Leonardo da Vinci's wood lathe

[echnidna]

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[Pat]

Looks to much like hard work to me:p

[rsser]

Wow, that's some handwheel.

[rhancock]

Even for a manual lathe, this one is amazing in its simplicity! No highly worked components, no leather belts, a very simple stock. Fanatastic!

I do think it was designed for a very short, hard working life for the operator though. He's balanced on one foot, with a bent back, with all his weight pushed forward against the blank. You'd have to be very fit to do this for more than about 10 minutes. A working day (10 or 12 hours in Da Vinci's time!) would cripple you in 10 or 15 years at most, so by the ripe age of 30 you'd be well past it!

I'd love one of these though!

[rsser]

If turning was a craft - and old woodblock prints suggest it was - then the hours of work would've been daylight only.

And in the middle ages in Europe and England, there were in the order of 100 - 150 holidays (saints days, feast days etc). So averaged out over the year they worked less hours than we do.

Crafts were governed by guilds - a combination of a cartel and a trade union. The ACCC would've had a fit.

[rodent]

Unless you worked in the kitchen ern or in our case the bar-b-q , or in your case webber.:doh:

[Skew ChiDAMN!!]

Wow, that's some handwheel.

That's a perfect example of what I keep saying about manually driven lathes... the bigger the flywheel (in mass) the easier the turning.

A tad harder to get up to speed, but a lot harder to stall out under tool pressure. :2tsup:

[rhancock]

I was thinking just that this morning when the thunder woke me up! Is it the mass or the diameter of the wheel? I'm thinking that a large wheel like that is going to take up a lot of space, so could you use something like a bike wheel with lead weights? or do you need the large diameter?

[Gra]

Its weight. What you are creating is a flywheel, the idea is its mass creates inertia and wants to keep spinning when you stop or slow the pedaling. The problem is the more it weighs the harder it is to get started, but it then keeps going for longer and smooths out the inputs. (To a point of cause). Your problem is to find that point...

Neil

[pawnhead]

I believe that it would be a ratio between the mass and the diameter.

A small mass with a large diameter would have the same effect as a large mass with a small diameter. They'd both require the same input energy to achieve the same inertial resistance, and they'd both have the same RPMs, but the smaller mass would have a greater speed at its outer edge to compensate for its lesser mass.

[rhancock]

That makes sense. So using lead weights around a bike wheel could be worked to give the same momentum as the larger wooden wheel.

[echnidna]

there are a few treadle/pedal lathe plans around with small heavy flywheels

[rhancock]

I suppose cast iron flywheel would work too.

[Skew ChiDAMN!!]

Pawnhead has the physics right. :)

The main problem with fastening weight to the rim of a light wheel is simply ensuring they don't come adrift. They hurt when they do. DAMHIKT. :B

If it's going to be belt-driven, usually around the outside of the fly, then a simple wooden wheel around 2" thick will not only seat the belt properly but have enough mass to be usable.

Oddly enough, doubling the mass of the wheel doesn't seem to make it twice as hard to spin up, but it does seem to deliver more than double the power to the headstock.

[bentley]

If it had a lot of teeth around the wheel it could be used as a combination wood lathe and circular saw leonardo probably thought of that to but decided not to include it after he lost a couple of fingers.:D:D:;

[pawnhead]

That makes sense. So using lead weights around a bike wheel could be worked to give the same momentum as the larger wooden wheel.That looks like a pretty big, and quite heavy wheel compared to a bike wheel. But the further out that you put your mass, the more economical it becomes in terms of mass used, so having the mass concentrated around the edge of a pushbike wheel would be better than a solid wheel of the same mass, unless it had a larger diameter.
The better balanced it is, the less frictional loss you'd get as well. Two opposing arms with lead weights on the ends would do the same job. The longer the arms, the more power, so you'd just have to drill an axle hole in the middle of a decent sized 6x2, and throw a lot of weight on the ends. (Of course, you'd better put a decent guard on it as well :oo:)

To make it really compact, just mount a tiny black hole on an axle. :cool:

Oddly enough, doubling the mass of the wheel doesn't seem to make it twice as hard to spin up, but it does seem to deliver more than double the power to the headstock.It's just a pity that we can't unlock the secret (http://www.besslerwheel.com/) eh? :wink:

[rhancock]

Maybe he found a black hole lying around.

I was thinking a bike wheel would be good from a friction point of view.

[rhancock]

That looks like a pretty big, and quite heavy wheel compared to a bike wheel. But the further out that you put your mass, the more economical it becomes in terms of mass used, so having the mass concentrated around the edge of a pushbike wheel would be better than a solid wheel of the same mass, unless it had a larger diameter.

I was trying to work out whether I've got enough lead fishing weights to make it work, or maybe lead pipe. But the point about it coming off is a worry. A couple ofhundred lead weights flying around the workshop:o

And then I started to get creative, and I was trying to work out how much weight you'd get if you filled a bike tyre with water. Not much I think is the answer.