Wooden Gears

[Bo’sunParticipant @bosun58570]

As I understand it, most woods will carve or cleave better when they're green, as the cellulose in the structure is still essentially liquid. As the wood dries out, the cellulose hardens and the moisture dries out, gluing the cells together, making some timbers like concrete.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, just for interest, this was a display at the 2017 MMEEX. I don't know if it was aimed to be a static display or whether it was a working model. I guess it could only have one fire up display though.

Regards Nick.

[Roger BestParticipant @rogerbest89007]

Plywood gears? – no problem.

 

Edited By Roger Best on 22/08/2020 01:03:00

[HopperParticipant @hopper]

Posted by Michael Gilligan on 15/06/2020 12:38:48:

A philosophical question, which probably only Mick H’s son can answer:

Does ready-made ply qualify as ‘wood’ ?

… or, as an ‘engineered material’ would its use be considered cheating ?

MichaelG.

Well it's called plywood.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Hopper on 22/08/2020 01:38:42:

Posted by Michael Gilligan on 15/06/2020 12:38:48:

A philosophical question, which probably only Mick H’s son can answer:

Does ready-made ply qualify as ‘wood’ ?

… or, as an ‘engineered material’ would its use be considered cheating ?

MichaelG.

Well it's called plywood.

.

Or you could put the emphasis on ply instead of wood

It is an ‘engineered material’ constructed from wood.

… Hence my question.

MichaelG.

[HopperParticipant @hopper]

Is a boat made from marine ply a wooden boat?

[Michael GilliganParticipant @michaelgilligan61133]

That probably depends upon the the constructor’s and/or the examiner’s opinion.

… Which was the very essence of my question:

A philosophical question, which probably only Mick H’s son can answer:

MichaelG.

.

Unless you happen to be Mick H’s son … can we leave it at that, please.

[HopperParticipant @hopper]

Enquiring minds want to know.

[Michael GilliganParticipant @michaelgilligan61133]

O.K. … if you must labour it, Hopper

My personal opinion is that factory-made plywood does not qualify as wood.

The reason for posing my question was that [not knowing Mick or his Son, or the circumstances], I am not aware of whether this is a ‘fun project’ or a ‘design & manufacturing’ exercise. … It may, for all I know, be subject to assessment.

Many years ago, I made some hair-slides for my wife : These were laminated, by me, from layers of wood veneer.

As such : I would say they were (a) made from wood, and (b) demonstrated my understanding of how wood can be ‘engineered’ to make better use of its characteristic properties.

IF the gears in question are to be ‘assessed’ then I would expect the ‘plywood’ to be manufactured, not bought-in, by Mick’s son … to demonstrate his understanding.

Your opinion may differ, and I respect your right to hold it

MichaelG.

[JasonBModerator @jasonb]

I hope you cut your own veneers Michael as bought in would see you loose a few points

Which brings up the question of where to draw the line between "factory-made" and home made, should Mick's son be buying in prepared timber, cutting from sawn boards or starting with green wood and planking and drying his own?

[Michael GilliganParticipant @michaelgilligan61133]

All of which takes me back to my original:

[quote]

A philosophical question, which probably only Mick H’s son can answer:

Does ready-made ply qualify as ‘wood’ ?

… or, as an ‘engineered material’ would its use be considered cheating ?

MichaelG.

[/quote]

[pgk pgkParticipant @pgkpgk17461]

…or planting the trees from hedgerow harvested seed..

…then you have the problem of glue, rearing your own animals to harvest the hooves…

..or pine resin glue

pgk

Edited By pgk pgk on 22/08/2020 10:38:20

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Michael Gilligan on 22/08/2020 09:29:12:

.

IF the gears in question are to be ‘assessed’ then I would expect the ‘plywood’ to be manufactured, not bought-in, by Mick’s son … to demonstrate his understanding.

.

PostScript: For use in wooden gears, I would also hope to find some of the plies to be arranged as ‘pie segments’

MichaelG.

[egaParticipant @ega]

The pie segments approach would also serve for a wooden pulley.

Pine resin: is the YouTuber right to call it epoxy?

[Gary WoodingParticipant @garywooding25363]

Posted by pgk pgk on 22/08/2020 10:37:46:

…or planting the trees from hedgerow harvested seed..

