Model Boat Mayhem

Technical, Techniques, Hints, and Tips => Other Technical Questions... => Topic started by: Mark47 on July 05, 2009, 02:02:18 pm

Title: Gear removal from motor shaft????
Post by: Mark47 on July 05, 2009, 02:02:18 pm
Can anyone tell me how to remove the gear cog off of a motor?

I've just rescued a nice 550 5 pole from my old cordless drill and can't figure out how to get the gear cog off the shaft. I don't see any locking hexes.

Many thanks, :-))

Mark
Title: Re: Gear removal from motor shaft????
Post by: malcolmfrary on July 05, 2009, 04:32:21 pm
Assuming that the cog is no longer required, I would cut a slot in a piece of steel, or get two pieces, and support the cog across a vice/ couple of lumps of wood, then use a centre punch, or nail as it is sometimes known, to smartly whack the end of the shaft with the small lump hammer.  This should then start its retreat down the inside of the cog.  Repeated blows will chase the shaft out of the cog.  Or buy a proper tool (probably not an option).
Often, the cog will have been a shrink fit, heating it to expand it might not do the motor any good.
Over to proper engineers.
Title: Re: Gear removal from motor shaft????
Post by: catengineman on July 05, 2009, 04:37:18 pm
Rather than shock your motor why not grind one side of the cog until it is thin enough to snap then just pull the remaining part off, or use a dremel cutting disc and slice down to the shaft (but not through it) on both sides and the cog will just drop off



R,
Title: Re: Gear removal from motor shaft????
Post by: Martin [Admin] on July 05, 2009, 05:20:16 pm

Do it carefully Mark. Ever time I've tried (without the proper tool), I've totalled the motor.  >:-o

http://www.nitroplanes.com/exceed-rc-motor-gear-puller.html

http://www.xheli.com/mogepu1mshby.html

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXHHN3&P=ML

http://cgi.ebay.co.uk/Xtreme-Pinion-Gear-Puller-Remover-EA-019_W0QQitemZ320360529656QQcmdZViewItemQQptZUK_ToysGames_RadioControlled_JN?hash=item4a96f9bef8&_trksid=p3286.c0.m14&_trkparms=65%3A10|66%3A4|39%3A1|240%3A1318|301%3A1|293%3A1|294%3A200

http://cgi.ebay.co.uk/Tools-Gear-Puller-UK_W0QQitemZ350222203199QQcmdZViewItemQQptZUK_ToysGames_RadioControlled_JN?hash=item518adeb93f&_trksid=p3286.c0.m14&_trkparms=65%3A10|66%3A4|39%3A1|240%3A1318|301%3A1|293%3A1|294%3A200

Title: Re: Gear removal from motor shaft????
Post by: portside II on July 05, 2009, 06:26:14 pm
the last time i removed a cog from the shaft of a motor , i clamped the cog tightly in the vice and with a pair of safety goggles for protection  :-)) i split the cog with a cold chesil and hammer , sorted  :-)) .
daz
Title: Re: Gear removal from motor shaft????
Post by: Mark47 on July 05, 2009, 06:40:30 pm
Thanks for the input. :-))



Do it carefully Mark. Ever time I've tried (without the proper tool), I've totalled the motor.  >:-o

http://www.nitroplanes.com/exceed-rc-motor-gear-puller.html

http://www.xheli.com/mogepu1mshby.html

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXHHN3&P=ML

http://cgi.ebay.co.uk/Xtreme-Pinion-Gear-Puller-Remover-EA-019_W0QQitemZ320360529656QQcmdZViewItemQQptZUK_ToysGames_RadioControlled_JN?hash=item4a96f9bef8&_trksid=p3286.c0.m14&_trkparms=65%3A10|66%3A4|39%3A1|240%3A1318|301%3A1|293%3A1|294%3A200

http://cgi.ebay.co.uk/Tools-Gear-Puller-UK_W0QQitemZ350222203199QQcmdZViewItemQQptZUK_ToysGames_RadioControlled_JN?hash=item518adeb93f&_trksid=p3286.c0.m14&_trkparms=65%3A10|66%3A4|39%3A1|240%3A1318|301%3A1|293%3A1|294%3A200



