Question

[agd68]

I've heard a couple of terms I'm not sure about. What is crown and trapping a back when talking bows ?

[Del the cat]

Crown is the high point on the curved back of a bow.
If you take a log and split it in two, you get a D shape, the flat face would be the belly, the curve of the D would be the back, the crown is the high point in the middle of the curve.
I have no idea about the other term... is there a prize for the best answer?
Del

[Diligence]

Trap refers to trapezoid.

It's when you shape the bow cross-section to look roughly like a trapezoid.  The narrow portion of the trapezoid is the bow's back, the belly is the wide part.

I'm not sure what woods it works best on, but it allows the back to be narrower (i.e. less mass) and still have the tension resistance needed (some woods are much better in tension, so it can be narrower).  The belly needs to be wider as some woods are much weaker in compression.

Okay Guru's, did I get it right?

J

[aaron]

right... you trap woods like black locust to give them more strength in the belly. (or for example with bamboo backing- the bamboo can be too strong for some belly woods and so you might glue a narrower strip onto a wider belly.)

[HoBow]

You can also trap the back of a bamboo backed bow. This is done by taking a scraper and run it down the corner of the boo on each side to make it more trapezoidal. I only know this because of David's class at the Classic. (There's a plug Mr. Knight )

[Simple Hunter]

 
     I am not as experienced as some on here but I made a hickory sapling bow and correct me if I am wrong but the high crown would make the back trapped?

[aaron]

yes,
a high crown and flat belly is the same effect as trapping.

[adb]

"Trapping" the back of a bow means to cut a facet on the square edges of the bow's back, making the x-section a rough trapezoidal shape. It transfers some of the stress to the belly. I've used it extensively on bamboo backed osage bows, especially with R/D designs. It seems to excel with flat belly profiles, also. Having square edges anywhere on a bow is not a good idea, as it becomes the focus of stress, making failures more likely. Round all the edges. I trap all my bows to some extent, some much more than others.

[agd68]

Thanks for clearing it all up .