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Gday all, looking to build a wooden clock and I'm looking for some advice on timber selection for the gears. Ply seems to be the material of choice but I would love to use solid timber. Thinking of using blackwood, slabsawn/quatersawn, can it work or should i just use ply.
p.s. Using ply breaks my solid timber heart...
I am no expert and haven't made one but the clock guy at the woodworking show a few years ago was making his own laminations a few mm thick and gluing them at right angles to each other for stability.
I am interested in other peoples answers as I plan to start my own first clock soon. Plans arrived the other day.
G'day Y'all
tg04se
Any hardwood is OK for a clock. Ply is better because it is more stable than solid wood. The clock gears with the pointy teeth are very picky about the spacing between the arbors and expansion of the gears due to humidity can cause the clock to stop running.
You can make your own ply by resawing scraps, drops, cut-offs or rough sawn planks, glueing the strips edge to edge and the laminating the strips into plys.
Solid steel pins set in brass tubes make good arbors but you need to get them located correctly and drilled accurately.
Just about any tooth profile can be made to work if you put enough weight on it but the smoother the tooth surface and the more accurate the profile means you can use less weight.
If you get stuck, I have a CNC machine and I cut cut clock parts.
Rgards
Joe
I made the gears for several clocks using solid Satin Box (very fine grain ), any hard wood , dry and close grain will do. The clock in the attachment will be 6 years old in October, not showing any signs of wear, timing wheel teeth , pallets, arbors and bushes were all made from Lignum Vitae.
Details of the clock and how I cut the teeth was on Woodwork Forums a few years ago , but I can't find them now. regards John.
Rock Maple is extremely stable and quite hard-wearing as well. Just depends if you're willing to pay for the privilege.
For our clock kits (Clock Kits | Wooden Clocks | Clock Plans | Wooden Gear Clock Kits), we use Baltic Birch plywood for the gears. We recommend this for our patterns as well. Baltic Birch is preferred over regular birch plywood because it has more plies and the interior plies are of higher quality (no voids or junky material in the center). This is important when forming the gear teeth. Although it is possible to make 1/4" thick 8" diameter gears from solid hardwood, you have to have some very stable wood
http://wooden-gear-clocks.com/images/serpentine175.jpg
I use African Rosewood. If you build up the blanks using 30 deg segments cut
along the grain edge glued to become a complete circle (the last one will
have to be adjusted to make up for compounding slight angle variations) you will find that they are much stronger and more resistant to warping.
After glueing face both sides and then cut the teeth. Photo of clock with gears and plates made that way attached.
Findings...
Did a few different things with the gears. Used blackwood for all the gears. 2 ply at 180 deg(flipped over and glued, 1/4" total thickness) seemed for some reason that I don't understand to be the worst, bowed significantly with the weather. Solid timber(blackwood) at 1/2" seemed better. Made a 6 ply blank that ended up 1/4", the king, for the click gear and hands etc.
Results...
Solid can work and my wonky bending wheels still work fine, look good to, but for the escape wheel I wish I had used at least 4 ply. Mine is 2 ply mirror fashion and works but its a bit wonk and ticks louder on 1 side and quieter on the other.
Solid definitely works but ply works better for the important bits.
Ehh, this is probably well established already, but where's the fun in that!
As an aside would " lignum vitae" be any good for the gears in a clock
It is very hard,stable and self polishing so won't wear out. It used to be used for mallets and fids and such items that need to be hard and not wear out.
Also as bearing surfaces in fairing plates on ships where the propellor shafts came out int the underwater sections
Cheers
Peter
G'day Y'all,
A man called Rabbit , who made more clocks than just about anybody, recommends that lignum vitae not be used for the body of clock gears because it is oily and attracts dust and dirt. He does recommend it for use as the pallet nibs and for the teeth in the gears.
Regards,
Joe