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Gear Pullers - any suggestions?


melmerby
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Hi all

I'm using a stepper motor in a project, the ideal one I already have but need to remove the present gear to put a GT2 pulley on the 3mm shaft.

I purchased one of these:

https://www.ebay.co.uk/itm/Alloly-Gear-Bearing-Puller-Remover-Tool-Set-for-RC-Motor-Pinion-Helicopter-Parts/303736880104?hash=item46b820fbe8:g:UWUAAOSw6G1fkWCb

 

Unfortunately the gear is rather stubborn and all I have managed to do is bend a couple of the supplied pins.

I tried cutting through it but completely smoothed off a mini circular saw blade!

 

Would one of these be any better:

https://www.ebay.co.uk/itm/Walkera-Metal-Motor-Pinion-Gear-Puller-Remover-Tools-Set-For-RC-Helicopter-Y2/153900202855?hash=item23d52abb67:g:05oAAOSwbRFelRlt

 

 

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Probably best to accept its not coming off, grind out the centre of a pulley so it fits tightly over the pinion and glue it in place with some half decent super glue.

The pins are the weak point, finding decent ones is challenging old axles are good.  If you can turn them down in the lathe they are too soft.  If the pins don't fail then the V which goes behind the gear will usually bend or snap.  

You could crush the gear and hope it doesn't bend the shaft, It's my go to method, or heat the gear which usually results in the gear being reusable but the motor being scrap, even if it doesn't actually catch fire!.    Best of luck

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P1050192.JPG.008f5322a8aab85e0d0490fe3cbe95d2.JPG

 

By coincidence, I've tried both of the gear pullers you've mentioned, melmerby.  I wanted to remove the worm gears from a number of the mitsumi motors I've got.  The motors have a 1.5mm dia shaft. First I bought the red one, firstly the gap at the base of the puller is too wide for the gear/shaft so i had to make a brass insert to stop the worm moving.  As can be seen I did manage to pull gears off, but soon the pin started to bend, straightening it didn't last long before it bent again then it broke. I managed to reduce one of the other bigger pins but that didn't last either. 

The silver one is I think a better proposition, shifted some more gears but you will notice the bent pin....they are both probably fine for removing nylon gears used with r/c cars etc. but a small shaft is pushing it.

 

My experience matches David's suggestions in the previous post, your suggestion to crush the gear is a good one I'm going to try.  With my problem I can just cut the brass worms off with a hacksaw, but originally I though I'd try and keep the worms for some unknown project aeons hence...

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3 hours ago, railroadbill said:

P1050192.JPG.008f5322a8aab85e0d0490fe3cbe95d2.JPG

 

By coincidence, I've tried both of the gear pullers you've mentioned, melmerby.  I wanted to remove the worm gears from a number of the mitsumi motors I've got.  The motors have a 1.5mm dia shaft. First I bought the red one, firstly the gap at the base of the puller is too wide for the gear/shaft so i had to make a brass insert to stop the worm moving.  As can be seen I did manage to pull gears off, but soon the pin started to bend, straightening it didn't last long before it bent again then it broke. I managed to reduce one of the other bigger pins but that didn't last either. 

The silver one is I think a better proposition, shifted some more gears but you will notice the bent pin....they are both probably fine for removing nylon gears used with r/c cars etc. but a small shaft is pushing it.

 

My experience matches David's suggestions in the previous post, your suggestion to crush the gear is a good one I'm going to try.  With my problem I can just cut the brass worms off with a hacksaw, but originally I though I'd try and keep the worms for some unknown project aeons hence...

 

The quickest way - though destructive - is to longitudinally cut the worm, with a mini cutting disc, nearly down to the shaft. Then place the worm on the slightly opened jaws of a vice and split it - by placing a cold chisel in the cut and giving it a sound whack with a hammer.

 

..... or buy Mitsumi motors sans worms from me!

 

John Isherwood,

https://www.cctrans.org.uk/products.htm

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After I put up the original post I remembered I had some composite 20mm cutting discs with the multitool and have since cut off the pinions from 2 more stepper motors.

Both were hardened steel gears but after cutting a portion away they came off easily.

Both had the gears very close to the face of the motor so no room to get any jaws behind them with a puller.

The first one I did that had a brass gear and plenty of room behind it came off easily with little effort.

All have 3mm shafts.

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On 26/01/2021 at 19:23, DavidCBroad said:

Probably best to accept its not coming off, grind out the centre of a pulley so it fits tightly over the pinion and glue it in place with some half decent super glue.

The pins are the weak point, finding decent ones is challenging old axles are good.  If you can turn them down in the lathe they are too soft.  If the pins don't fail then the V which goes behind the gear will usually bend or snap.  

You could crush the gear and hope it doesn't bend the shaft, It's my go to method, or heat the gear which usually results in the gear being reusable but the motor being scrap, even if it doesn't actually catch fire!.    Best of luck

You sir are a genius! I put the gear on each motor in the jaws of my hefty old bench vice, squeezed it and the shaft came straight out when I released it. Did the rest of the motors that still had worm gears on in a few minutes. 

Cheered me up no end, thanks!

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7 hours ago, railroadbill said:

You sir are a genius! I put the gear on each motor in the jaws of my hefty old bench vice, squeezed it and the shaft came straight out when I released it. Did the rest of the motors that still had worm gears on in a few minutes. 

Cheered me up no end, thanks!

What material were the gears?

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On 27/01/2021 at 17:55, railroadbill said:

P1050192.JPG.008f5322a8aab85e0d0490fe3cbe95d2.JPG

 

... the red one, ... but soon the pin started to bend, straightening it didn't last long before it bent again then it broke. I managed to reduce one of the other bigger pins but that didn't last either. 

 

 

Same thing happened to my red one. It looks to be of good quality but the mandrels are far too soft. I shall attempt to drill the threaded bit to accept a hardened steel pin.

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On 26/01/2021 at 18:45, melmerby said:

Hi all

I'm using a stepper motor in a project, the ideal one I already have but need to remove the present gear to put a GT2 pulley on the 3mm shaft.

I purchased one of these:

https://www.ebay.co.uk/itm/Alloly-Gear-Bearing-Puller-Remover-Tool-Set-for-RC-Motor-Pinion-Helicopter-Parts/303736880104?hash=item46b820fbe8:g:UWUAAOSw6G1fkWCb

 

Unfortunately the gear is rather stubborn and all I have managed to do is bend a couple of the supplied pins.

I tried cutting through it but completely smoothed off a mini circular saw blade!

 

Would one of these be any better:

https://www.ebay.co.uk/itm/Walkera-Metal-Motor-Pinion-Gear-Puller-Remover-Tools-Set-For-RC-Helicopter-Y2/153900202855?hash=item23d52abb67:g:05oAAOSwbRFelRlt

 

 

 Hello keith, I'm assuming you have a Dremel- type grinding disc. I have used  those in the past to cut both worm & gear to get at the shaft (s).

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On 18/03/2021 at 16:18, tomparryharry said:

 Hello keith, I'm assuming you have a Dremel- type grinding disc. I have used  those in the past to cut both worm & gear to get at the shaft (s).

I mentioned on the 27th Jan that I ended up cutting them off with a slitting disc.

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3 hours ago, tomparryharry said:

 

Sorry Keith, I don't always get to read all of the posts on here. I do try, however.

One of the stepper motors is now in use driving a re-vamped traverser on my layout.

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