What's the best way to remove a sprocket from a Motor shaft?

[Rob Pulham]

Hi all,

I am looking for a bit of advice on how to remove a sprocket from a motor shaft without damaging the motor?

I bought 10 Canon motors from America - they were a bit of a bargain in so much as including import duty they worked out at £7 each. However on arrival today five of them are as advertised without a gear sprocket but the other five have one as shown below.

I have contacted the seller who has promised to send me another five without sprockets so I look like I have gained five extras. - If I can safely remove the sprocket without damaging the motor.



All ideas gratefully received.

 

[Eastsidepilot]

Rob, use a gear puller, I believe G.W.Models ? who sell the riveters can supply.

Col.

 

[Dog Star]

Or - cut through the gear, down the side of the shaft, to remove most of one side of the gear... then continue to remove gear metal by use of a flat file until the gear loosens its grip on the shaft.

Or - treat the gear wheel as a nut and use a sharp chisel to split the gear.

 

[Healey Mills]

I bought 10 Canon motors from America - they were a bit of a bargain in so much as including import duty they worked out at £7 each. ...

Wow Rob, that is a very good buy!! I'm envious

Cheers
Lee

 

[Rob Pulham]

Hi Lee,

These are the ones - 10 X Canon DN22 Precision Model Train 12 VDC Motors with Connector - 12 V DC
With the exchange rate I paid £54 something including postage but then had £14.99 VAT and post office fees on top when they arrived.

 

[Healey Mills]

Hi Lee,

These are the ones - 10 X Canon DN22 Precision Model Train 12 VDC Motors with Connector - 12 V DC
With the exchange rate I paid £54 something including postage but then had £14.99 VAT and post office fees on top when they arrived.

Hi Rob,

Thank you for the link.

Cheers
Lee

 

[simond]

Rob

Simple if crude: hold the pinion in a vice, with the motor out sideways, and use a file to remove most of the pinion. The difference in hardness between the brass pinion and the hardened steel motor shaft will be very obvious. Once you have filed away most of one side of the pinion it will pull off with little effort. Try not to file the shaft!

It is probably worth putting blu-tak around the shaft to keep the filings away from the bearing, and taping up any holes in the motor, but this is less critical as the magnets won't attract brass filings.

Should be easy.

Best
Simon

 

[Bill Bedford]

If you want to reuse the gear, remove it with a gear puller, if not support the gear and cut it with a cold chisel.

 

[Rob Pulham]

Thanks for the suggestions all.

I plan to wait until I am sure that the seller doesn't ask for them to be returned before having a go at removing any of the gears.

 

[Rob Pulham]

It looks like the seller was as good as his word, I had a note from the PO today that I had a parcel that needed import duty/PO fee of £11.98 paying and he hasn't asked for anything returning so it looks like the 5 motors with the gears will stand me at a princely sum of £2.40 each

 

[demu1037]

Rob
I asked the same question to (a)BC at the weekend (and Portescap 26n in my case) and cut/file was his advice

Andy

 

[auld_boot]

I made a puller from 3 screws and a bit of brass bar, as long as you can drill straight and tap a thread for the screws it should work ok. I would put up a picture of it but I must have put it 'somewhere safe'. Hopefully this crude diagram will show what I did, if I recall the bit of brass bar (in black on the diagram) was the earth pin from a 13amp plug. The worm and shaft are the red bit, tightening the green arrowed screw pushed the shaft.


EDIT Just remembered I filed a slight round into the head of the two screws holding the worm so that they could overlap the shaft a little. If only I could find it...

 

[Rob Pulham]

Cheers AB,

That is a simple enough concept to have a go before resorting to cutting and filing.

I could possibly simplify it further by using nuts rather than tapping on the outer two screws

 

[Overseer]

I keep forgetting to respond to this thread, but now that I have remembered -
Instead of being violent to the gear, I think the easiest way to remove the gear from the motor shaft is to heat the gear with a largish soldering iron and it should drop off, or need a small amount of assistance. Brass has a coefficient of thermal expansion approximately double that of steel so will expand more and become loose, especially if you heat the gear without heating the motor shaft much. A screw driver will probably be enough to push the gear off the shaft. Worth a try anyway, the motors are not too valuable as they are the 3 pole DN-22 version rather than the more expensive 5 pole version with an EN-22 code.