Designing a Plinth

Joe, let me ask you this. How did you establish the outer circumference of your platter? Were I to make one, I was considering attaching stock to top and bottom and turning it on the lathe. A shaper and jig might work. Of course, a band saw and shaper is the usual choice for non-critical stuff but I am thinking that the circumference should be pretty damn consistent to achieve rotational stability. What have you found in this regard?

Jim, the dimension is based on 1/4" thicknesses. 3/4 = 3/4", 4/4 = 1", 6/4 = 1 1/2".....Joe's mention of 8/4 cocobolo is 2 inches thick.

The West Penn site is interesting. There are MANY sites offering exotic hardwoods these days, some more reputable than others. In the end, most all are very good places to go look at pictures of different woods and to learn of some their characteristics. However, it is always best to find a dealer locally if at all possible. That way you can go take a look and decide for yourself with some expert advice many dealers can provide. Plus, the shipping costs for more than just a small amount of wood can be STEEP. I know of quite a few folks in the business of using exotic woods. Depending on where you are located, I might be able to offer a suggestion or two. IMHO, it is worth a couple hours drive if it means being able to select just the right piece or, perhaps more importantly, have the ability to reject a piece without the hassles and expense of returns.

One reason I ask about using the lathe (or a shaper) is that I would then gouge a groove or five and then use some bandings to highlight the platter edge, examples of which can be seen in the link below. There are a variety of other source for these bands, too. I have modest collection of inlay patterns I've used when building other furniture and my uncle has a set he has made that is downright staggering - though his skill is at a level that mere mortals such as I can only aspire! ;-) The variety of inlay possibilities that might be applied in the crafting of a plinth seems endless and well, exciting, at least to me.

Bandings

This is from the West Penn site:

"DALBERGIA RETUSA

Cocobolo is a member of the Rosewood family. It grows in the drier uplands on the Pacific side of Mexico down to Panama. Extremely oily it will reject almost any finish except wax. It shines up to a nice luster. Even an oil based varnish will not stick. There is no treatment that will make it suitable for bonding with glue, but it can be nailed or screwed easily. It is waterproof which is excellent for making knife handles. It smells like lilacs while it is being sawn or sanded. It varies in color from red to yellow and striped with black to lighter black. It darkens with age."

Sounds like drivel to me since I've done everything to it that they say can't be done. Also, I only paid $14 a foot for 8/4 that has been sitting since the 1920's.

David: On the platter we've been "having a time" as they say. I finally found that the best way do do it is with a router. Band saw down to close, and then use a template I had made out of steel. A friend of mine has access to a machine shop at work so he had a couple different ones made. This will make it a hell of a lot easier to try different arm boards and plinths. I can also get perfect cauls for gluing the veneer. May go the vacuum bag route here, not sure. I like doing things the old way some times. I'm going to do another plinth for myself too. I need to have two set up to evaluate pieces as they are made.

Our biggest lathe will only turn 11" so we have had to come up with alternative methods. I wish we had one that would turn 14" for the options it would give me. But, I can do just about anything either with a router, shaper, or by hand that I cound do on a lathe. Just about.

Teres uses Jatoba cores for it's platters. CB only made one solid cocobolo platter for the 340. The prototype is 4" thick and weighs 40 pounds! I'm shooting for the same size. I'm doing it in two pieces so you wont see any of the holes for the lead. I'm also trying some different lamination methods for stability. Veneer will be a must for cosmetics. Maybe some banding or inlay. But first I want to make sure it will work. I won't know how true it will run till I get it mounted. But, I'm no rookie!

Jim, 4/4 designates the material thickness. 4/4 would 1" thick, 8/4 would be 2" thick. 5/4 for example would be 1 1/4" thick. BUT, (just to confuse matters) this is not always the actual thickness.

The site offers "dimensional hardwood lumber". A 1"x4" is actually 3/4" x 3 1/2". Although, I don't know if that is the case with lumber of the "non dimensional" type. You would need to consult with the other contributors to this thread, as I have no expertise in this subject.

Jphii, I also found that highly unusual. But again, I won't pretend to know anything about this stuff, cause I don't. From the theoretical mechanical/electrical design/engineering aspect, I could hold my own. But when it comes to the actual woods?

I subscribe to the old theory:

"Better to be silent and thought the fool, than to open the mouth and remove all doubt".

Something like that, but I'm sure you understand what I'm attempting to say.

I was actually trying to find a website that provided resonance/excitation frequencies, and vibration dissipation characteristics of wood (I have no life), but with no success. Does anyone know of such a site?