Hornby 040 Chassis Modifications

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Geeky Gecko
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Hornby 040 Chassis Modifications

Postby Geeky Gecko » Sat Aug 02, 2014 4:09 pm

I've managed to find time recently to sit down and modify another Hornby 040 chassis by including a second stage of gearing to improve the slow running capabilities. Hopefully I can now find the time post a 'How to ...' guide.
Just to make sure there is no confusion here is a picture of the model in question, and a picture after the modifications have been made. I recommend using the chassis with cylinders, as they should help retain strength. The connecting rods are irrelevant.
Image Image
Here are some drawings.
Image Image
Since the article was written for the Railway Modeller, I have improved and simplified the design.
My remit was to improve the slow running characteristics of these models whilst using the basic Hornby controller. Although not relevant here, this design should still fit within the confines of the Class 06 Diesel and the Saddletank Loco (after some modifications to the running plate), and require the minimum of expenditure.
You will need:
Styrene sheet (plasticard) of thickness 1mm (40 thou) and 0.25mm (10 thou)
Styrene cement (I like Revell Contacta Liquid) and superglue or contact adhesive
Steel Rule
Knife
Junior Hacksaw Blade
Side cutters
Bent nose pliers
Drills (1.5, 2.0, 2.5, 3.0)
2.0mm rod
2.0mm top hat bearings
Gearwheels and Worm (Squires GS0220, GS0200 (optional), GS0305)
Biro tube (empty) to fit over 2mm rod
Small screw similar to that fitted to chassis
Electric cable
Soldering iron and cored solder
Small screwdriver


Start by removing any weights fitted, then the motor mount and motor. Discard the motor mount. Using the bent nose pliers carefully lever the worm from the shaft. Clean all parts.
Using the smallest drill make holes in the side plates behind the cylinders and then enlarge up to 3mm diameter.

Image Image
Cut down to the holes with the side cutters and trim with a knife to form two slots for the gear wheel.

Image Image

Now drill a 1.5mm hole in the base of the chassis. Located between the axle and the cylinders inside the chassis moulding you should find a circular moulding mark. Drill the hole in the centre of this circle. This will be used to secure the bearing support.

The spur gear is obtained by modifying the double gear wheel. Push the gear part way onto the shaft of the motor. Temporarily apply power to the motor while lightly holding the saw blade against the gear so that it cuts a slot and separates the large gear wheel. Remove any burrs from the edge of the newly made spur gear with a knife.
Image

[Edited 9/8/14 10.55 for the following addition]
This is where to drill the hole to secure the bearing support.


Image
Last edited by Geeky Gecko on Sat Aug 09, 2014 12:03 pm, edited 2 times in total.
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Postby Longvallon » Sat Aug 02, 2014 5:06 pm

Excellent thread. Thanks for sharing your work with us. :D
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Postby Artizen » Sun Aug 03, 2014 1:01 am

Gnice.

Any chance of a video showing off its slow-running capabilities?
Ian Hodgkiss
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Postby Geeky Gecko » Tue Aug 05, 2014 7:47 pm

Thanks, Chris and Ian, and I'll try a video soon, maybe at the weekend.

I am not the person to give advice on using styrene sheet. I tend to use it only for making chassis, so the following applies to all materials.
I looked at the dimensions of the parts needed for the construction. and then cut a number of strips from the 1mm sheet.

Image

I marked the widths using dividers to improve accuracy, and marked the centre line as this is often helpful for further measuring purposes.
Set the dividers to half of the required strip width and make two marks. Repeat at the other end. I apologise to all you Grandmothers for telling you how to suck eggs.

Image Image

BEARING SUPPORT

I started by cutting all the parts required.

Image

I then drilled a 1.5mm pilot hole for the bearing in the relevent part.
This is located centrally 8.5mm from one end.
This is a critical dimension as it fixes the height of the worm for the drive.

Image

I then fixed one of the 5mm x 6mm pieces (by the longer side) to the first part, so that the hole is as far away as possible. It should be located centrally and at right angles.
Check with a square or the end of the steel rule.
The second identical piece was affixed on top of the first.

Image Image

Referring to the pictures below it should be possible to follow the next steps. Ensure that everything is square and central.

