Wood to use for pulley?

[rotorque]

Hi guys/girls,

You will have to forgive my naive questions here as I a newbie to wood working in general.

I have an application that requires the use of two v-belt pulleys that are non standard diameters. I am having trouble finding aluminium pulleys that will give me the required ratio......so.... I thought that I may be able to get a couple of wood pulleys lathed up to satisfy the requirement.

I have a couple of questions.....

1. Is wood strong enough to be used as pulleys? More so the pressure on the sides of the v-belt groove.
2. How much "meat" would you need around the groove to make it reasonably strong?
3. What wood would be appropriate. I assume a hard wood would do the trick, but have no idea.
4. How much heavier would a wood pulley be compared to a metal one?
5. do you think heat is the number one concideration?

Thanks in advance for your help. I will post the above in the general forum.

Cheers

Paul

[E. maculata]

The legendary south american the one & only Lignum Vitae was used for centuries for this purpose, if you want the next best I'd go Grey Ironbark for shear strength & longevity, or tallowood if some sort of self-lubrication property is needed. A certain Gum I'm vaguely aware of could be used too

[E. maculata]

Hi guys/girls,


1. Is wood strong enough to be used as pulleys? More so the pressure on the sides of the v-belt groove. I reckon more than strong enough if you use the correct type
2. How much "meat" would you need around the groove to make it reasonably strong? NFI, probably same as alloy ones, seeing as many hwds are much tougher than aluminium
3. What wood would be appropriate. I assume a hard wood would do the trick, but have no idea.see above
4. How much heavier would a wood pulley be compared to a metal one?What metal? which timber?
5. do you think heat is the number one concideration? will affect wood much less than aluminium and in many circumstances reacts better than mild steel

clear as mud

however if high RPMs' are involved I'd be worried about balance issues as I just noticed your username Rotorque=rotary type maybe?

[Cliff Rogers]

G'day Paul.

Where in NQ are you?

I made some very big pulleys out of sheets of ply for my monster lathe.
I glued & screwed 2 roughly rounded sheets of 16mm ply together, mounted it on the shaft, hooked up a temporary drive to the shaft & turned them square across & then turned a grove in them.

I could have done something similar with a router & a tramel bar but I didn't think of that at the time.

I gave them a coat of waterbased sealer & they are still going fine after about 6 or 7 years.

[rotorque]

Thanks E. maculata,

Your a sweet talker. I was hoping the answers would be positive.

As far as weight goes, probably comparing to an aluminium pulley, as I am trying to keep the weight down.

Can I assume E.maculata is a "certain Gum", I will have to do a google search on that one.

The RPM will be around 1700 reduced to 400 via two sets of reduction sheeves.... I don't think it is exceptionally fast, what sort of RPM does a lathe spin at?

Thanks for your help so far..... awaiting as much info as possible.

Cheers

Paul

[rotorque]

Hi Cliff,

Sorry, posted without reading your message. I am up near Proserpine, enjoying the heat......not.

From what I have learned so far regarding pulleys, the bigger the better in relation to the physics of pulley strength and belt life, but I won't need anything quite as big as yours. Probably only about 18 inches in diameter for the drive pulley and an appropriate size for the slave pulley to get the appropriate ratio (am yet to calculate the required size because I am not sure of my gearbox ratio as yet)

Thanks mate

Paul

[Cliff Rogers]

Proserpine.... Are you a woodturner?

Do you know about this?

http://www.proserpinewoodturners.com/Order_Form.html

My bigest pulley is not much bigger than 18".
It is bolted to a flywheel off a truck.

Eucalyptus maculata Spotted Gum not to be confused with
Eremophila maculata Spotted Emu Bush ....
some people don't thing that is funny.

[rotorque]

No, I had no idea they existed.

Fantastic.....

I am in the homework stage of my application at the moment, so the questions are tentative. Having said that, if in fact there are no real arguments about using wood pulleys then my project has just lept ahead by a couple of weeks at least.

I just looked up the "spotted gum", and found a site that quoted the uses of this hard wood..... "engineering" was one of the items...... good stuff.

No I'm not a wood turner, but I do own a lathe (handme down from the father inlaw, haven't used one since high school) I work in the aviation industry normally so am blissfully unaware of what is involved with turning up a couple of pulleys.

The link you provided will help a hell of a lot......

Really appreciate it, thanks.

Paul

[Cliff Rogers]

They are a great bunch & it's only 3 weekends away now.

You may have to give CJ a call to see if there are any vacancies or just make a day visit to meet them.
They are a mad mob, have a look at their monster lathe.

[echnidna]

I've seen a coupla wood pulleys years ago, they were either sugar pine or kauri.

[rotorque]

Thanks Bob,

I will list all the wood types offered and try to work out the best one.......

If there is any one type that is exceptionally suited to the role, I would love to hear it..... As it stands, so far there are a couple of options which is great..

Paul

[echnidna]

Expect redgum would be good as it was used as prop shaft bearings in the murray river paddle steamers.

[E. maculata]

Eucalyptus maculata Spotted Gum not to be confused with
Eremophila maculata Spotted Emu Bush ....
some people don't thing that is funny.

Nah Cliff I reckon the Spotted Emu bush was well done, actually quoted it for quite a while, meanwhile I got doubly reclassified back to Euc, but my location changed while no-one was looking

[Cliff Rogers]

Nah Cliff I reckon the Spotted Emu bush was well done, ..

I didn't mean you, it was some body else that didn't think that was very funny.
They got fairly agro about it.

[reeves]

mm nice project, maybe the weight or stress on the wooden pully is more at the center than the outside, hence a stenghtening taper so the pully is wider where it meets the axle or join..that where u may have stress issue at high RPM..

as for wood type, trial and error, Cliffs ply story is good, MDF is stable and strong..or u could get funky with some mulga or hard dersert woods, ironwood...boree....even iron bark....
some woods will definalty come apart at high speeeds and 1700 is pretty high for wood,,,i'd try some blackwood...or other light strong acacia, hickory...try rosewood...
i have used Kwila, that hard decking timber from Indonesia in some tools with success..u can find it at the local tip in building offcuts and waste bins...

good luck and let us know how it goes...

cheeeeeeeeeeeers