gregh
electronics, computers and scratchbuilding
Recently I visited a local hobby shop with some mates for THEM to make some purchases. I wasn't there to buy anything, but this PIKO 0-6-0 motor block took my fancy for AUD 110. The two outer axles are driven, and the centre axle wheels are flanged but have about 5mm side play. Connecting rods not supplied. Wheels are 35 mm dia at a spacing of 57mm.
I wasn?t too impressed with it once I got it home. As usual I start off by doing some bench electrical tests. Takes 400 mA with its wheels in the air - ie the motor and friction losses. That's over twice Aristo blocks? current.
Then I tried holding the wheels to get the stalled current, but I could hear the gears slipping. I noticed that 2 screws were missing from the top plate, so I assumed the looseness is a problem.
On the track, it couldn?t pull the skin off a rice pudding.
At least it's easy to pull apart. I took the top plate off and added a bit of cardboard to provide more force onto the motor and put in 4 screws. Also no grease on any gears, so added some Vaseline.
While it was apart, I took the wheel pickups and skates off as I will use battery power.
Once I removed the skates it was better. With 300g weight on it could take 3 bogie wagons up 1:25 easy, taking 900mA. I only tested it at that load as it will be a small loco.
Speed worked out at around 4 to 5 kph per volt, so 50 kph will need a 10V (8 NiMH cell) battery.
My original thoughts were to make a 2-6-0 tender loco, but I saw this pic of a NSW small tank from the 1880s.
It had no dome and inside cylinders so will save me a lot of work making those! It will be for my granddaughter to use. I thought of just a simple forward/off/reverse switch, but I had a spare 433 MHz RC unit so will use it, with a Picaxe for motor control and sound. (If it works OK and is not too power hungry, and can pull a decent load, maybe I?ll buy another motor block for a 2-6-0.)
Planning[/H2] My usual method of drawing the plans is to take a side-on pic of the wheels and of the loco. I then crop the loco below the running board and paste both in to Word. If I adjust the screen ?%? (?zoom?) to 68%, the screen prints full size on A4 paper.
I shortened the drawing to suit the wheelbase, then I found I had to stretch the tanks to 110mm to take two, AA cells along ? there will be 4 in each tank. I had to stretch the height so the boiler was the 57mm OD for the tube I had. And stretch the cab a little to fit the speaker in.
Then I used Word Draw to outline around the pic to get a simple, full-size drawing.
Now the hardest part for me - how to fit everything in and be able to access it, with the minimum number of plugs and sockets. This planning usually takes more time than building it !
As you can see, the only place I could fit a speaker is a 50mm type in the cab floor. The electronics will be in the boiler above the motor block. This way everything will be mounted in the body of the loco with just a 2pin plug to the motor. The On/off switch will be glued under cab and charging pins under rear buffer beam. The whole body will lift off the motor block and be held on by 3 screws from underneath.
Getting started[/H2] Finally I actually started work. First I needed a way of supporting the body on the motor block, so I contact glued 2 pieces of 18x18mm aluminium angle across the front and rear of the motor block.
The running board was cut out of 1.5mm styrene. Then strengthened with 3 more strips of 1.5mm glued underneath it lengthways. Wooden dumb buffers (my standard) glued to ends. This pic is the underside ? not very pretty is it?
Then time to start on the body, using 1.5mm styrene ? I?m using black more often these days.
The boiler is a piece of 57 mm OD plastic pipe. The smokebox is 0.5mm styrene with rivets embossed and contact glued around the boiler. I turned the funnel from a bit of 15mm dia elec conduit. And some styrene strips for the cap. And that?s the basic ?carcasse? finished.
I wasn?t too impressed with it once I got it home. As usual I start off by doing some bench electrical tests. Takes 400 mA with its wheels in the air - ie the motor and friction losses. That's over twice Aristo blocks? current.
Then I tried holding the wheels to get the stalled current, but I could hear the gears slipping. I noticed that 2 screws were missing from the top plate, so I assumed the looseness is a problem.
On the track, it couldn?t pull the skin off a rice pudding.
At least it's easy to pull apart. I took the top plate off and added a bit of cardboard to provide more force onto the motor and put in 4 screws. Also no grease on any gears, so added some Vaseline.
While it was apart, I took the wheel pickups and skates off as I will use battery power.
Once I removed the skates it was better. With 300g weight on it could take 3 bogie wagons up 1:25 easy, taking 900mA. I only tested it at that load as it will be a small loco.
Speed worked out at around 4 to 5 kph per volt, so 50 kph will need a 10V (8 NiMH cell) battery.
My original thoughts were to make a 2-6-0 tender loco, but I saw this pic of a NSW small tank from the 1880s.
It had no dome and inside cylinders so will save me a lot of work making those! It will be for my granddaughter to use. I thought of just a simple forward/off/reverse switch, but I had a spare 433 MHz RC unit so will use it, with a Picaxe for motor control and sound. (If it works OK and is not too power hungry, and can pull a decent load, maybe I?ll buy another motor block for a 2-6-0.)
Planning[/H2] My usual method of drawing the plans is to take a side-on pic of the wheels and of the loco. I then crop the loco below the running board and paste both in to Word. If I adjust the screen ?%? (?zoom?) to 68%, the screen prints full size on A4 paper.
I shortened the drawing to suit the wheelbase, then I found I had to stretch the tanks to 110mm to take two, AA cells along ? there will be 4 in each tank. I had to stretch the height so the boiler was the 57mm OD for the tube I had. And stretch the cab a little to fit the speaker in.
Then I used Word Draw to outline around the pic to get a simple, full-size drawing.
Now the hardest part for me - how to fit everything in and be able to access it, with the minimum number of plugs and sockets. This planning usually takes more time than building it !
As you can see, the only place I could fit a speaker is a 50mm type in the cab floor. The electronics will be in the boiler above the motor block. This way everything will be mounted in the body of the loco with just a 2pin plug to the motor. The On/off switch will be glued under cab and charging pins under rear buffer beam. The whole body will lift off the motor block and be held on by 3 screws from underneath.
Getting started[/H2] Finally I actually started work. First I needed a way of supporting the body on the motor block, so I contact glued 2 pieces of 18x18mm aluminium angle across the front and rear of the motor block.
The running board was cut out of 1.5mm styrene. Then strengthened with 3 more strips of 1.5mm glued underneath it lengthways. Wooden dumb buffers (my standard) glued to ends. This pic is the underside ? not very pretty is it?
Then time to start on the body, using 1.5mm styrene ? I?m using black more often these days.
The boiler is a piece of 57 mm OD plastic pipe. The smokebox is 0.5mm styrene with rivets embossed and contact glued around the boiler. I turned the funnel from a bit of 15mm dia elec conduit. And some styrene strips for the cap. And that?s the basic ?carcasse? finished.
superb
It looks absolutely "spot on".
