Blog- brightspark's Blog - 76010 making the wheels go round

RSS Fetcher · November 28, 2014

I was hoping by now to have had a working chassis ready for testing on the EMGS test track at ExpoEM south.

However I have not achieved that goal because;

1. The chassis is almost ready but not quite there yet.

2. The EMGS Test track is, I believe not going to be at Portsmouth.

3. It is not ExpoEM South anymore, it is the South Hants Model Railway Club Exhibition

However I will be there on the EMGS stand with the 76010 and 76009 and 76011!

Yes another one! At the Tolworth Show I acquired another chassis kit. This is a Kemilway chassis circa 1980 an updated version of something that first appeared in 1975. I believe that these were among the first etched chassis to come onto the market.

Pictures of the Kemilway kit. The packet notes makes interesting reading.

However an update on 76010.

While the paint was drying on the chassis I made a start on the drive train. I purchased with the kit a Mashima motor and gearbox. I had already assembled the gearbox body and test fitted it to the chassis and to the motor.

It strikes me that there must be a logical sequence to this and so with help from Mr Rices book I proceed in this manner.

1st step. Check that the motor is a runner and not a dud. That means connecting it to flying leads and crocodile clips and test it in both directions. It should run smoothly and quietly.

2 confident that the motor is good we can now go down the route that may invalidate any warranty. Solder on the flying leads that will eventually be installed into the loco. Leads should be a generous length as they can be shortened later. Test the motor to make sure that nothing has gone amiss.

3. Press on the flywheel making sure that you apply pressure to the shaft of the motor and not the motor body. Test to make sure the flywheel is true and that the motor is happy.

4. The gear box is already folded up... but I hadn’t installed the intermediate gear so had to open out the gearbox frames slightly to get this in. I don’t use any locking agent to hold the small fixed gear on as it is an interference fit. But to help ease it on and to reduce the chance of galling (burring up in between the shaft and the gear) I take the trouble to freeze the shaft (in the freezer for a few hours) and warm the gear wheel (In the oven while cooking something) before I assemble.

5. The grub screws tend to push the gear wheels off centre so I filed a flat onto the shaft for the screw to locate against and when happy that it is not too tight lock the screw with a bit of cyno (superglue) on the head.

6. With that done I then test down each section of the gear box with worm to intermediate gear (primary drive) and then intermediate to the driving axle (secondary drive). So by now I have a smoothly operating gearbox and motor.

A very blurry picture of testing the meshing of the worm drive (stage one) with a paper packing strip. Is it grinding or is there too much freeplay?

Checking the freeplay with a cocktail stick.

Next comes the wheels. I use Gibson, because they carry stock. There are better wheels out there, but I would like to get the loco built and running in this lifetime. Gibson wheels have a small hole in them for the self tapping screw to go through. Unfortunetly the screw head fouls the “washer” on the back of the wheel. So I countersink the back so that the screw head sits flat. It may be a good idea to lock these in with a bit of cyno as well. Oh and run some cyno between the tyre (the metal rim) and the plastic centre. Gibson wheel have had a habit of throwing tyres and this is a simple fix. Oh yes and remove any moulding pip on the back of the wheel as well.

I had a go at blackening the tyres of the wheels using Carrs products. I have not quite mastered this as I get a thick gloop on the wheels. But at this stage I do a general clean up and remove this excess gloop and the wheels don’t too bad.

With the chassis back from the paint shop I can start assy. First check that the painters didn’t gum up the threads or the coat the bearing faces. If they have clean these up now.

Now quartering wheels has always been a problem for me, and I have been frustrated for years by being unable to get coupled locomotive wheels to go around. There has been published many accounts and “helpful” advise as to how to achieve this along with so many “skilled”(in that they got wheels to around) modellers who have tried to explain to me how to do it. Fortunatley I have had the wisdom of one excellent craftsman in this field and I think that I have finally managed to unlock the secret. Here is how I now do it.

1. Buy a GW quartering jig! It is wonderful and does the job (usual disclaimer)

2. Oh this is where I had a problem...

You see the weigh shaft mechanism fouls the quartering jig. So it had to be unsoldered. The paint shop foreman is going to have a fit when he gets this back. Anyway the front wheels go on with a thin fibre washer behind them to stop any side play with the risk that the wheel, connecting rod etc will foul the piston assy.

The middle wheels are assembled without washers as It may be desirable for them to float a bit around corners.

The rear wheels have washers as they are the driving axle.

Solder the weigh shaft back on.

The GW quartering jig in action. Except the weighshaft is in the way. Oh well out with the soldering iron.

Now this is the clever bit.

3. Open out the holes in the coupling rods to fit over the screws. Holes will be about 1mm and open them with a Broach as you can also get the hole square.

4. Then....and this is the clever bit...working from the driving axle fit the coupling rod upside down and only on the driving wheel and the middle wheel.

5. Rotate the wheels and chances are you will find a tight spot. The area to look at is the side where the rods are at 3 oclock/ 9 oclock. See which face (fwd or aft) is rubbing against the pin and with a rat tail file, remove a small amount of material. And by small I mean a few strokes of the file. It may also be better to not touch the hole on the driving wheel, so you make all the adjustment on the middle wheel. Keep repeating until the wheels rotate freely.

How freely? Well first of all you shouldn’t be removing a huge amount of metal from the rods so don’t go looking to make a great big sloppy hole. The model should be able to roll down a slope under it’s own weight without locking up. When you have achieved this, test the motor and make sure the loco move along smoothly.

Then turn the rods the correct way up and do the same exercise with the remaining wheels.

And that is basically it. Check that each bit of the model is free running before moving onto the next. So here is the model at it’s current state of play. The pick-ups have been added, and it was very satisfying to see the loco chug along a bit of track under its own power, as well as the brake gear. Con rods are about to be mounted and set up.

Con rods being checked for free movement. Its a satisfying feeling seeing the loco move off smoothly for the first time.

At the moment it is all boxed up for dabbling with at the Portsmouth show tomorrow (29th Nov 2014). I will have all the models there including some examples of the original Kitmaster. If you are there come and say hello.

Andy

ps I thought that I had taken more photos of this part of the build...but I didn't so apologies.

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