rings

[chas]

Does anyone have an opinion or any information on how much strength metal rings add to sockets? Like how much less often sockets crack on flutes with rings vs. ll-wood flutes? I've ordered an all-wood A-Bb-C combo from Casey Burns, but am having second thoughts about the lack of rings. One data point is that I have a boxwood flute on which one tenon goes out of round in the winter, so the ring keeps it from completely losing its shape.

(Yes, I've asked Casey, but am interested in other points of view.)

TIA, Charlie

[Nanohedron]

I'd never seen ferrules on tenons until I'd seen a Hammy. Although it was blackwood and less likely to undergo warpage than boxwood, I thought it was a good idea in that it couldn't hurt, at least.

Ferrules on sockets, on the other hand, are probably a must. Unlike tenons, sockets are more likely to be at risk of cracking as they must bear the internal pressure of tenons, and ferrules would be a measure to help against that although not a guarantee. I would think that a strong ferrule would affect how much boxwood would warp right at the socket and tenon.

[Loren]

Metal rings or bands on sockets add a huge amount of strength, and so can make a significant difference. This is particularly true in the case where an instrument is dropped or sat on (accidentally we'll assume....) - in this case an instrument without metal support rings/bands nearly always suffers seriously cracked or often shattered socket. I see lots of these repairs every year, it's really amazing how often people put their instruments down on a chair, and then forget about it before sitting down Also table roll offs are common as well.

Well fitted rings can also make a difference in the ovaling that happens seasonally with some woods.

So, if it were me, I'd go for the rings, but then I'll be here to repair your instrument should you decide to skip them Charlie

Loren

[Unseen122]

Well Chas I know you well enough to know that you are probably going with Boxwood in which case I would say go for the rings, but if I am making an ass out of u and me and you are getting Mopane or Blackwood I would say you are probably fine with out rings.

[Sillydill]

Hey Chas,

ANYTHING FOR THE SAKE OF SCIENCE!

The problem with wood is that it has a relatively low tensile strength (can easilly be pulled apart, or split). Wood has a relatively high compressive strength (hard to compress). Typically with wood the tensile strength is approximately half the compressive strength (both measured perpendicular to the wood grain).

To compensate for the low tensile strength rings are added.

Good woods have a tensile strength of about 600 psi (perpendicular to the grain).

Sterling silver has a tensile strength of about 45,100 psi or roughly 75X that of the best woods.

The smallest rings I've seem on a flute are about 12 gauge half round, with a diameter of 0.0808 inches. This yields a tensile strength of the band of 116 psi.

But the problem is how are the rings applied, most are just slightly oversized and cemented on. McGee dries his wood (shrinking it) applies the rings and then lets the wood rehydrate at 50% relative humidity.

Casey Burns uses substantial turned rings that should be exceptionally strong if tightly applied.

Was this more than you wanted to know???

Keep Makin Music!

Jordan

P.S. If someone knows of a good source for Tensile Strength and Hardness tables for woods typically used for flutes would you please let me know. THANKS!

[SoTX]

Casey's ringless flutes have a sort of ring of thicker wood at sockets. I'm paranoid, however. In the concave area between the bead and the "wood-ring" I wound some brown polyester saddle-making cord, using the "loop and yank" trick known to all former boy scouts. I made it very tight. This pre-stresses the wood, transferring some of its compressive strength into tensile strength.

In the flutes I've made, I've done the same, only more so, in turned channels. I made up a test joint, not on a flute, and tested it to failure. The wood between the binding and the end of the socket cracked, but the crack stopped at the beginning of the binding and when the force was released the crack closed and was invisible. Prying with a pipe I was able
to damage the inside of the socket enough to collapse the joint, but it took a good deal of work. A simple crack was never an issue.

My flutes are all under five months old, but the wrapping doesn't seem to be loosening. Time will tell. One of my mechanical engineer friends recommended polyester because it doesn't creep nearly as much as nylon.

For me, the advantage is a nearly indestructable socket and I don't have to learn silversmithing.

Having "pre-stressed" it, I don't worry about my ringless CB flute.

-- Don Varvel

[David Levine]

For me, the advantage is a nearly indestructable socket and I don't have to learn silversmithing

You'd not have to learn silversmithing. You would order a bunch of rings in the sizes you need, then turn the wood down to accomodate the ring. You don't make a ring to the size of the flute.

[Matt_Paris]

You don't make a ring to the size of the flute.

Excuse me David, but all the makers I know do... Using silver thread they curve, weld and turn to obtain the traditionnal "D" shape.

I'm sure it is also possible to buy rings, but that's not the technique I have seen.

[jim stone]

I have a CB all wooden boxwood C and a CB all wood
blackwood/mopane Bb. Both have done fine for several years.
Casey has very clean and apparently very stable
boxwood. As the tenons are thread wound, it's
easy enough to adjust pressure on sockets; indeed,
thread keeps compacting so that sockets tend
to be a bit loose. I don't see any problem.

Of course I haven't sat on these flutes yet.

[Doc Jones]

My CB boxwood is ringless. No trouble for several years.

This, of course, means absoultely nothing.

The best info would be from Casey... ie how many cracked sockeys has he had returned over the years.

Cheers,

Doc