"Richard Smith" wrote in message ...

"Jim Wilkins" writes:

"Richard Smith" wrote in message ...
..
Boot off a CD-ROM? Could do?

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Can do easily.

...

There's a mini-computer called a "Raspberry Pi". Designed by group
endeavour of hobbyists. Meant for education. Uses a "merchant"
embedded-chip for eg. washing machines as its processor.
Might look if that offers a way.
Lots of devices been matched to it.

However, note you "PC architecture / QBasic" way.

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Sure. The Pi has the advantage that you can buy and plug in an A/D converter
to read the pressure sensor, and a keyboard and display to monitor the test,
no technician bench skills required. I haven't played with one and don't
know the learning curve for it. Are you generally familiar with computer
hardware and software architecture?

As for the eccentric, I considered it because you could vary the piston
stroke, but you'd need a lathe to make it, the pump drive is more than a
friend could whip out in a spare hour. A pump built into the cylinder end
might give the fastest cycle rate because there's no flow restriction. You
could fine tune the peak pressure during operation with a screw that
displaces oil. A cheap used tie-rod cylinder with a scratched bore could be
cut down to be your pressure chamber. Cylinder rebuilders can provide the
tubing in any length.

On my tractor's homebrew bucket loader attachment hydraulics I turned the
head of a bolt round and grooved it for an O ring, so it can screw into or
out of the oil space without leaking. It operates the variable pressure
relief valve I made to replace the fixed relief the control valve came with.
The tractor's front tires turned out to be the weakest link that limited how
high I could set the pressure.

The decision comes down to what you can build or buy. I've spent significant
time and money becoming able to build what I or the customer wanted,
electrical, optical and mechanical. Right now I'm upgrading my sawmill and
its overhead gantry hoist to handle a larger log than it was designed for.

The sawmill is a large horizontal bandsaw made from salvaged motorcycle
wheels. Thursday was lost to the miserable task of prying off the drive
wheel's tubeless tire, scrubbing the corroded bead seating surfaces and
getting it to hold air. The slow air leak reduced the blade's initial 500 lb
tension and let it wander in the 20 inch long cut. I learned manual tire
repair at the Hardway School (an Army motor pool) on split rim truck tires.
As the tire store manager told me, a 2" right angle air sander is the
perfect tool for cleaning up a leaking rim. My tractor's rusted wheels will
be its next victims.

Would fatigue cracking in oil be similar enough to cracking in air, which
oxidizes freshly exposed steel?