My Modified Build of Elmer's #3 O.C.R.

cfellows · Mar 18, 2009

Lookin good, MB, hope mine turns out half as nice!

Chuck

Metal Butcher · Mar 19, 2009

I finished the cylinder head and pipe flange by making their gaskets. In the past I tried using scissors to cut gaskets that were traced or marked out with dividers. I also attempted to use commercial punches and none or these methods gave me good results. A quick but simple idea came to mind while rushing to finish a build. Using spray adhesive I glued a piece of gasket to the bottom of a round cylinder and trimmed of the excess with an Exacto knife. It worked like a charm and the trimmed edge was as good as it gets. The bolt holes were next, but trying to trim them out with the same knife was making a mess of the gasket. While trying to think of a method a simple solution became apparent. A punch with a matching die would do the trick. The photo below shows the method I have been using ever since.
I drill the exact size clearance hole used on the cylinder head in a piece of scrap and machined a pin to the same dimension minus about .002". Then using the M/D quill movement, I simply punch and turn, punch and turn, until all the holes are done. This method works with gasket paper and Teflon sheet.

To make the flywheel I had to use the only piece of brass on hand that was close to the correct size. This turned out to be a 1-1/2" piece of hex. Since the original plans called for a round plain drum style flywheel the hex would need to be machined down to my planned 1-3/8" size and then cut off. Since I was starting out with a hex that would self index, the addition of a visual dimension became apparent by simply adding six holes to the basic flywheel design. A process I laughingly refer to as "Swiss Cheesing." The hex was faced and turned to dimension along with a 7/16 hub protruding .050", and the 1/4" crank shaft hole was center drilled,drilled, and reamed. Then when the cut off on the opposite end came close to the hub dimension, I stopped leaving the flywheel attached to what was left of the hex. The photo below shows this stop point.

After setting up a vise stop and clamping the hex in the vise, the head of the M/D was centered on it, and then the hand wheels were zeroed out. I eye balled a nice offset for the first hole at .410" off center. Then I center drilled the 6 locations by indexing the hex and followed by drilling them 19/64". To minimize the tedious and often overlooked finishing of the holes I used a .312" (3/8") reamer. The picture below shows the start of the drilling operation. The flywheel was returned to the lathe for cut off. Then after a protective double layer of tape was wrapped on the outside diameter of the flywheel, the facing and addition of the 7/16" hub was completed on the cut-off side.The photo below shows the center drilling complete and the first hole drilled.

To drill and tap the flywheel for a 6-32 set screw I used the quick and simple eye ball method. After the decorative hole and the crankshaft hole were lined up using a drill bit from the front. Then the center of the flywheel along its length was located by the traditional method of moving the spindle back to center line 1/2 of the flywheels length. The flywheel was removed from its setup for a final cleanup. I used a ¼ and 5/16 hand reamer to remove any burs caused by the drilling and tapping. The picture below shows the line-up process.

-MB

Metal Butcher · Mar 20, 2009

Late last night I finished all the machine work and I did a quick assembly of the engine for a test run to see that all was well. My heart sank when the engine refused to do anything but leak air. I pulled the head off and rotated the flywheel to find that there wasn't any air coming from the port at the top of the cylinder! I was getting frustrated, how could I have blotched up the valve this badly? I started thinking that maybe I didn't finish drilling a valve hole but then I recalled checking and cleaning each one.

There was nothing more to do except start taking the engine apart. When I split the union and rotated the upper half I found the problem. My flange gasket was missing a central air hole! Apparently I overlooked adding the central hole when the six bolt holes were punched. After a good laugh I modified the flange gasket and finished up the assembly.

After I pressurized it with 5 pounds of air it started on its own. After a few minutes the pressure was lowered to 2 pounds to test the reversing valve, and it ran equally well, and at the same speed in forward and reverse. I tried switching the air line between the two available ports and they worked equally well. This would allow me to face the reverse valve during demonstrations, with the fly wheel on my right, and the airline plugged in from behind.

Today I did all of the file work and sanding. I decided to use a 220 grit sandpaper finish on the aluminum and 600 on the cylinder and columns. To protect all the parts from tarnish they received an automotive surface sealant ("poly" type sealant.)

Below are the final pictures of my modified version of Elmer's #3 Open Column with Reverse. I hope you enjoyed my build, as much as I enjoyed sharing it with you.

-MB

BMyers · Mar 20, 2009

Nice work MB. I have yet to be able to build an Elmer engine. Too tiny for me. Looks like a POM nominee to me !
I am impressed :bow:

Metal Butcher · Mar 20, 2009

BMyers said:
Nice work MB. I have yet to be able to build an Elmer engine. Too tiny for me. Looks like a POM nominee to me !

I am impressed :bow:

Thanks!

I know what you mean about being a bit to small. The #3 Open Column with Reverse is a little easier than some. I built it 50 percent larger to fit in with other engines in my collection.

Take a look at Elmer's H-Quad, Its a much larger (already up sized) model than most, and its easy to build. Its also a really good running design with a reverse valve.

-MB