Engineering Problem

[tim_jones]

I wouldnt worry about the noise, it is half the fun after all

Regards

Tim

Geoff, I can make you that gearbox. And not for £25 labourcharge an hour. Contact me.

Trilibium uses a mod 2 beval gear and its well niosy!. why not go for it and enclose it in a 1mm ali box, fill it with grease and it should be fine. as long as the ali isnt suppoting the bearings the shafts run in.

[Mouldy]

I would of thought helical gears were another option? Not sure on there effeciancy etc but itd do the job. As James said if you make an enclosed gearbox it should block out a fair bit of noise and keep the gears swarf-free

[mark_m]

The problem with bevel gears and in particular spiral cut bevel gears is the huge lateral loads they put onto the supports. This requires a chunky gearbox with heavy bearings. If you are planning to use this gearbox for a spinner, the tough supports and big bearings are what youd want anyway.
If youre using it for anything else though I can think of some lighter alternatives Only thing is they would take up more space and are probably not as robust.
1. Universal joints. you would probably need at least three joints in series, with bearings supporting the intermediate shafts.
2. flexible shaft:http://www.lara.com/cgi-bin/store/commerce.cgi?oc=WI-FDhttp://www.lara.com/cgi-bin/store/commerce.cgi?oc=WI-FD
They would probably take the torque and might even allow a bit of cushioning to pretect the mag from impact torques. You might have a problem with them whipping so youd have to support them along their length. This would take space but not much weight.
3. polyurethane belts twisting through 90. This could work well and be light. 8mm belt around 80mm pulleys should be able take the torque.

[big_nipper]

Geoff, Youve seen big nipper, we use right angle drive threw bevel gears and they are not noisey (well not much), maybe you could use something like this, they have thrust bearings behind them. They are out of Roder plants gearboxes and they are not hardended, if they work for our drive then they should be OK for you. They are not normal bevel gears and have a strange teeth profile (nearly flat) and are bigger than mod 2.

A picture of them is here:
ftp://http://www.bignipper.no-ip.org/Series%207%20Big%20Nipper/Making%20of/Picture%20010.jpghttp://www.bignipper.no-ip.org/Serie...ture%20010.jpg
But its quite big (1.7MB). Of course you would save weight if you didnt use 1 thick Ally for the mounting.

RS sell some small right angle drives but not sure without looking them up what torque they can handle.

Another suggestion is to use the gearbox of an anglegrinder (something we are considering) and these are rated at those speeds and are quite strong and light and cheap.

[robjones]

I dont know when you are coming up to denbigh next weekend Geoff but there is a pretty big ex-MOD scrapyard in the town. They sell tons of parts, hydraulics pneumatics and gears of all shapes and sizes. Also sell manganese steel (armour) too. The catch is that they are closed on Saturday.

quote:

So you havnt met our Astroflight powered featherweight spinner or our Lynch powered heavyweight spinner yet have you Ceri?!! - Geoff

True, I havent had the oppurtunity to meet those 2 in battle, yet.

I also dont want to

[geoff]

Thanks for all the input guys, I think I need to give this some further thought.
Ceri, both of our machines will be at Denbigh next weekend, If you can make it, introduce yourself and Ill give you the guided tour!

Geoff.

Id stay away from Geoff, dont accept the sweets he gives you!

LOL!!

Mind you the ones from his Wife and the other Female member sweets are nice. Should i be worried? Naaaa!!!!!! LOL!

Mr Stu