Thread: Wooden Gears

Yellow Box

The ideal timber is Lignum Vitae, however very hard to get and very exxy too. Threatened species.

If you're lucky you may find a set of really old lawn bowling balls at St Vinnies or somewhere. These were made from LV.

Its a good question, what timber for wooden gear wheels. In the American wooden clocks c.1800 supposedly they used apple and pear woods because they are close grained and have a high resin content, or so says the website www.clockmagic.com/clock_lore.html

In Australian timbers Boas 1947 "Commercial Timbers of Australia" is usually pretty good for specialised uses of timbers across the range of old trades. It cops out on gears though, suggesting that "hardness, smooth-wearing and non-splitting are the qualities required", but then suggests "the most satisfactory material for this purpose is improved wood" . On the other hand, Boas suggests for wooden screws (e.g. workbench vice screws) they need to be "hard, smooth working, uniform fine textured timbers", so to use Ivorywood (Siphonodon australe), Kanuka (whatever that is), Grey Box (Eucalyptus hemiphloia and E. largeana), or Crow's Ash (Flindersia australis). Sheaves (the wheels of pulley blocks) he writes, need "hardness, smooth wearing, and non-splitting", suggesting Coachwood (aka Scented satinwood, Ceratopetalum apetalum), Silver ash (Flindersia spp.), Blackwood, Crow's ash, and Brush box.

That's a fairly wide range of possible candidates, although almost all are pretty unusual. Has anyone on this forum actually made wooden clock wheels from Australian timbers?

Hi Loxsan,
There is an article about wooden geared clocks in a FWW publication, which I have at home...something like Workshop Specialties. It is about a US guy, so no doubt he uses timbers readily available over there.
There is another guy who makes wooden gear and pulley driven kinetic sculptures, not clocks though: try here http://www.woodthatworks.com/index.html

He uses "Solid birch plywood is the main material in the sculptures.
It is a solid hardwood plywood with the interior plys being
of as high a quality of wood as the surface veneers.
I use a plywood verses a plain hardwood because of its stability.
For the sculptures to keep moving in all environments,
the wood must be as stable as possible.
This type of plywood is imported from the Baltic region either
from Finland or Russia."

Cheers,

I'm inclined to think that the gears would be best radially laminated to eliminate the possibility of teeth shearing on the crossgrain, so even blackwood should work well in such case.

Even straight grained redgum should work very well as it was used for bearing blocks in the old paddlesteamers. But its too short grained to cut the teeth of a gear out of a single piece.

Or perhaps make the blanks from shop laminated ply in appropriate timbers.

Originally Posted by Bodgy

The ideal timber is Lignum Vitae, however very hard to get and very exxy too. Threatened species.

If you're lucky you may find a set of really old lawn bowling balls at St Vinnies or somewhere. These were made from LV.

Carbatec in Melbourne has some for sale - not cheap though.

One of these days, I want to raid the stern tube A brackets on the old steam-powered warships. They were predominantly LV as the bearing material. (Well the ones I served on certainly were).

OK, the publication is Woodshop Specialities, and has a chapter on wooden clocks by John R Lord. It has some great detail drawings of systems and construction techniques. There are several people's work featured, and the timbers used in construction include: bird's-eye maple, Brazilian rosewood, cocobolo, white oak, holly; whereas wheels/gears are made from quatersawn black cherry, walnut rims with birch teeth, and various laminated 'hardwoods'.
One technique is to make a laminated disc and insert seperate teeth into slots cut on a tablesaw (indexing jig). This allows the grain of each tooth to be in the direction for max strength, no snapping of cross grain. I know a similar thing is done on a larger scale in old windmills, and the teeth can then be removed and replaced.
Loxson, I'd suggest you get a copy of this softcover, a fair bit of detail, although not full plans!
Cheers,

Thanks for the suggestion, I'll try that approach

Bob, Thanks for the suggestion, I've got some info on gears laminated from veneers but have not tried it yet. As an old engineer I probably look for the 'quick fix' way rather than the right way.
Regards
Dave Behrens

Thanks for the suggestion, I'll look into those areas.

Regards
Dave

Thanks for the info, Ive read another of your pieces on clockworks and it's been helpfull. I've looked at a number of web sites which have shown design but not gone into timber details. I'll follow up your suggestions.
Regards
Dave

hi there,
I have a set of plans for a grandfather clock and the timber used for a lot of the gears is Sheoak with Jarrah used for bushes and caps etc.
Cheers
Max

I use Satin Box for the gears in the clocks I make. Hardwood ,very fine grain ,it was recommended to me by a ex Forrestry Commission employee.
Took some finding a small quantity ,which was cut in the Otway Forrest many years ago. If you look on the thread Wooden geared clocks,there is one of my clocks. As for Lignum vitae ,its very expensive. Was up in Sydney last week and went to Trend Timbers for some to use for bearings and pallets in clocks. After scraching around for 1/2 an hour ,they found 3 small pieces ,which I took ,($90).
good clock making Nine Fingers