Modified gear box for Hornby L1 and similar

[relaxinghobby]

 

This chassis is a cut about and abused Hornby L1. I'm trying to squeeze it up into an old M7 body to make a LNER A9 0-6-2t. That is a big old fashioned motor, to big to fit inside the boiler or tanks so it had to be moved back, even so it just fits inside the cab.

 

My junior hacksaw has been hard a work cutting back bits off the chassis lump. This one seems to be a very hard version of Mazdak. It has taken a lot more effort than usual, a lot of metal has been removed and now some sort of drive shaft and gear box must be devised.

 

I have some cheap radio control toys that provide some nice gears and steel shafts. The toy and model industry is all nicely standardised and metricated so every thing seems to be compatible from what ever source model or toy mechanism it comes from. Maybe the same factory in China?

 

 

The yellow gear is being used as a shaft bearing. The Hornby gears are safely away stored in a plastic bag whilst the hacksaw has been flashing about.

 

 

As usual these sort of conversions take a lot longer than expect as unforeseen problems always crop up and have to be puzzled out.

 

Any ideas on hold to hold the new drive shaft in position ?

 

I intend to connect it to the motor with a short bit of rubber tube, maybe even fit a flywheel on it too.

Edited December 11, 2022 by relaxinghobby
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[manna]

G'Day Folks

 

A small bit of flat brass with a 'U' shaped cut out, slid over the drive shaft and glued to the upright (just behind the brass worm gear)  Unless you want to screw it into place.

 

manna

[relaxinghobby]

 

 

So far the chassis runs but after just a few dozen inches the white tube slides towards the motor and disengages. Bzzzzzzzzzz.

 

It's a push fit on the two metal shafts and helps align the motor and right hand gearbox shaft but not tight enough to stay put as soon as more than about one quarter power is applied.

 

I managed to saw a slot into the end of the gearbox shaft as I had heat treated it so the steel was soft enough to cut it to length. That's where the piece of wire passes through and makes a flexible joint. But when the motor is running in one direction the white tube unwinds back towards the motor and the wire disengages from it's slot. That's why the motor end is packed with washers and loose nuts to act as spacers. Allows no room for the tube to slide.

 

This has introduce some friction which is not good.

 

I could not cut a slot into the end of the hardened motor shaft. Saw blades just skate of of it. I dared not heat treat it as I would just melt the motor innards. Heating the gearbox shaft was easy as it can be separated from everything.

 

Iain Rice in his book on chassis building recommends a length of neoprene rubber tube to connect two shafts, if I can find some?

 

I need a fixing to hold the front of the motor more securely.

 

Thanks for the suggestions Manna and 313201, what is your avatar 313201? I'll try them or something inspired by them next. But remember I am totally incapable of any sort of precision metal work so making brackets to hold the motor exactly in a precise position is unlikely.

Don't worry about the gear box end when the top piece is screwed down the yellow cogs which are really a bearing as used here are held in the correct place so the worm and cog wheel fit together.

Edited January 1, 2023 by relaxinghobby
editing

[bobthemilk]

Iain Rice in his book on chassis building recommends a length of neoprene rubber tube to connect two shafts, if I can find some?.............................

 

Hi relaxinghobby

 

Flexible fuel pipe from a radio control petrol engined boat/plane/copter/car emporium may do the trick

 

regards

 

bobthemilk

Edited January 9, 2023 by bobthemilk
typo

[Barclay]

Hi Branchlines sell neoprene tube for this purpose. 

[DCB]

How is it going?      It looks to me as if the motor and shaft are slightly out of line,    I had a long and ultimately futile battle with a Comet chassis and ended up supporting the worm shaft both sides of the worm a la Airfix 14XX to keep the gears in mesh .  If you support the worm both sides and leave a short shaft you could use an Airfix 14XX drive shaft.     I didn't have room for the drive shaft. The motor was a DS11 (?) with a long shaft.    I sold the damned thing on eBay to preserve my sanity.   I have used neoprene tubing in the past, it never works for long,    And rubber belt drive, that can work, see Jouef, but they are  a PITA.   I bodged my Jouef 2-8-0, I mean 1-4-0 with a traction tyre for a belt in the end  before flogging it on eBay.

  However.  Do you have a brass worm to fit the motor shaft, if so that could be the anchor for the drive coupling especially if the worm shaft is the same diameter.  then again you could drill a brass bar to be an interference fit on the motor shaft and a looser one on the worm shaft, heat the bar, slip and slip it on the motor shaft and hopefully when it cools it's tight, then loctite the worm shaft to the other end. I have drilled bar by putting the bar in a drill chuck and the drill bit  in a vice to get it centred in the past before I acquired a lathe.    

Anyway just hoping its all going OK

[relaxinghobby]

Thanks DCB for your comments.

I have found some small bore rubber tube to replace the flexible shaft connection. I think it is fuel hose for miniature engines as used for flying models. So check out a flying model model shop or website.

On fitting it  it immediately made everything run smoother.

 

 

With the close up photo I can now see the motor is out of alignment, I only just noticed this when preparing the photos.

The yellow cogs at B are acting to extend the gear box bearing which is only in the metal behind B. The yellow cogs are securely set into some black Epoxy 2 part glue. The red bracket shows the effective length of this extended bracketry.

At A there is some card packing so I can lower the motor by removing a layer or two.

 

 

At C there is a bracket holding the end of the motor. That screw is the only fixing.

It's a bit meager as a solution  perhaps a more solid fix and something at the front of the motor too except just the two vertical pillars coming up from the chassis block.

 

As an example of accurate metal work this is taxing my skill level.

Edited May 3, 2023 by relaxinghobby
editing

[relaxinghobby]

Belt and braces.

The metal bracket at the end of the motor can slip allowing for the motor to move up and out of alignment.

The bracket was originally from the original  format and motor position which was higher. As the slot in it that goes around the shaft housing sticking out the back of the motor. The slot in it is too long I could not remake it to accurately fit around the motor and hold it firm.

So a brass strip belt from 10 thou' held in place by a bolt running through a horizontal hole drilled through the chassis. The hole is almost horizontal as I only have a hand held drill but this quick fix works. It holds the motor down firmly.

It will be out of sight up inside the new body.