Author Topic: How to cut backing strips?  (Read 6574 times)

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Offline russell

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How to cut backing strips?
« on: January 31, 2015, 08:45:37 pm »
I've done some searching, so I'm not being lazy - just want to make sure I've got this right.  It looks like the general consensus is quartersawn as opposed to plainsawn.  And 1/8" - 3/16" thick depending on type of wood. Is that about right?
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   John 14:6

Offline Peacebow_Coos

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Re: How to cut backing strips?
« Reply #1 on: January 31, 2015, 09:04:44 pm »
Sounds about right

Offline bubby

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Re: How to cut backing strips?
« Reply #2 on: January 31, 2015, 09:17:39 pm »
Make sure you cut them a little heavy so you can get the saw marks out
failure is an option, everyone fails, it's how you handle it that matters.
The few the proud the 27🏹

Offline russell

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Re: How to cut backing strips?
« Reply #3 on: January 31, 2015, 09:25:26 pm »
That makes sense. Didn't think of that one - thanks.
->>>--------->
   John 14:6

Offline bubby

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Re: How to cut backing strips?
« Reply #4 on: January 31, 2015, 10:09:53 pm »
I cut mine with a tablesaw and run them thru a surface planer
failure is an option, everyone fails, it's how you handle it that matters.
The few the proud the 27🏹

Offline russell

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Re: How to cut backing strips?
« Reply #5 on: January 31, 2015, 10:33:45 pm »
That's kinda what I was thinking. I guess my main concern is plain vs quarter sawn. I think flat vs edge grain means the same thing - I think?
->>>--------->
   John 14:6

Offline Knoll

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Re: How to cut backing strips?
« Reply #6 on: January 31, 2015, 10:51:31 pm »
Make sure you cut them a little heavy so you can get the saw marks out
Yep, just learned that the hard way!  By time get saw marks out these maple backing strips will be so thin that they'll only be useful for red oak bellies!   :o
... alone in distant woods or fields, in unpretending sproutlands or pastures tracked by rabbits, even in a bleak and, to most, cheerless day .... .  I suppose that this value, in my case, is equivalent to what others get by churchgoing & prayer.  Hank Thoreau, 1857

mikekeswick

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Re: How to cut backing strips?
« Reply #7 on: February 01, 2015, 03:48:24 am »
Flat sawn, quarter sawn, rift it doesn't matter the key thing is straight grain. A flat sawn board is the easiest to read and 1/4 the hardest but at first glance it looks like it should be the other way round! Even a tiny deviation from straight on a 1/4 board can mean very bad things.
Some people think flat sawn backing don't work but think about a decrowned stave...that's essentially flat sawn and they don't break as long as you keep the lines parallel = straight grain.
I prefer flat sawn.

Offline Springbuck

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Re: How to cut backing strips?
« Reply #8 on: February 01, 2015, 05:18:39 am »
   Mike it right here.  I'll take a flat sawn hickory back, for sure.  The hard thing about quartersawn is there is actually no way to tell if the grain runs straight back to front.  The lines are nicely parallel, and SHOULD be just fine, but that is examining the rings from the side.  The radial grain could be doing what the heck ever it wants.

In Torges TBM series he shows how to take a large flat sawn board (4/4ths at least) and turn it into several blanks for kids' bows.  He showed how ripping down the center of a perfect flat sawn board, with parallel ring lines on the faces, will give you several perfect quartersawn backings.  That method is great.  But, I have had several failures of backings, even with hickory and white oak, where I bought QS stuff that looked good, but which had radial grain running through diagonally.

  I once bought a 4' long, 8.5" wide, 3/8" thick hickory board off ebay (advertised for scroll saw work) with perfect grain lines running straight and parallel the whole width of the board, back and front.  I cut it into 2" wide strips, then ripped each of those into 1/8" plus thicknesses.  The grain ran through fron to back on those that they snapped when bent just a few inches, before even being glued to a bow.  The grain ran back to front diagonally in less than 1" through the 1/8" thickness.

  Just saying, quartersawn isn't magic by itself.  You gotta pay attention to how it gets there.

Offline russell

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Re: How to cut backing strips?
« Reply #9 on: February 01, 2015, 09:03:45 am »
Thanks mikekeswick and Springbuck. I kinda thought plainsawn had similar attributes to peeling a stave down to one growth ring (grain-wise anyway) - just wanted someone with more experience than me to confirm it. I understand watching what the grain does is important. Wood is an amazing thing. Thanks guys.
->>>--------->
   John 14:6

Offline Hamish

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Re: How to cut backing strips?
« Reply #10 on: February 01, 2015, 09:28:53 pm »
You want the grain to run no less than 2& 1/2 " from back to belly/core side on a 1/8th " thick backing. A little less might still be useable with a wider strip. 2 and 1/2" = 20 x 1/8"= 20;1 ratio. If you backing was 1/4" thick the grain should be no less than 5", to keep the 1:20 ratio.
Grain orientation is not too important. Flatsawn can cup a bit, but it will clamp flat.
                           Hamish.

Offline russell

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Re: How to cut backing strips?
« Reply #11 on: February 01, 2015, 10:03:14 pm »
Do you mean where a grain line "leaves" the back of the strip (looking from the side) and travels to the belly side?  That distance the grain travels should be no less than 2 & 1/2"?

Sorry for all the questions. I've worked with wood since I was a kid, but only fiddled with a few board bows. No shooters yet, but gettin antsy to have a real go at it.
->>>--------->
   John 14:6

Offline Wooden Spring

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Re: How to cut backing strips?
« Reply #12 on: February 02, 2015, 11:23:15 am »
I always cut mine a bit thick to begin with, and then run them through the thickness planer to an exact 1/8". I then glue it on with Aerodux Resorcinol that I get from amazon for about $64 a quart. It's expensive, but after having problems with Titebond 3 stretching and giving up on a hot day, I decided to go industrial strength.

When it comes to hickory, you really don't NEED quarter sawn stuff. Hickory is actually pretty forgiving, even if you have less-than-optimal lumber, it will still make a great backing strip.
"Everything that moves shall be food for you..." Genesis 9:3

Offline bubby

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Re: How to cut backing strips?
« Reply #13 on: February 02, 2015, 11:44:30 am »
How hot was it when the tb3 gave up on you, during the summer here it is routinely above 110 deg and i have not had that happen
failure is an option, everyone fails, it's how you handle it that matters.
The few the proud the 27🏹

Offline Wooden Spring

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Re: How to cut backing strips?
« Reply #14 on: February 02, 2015, 12:12:10 pm »
How hot was it when the tb3 gave up on you, during the summer here it is routinely above 110 deg and i have not had that happen

It was a balmy July day in North Georgia. Around 95 degrees but with 100% humidity since we were camped next to a creek all weekend. It was like this for 3 days, and our bows were under a fly tent. Most of the day, the bows were being used and in the sun. At the end of the weekend it exploded in my hands.

Iv'e had it happen to a couple bows, and Titebond 3 just doesn't seem to ever dry solid - it always stays flexible. So, for safety sake, I switched to a non-water based glue, Resorcinol, and I haven't had a problem since. Actually, during destruction testing of the glue, the resorcinol actually ripped apart the wood fibers of the bow. It's used back home in coastal NC to build boats, so if it'll withstand being submerged in saltwater with no degredation, it should be fine for hot and humid weather up here.
"Everything that moves shall be food for you..." Genesis 9:3