Image Image

When dry, carefully drill the hole from the rear keeping the drill vertical. Ensure the hole is central.
It may be possible to make some slight correction with a round needle file if necessary.
Enlarge the hole to suit the bearing (3mm).

Image Image

Push the bearing into the hole as pictured ensuring that it fits squarely. Be careful not to damage the thrust surface. If the fit is not tight use a drop of superglue.
Be careful not to get glue on the surface of the bearing. The edges should be trimmed so that it will fit within the chassis.

Image Image
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Postby Geeky Gecko » Sat Aug 09, 2014 1:38 pm

The Bearing Support in position.

Image

THE MOTOR MOUNT

The parts needed for the whole, . . . . . . . . . . . and the parts for the first stage.

Image Image

The stages in construction.
Image Image
Image Image

Before fitting the top it might be worth adding some weight, ensuring enough room for the shaft and the screw.

Image
With reference to the picture above make sure that there is sufficient
clearance at the places indicated.

Ensure the shaft will not contact here.

Trim here to allow fitting between the moulded pips in the chassis.

Trim or file to allow clearance for the electrical wiper pick-ups to move freely.

Cut enough material here to ensure this area does not contact the top of the chassis.

Trim here to allow the motor to sit flat on the upper surface.


Here in position.

Image
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Postby Geeky Gecko » Wed Aug 13, 2014 7:30 pm

THE LAYSHAFT

Image

I cut a 29mm length of 2mm steel rod and filed a chamfer on both ends and then polished it with some fine grade wet and dry paper.
Carefully push the shaft into the Hornby worm you have removed from the motor shaft.
If you countersink the hole in the end of the worm it should be easier. Once started the shaft was driven into the worm with a small hammer.
The shaft needs to protrude out of the worm by 3 or 4mm, A small nut used as an anvil is used to achieve this.
I then pushed a length (4-5mm of biro tube) on to the shaft, along with a washer at each end.
This length will need to be found through trial and error by fitting the parts to chassis.
The shaft needs a small amount of longitudinal movement. It also needs to turn freely.
Ensure the meshed gears have a small amount of play, and the bearings are in alignment.
I needed to add shims of 0.25mm styrene below both pieces as in the picture below, raising the motor mount and tillting the bearing support.
I do this dry without oil.

Image

Ensure that everything is in order before fitting the spur gear as it will be difficult afterwards.
The larger of the spur gears needs to be fitted to the shaft – make sure you have pushed the shaft through the bearing mount the correct way.
With the shaft removed from the chassis push the shaft into the gear far enough so that the gear will align with the slots you have cut in the chassis.

Image

Refit everything to the chassis and make sure everything turns freely and does not catch anywhere.
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Postby Geeky Gecko » Sat Aug 16, 2014 9:57 am

THE MOTOR SHAFT

A length of 2mm rod now needs to be cut and finished as before. This needs to be about 15mm long.
A 10mm long worm from the same range of gears was used as a method of extending the shaft.
This is used instead of the length of biro tube I used originally, and is rigid enough to be able to eliminate the second bearing from the design.

Image

Push this worm onto the motor shaft and insert the rod so that approximately 5mm of each is in the worm.
Then fit the small spur gear onto the extended shaft far enough so that it lines up with the larger gear when the motor is fitted into position.

Image

You will need to fit a thickness of styrene between the motor and its mounting so that the gears mesh with a small amount of play.
Ensure the motor is fitted centrally and parallel as this will affect the meshing.
I find it better to fix some styrene to the motor first if using contact adhesive, before using styrene cement for final fixing.
The motor terminals will now need to be connected to the wheel wipers.

Image
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Re: Hornby 040 Chassis Modifications

Postby docnjoj » Sat Sep 23, 2017 3:56 pm

A shame botophucit got to these pictures!
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Re: Hornby 040 Chassis Modifications

Postby docnjoj » Sun Oct 22, 2017 4:14 pm

Good news! They seem to be recovered. I'm not sure if it was from the download recovery program I am using or because the author recovered them? Great article and useful for many regearing projects.
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After extensive recalculation, I have determined that the meaning of life is NOT 42! The secret of life, however is "enjoying the passage of time" (James Taylor)


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