This is my first attempt at building a steam engine. Most everything I have made in the past was either for my model railroad, repairing clocks, making tooling or repairing equipment for my business and others.
This engine is a kit sold by Octura Models in the 1950's. It was given to my friend, Lee Brown, by someone who had it since the mid 50's. The castings should be well cured by now. There are no instructions, just prints and a box of castings. This is pretty much old hat to those who have been building for some time but it's pretty exciting for me. We'll see how this works out. Be patient, this is gonna take some time.
This is the stat from the corner of the print. Due to the age of the prints they were becoming somewhat fragile so I made copies to work from. I kind of like to keep things original.
I have started construction by first milling the flywheel arbor pedestals and the cylinder mounts to the proper height and then drilling the mounting holes and preparing them for tapping.
Next I milled the pockets for the flywheel arbors. Most of the setups are pretty straight forward. Biggest thing with castings is to go slow. Measure twice and cut once. Bar Stock is replaceable but a 50 year old casting is not.
Tapping the holes in the pillars is the next step. The tapping machine was purchased used quite inexpensively. I had not ever used it. Most holes I tap are small and I had felt the machine would not be sensitive enough for small taps (8-32) and that I would experience breakage. To my amazement I had wonderful feel and control.
The next step was to layout the clearance hole for the cylinder. The cylinder mounts to the front of the purple part of the casting. A clearance hole is needed for access for the piston and connecting rod to pass on to the cylinder.
Boring is done with an import boring head and a carbide tipped boring tool. Normally I would use HSS but for a quickie job it was not worth grinding a bit.
Facing the casting is necessary so that the cylinder is mounted perfectly perpendicular to the base. This pretty much finishes the base with the exception of drilling the holes in the tabs used for mounting the casting to a base or stand of some type. Also the cylinder mount has yet to be drilled and tapped but will be done later after the cylinder has been drilled. Then the cylinder will be used to mark the precise points for drilling the mount.
This shows the machining of the front of the steam chest. Holding the odd shaped casting is awkward and the overhang is a bit extreme making slow, shallow necessary. It all worked out well with a 4 jaw and packing.
Dilling the steam chest.
Threading the steam chest
This shows the slitting of the slide valve. The coarse slitting saw run at a rather fast speed and slow feed cuts the bronze casting quite nicely.
I am boring the slip ring that operates the slide valve. The slide ring will be split later. Hopefully I am doing this in the correct sequence.
I've made a go no go gauge to test the bore. The gauge has a hole which fits over a center on the rotary table which will be used for rounding up the out side of the slip ring.
This view shows the rounding up of the outside diameter of the slip ring.on the rotary table. The center of the table is made from a JT/MT2 drill chuck adapter. I have several of these made in various sizes from 1/4 inch to 1/2 inch.
Click on the thumbnails to view them in a larger size.
I will abandon the slip ring project for the time being and get on with working on the slide valve ecentric. The OD has been turned and now begins the boring for the main shaft. I am using a center finding wiggler to find the center for the bore. This would normaly be done with a dial test indicator but since this a rough casting I marked out the center and used the wiggler. The outside of this protrusion will be rounded up next. After the ecentric is finished I will return to the slip ring and finish it to fit.
The slide valve ecentric has been drilled and reamed to proper size and now comes the rounding up of the shaft portion of the ecentric. This is being rounded up on the rotary table. It is now ready to go to the lathe.
The groove for the slip ring has been turned and the ecentric is now being parted off.
This is the completed part. Edges have been cleaned up and with the exception of drilling and tapping for a set screw to fasten the ecentric to the main shaft the part is finished. Some of the original surfaces of the casting are still apparent. The casting was extremely crude and not of the best quality. There are flaws and small voids which can be seen in the enlarged photo. They are, however, cosmetic and will not affect the usefullnes of the part. Now it's back to working on the slip ring.
I am using a die filer to shape some of the odd pieces that are not readily or easily machined.
This is my die filer I machined from a kit. I do not use it often but when I do nothing else works quite as good.
Behold, God is my salvation. I will trust and not be afraid; For the Lord God is my strength and song, and He has become my salvation.
Isaiah12:2
I am just returning from a six month hiatus recovering from a couple of surgeries. I have been out of the shop but now am ready to start making chips again. Hopefuly I can find more time to spend at the machinery.
