Chrysals or filing marks, Red Oak Bow Build..

[sevenmil]

Just thought I'd attach some photos of 2 new red oak bows I made for my nephews for Xmas this year. Both came up pretty well, except during the tillering process i cut too much weight off one bow.

I did have a question for you more experienced Boyers. On the heavier bow (about 50#), I noticed some diagonal marks on the lower limb. I couldn't tell if they were filling marks or the dreaded Chrysals/Frets forming. The marks are not really uniform and start near the fades, appear again in near the middle of the lower limb and a bit higher toward the top of the limb. What do you think, filing marks or over stressed lower limb. The bow tillered pretty evenly (see photo), so I think they may just be tool marks I didn't sand out properly ?

[yeoman]

Can you take any close-up pictures of the suspect marks?

If you unstring the bow and place it back downwards on a table, how much set does that limb have? Looking at the limb from the side, at what point does it most aggressively start to take the set?

A file mark will be an indentation, while a chrysal will be raised from the surrounding surface. Are you able to determine which way the mark goes?

[sevenmil]

Thanks again Yeoman for your help. I could take a photo but they are actually quite hard to see, but they looked like indentations, but then again that was unstressed. I have made 3 red oak bows now and 2 seemed to have developed these frets.

Unstrung this bow had the least set of the latest 2 bows I just made. I guess it was about 2 inches on both limbs. The funny thing was the bow with the marks, was the better tillered of the two bows - I mean both limbs were moving nearly exactly the same, so I am buggered as to why the frets are forming?

[sevenmil]

Sorry in regard to the other question about the direction of the marks, they are diagonal across the grain, not horizontally across the grain, but at an angle and that is why I thought they may still be file marks as I used a rough rasp at an angle during the tillering process.
I wish I could take a photo, but I have since given the bows away at Christmas....

[yeoman]

If you can get a hold of them again you might try this:

Shine a bright light at an acute angle to the bow's surface and look at the marks from 90 degrees. If there's a shadow on the bottom half, they're raised, and are chrysals. If the shadow is on the top half, they're indentations, and thus file marks.

If that doesn't do it for you, hold the bow as if you were still tillering it, and mime rasping away at it. Does the angle of the mark match your rasping angle?

A chrysal will protrude whether or not the bow is stressed.

Dave

[sevenmil]

Thanks again Yeoman. I actually did do hat you suggested in regard to mime rasping and it was exactly the same angle. The marks didn't protrude, so maybe they are file marks ?

The bows are in Victoria now (I am in NSW), so I probably won't see then for a while, but I'll ask my nephews how it is going.

I am planning a 4th red oak bow, this time without a backing and a larger riser/handle. Aside from picking a straight grained piece of red oak, any advice as to not breaking it?