Martin,

I didn't even know there was a tool for the job ;), and my missus thinks I have every tool under the sun. O0


Mark
Title: Re: Gear removal from motor shaft????
Post by: ray123 on July 05, 2009, 09:58:50 pm
Rather than shock your motor why not grind one side of the cog until it is thin enough to snap then just pull the remaining part off, or use a dremel cutting disc and slice down to the shaft (but not through it) on both sides and the cog will just drop off



R,
i did the same  a tryed & tested way :-))  (but i did put some tape over the holes at the end so as not to get any cutting dust inside the motor) regards ray
Title: Re: Gear removal from motor shaft????
Post by: catengineman on July 05, 2009, 10:36:26 pm
Do it all the time at work its probably the fastest way to remove old bearings from conveyor roller shafts.

R,
Title: Re: Gear removal from motor shaft????
Post by: Martin [Admin] on July 06, 2009, 12:46:00 am
If it's a brass gear, I once clamped it up in a vice and it squashed it right off.
 As Ray says, seal up any holes in the motor to prevent any ingress of any FOD!
Title: Re: Gear removal from motor shaft????
Post by: Mark47 on July 06, 2009, 08:31:26 am
If it's a brass gear, I once clamped it up in a vice and it squashed it right off.
 As Ray says, seal up any holes in the motor to prevent any ingress of any FOD!


No it's steel mate.

I tried the dremmel last night, but the but the motor shaft is too short to cut right through on both ends of the gear. I'll need to get a smaller circumference cutting disk to get it off. No real rush to use it. Just wanted to save it for a future ship, so I'll just keep plugging away at it until I get it off or have to throw it in the bin, which ever comes first. {-)

Mark
Title: Re: Gear removal from motor shaft????
Post by: Martin [Admin] on July 06, 2009, 08:59:41 am

'Place your bet .... now!'
Title: Re: Gear removal from motor shaft????
Post by: Mark47 on July 06, 2009, 09:22:46 am

'Place your bet .... now!'


 {-) {-) {-) {-) {-)

Mark
Title: Re: Gear removal from motor shaft????
Post by: boatmadman on July 06, 2009, 09:47:04 am
Tape off all the motor holes and file the gear until it exposes the shaft, it should then be easy enough to release from the shaft.

Ian
Title: Re: Gear removal from motor shaft????
Post by: Circlip on July 06, 2009, 09:48:56 am
You could try the old method some of us used to do with the brass gears, apply a soldering iron to the gear. The heat is usually enough to allow it to expand, Hey you may actually be able to re-use the gear. Tight a**e Yorkshire tricks again.

      Regards    Ian.
Title: Re: Gear removal from motor shaft????
Post by: derekwarner on July 06, 2009, 09:58:00 am
Mark47.....there are alternate pinion removal methods

1] hold the 550 motor with the 10 mm diameter pinion engaging your standard 6" bench grinder wheel

..so 3.14x152=477.28mm circ of the grinding wheel........3.14x10=31.4mm circ of the pinion

..say 6000 RPM of the grinding wheel would be approx 92000 RPM of the pinion being ground......... <*< ....best not try this approach

2) hold the 550 motor with the 10 mm diameter pinion engaging your standard 6" bench grinder ...however with a lower pinion gear lobe secured with a pair of medical pincers to eliminate the pinion rotating

...grinding the brass pinion gently will break the shrink fit  & release the shaft :-)) ....Derek
Title: Re: Gear removal from motor shaft????
Post by: bogstandard on July 06, 2009, 07:11:48 pm
Oh! you naughty person Derek Warner.

Fancy telling someone to grind a brass pinion off on a grindstone, when you should know you never grind anything softer than ferrous on a bonded wheel.

