A Larger Mill Engine

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Philjoe5

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I'm not sure if this post goes here because I do have a running engine but since I'm not finished working on it, I guess it's "in progress".

Here’s an update on the mill engine I've been working on. It’s 1.5x larger than the scale model I'd built previously. I decided to try this approach because the basic engine design is pretty rugged (in my mind) and it would give me practice in taking a set of engine plans and rescaling them (either up or down). What surprised me the most was the actual magnitude of a 50% increase in size. For example, shown here are two connecting rods, the 1x and 1.5x scale.

1xand1_5xconrods.jpg


Here are all the parts arranged on the half inch steel baseplate stock

15xscaleengineparts.jpg


I need to machine the baseplate and eventually paint it. It’s a piece of steel ½” x 8” x 24” and it’ll be a challenge to work with since its dimensions in the x-y directions far exceed my mill/drill table capacities.

I made a protoype of the baseplate using ½” plywood. A photo of the engine mounted on this temporary baseplate is shown here compared to its original scale model:

MillEngines.jpg


The video of the engine’s first run is shown here. As soon as I assembled this engine it ran but it wasn’t too smooth. Tweaking the valve timing improved that.

[ame]http://www.youtube.com/watch?v=SY56iahDoGs[/ame]

After about 30 minutes of running I’m able to run the engine now at about 5 psi and the movement has gotten smoother. I’ll spend a few weeks on the permanent steel baseplate and get that painted then post a picture.

Cheers,
Phil
 
Phil,

Very nice engine ! :bow: What's her bore and stroke? What plans did you base it from, I like the rotary valve motion.

-Bret
 
The bore is 1.500" and the stroke is 2.062". The engine is based upon plans by Ray HasBrouck. It's a horizontal mill engine.

Cheers,
Phil
 
Nice Job there!!! I want to build some bigger engines some day.

Wes
 
That's nice work Phil and very impressive that it will run at only 5psi :bow: look forward to seeing it when completed.

CC
 
Impressive and quality machining how long did it take you so far? Mike
 
looks and sounds real nice.
 
Thanks to all for the kind words and encouragement. I started this engine in early May, so you're looking at about 2 months of effort. My experience building the smaller scale models helped a lot, in fact I was able to use many of the same fixtures.

I'm going to throw a question out there. This engine has about 3.4x the displacement of the original engine. I run my engines off a little 2 gallon compressor with preset cutin/cutout pressures. When I pump up the tank and the compressor shuts off, I can get a 90 second run before the compressor kicks in on the smaller engine. Does that mean for the same efficiency I should get a 90/3.4 = 26 sec run on the larger engine? ???

Cheers,
Phil
 

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