Author Topic: Tip bending jig  (Read 680 times)

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Offline paulc

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Tip bending jig
« on: January 01, 2019, 03:21:34 pm »
Can folks post the form you use to bend/flip tips? I made one today with basically no idea what I'm doing. I used a #10 can to get the bend...if that makes sense. I'll put up a pic tomorrow. I made the form out of plywood w the intent of clamping the tip to the form once it has bent using either oil and heat or steam....

Thanks, Paul

Offline DC

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Re: Tip bending jig
« Reply #1 on: January 01, 2019, 03:57:56 pm »
This is a link to Marc's jig. Since I started using one like this I can get curves with a 1 1/2" radius in Yew. It screws to the movable jaw on the vice so the vice is the tip clamp. I clamp the metal strap in position and steam the tip and the metal together. Then I clamp it in position in the vice and bend away. You have to support the other tip and the bow and figure a way of holding it in place.
https://www.primitivearcher.com/smf/index.php/topic,62668.msg878994.html#msg878994
« Last Edit: January 01, 2019, 04:02:17 pm by DC »
Vancouver Island
If you don't have any questions you must not be paying attention.

Offline chamookman

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Re: Tip bending jig
« Reply #2 on: January 01, 2019, 09:46:06 pm »
Back in the Day, steam & over the Your knee worked pretty darn good, til Folks said We needed a jig  (lol) ! Bob
"May the Gods give Us the strength to draw the string to the cheek, the arrow to the barb and loose the flying shaft, so long as life may last." Saxon Pope - 1923.

Offline BowEd

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Re: Tip bending jig
« Reply #3 on: January 02, 2019, 03:06:27 am »
Varying degrees of bend on a 2" by 4" has worked for me.Making sure limb alignment is good.

I'll add here showing varying degrees of bend.4 different degrees of bend.Made in pairs from 30 degrees to over 75 degrees.The bending forms are 2" by 4" being 1.5" wide and the dry heat tempering look alike forms are 3/4" wide.Tips are usually 3/4" wide when bent.


« Last Edit: January 12, 2019, 03:35:40 am by BowEd »
BowEd
You got to stand for something or you'll fall for anything.
Ed

Offline paulc

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Re: Tip bending jig
« Reply #4 on: January 02, 2019, 03:30:13 am »
THanks a bunch y'all...I won't post a pic of my "primitive" form :-)  But I may go back and steal some of your ideas...Paul

Offline ohma2

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Re: Tip bending jig
« Reply #5 on: January 02, 2019, 05:59:14 am »
I used a setup like Eds for years,they always gave me good results.

Offline DC

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Re: Tip bending jig
« Reply #6 on: January 02, 2019, 06:22:29 am »
BowEd, the little metal straps you use to hold down the tips, do you readjust them for different bows, or do you make all your tips the same thickness/size for bending?
Vancouver Island
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Offline txdm

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Re: Tip bending jig
« Reply #7 on: January 02, 2019, 06:22:52 am »
What is commonly used for metal straps? (What do I look for at the hardware store?)


Offline JohnL

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Re: Tip bending jig
« Reply #8 on: January 03, 2019, 08:01:21 am »
txdm,

     Go to the building materials section and look for anchor straps, which are used to tie roof rafters to stud walls.  They are paper-thin, galvanized steel, which bend easily and won't rust in the wet conditions or boiling/steaming.  They are about 1 1/4" wide and have a series of nail holes in them.  The ones I had were about 20" long, I think.  I cut mine down to about a foot long.  Make sure whatever you get is at least a foot long, so you can clamp the strap to the limb, well outside the area to be bent.
I just recently started using straps to bend my recurves, and I wish I'd done it years ago!  Takes all the heartache out of bending tight recurves.  With the straps, you get no splintering or cracking in the belly.  My personal touch to the strap approach, was to put one end of the strap in my vise, a 1/4" deep, and bend it over into a tight 90deg. bend.  This will give you a 1/4" long catch on the tip end of the strap (think of the tab on a tape measure), that will keep the strap in tension, when you put the limb in your jig and bend it around.

