Brass gear fitting tips?

[anthony0372]

I have a brass gear that is slipping and stopping my old Hornby class 5 locomotive from running, on the motor shaft of one of my older 3 pole motors, I don’t have any other brass gears to use... any advice on how to make the gear clamp on the motor shaft again without useing loctite or superglue? Also if I replace it, how do I push it down the shaft because I read these can be a real pain to replace!

[Ruffnut Thorston]

I have fitted brass driving gears to Ringfield motors.

 

I used a small vice, to press the brass gear onto the shaft.

 

I used a nut with the hole a close but loose fit over the motor shaft as a spacer to allow the gear to be pressed down the shaft to its proper location in relation to the back bearing.

 

The motor needs to be stripped down, with the faceplate removed, to allow both ends of the armature shaft to be trapped in the vice.

 

It is essential not to overdo the pressure, as otherwise damage can be caused to the ends of the shaft. In extreme cases, it is possible to bend the shaft.

 

The gear has a tapered hole, and goes onto the shaft end easier the correct way around.

 

Whatever...take your time, and work methodically doing this kind of job. 😀

[DEREK123]

I agree with Sarah. I too have fitted many , basically in a similar fashion..

There is nothing wong in adding a very small amount of loctite to the gear ( outer side ) ... not the shaft !! ...... ( ie don't get any on the back bearing / bush. )

There are different loctites types and makes, so I hope we have an "engineer" who will give you the benefit of his experience which I am sure is better than mine. I use one called " SURELOC..(CA120) " and never had a problem

Derek

[96RAF]

I agree with the press it on technique as this is kinder to the shaft than tapping it on with a hammer as this can damage the shaft end, the gear or even bend the shaft.

 

As to loctite (or thread lockers as they are often known - other ‘tites are available), if the gear is the correct bore for the shaft then it will be an interference fit which is why we press it on, and does not therefore need additional glue. If it is a slacker (push or running) fit due to being the wrong gear and you need to secure it there are various grades of loctitie, ranging from - easy to break for dismantling - to - you have to destroy the parts to get them apart. You can get a range of these in most DIY stores and definitely a car accessory shop. I would go for the hard setting type, because you do not want it to fail in service and if you ever have to get it apart again then you can crush the gear and fit a new one.

 

For  more info on grades of loctite see here https://eezee.sg/blog/whats-the-difference-between-colors-of-loctite-threadlockers/amp/

Don’t get too bogged down by their ref to thread sizes, its the securing qualities we are looking for, but of particular interest is the penetrating type, but you have to watch it doesn’t creep too far and bind up the whole motor.

[anthony0372]

I have fitted brass driving gears to Ringfield motors.

 

I used a small vice, to press the brass gear onto the shaft.

 

I used a nut with the hole a close but loose fit over the motor shaft as a spacer to allow the gear to be pressed down the shaft to its proper location in relation to the back bearing.

 

The motor needs to be stripped down, with the faceplate removed, to allow both ends of the armature shaft to be trapped in the vice.

 

It is essential not to overdo the pressure, as otherwise damage can be caused to the ends of the shaft. In extreme cases, it is possible to bend the shaft.

 

The gear has a tapered hole, and goes onto the shaft end easier the correct way around.

 

Whatever...take your time, and work methodically doing this kind of job. 😀

Thanks for the Information...  can you provide a link to a small vice that would be perfect for this type of project to buy, or is that against the rules of the forum? If so, just give me the name of it and I’ll look it up.

[Ruffnut Thorston]

I don't know of an actual example, we've had ours for many years.

 

But basically any vice that will open up enough to get the armature and motor casting in, with the gear on.

 

There are a lot of vices out there.

 

 This one looks similar to ours, except for the base.

 

http://www.ebay.co.uk/itm/2-50MM-REVOLVING-SWIVEL-MINI-BABY-VICE-MODEL-MAKING-BENCH-TABLE-FIX-CLAMP-SMALL-/271899412716?_trksid=p2349526.m4383.l4275.c10

[96RAF]

You may get away with one of those ratchet action clamps similar to the mechanism used by mastic guns.

[walkingthedog]

I use a small G clamp.

 

https://www.amazon.co.uk/Amtech-W5690-Heavy-Clamp-2-Inch/dp/B00LQQY7PQ/ref=sr_1_7?keywords=Small+g+clamp&qid=1576592237&sr=8-7

[Margate_Era_FTW]

I use a small G clamp.

 

https://www.amazon.co.uk/Amtech-W5690-Heavy-Clamp-2-Inch/dp/B00LQQY7PQ/ref=sr_1_7?keywords=Small+g+clamp&qid=1576592237&sr=8-7

Using my old account  to bypass waiting 24 hours to post again, how do you use a g clamp your way to press the gear on? I never used a g clamp before and would like to know how to use it properly

[96RAF]

Many G clamps have a dimple in the pads whih helps locate the nds of the shft against slipping shaft.

Put the gear on the fixed pad and hold the armature onto the screw end pad as you turn the thumb screw to slowly mate the shaft and gear together. Make sure everything is kept aligned as you tighten the screw until the gear is fully home.

[walkingthedog]

Thanks for posting that Rob. A G clamp is basically a vice isn't it. 

[VESPA]

Firstly you can hold the gear on the G clamp witha bit of Blutac. Secondly you could also heat the gear slightly held on long nose pliers so that it expands and slide in on the hsft to the correct position.

Lastly the latter reminded me of a job I did renovating a car gearbox. I renewed all the bearings and layshaft, baulk rings seals etc with the last job being the main shaft which had two phosphor bronze bearings seperated by a very thick washer/ bearing face with a + shaped hole in the centre. This was to allow two tangs/dogs to locate in it. After removing the old worn out bearings the first  new one was heated and slid down the shaft. Simple. Then the large washer / bearing slid over the two tangs /dogs. The next bearing was heated and slid down the shaft and I missed the locating part of the washer and it cooled before located. No amount of heat would expand it again so I had to cut it off and get another. Luckily that went on OK and the gearbox was fine when fitted back on the car. This tale prompts me to mention that the similar method is used for putting new railway tyres on loco wheels and if it is not done right,  the first time,  has to be cut off and a new tyre is required at great expense.

[96RAF]

Thanks for posting that Rob. A G clamp is basically a vice isn't it. 

 

 

It certainly is.

Pity I didnt spell check it before posting all that gibberish on the first line.

[anthony0372]

Thanks for all the advice, I think I’m ready to tackle the issue now.