread the nut onto a 5/16" bolt like this:

 (http://img.photobucket.com/albums/v612/30coupe/Archery%20Stuff/gizmo2.jpg)

Then I tap it into the hole like this:

 (http://img.photobucket.com/albums/v612/30coupe/Archery%20Stuff/gizmo.jpg)  

I thread the bolt on far enough so that the bolt gets into the 5/16" hole. That keeps everything lined up and the nut won't tip as you drive it in. Once it bottoms out in the 1/2" hole, it should be pretty straight anyway.

See, I'm not totally stupid, even though I did appear to be in my other post.    :rolleyes:

My apologies, sir!    :notworthy:
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: wood carver 2 on January 22, 2012, 08:32:00 PM
More than one way to skin a cat eh?  :thumbsup:  
Dave.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: mwosborn on January 22, 2012, 11:14:00 PM
Yep, gotta love the gizmo - regardless of the bit size used to make it!  :D    Thanks again Eric.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Buemaker on January 23, 2012, 06:28:00 AM
Da "Gizmo Man". Always interesting to see gadgets that makes things easier. Bue--.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: snibbling on March 17, 2012, 08:50:00 PM
Hello all! Very new to bow building so just looking for some feedback! I just made this from a spare piece of 3/4" red oak. Is this to small or will it still work?


  (http://img32.imageshack.us/img32/3771/0317122033.th.jpg) (http://img32.imageshack.us/img32/3771/0317122033.jpg)
left click to open in bigger in new window. i placed a standard house key for size comparison.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on March 18, 2012, 08:28:00 AM
You really need to make one about 6" long, the shorter ones don't work very well. I have tried a bunch of lengths and always come back to 6".
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Jeff Vadney on March 22, 2012, 11:54:00 PM
I thought the "Gizmo" was a great idea. I made one the same design only out of steel. Brazed the 5/16" nut onto an 1/8" thick piece of steel the same dimensions as the wooden one. Put the nut on top of a bigger nut and brazed them both so the pencil did not stick through too far. No need to taper the ned. Not as beautiful as wood, but if you can work with metal. it is very handy
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on March 17, 2014, 09:00:00 AM
Let's take this to the top for all the newbies who haven't seen it.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Roy from Pa on March 17, 2014, 09:07:00 AM
Good thinking, Eric...
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Zradix on March 17, 2014, 03:08:00 PM
Love em!
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: takefive on March 17, 2014, 03:50:00 PM
A Gizmo and a dial calipers take so much of the guesswork out of tillering    :thumbsup:
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Shakes.602 on December 06, 2014, 01:23:00 PM
Yes sir, I am still using the First Design Gizmo you sent me, many moons ago! You cant beat a Gizmo for Quality Tillering Help!! Thank You for the Help Mr. Krewson!!
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Roy from Pa on December 06, 2014, 01:40:00 PM
Yupper, the gizmo sure has helped me up my game.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Bowjunkie on December 06, 2014, 07:05:00 PM
I've never used one. I'm not sure how much good it would do me at this point, and to be honest, I have a few reservations, but I'll likely make one soon just to play with it under certain circumstances. I've got enough other bend, thickness, and taper gauges, indicators, and such... what would one more hurt? I think it's a great idea, but should be used with discretion.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Roy from Pa on December 07, 2014, 08:06:00 AM
Yes bowjunkie, it has it's limitations in certain bow limb designs, but whatever the design, it helps in the early stages of tillering. Quit being so old fashion stuck in the mud Jeff. LMAO
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: bowberry on August 17, 2015, 10:02:00 PM
last year, before I read this thread, before I found trad gang I saw someone some where write "use a short stick and compare the gap".
Now, because I am a super genius and a machinist I made one with a dial indicator. So I cracked a beer and started writing down tons of numbers, comparisons ect.I had to re learn trig and teach myself calculous.You see, what happens is this; you measure along bothe limbs and write down say 40 numbers.Then you scrape a tiny bit in one little area and remeasure. ALL the numbers from BOTH limb are now different. Its all conected in some sick twisted way. After three hours my brain melted and I blacked out. When I awoke I threw the evil device away.Had I only known about the pencil. Ah.. the pencil. The pencil could have saved me. I guess it's true. sometimes less is more.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on August 17, 2015, 11:15:00 PM
Yep, simple ideas from simple minds.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: DaveMac on August 18, 2015, 09:22:00 AM
Can the gizmo be used on elliptical tillers or reflex - deflex bows? If so how?
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Roy from Pa on August 18, 2015, 09:27:00 AM
It can be used in the early stages to get an even bend in the mid limb to inner limb area, but not for the final tillering stages.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on August 18, 2015, 11:45:00 AM
Yep, you need to adjust the bend in the fades and stiffen the tips after you get the rest of the limb bending right with the Gizmo.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: darin putman on August 18, 2015, 11:15:00 PM
Aside from all the instruction of Eric Krewson the Gizmo has really been a great help for me on how to properly tiller a bow, just had to follow Eric's instructions and trust the Gizmo! Thanks Eric!
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Eric Krewson on August 28, 2015, 09:57:00 AM
Where the gizmo shines is getting the limbs bending right on the long string before you go to low brace with the short string.

If you adjust the gizmo to the deepest spot on the weakest limb when you start tillering on the long string and keep that setting while you work on both limbs removing wood, you can get to the short string without any hinges or oops type surprises.
Title: Re: The Evolution of the Tillering Gizmo, Lets Make One
Post by: Fritz on August 28, 2015, 03:05:00 PM
I'm a novice bowyer with only 4 bows under my belt. All 4 bows are still shooting today and would not be if it weren't for your gizmo. Thanks Eric for a great little tool.