Sunday, August 19, 2012

Metal Bracelet Desgin

Perhaps the next production item will be a stainless steel bracelet for my Ka La watches. In keeping with the theme of the curved lug "rings" on the watch case, I have designed a metal bracelet with curved links.

The below CAD render does not include the end pieces that will attach the links to the watch case, but it does give a good idea of how things would look.

The bracelet links are just over 23 mm wide at the widest part of the curve and 20 mm where the links join each other. The link thickness is 4 mm and the links join each other on a 12 mm spacing. I have designs for the end pieces and a "half-link" already drawn in Corel Draw (2D). Next I need to redraw these pieces in my 3D CAD program.

The bracelet will close via a butterfly deployment buckle. I have reviewed the design of a number of fold over clasps on metal bracelets and quite honestly, too many of them are "cheesy" with thin and roughly finished parts. And they seem to fall into one of two camps: they fail to stay closed (folded over) or they are too tight and are very hard to unclasp. A butterfly deployment (with spring releases) avoids these issues which friction lock with folder over clasps suffer from.

The "half-links" will allow the bracelet length to be changed by 6 mm when a full link (12 mm on center) is too large of an adjustment. For comparison, most leather straps have a 6 mm hole spacing. One of my pet peeves with metal bracelets with a 10mm, or more, inter-link spacing and no other adjustment options. They often seem too loose or too tight when a single link is added/removed. A "half-link" solves this problem for most people, but too many bracelets fail to have either one or otherwise provide for micro adjustment at the buckle.

I'm considering using to see if I can fund the production of these bracelets. If so, the supporters would receive a free metal bracelet upgrade (a $100 value) with the purchase of a Ka La watch. I will get an cost estimate from my watch case maker and go from there on deciding how much I would need to fund via Kickstarter.

Update: Below is the render (above) with a photo of a Ka La Ref. 10111 composited into it.

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