Electric Cracker

[-steves-]

A friend likes the design of the Cracker loco, but asked if I could do a 3D printed electric one. So I have sat down with CAD for a couple of days and I think have the basis of an E-Cracker. It will still have the 3 gears, a flywheel and a pretend working oscillating engine. The chimney is purposely long as he likes long chimneys.

This is the ROUGH sketch up so far.

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Cad Cracker 2.png (178.1 KiB) Viewed 2697 times

[philipy]

Interesting project Steve.
Keep us updated please.

[-steves-]

Interesting project Steve.
Keep us updated please.

I will do. It all depends on whether I can get it all working and the gears to mesh etc. My gears are thin plastic and I have a suspicion that any play in the axle will enable the gears to be hit and miss. It might take a few washers to pad out any play or I might need to invest in some wider gears, or even make some if push comes to shove.

[-steves-]

I am now able to provide a short video of the basis setup working. There is still lots to do, but at least the theory seems possible.

[philipy]

That looks good. Are you using the small ball bearings on the axles?

[-steves-]

That looks good. Are you using the small ball bearings on the axles?

No, just brass bushes as the axles are only 2mm. That was to be honest down to the gears I had to hand which were 1.95mm bore. If i had used 3mm axles as originally planned then I was going to use small ball bearings.

[-steves-]

If anyone is interested then I "might" decide to publish the files to print one. It is however extremely fiddly to get all the gears lined up and all the bushings in the right place so the axles don't have too much end play and mess the gears up. You have been warned, lol

It requires 2mm axles of 46mm and 51mm, 2 of each and a bit for the piston rod too. Brass tube with a 2mm bore, 3mm OD, cut to just 1.5mm to 2mm each. Some 40 tooth Mod 0.5 gears, a ten tooth (I think from memory) Mod 0.5, a 30 tooth Mod 0.5 main drive gear and a worm gear to match a 280 motor. A load of 5mm, 6mm, 8mm and 10mm M2 screws. 2 of M3 x 6mm plus M2 and M3 grub screws. I think thats about it, other than a 3D printer. It also requires a li-ion 16340 battery for drive as it's the only thing that fits in there. Possibly a battery holder for the battery as I think it will be a remove to charge battery and I can't currently think of anywhere to put a charge jack, simply as there is no room.

[philipy]

For me, I think it's on the mental back burner for now. I'm just looking at Drew's Thornas and I have half a DeWinton waiting for me to regain momentum on, but I do like the look/sound of it.

[-steves-]

For me, I think it's on the mental back burner for now. I'm just looking at Drew's Thornas and I have half a DeWinton waiting for me to regain momentum on, but I do like the look/sound of it.

I just looked at the Thornas too. I have downloaded the files, but honestly don't have the time to print it, let alone build it at the moment, but "one day" I will. I do like he has done both 32mm and 45mm versions on the download

[drewzero1]

I just looked at the Thornas too. I have downloaded the files, but honestly don't have the time to print it, let alone build it at the moment, but "one day" I will. I do like he has done both 32mm and 45mm versions on the download

I should mention that the 45mm files have not been tested in the real world, just digitally eyeballed, so there might be issues with the cab steps or other pinch points. I'm hoping to build a 45mm version (or at least the chassis) soon to run on a friend's loop and I'll let you know how it goes (and update the files if it doesn't).

The Cracker looks like it would go well with a tram body over it, maybe with some access doors left open to show off the mechanism and flywheel. I'd be interested to try building one but it'd be a while until I got around to it for sure.

[-steves-]

Well I think the CAD work is done, just got to print all the bits now and see if they all fit together as expected.

I wonder how many CAD workers try and view the picture below in 3D and try to spin it round to view it? Why do I think this, because it's something I do myself, lol

Cad Cracker 3.png (252.25 KiB) Viewed 2566 times

[philipy]

I wonder how many CAD workers try and view the picture below in 3D and try to spin it round to view it? Why do I think this, because it's something I do myself, lol

...although I haven't done it with one.

[-steves-]

I wonder how many CAD workers try and view the picture below in 3D and try to spin it round to view it? Why do I think this, because it's something I do myself, lol

...although I haven't done it with one.

Phew, at least I am not the only one

[-steves-]

Well here is the almost finished loco. It need a few more coats of paint and a bit of tidying up, but it's there and it all works. I can't show a video of it going around the line as the line is in pieces at the moment awaiting repair, so just some still shots I am afraid. This is not my best paint job, it was done in a rush, with a big fat brush, not sprayed, just to have a rough feel how it might look, also no rubbing down has been done on the model. The cab is also not glued on at this stage, neither is the driver, lol.

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[Old Man Aaron]

Never thought I'd see an electric Cracker! Neat!

[Scrat]

This is addictive.

I have just dug out my cracker (started mid nineties) and made the buffer beams.
So now I have a part-finished boiler and everything below the footplate.

[-steves-]

This is addictive.

I have just dug out my cracker (started mid nineties) and made the buffer beams.
So now I have a part-finished boiler and everything below the footplate.

Strangely enough, I am considering building a steam on as they were meant to be, it's cute and I kinda like it. As you say, quite addictive.