Bridge Cap Grain Angle

[Ron Nossaman]

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>Got to thinkin'........
>
>My understanding of bridge cap material grain angle is that is should=20
>follow the curvature of the bridge as close as is possible because maple=20
>is strongest regarding compression forces to application of that force=20
>parallel to the grain.
>
>So in the upper treble where the strings are roughly perpendicular to the=
=20
>bridge, this would work just fine. But in the tenor section where the=20
>strings might be 45 degrees to the bridge, does this rule hold true? Would=
=20
>there not be some advantage to having the cap grain perpendicular to the=20
>strings?
>
>Any thoughts?
>
>Terry Farrell


Lacking better sense, I'll bite. I try orient the grain in the treble=20
somewhere between parallel to the bridge in the treble, and parallel to the=
=20
bridge in the tenor. Not for compression strength, but for ease of hand=20
notching. The idea being not having the grain too nearly parallel with the=
=20
pin rows in the treble (for notching), but nearly enough parallel with the=
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bridge to get enough long grain on the bridge to discourage splitting (for=
=20
longevity). In the tenor, I go parallel to the bridge. There are two=20
reasons for this, three counting the notching concern. Parallel to the=20
bridge uses capping material more efficiently, and bridge caps don't=20
typically split and cause problems in the tenor anyway. Loose pins in the=20
tenor don't cause false beats like they do above the agraffe section. I=20
think it's frequency related, so it's less critical down there. Using=20
laminated capping stock in the treble nearly eliminates structural=20
(splitting) concerns, but might aggravate notching problems. high angle=20
(90=B0) cross plies are hardest to notch by hand, which is why I thought of=
=20
low angle (10=B0 or so) cross ply capping as a decent compromise short of=20
building a power notcher. I didn't invent the idea, I just thought of it=20
independently after others already had. Anyway, that's my take. Yet another=
=20
compromise.

Ron N

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