Primitive Archer
Main Discussion Area => Bows => Topic started by: iowabow on July 20, 2011, 11:23:14 pm
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I retitled this post so that people could share ideas and and discuss projects that they are working on.
Ok when I was at twin oaks I had a discussion about how to build a bow bending jig. I forgot to ask how long I need to make the jig. Now my bow will be 62 inches long so should the jig also be 62 inchs long
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If your talking about a caul I make mine 72" so I can handle any length bow I may try. The shorter the bow the less relfex obviously.
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ok the jig was layed out so that it was divided in half and then each half into 12 segments along its length and width Then progressive lines drawn and then cut along the line to create jig.
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http://paleoplanet69529.yuku.com/topic/6220/How-To-Build-And-Use-A-Simple-Caul#.TieKrGfEb7g
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Blackhawk posted a pretty good link John. I used the same buildalong when I built mine, I just added a bit more curve. This should answer your questions. :)
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Okay try to picture this. Start with a 72" 2x6. Draw a center line with a tri-square across the width of the board (at 36 inches doing the math). Draw subsequent lines 6 inches away from center on both sides of center. The 6th line from center should be at the end of the board. Now, take the end of the board, start at the top draw 5 marks every 1/2 inch. Do this on both ends of the 2x6. The bottom (5th) mark will be 3-inches down from the top. This will provide a 3 inch reflex at 72 inches. So, if you draw a horizontal line from your first 1/2-inch mark to your 1st (6 inches from center) 6 inch mark you will have an intersecting point. Do this for the 2nd 1/2 inch mark on the edge to your 2nd (12 inches from center) mark and so on. Do this on both ends of the board. Where each of the lines intersect, you will connect the dots forming your arc. Cut out the arc.
Hope I explained it in words well enough. If I didn't, I'll post a picture of one of mine.
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It was explained to me that the curve becomes increasing greater at it reaches the tips due to the math in the layout. I can't remember his name but he explained that the increase in ratio was required because the bow will tend to take more set as you proceed to the tips. So I was wondering if that meant that each bow length would require a seperate jig so that the math ratio would work out corrrectly.
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Gary Davis shows the making of a form complete with his math and layout. (picked up the DVD from 3 Rivers)
Rattlestick Bows.
I'll be building one this weekend... ;D
-gus
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Gary was who he was talking to.It is a good DVD. :)
Pappy
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You can use the same form for most bows. You can increase or decrease reflex by using shims,and change where you want the reflex the most by shimming. That link will answer everything
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Yes, what I tried to type out is Gary's method.
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Sounds like Gary's method !
yes you will want differant length forms for diff. length bows but only if your off by more than a few inches !
the video will show you that Gary uses several diff. ones
I recommend anyone that does not have the video get it!!!!
Guy
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Watching Gary's DVD even as I type this...
Sorry I have been known to beat a dead horse... ;D
Yes Sir Pappy I do like Gary, he has been very helpful, and I like his style.
Have one of his bow staves leaning in the corner.
Being a new builder-in-training (can't say young cause I ain't) I use his stave and DVD for guidance quite a bit.
And I'm assembling one of his jigs this week. :)
-gus
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i will be ordering one tonight
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Thanks everyone for responding to this post all of the information was great! I will post a few picks of the jig once I get it done.
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I don't have one. I should get with the 21st century of selfbowyery. :) Jawge
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Just finished my Gary Davis inspired 72" (3"x 1/4") layout Jigs.
Along with one of Gary's staves.
And tillering stick made out of found Rosewood.
My uncle works for the Railroad and finds the coolest wood.
-gus
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The Caul/jig turned out nice, I use mine all the time...it's a very useful tool.
Your tiller stick ROCKS....very creative and unique, I love it! 8)
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Thank You Lee.
Have already discovered the first design flaw in the Caul/Jig that I built.
Should have cut the bottom of the rest to the same curve as the top.
To give a better/straighter clamping angle. In reviewing Gary's design I see that all of his cauls are cut in this manor.
Initially I thought this as for aesthetics, but that doesn't seem to be the case.
I can fix this one without taking it apart, but it won't be as pretty... :)
Wasn't sure what the wood was in the tillering stick till I started sanding it down.
It looks and smells like Rosewood. My uncle picked it up because it had been sitting out in full exposure for many years and yet was stll true/straight and heavy.
He gifted me a couple pieces of it about forty five inches long and an inch thick. hopefully it will impart some good juju into my bows...
Gotta love finds of this nature.
-gus
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Hey, I was thinking instead of starting a new thread, if it wouldn't be too rude of me, I was wanting to ask if anyone knew a good link to a threadabout a "steam bending in recurve" form or just knew of anywhere I could find some info,..need to build a good one I can strap down my steamed in recurve and strap the metal strap down as well to not get splinter lifts (hopefully). What I am using right now just don't cut it...
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I think this thread is gread for showing and discussing bow jig. Mabye I will retitle the thread bow jigs.
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Here is the jig that I made from the instructions form Gary's video.
(http://i1131.photobucket.com/albums/m559/iowabow2/2011-07-25184805.jpg)
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Looking good...
Now all I need is to find a blue light special on ten inch C-Clamps.
;)
-gus
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Your jig looks great you cant go wrong follwing Gary Davis video he is a great bow makeri learned from Gary 20 yrs ago he is a great teacher take care. Old Timber Bows
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Hey Old Timber! Welcome to the forums!
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I'm thinking of building a Recurve jig.
Ran across a good looking jig during a deep search but guess I didn't save the photo.
It was just a shorty allowing for just the last ten or so inches of the bow limb to be bent and clamped.
Might build two of them so I can do both tips at once.
Iowabow, do you think you will need to concave the bottom of your jig for a better clamping angle?
Or do you think you will be ok as is?
-gus
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Good job on the form!
Welcome to PA Old Timber !!
Guy
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Do I need to concave the back? I can... it would not be hard to do. Is that what people do?
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iowabow,
I'm not sure I used that term correctly.
Below is a pic of some of Gary's Cauls.
Note that he cut a matching arc on the bottom of the board that his bow stave rests on.
It gives a matching surface on the bottom of the jig for the lower jaw of your clamp to bite on.
I think I will be cutting this bottom arc on my jig/caul.
This photo is Gary Davis' work, I just cut it to fit on this thread.
If I am not supposed to do this please let me know...
-gus
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Ok here is a better picture of mine do I have the curve you are talking about? Also here is picture of the new tillering tree
(http://i1131.photobucket.com/albums/m559/iowabow2/2011-07-26163949.jpg)
(http://i1131.photobucket.com/albums/m559/iowabow2/2011-07-26152338.jpg)
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iowabow,
Its probably not that big a deal.
here is what I was talking about.
You and I built our cauls like drawing #1.
Gary Davis built his like drawing #2.
No worries... ;)
-gus
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It all depends on how big your clamps are either way will work
but allot less adjusting of clamp size if you go ahead and curve the backs too
Plus it squares the force a little more to the face of the curve so less sliding around and such!
Guy
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Well the good news is that I did not glue the thing together. I can take it apart and cut the other curve. The bad news is; (all newbies read this!!!!!!!) I put wheels on the bottom of the bandsaw to make it easy to move. But I was holding the table part and broke it off. Now thirty dollars later I have parts on the way. NEVER MOVE by holding table top!!!