Just wait 'til I tell the teacher. :}

John


Title: Re: Gear removal from motor shaft????
Post by: Mark47 on July 06, 2009, 08:48:55 pm
As I said in an earlier post, it is not brass it's steel. It came from a cordless drill. I would not have asked if it was brass, that's easy to get off, but steel that's a whole other problem. O0

Mark
Title: Re: Gear removal from motor shaft????
Post by: bogstandard on July 07, 2009, 06:53:27 am
Mark,

I noticed you had said steel, it was just me having a bit of fun with Derek. I wanted to get him huffing and chuffing.

In fact I have removed hundreds of the damned things, both steel and brass.

I use a pair of very strong and specialist electricians side cutters. Just put the cutting edges into the teeth from the end and squeeze, it works every time. The gear just falls in half.

I didn't want to mention it because people would try to use their cutters they bought from the market stall, and they would just end up with a pair of cutters in two separate pieces. But now it is out.

Bogs
Title: Re: Gear removal from motor shaft????
Post by: Mark47 on July 07, 2009, 07:08:21 am
Mark,

I noticed you had said steel, it was just me having a bit of fun with Derek. I wanted to get him huffing and chuffing.

In fact I have removed hundreds of the damned things, both steel and brass.

I use a pair of very strong and specialist electricians side cutters. Just put the cutting edges into the teeth from the end and squeeze, it works every time. The gear just falls in half.

I didn't want to mention it because people would try to use their cutters they bought from the market stall, and they would just end up with a pair of cutters in two separate pieces. But now it is out.

Bogs

Unfortunately, I don't have a set of cutters, may have to invest in some O0

Mark
Title: Re: Gear removal from motor shaft????
Post by: derekwarner on July 07, 2009, 07:24:25 am
Mayhemers....what bogstandard does not realise is that 'Australian >>:-( Abrasives'.....have recently developed a new grinding wheel material based on aluminium hydroxide "7"  + silica + graphite [al+{O2...7}+{H7}+Si +C4]...I thought that would have been simple  %% %)

One of the unique qualities is that it does not 'load up' when grinding non ferous metals

Mark47...my apologies...yes when I re-read your posting....clearly 'steel' is the operative word as mentioned...mind you if it were brass I would recommed the newer [al+{O2...7}+{H7}+Si +C4]...wheels .......

Just try & GOOGLE ....[al+{O2...7}+{H7}+Si +C4]...the results would be interesting........Derek  {-) O0
Title: Re: Gear removal from motor shaft????
Post by: bogstandard on July 07, 2009, 12:05:40 pm
Hook, line and sinker Derek.

How long did it take you to find that answer.

In fact, you are now one up on me, I have never heard of what you are on about, must investigate that one.

But on the other hand, how many other people on here haven't heard of it as well, and by your recommendation, would just go ahead and grind away on a standard ali oxide wheel.

Just to update the people on here, as some most probably don't have an engineering background.

Any material that is not ferrous or above, should NOT be allowed to touch an ali oxide bonded grinding wheel (normally fitted to the cheapo offhand grinders that are available everywhere), unless it has been specially bonded to allow grinding of softer materials.
The harder the material, normally the softer the wheel to be used. So softer materials must use a much harder wheel.

The soft particles from whatever you are attempting to grind clog up the gaps in the bonded wheel, and force the oxide particles apart. This can lead to catastrophic failure of the wheel, which propel at high velocity, in all directions, pieces of the fractured wheel. If a piece hits you, expect very deep penetration wounds.

I had my woodworking neighbour come around last week to have his screwdriver reshaped. I knew he had a grindstone, and I asked him why he didn't use that.

'Oh I never grind metal on my wheel, I only use it for wood, and besides, it is all clogged up, and you haven't got a spare one knocking about anywhere'.
This was from someone who thinks that metal is any other material harder than aluminium. He never asks for brass or steel, just metal.

After reading him the riot act, not only did I refuse to give him one of my many spare wheels, I refused to do his screwdriver mod as well.
Up until now, he has been exceptionally lucky.

Do you feel lucky, when sharpening your pencil on the grinder?

Bogs