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jdunmyer
04-23-2013, 08:01 PM
You've seen pics of my Muley sawmill a while back, so you
know what I'm talking about.

The thing was a great success at the 2 shows in Florida, and I'm looking
forward to exhibiting it at this Summer's getotgethers. Although I've tried
it with both the Star and Vaughn engines, they seem to be a bit underpowered
for the job, so the Olds will remain the prime mover.

However:

I've been thinking about building a steam engine, something of the "Mill
Engine" variety, with a mind to operating the sawmill with it. It would have
to be along the lines of at least 1 1/2" bore X 2" stroke or perhaps a bit
larger, maybe 2" X 3". A working governor would be required, and I'm
noticing that such a device isn't a given on all models. Was just at the
N.A.M.E.S. show this past w/e and most steam engines did NOT have one.

In addition, if I'm to build a steam engine, it must operate on live steam,
compressed air isn't going to cut it. I'm not too worried that I can't build
a suitable boiler, but it will obviously add a bunch to the complexity.

Thoughts?

gizmo2
04-23-2013, 08:58 PM
PM Research has the model 4 and model 6 kits, 1 1/2" bore 2 1/2" stroke both rated about 1/4 horse. One is vertical, t'uther horizontal. Cast iron and bronze castings, fittings, all need machined. These may have the power to run your mill.

JCHannum
04-24-2013, 09:24 AM
Jim, you might check with Tiny Power. This link is to their 110 engine which is a twin derived from their 109 engine which is not shown. The 109 is a single cylinder, 1-1/2" X 2-1/4". Their Ajax engine is a beauty, and should be ample for the saw mill as well.

http://www.tinypower.com/store.php?crn=56&rn=251&action=show_detail

There is a difference between the power produced by a model steam engine versus a model IC engine in that steam power is produced in the boiler, not the cylinder and not subject to the same scaling factor that IC is.

jdunmyer
04-24-2013, 04:44 PM
I've looked at both those sites, and like the model engines.

Here's a video of a model, with an attached boiler: http://www.youtube.com/watch?v=8FXeYKvQQ6o

At the moment, I'm unsure of how much power I actually need. Perhaps the next thing I should do is build a torque arm for the pulley on the Olds so I can calculate the power. I did that for the Vaughn, and it figured out only 1/20 Hp. Of course, that actually is [just] enough to run the sawmill, and the 1/8 Hp electric motor runs it in fine shape, even at a very low RPM.

I know that it's possible to calculate the Hp of a steam engine, so I should be able to determine the required size.

JCHannum
04-24-2013, 08:19 PM
A quick and dirty calculation of the Ajax engine at 130 PSI and 250 RPM yields approximately 1/3HP, which sounds reasonable compared to the information on the Tiny Power 110 engine.