A trap question?

[Jermcramp1]

I need to fix a gouge in my handle fade on the back side o the bow, I think I can reomove the cut if I trap the back, how far on the side and back should I make the trap?

10" static 2"fade 12" working 2" fade 4" handle

working limbs are 2" wide as of now but I havent started working on it yet, handle is 1" wide, just cut out the shape.

hickory molly with walnut handle, I'm looking for 40-45# @ 28"

Any advice would be greatly appreciated.

[PEARL DRUMS]

I usually use a compass to draw 1/4" wide lines down the back and sides when I want to trap evenly. Rasp until you hit both lines and you end up with an even cut.

[Jermcramp1]

Thanks pearl drums, not to seem lazy but would a router be too much of a risk? or does it need to be more of a square angle?

[PEARL DRUMS]

I suppose a router would work, but power tools got you in this jam correct?

[Jermcramp1]

Point well taken...

[Dave Worden]

Okay guys, what is trapping?

[SportHunter]

You can use a spokeshave to trap after marking your lines. Finish off with a file and or sandpaper.

[mwosborn]

I am with Dave - What is trapping?

[4est trekker]

Trapping (which refers to "trapezoidal" is the process of equalizing the tension strength of the backing to the compression strength of the belly (or vice versa, referred to as reverse trapping).  It is accomplished by giving the limbs a trapezoidal cross section ("trap")...  / \\

In the case of hickory, which is strong in tension but weak in compression, if wood is removed from the back, it forces less wood to do the same amount of work.  Thus, it will be more difficult for the back to overpower the belly, which can cause undue set, fretting, etc.

In some woods which are strong in compression but weak in tension, it may be necessary to reverse trap the bow so that there is more wood being pressed into tension on the back.  

Trapping is also used from time to time to simply reduce both the mass and draw weight of the bow, particularly in fiberglass and bamboo backed bamboo bows.

Sure hope that helps.

[Jermcramp1]

Well guys I trapped the back, and it worked perfectly, the gouge is gone!!!

Sorry I never put pics up but I will of the finished bow. I have it shaped and floor tillered, glueing on some tips now.

Will post pics tomorrow.


O trapping makes the back look like    / \\  if it was belly side down... and reverse trap would be \\ / if it was belly side down...It looks pretty cool too.

[Wally Dye]

I recently was fortunate to swap for a longbow made my MR Hamilton.  I found a section of the Traditional Bowyer's Encyclopedia online where there is a great chapter on him.
I know nothing about his "Scorpion" but, have heard they performed well. It is an absolutely beautiful bow.  You can see from the finish and details the work he describes putting into each bow is there.
In the article on him, he goes into some depth on his design development.  He worked with the Marines at 29 Palms and apparently used the computers to help with his design work (used the barracks toilet lids for curve design).
He did some testing.  Made one bow with Trapezoid limbs, another square and the third with reverse trapping.  When he tested them, the normal trap had the least cast, the square next and reverse trapping performed the best.  I had a Centaur that was "reverse trapped" to reduce weight and  it outperformed the other 2 I had.   In reading the description H Lee Robinson has on his website (Protege Bows, Keep It Simple Archery), he has incorporated reverse trapping to maximize performance. I am the proud owner of his TGS #1 (TradGang Series) and it is a performer, fast, smooth and dead in hand, just as he describes.
I have no idea what sort of performance increase reverse trapping can provide.  I expect it certainly depends on the construction and materials used but, I agree, it certainly looks cool and from looking at my 2 reverse trapped bows, it doesn't take much.
Might be something worth looking into.

[Art B]

What type bows are you referring to Wally? Are these glass backed, all wood laminates or selfbows? Sorry, but I'm not familar with Mr Hamilton's bows  ............Art