–John

Offline simk

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Re: Tip bending jig
« Reply #9 on: January 03, 2019, 08:22:28 am »
Paulc, i've also bent a few. I usually was successful when i prepared the wood with grat care. If i didn't stay on one ring or if the wood had any irregularity it cracked. Just my 2 cents (-;

Offline DC

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Re: Tip bending jig
« Reply #10 on: January 03, 2019, 08:41:18 am »
Yes, I've found that a nice smooth surface with rounded corners helps. The thinner the better.
Vancouver Island
If you don't have any questions you must not be paying attention.

Offline txdm

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Re: Tip bending jig
« Reply #11 on: January 03, 2019, 09:12:37 am »
txdm,

     Go to the building materials section and look for anchor straps, which are used to tie roof rafters to stud walls.  They are paper-thin, galvanized steel, which bend easily and won't rust in the wet conditions or boiling/steaming.  They are about 1 1/4" wide and have a series of nail holes in them.  The ones I had were about 20" long, I think.  I cut mine down to about a foot long.  Make sure whatever you get is at least a foot long, so you can clamp the strap to the limb, well outside the area to be bent.
I just recently started using straps to bend my recurves, and I wish I'd done it years ago!  Takes all the heartache out of bending tight recurves.  With the straps, you get no splintering or cracking in the belly.  My personal touch to the strap approach, was to put one end of the strap in my vise, a 1/4" deep, and bend it over into a tight 90deg. bend.  This will give you a 1/4" long catch on the tip end of the strap (think of the tab on a tape measure), that will keep the strap in tension, when you put the limb in your jig and bend it around.

–John

Thanks for the advice! I've broken every one of my attempts to add even moderate recurves on hickory using steam or dry heat. I'm hoping this will help me get it right.

Offline PaSteve

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Re: Tip bending jig
« Reply #12 on: January 03, 2019, 11:03:21 am »
JohnL, great idea about the 90° bend in the strap to keep the tension. Thanks

Offline BowEd

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Re: Tip bending jig
« Reply #13 on: January 03, 2019, 11:16:08 am »
BowEd, the little metal straps you use to hold down the tips, do you readjust them for different bows, or do you make all your tips the same thickness/size for bending?
I generally make all my tips close to the same thickness.Around 9/16" thick tip thickness is usually the norm.I steam tips belly down on the pot at a hard boil with a towel over the tin foil to get it as hot as possible when doing it on the stove.The tip hold down straps can be repositioned for thinner or thicker tips too by repositioning with screws.A wedge can be put in there too while bending.Time is of the essence when steam bending so everything needs to be in position so no time is wasted.I try to get it bent within 15 seconds on my bending forms on a table by the stove.I don't bend cautiuously.I go for it and let it be.Preparing that belly surface well is good advice too.
I've ruined a couple but overall the majority worked out well.
THanks a bunch y'all...I won't post a pic of my "primitive" form :-)  But I may go back and steal some of your ideas...Paul
That's what this site is all about.Good luck.
BowEd
You got to stand for something or you'll fall for anything.
Ed

Offline JohnL

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Re: Tip bending jig
« Reply #14 on: January 11, 2019, 05:35:47 pm »
Hey txdm,

     I've had little luck getting hickory to move much with steam, and no luck with dry heat.  I suggest boiling hickory.  Boil with the wood to be bent submerged in the pot, for 45-60 min., checking the water level a couple of times along the way.  You should have your metal straps clamped to the limb, before you boil. Then, as quickly as possible, get it in the form, bend in one smooth motion, pulling the limb around the bend and clamp.  Let it sit in the form, in a warm dry place till the next day, to let most of the moisture slowly leave.  Then use dry heat to lightly toast your recurves, to lock-in the bend, and you'll get very little spring-back, when you remove the clamps.

–John