…then you have the problem of glue, rearing your own animals to harvest the hooves…

..or pine resin glue

As somebody once said, "If you want to make an apple pie from scratch, you must first create the universe".

[Roger BestParticipant @rogerbest89007]

The issue is making the best of the resources available, not being restrictive; innovation is king in the real world.

I say ply is wood enough.

[Howard LewisParticipant @howardlewis46836]

So far, no one has mentioned MDF. It has no grain, but the dust is reputed to be pretty nasty.

Or it totally out of court mas not being real wood, instead of ,as I understand it, resin bonded wood dust?

Howard

[pgk pgkParticipant @pgkpgk17461]

Posted by ega on 22/08/2020 10:52:38:

The pie segments approach would also serve for a wooden pulley.

Pine resin: is the YouTuber right to call it epoxy?

Epoxy is probably millenial-speak for glue

pgk

[egaParticipant @ega]

Posted by pgk pgk on 22/08/2020 12:48:16:

Posted by ega on 22/08/2020 10:52:38:

The pie segments approach would also serve for a wooden pulley.

Pine resin: is the YouTuber right to call it epoxy?

Epoxy is probably millenial-speak for glue

pgk

A "respectful" virtual elbow bump to you for being in touch with youth!

The dictionary says "synthetic" resin but does that preclude epoxy resin from occurring in nature?

I am reminded that petrified resin becomes amber which is not unlike a blob of cured Araldite.

[Tim StevensParticipant @timstevens64731]

Whatever wood you decide on, you need to understand that wood is strong along the grain, but weak across it. That is why plywood is mentioned above. In practice, making your own from layers of veneer might be best.

And then you need to work out how to cut the teeth without destroying the outermost edges. Once you are sure that the laminations are properly stuck together and waterproof, it would help to add an extra sacrificial layer both sides using a water soluble glue, cut the teeth ignoring the fact that bits flake off, then soak off the outsides.

Good luck

Tim

Edited By Tim Stevens on 22/08/2020 15:31:17

[JasonBModerator @jasonb]

Though given the ease at which wood can be cut with a router and a lot of schools have small CNC routers then with a small dia cutter the gear could be cut flat with the tool following the path of the teeth rather than using a cutter at right angles to the gear. With an up/down shear cutter you won't even risk any tearout, also known as compression spiral cutters.

Edited By JasonB on 22/08/2020 16:12:43

[Tim StevensParticipant @timstevens64731]

An alternative gear-tooth cutting method, if you can access the kit, would be to draw out the gears in a CAD program and get them laser cut. This method uses a hot beam of light across the gear, so there should be no tendency to tear at the grain.

I think there are adverts in MEW for this sort of service.

Cheers, Tim

[John HaineParticipant @johnhaine32865]

If MDF is a possibility then you might also consider Valchromat, which is a similar product but using a melamine resin rather than formaldehyde. It machines very well, better tha MDF, and is much safer.

MDF can be sealed and strengthened by "varnishing" with PVA slightly diluted, or possibly better is a Ronseal product for treating wet rot, which is a resin dissolved in a volatile solvent. This soaks readily into the material without making it swell, then dries sticking all the fibres together making it much more resistant. Either would probably be suitable for Valchromat as well.

In boatbuilding plywood (and other woods) are treated with a liquid epoxy resin which soaks in and seals it, also making it much stronger. Look up "West System Epoxy".

 

Edited By John Haine on 22/08/2020 18:13:44

[GeorgineerParticipant @georgineer]

Posted by Tim Stevens on 22/08/2020 16:43:16:

An alternative gear-tooth cutting method, if you can access the kit, would be to draw out the gears in a CAD program and get them laser cut. This method uses a hot beam of light across the gear, so there should be no tendency to tear at the grain.

I think there are adverts in MEW for this sort of service.

Cheers, Tim

My personal objection to this would be an aesthetic one, because the cut surfaces are scorched black.

George B.

Edited By Georgineer on 23/08/2020 11:54:05

[Michael GilliganParticipant @michaelgilligan61133]

Resurrecting Mick’s thread, because I think this may be of general interest:

**LINK**

https://www.hodinkee.com/search?q=wooden+wheels

MichaelG.

[Author]

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