Unimat 3 bed protector.

Quite often I will cut off a part on the lathe with a junior hacksaw rather use a parting-off tool, this is kinder to the machine as parting off puts a lot of strain on such a small lathe. However, its easy for the blade to slip as you break through and damage the bed if you're not careful. So, I've made a bed protector from two pieces of 6mm MDF to sit under the chuck and protect the bed from the sawblade should it slip. It will also protect the bed from being bruised by dropped chucks, its easy to drop a chuck when changing them. 

Here it is in position;

And showing the underside;

Not bad for a few minutes work and some MDF offcuts. Now I need to make one for my Unimat SL.

Paul.

And another refurbished dock shunter...

 A black one this time, bought for £15 at a toy fair;

It was in good condition, but had those awful knurled wheels;

These were soon swapped for a new set, as detailed here. One minor problem was that the chassis block was quite worn, obviously this loco has seen a lot of use. I did have a stock of axle bearings made as I turned extra when I last did this job, but they were a sloppy fit so I had to machine up 4 new ones, .05mm larger than normal.

Here's the chassis back in one piece, I didn't strip it right down as its in pretty good condition and runs well;

There is a new light shield on order, although I should really make my own (or get some etched).

This loco is not quite what it seems, the chassis is fairly early judging by the sheet brass pick-ups and knurled wheels, and is possibly pre-1960s. The body is much newer and has Tri-ang/Hornby moulded into it under the footplate and the buffer stocks moulded onto the buffer beams with separate heads as per the last Dock Shunters made circa 1977. So there's quite possibly a 17 year age difference between body and chassis. This may help to explain the condition of the body, which scrubbed up quite well with a bit of soap and water;

This now takes the total up to 5, my original that I've had since childhood and 4 that have been refurbished. I don't think that's too many.

By the way, it behaves nicely with my new home-made controller.

Paul.

Mustard tin controller

My friend Les has a habit of building controllers. One of his was built into a Colman's Mustard tin, using a cheap Chinese PWM controller as found on eBay. His design is fed using the 16v AC, from the accessory output common on a lot of model railway controllers. He also made one for me (thanks Les), but I wanted to try my hand at making my own.

These are the parts I used;

And a list;

Kato Unitrack extension lead (to connect to either of my ovals of Kato track, N gauge for testing OO9 locos and HO for the Christmas trainset),

57gram mustard tin,

Adjustable voltage wall-wart (3-12 volts) (wall mounted transformer Seelion brand),

Crocodile clips,

Small cable ties,

Sleeved cable strain relief grommet,

16v 1amp resettable polyswitch fuse (to protect the motor in case of a stall),

Centre off DPDT toggle stitch,

7/0.2 stranded wire in red and black,

12v green pre-wired LED and cap,

Jack plug socket 5.5mm x 2.1mm (to connect to the wall-wart),

Heatshrink.

The first job was to drill the tin, starting at the lid with a 7mm hole for the controller. 6mm holes were drilled in the sides for the LED and toggle switch, then two more holes in the bottom, 8mm for the power socket and 10mm for the strain relief boot;

Next I wired the jack socket, with the LED and two leads to connect to the control board, noting the polarity of the socket;

Onto the control board itself. I found that circuit board was too long at the top, stopping it from being bolted in squarely. Easy fix with a razor saw, the one on the left is as supplied and the one on the right cut down;

With the control attached to the lid it could be wired to the jack socket, no soldering required as the board has clamps rather than pads. It could now be powered up, there's an LED on the board to show if its working;

Next job was to wire up the DPDT switch. I cut the Kato extension lead in half and used the half with the female socket as my output, to connect with my pre-wired Kato track;

Please don't be too critical of my soldering! I'm much happier soldering brass than electrics. Its worth noting that the output wire had to be threaded through the relief boot and tin before being attached to the switch due to the socket on the end.

Next up the polyfuse was soldered to the motor + wire and covered with heatshrink;

Then the switch was wired to the board (which is clearly marked as to what goes where) and the thing tested with a multimeter;

I'm pleased to say that it works rather well. Its been in use on the Christmas trainset, powering a variety of Hornby's cheaper offerings.

Here's the complete unit, with its wall-wart;

The other half of the Kato lead, with the male connector, was used to make a test lead;

My thanks again to Les, who not only built me my first controller but also gave me invaluable advice and encouragement when I made this one. He wrote a thread on the NGRM-online forum describing the build. 

And now the boring bit. I need to point out that I am NOT an electrician or electrical engineer, and this in NOT meant to be a how-to, just a record of how I did a job which may be of interest to others. I used a wall-wart for safety, I'm quite happy messing about with 12v but playing with mains voltage is beyond my skill-set. If you do choose to be inspired by this and build your own, you do so at your own risk, if in doubt get help. I really hate having to type this, I believe that those who read my writings are sane sensible adults, but this is the world we live in.

Paul.