Minimal contact arm rest

[Charles E.]

I know that there a couple of people here making their own arm rests so I thought I would share my design. Most others seem to make full contact along the entire length of the arm rest, mine has only minimal contact over the rib and kerfing. The cuts were made on the drill press using a "safty planer".

[mandroid]

the 2 I have just have a thin actual contact of cork, on the very edge which is over the kerfed lining the top & rim are glued onto...

[Jim Garber]

Joseph Cleary's armrest for my Campanella A-5 has minimal contact. It was the first mandolin I owned that had an armrest and I like his design. Obviously both of you are violin builders so carved chinrests are the inspiration.

[Charles E.]

Joseph Cleary's armrest for my Campanella A-5 has minimal contact. It was the first mandolin I owned that had an armrest and I like his design. Obviously both of you are violin builders so carved chinrests are the inspiration.

Nice piece of work,that.

[Eric Hanson]

Beautiful mandolin!
I too think the armrest is perfect for the mandolin. Is there any contact information for Joseph Cleary?

[sblock]

There are fundamental differences between a violin chinrest and a mandolin armrest. In particular, the violin chinrest has a fairly complex (sculpted) curved surface, designed to raise the chin above the instrument. It is that shape that dictates contact with both the chin, on one side, and the instrument, on the other. The mandolin armrest is not similarly constrained, and there would seem to be no compelling reason, other than someone's aesthetic notions, why a mandolin armrest should look like a violin chinrest.

The mandolin armrest is designed to make contact at the very edges of the rim on both the top and back. These locations form acoustic nodes, and they don't oscillate up and down in the normal modes of vibration. (The same is true of the violin.) Adding an armrest to a mandolin should not change its sound, in principle. And writing for myself, I have confirmed this in practice, as well. I listened carefully to three F5-style mandolins that I own, both with and without their McClung-style armrests (from Doug Edwards), and have been unable to discern any differences in tone, either way. In a similar fashion, mandolin accessories like the ToneRite, Carpenter jack, and pickguard are also designed to attach to nodal points that vibrate little, and don't contribute to tone.

Based on the foregoing, reducing the contact area of a mandolin armrest against the rim to the absolute minimum seems unlikely to do much, if anything at all, to affect the the tone. Furthermore, thinning down a section of armrest wood so that it's rigidly suspended over the rim sets up the possibility that it might be susceptible to some independent vibration of its own (or buzzing), which would be quite undesirable. Of course, whether or not that happens depends on the dimensions and stiffness of the suspended portions of your armrest design. Violin chinrests are carefully designed to avoid such buzzing, for example.

From my perspective, this design seems to "solve" a problem that most of us don't actually experience with our armrests, and it opens up the possibility of introducing some additional problems.

[Charles E.]

I would guess that most if not all makers of mandolin arm rests try to keep contact to a minimum and limited to the very edge. I can see the resemblance of the Cleary arm rest on Jims mandolin to a violin chin rest but I came at it with a mandolin arm rest in mind only.

[Jim Garber]

Beautiful mandolin!
I too think the armrest is perfect for the mandolin. Is there any contact information for Joseph Cleary?

Joe’s website: campanellastrings.com

[Charles E.]

Furthermore, thinning down a section of armrest wood so that it's rigidly suspended over the rim sets up the possibility that it might be susceptible to some independent vibration of its own (or buzzing), which would be quite undesirable. Of course, whether or not that happens depends on the dimensions and stiffness of the suspended portions of your armrest design. Violin chinrests are carefully designed to avoid such buzzing, for example.

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I tuned mine to a "G".

[poul hansen]

I know that there a couple of people here making their own arm rests so I thought I would share my design. Most others seem to make full contact along the entire length of the arm rest, mine has only minimal contact over the rib and kerfing. The cuts were made on the drill press using a "safty planer".

Nice. Where did you get the hardware?

[Charles E.]

You can get the viola hardware here.....

https://www.internationalviolin.com/...hinrest-screws

Make sure that the barrels are 30mm long.

[dhergert]

Love the violin edges on that mandolin Jim!