Playing with a Cracker.

[Tony Bird]

Hi, At midday it was 27C in the workshop. So, I decided to run a train on the garden railway, and in the cool edit a video made when it was running. I hope you enjoy.
Take care Tony.

[Keith S]

Nice video, Tony. I like those “Crackers”.

[Scrat]

After more than 20 years under the bench (including a house move) my cracker has come to the top of the bench again.
Chassis is complete, Boiler also.
I am now making the cylinder and the components around it.

The only thing I do not want to build according to the plans are burner and tank.
Is there any "off the shelf" solution the other cracker-builders can recommend?

[Tony Bird]

Hi,

As far as I know there isn't a commercially made burner small enough to fit a Cracker. I hope I have attached PDF is the burner drawing I designed which might help you..

Take care Tony.

Burner arrgt.pdf

(2.7 KiB) Downloaded 12 times

[Tony Bird]

Hi,

Sorry not the drawing that I hoped it would be I will try again. T

[Tony Bird]

Mod. Cracker drawing 5 burner.JPG (283.3 KiB) Viewed 650 times

[Scrat]

Hi tony,

thanks for the drawing.
I a just sorting out mistakes I made back then.
Now I have a well-running chassis. Binding has been dealt with.
I had to make new buffer blocks. The old ones were just filed. I made the new ones on my (tiny) mill and they are square. What a difference.
Made the cylinder yesterday.
I still hope to find some burner as I do not have the experience to make one.

My last attempt to copy the famous Falk burner turned into a pocket sized flamethrower.....

[Scrat]

While waiting for more brass stock for the cracker to arrive I did something different.
As I was not sure I could build the cylinder precise enough to actually work I took the dimensions from the cracker drawings, a flywheel from the box-o-bits and went to work.

Cylinder parts:


Beginning to look like a steam engine:


I only used stock parts from the bin.
This pillar has onve been grabbed by the mill and launched to the far corner of the workshop.
Some other parts also show their origin clearly.
As it was just a test engine, I did not clean up those marks.


Finished:




Of course, she did not run on the first try.
I had made a jig for drilling the ports as it is shown in the cracker drawings.
One hole in the jig was slightly off-centre but a jig is a jig and if this deviation is transferred to all parts, it will work, I thought.
Murphy paid a visit, I put the jig on upside down and of course the hole was in the wrong place.
I plugged the hole with 1mm brass rod soldered into the cylinder base, drilled again (right place this time) and....she runs.

I guess that is good enough to try the cracker cylinder now.

[Tony Bird]

Hi,

I guess that is good enough to try the cracker cylinder now.

I agree, but perhaps a mark on side of the jig? Good luck with your future endeavours, if I can be of help please ask.

Last year I built a large version of Cracker to 7/8ths scale using a Mamod cylinder. The model turned out to be a lot more powerful than expected.



Take care Tony.

[Scrat]

Hi Tony,

as we are in heavy snow these days there´s lots of time for the workshop.
I now have an air-running chassis. Not spots, no binding. (how did that happen?)
Ran it on the compressor yesterday.
Today I made the cab and smokebox.
I need to make fixtures for boiler and smokebox and then put the steam pipes in place.
The job I have put off until now is soldering the bushes into the boiler.

Not a long way to go any more.

[Scrat]

Some progress.

I tested the cracker on my big stationary boiler.
She ran at 40 psi so there must be something wrong.
But...better than not running at all.