Bevel gears on ebay

[geoff walker 1Participant @geoffwalker1]

Hi All,

Just looking at ebay item 141737552116, pair of bevel gears 2:1

No idea what sort of quality they are, they could be rubbish at that price, but lets assume they are good.

What is a realistic top "meshing" speed for gears of this type and size assuming that both are mounted on spindles with free running well lubricated plain bronze bearings.

I would like the smaller one and spindle to turn up to around 1000 rpm which would of course turn the larger one at 500 rpm.

Any ideas geoff

[geoff walker 1Participant @geoffwalker1]

[MWParticipant @mw27036]

This might make it a bit easier for people to respond…

**LINK**

Michael W

[JasonBModerator @jasonb]

They are not badly made, I bought a set to use on an engine governor so not that fast running but depends what you want to do with them. Some of the ones sold for angle grinders would probably be better for high speeds.

[geoff walker 1Participant @geoffwalker1]

Thank you Michael, must try harder and add a link next time!

…and thank you Jason, not seen those grinder gears, as you say they may well be better for a high speed application.

I am looking to make a detachable geared head drive for my potts milling attachment. I want to able to use the attachment in a vertical set up and turn the drive through 90 degrees using bevel gears instead of the jockey pulleys.

Just thoughts at present ………. regards geoff

[geoff walker 1Participant @geoffwalker1]

……..turn the drive from the overhead drive through 90 degrees.

[Tim StevensParticipant @timstevens64731]

The only problem you might face with gears from an angle-grinder is the ratio. As the ratio is not fixed to a nice fraction, as it would be to drive a camshaft or an ignition system, the designers choose teeth numbers so that the same teeth do not mesh together very often (as distinct from every turn or two turns, eg). That might not suit your purposes.

Cheers, Tim

Edited By Tim Stevens on 24/06/2017 17:29:54

[geoff walker 1Participant @geoffwalker1]

Hi Tim

The ratio would not be problem as I could counteract that with the pulley ratios from the overhead.

I notice that the angle grinder ratios are around 3:1 which would be fine.

Essentially I am looking for a nice smooth drive from o/head through to the potts spindle, which I suspect the a/g gears may give me. I don't get a really smooth drive via the jockey pulleys.

I notice that the a/g gears are a "buttress shape" so I assume they are designed to rotate one way only with the squared sides being the driver and driven faces.

If the larger of the two gears is mounted on the end of the potts spindle (with the spindle set vertical) then I would need the this gear to rotate clockwise when viewed from above.

From what I have seen on ebay they all seem to have this clockwise rotation?

cheers geoff

[Neil WyattModerator @neilwyatt]

The angle grinder gears are spiral bevel gears and ridiculously cheap for what they are. At modest speeds they run happily in either direction, I used a pair on Southam.

Neil

[geoff walker 1Participant @geoffwalker1]

Hi All,

I've decided I don't need a geared head, just turn the motor through 90 degrees and have a direct drive.

Think I'm on a winner with this, K.I.S.S. is sometimes the best way!!!

geoff

[Neil WyattModerator @neilwyatt]

See, that's where we need a 'like' button.

[geoff walker 1Participant @geoffwalker1]

Hi Neil,

Thanks, I like it as well.

Just started my first ever model steam project, a vertical marine engine and have been using the Potts to mill the ports in the cylinder block.

I have just upgraded the Potts specifically for this vertical set up, I'll have the details with you soon for your editorial perusal. geoff

[Neil WyattModerator @neilwyatt]

I must use my Potts one day…

Neil

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