Fixing a Problem: This kit was started by someone else many years ago. The cylinder had been bored but with a slight taper which had to be corrected.
A few minutes on one end of the cylinder with the brake cylinder hone and the slight taper was removed and I had a very smooth cylinder wall.
The next step was to round up the outside rim of the cylinder upon which the lagging will be mounted.
The first step was to turn a register pin on a drill chuck adapter. This will be mounted on the rotary table. I have given up turning tapers whenever I can use a drill chuck adapter instead. The pin is 1/8 inch diameter. I have made various slip rings to go over the pin for various other applications.
The pin fits the rotary table center hole. This is the basis for centering up the cylinder..
The next step is to turn a stump which fits the cylinder bore. The stump is end drilled with a 1/8 inch hole which fits over the pin on the rotary table.
The stump is placed over the pin, the cylinder is placed over the stump and the cylinder lagging rim is perfectly concentric with the bore.
This photo shows an alignment bar. It is used to check the alignment between the main shaft and the cylinder. I wish I could take credit for the idea but I saw the same thing done in either a Live Steam or Model Tec article. This may be a common technique but it is new to me. Unfortunately I do not have the article and cannot credit the author.
The nextstep is to drill the intake and exit ports in the cylinder.. this photo shows how I set the angle for the ports. You will see that the protractor has had it's leg cut off. The leg is originally about five inches long. Most of the things I make are quite small and the long leg always gets in the way so I shortened it to about two inches.
I am using a center finder to locate the intake and exhaust ports.
After locating the ports I mill a starting hole prior to drilling. The starter hole has a flat bottom and keeps the drill from wandering off center.
The ports can now be drilled in the conventional manner.
I'm back working on the steam chest. I had previously drilled and bores the steam chest for the valve rod. I now need to mill it to the proper dimensions. One edge of the steam chest to the centerline of the valve rod is critical and fussy to measure.
To facilitate the measurement I insert a transfer punch of the proper size into the valve rod port. Using a dial caliper I measure from the edge of the steam chest to the side of the transfer punch and add one half the diameter of the transfer punch.
The next part to be machined is the steam chest cover. How to secure it to the rotary table is the problem. I have not tried this with larger parts and heavy cuts. I use this tape to secure the part.
This is the tape I used. It is sold by Bron Tapes. I have no idea what the tape is called. A machinist friend who told me about it referred to as "Tape From Hell". When I went to the Bron dealer he knew what I was talking about immediately. It is a thin, clear, double sided tape with a transparent red backer. It is appropriately named. The part is removed by soaking with a solvent. The part is applied to the tape and tapped down with a wood block and mallet.
You can stop laughing any time now.
The project is threading the slide valve connecting rod with a 5-40 thread. The only die I could get at the time was a crummy hex die from the local box store. I was not about to also purchase a hex die holder. The drill chuck in the tail stock puts pressure to the die to get it started as well as starting it straight. Actually it worked quite well.
The cover is is completed and the tape held it securely. I clean the surface of the part and the table thoroughly with a solvent. Alcohol works well. I also use the tape to apply parts to the face plate on the lathe.
I get tired of running from the garage shop to the basement to use a smaller lathe for smaller parts. Here I have mounted a three inch four jaw chuck from a Unimat 3 in a six inch chuck. I am indicating the piston rod yoke for drilling.
The piston yoke has been drilled and is now being tapped for the piston rod.
Now is not the time to screw up the cylinder. Too much time has been spent on it. I am using the pre-drilled back head to line up the holes in the cylinder.
The holes are lined up and the cylinder is being drilled. The other end of the cylinder will be layed out and drilled in the same manner.
This stump used earlier is again used to center the cylinder on the rotary table.
It is important that the slide valve face of the cylinder be perfectly perpendiculat to the base. I am using a cheapie surface plate, square and clamps to locate the cylinder. My surface plate is a polished piece of marble floor tile from Home Depot for five or six bucks.. When I get a contract from NASA I will buy something better.
After lining up the cylinder to the base I use transfer punches to mark the base for drilling. Just a few more parts and the engine will be reay for assembly.
I am using a center finder to locate the pre-punched marks for drilling holes required for mounting the cylinder and backhead.
After spotting the first hole location using the cylinder head for a template I drill the first hole then drop in a transfer punch to hold location and then drill the rest of the holes.
The next step is to drill the holes for the steam chest. I have located the holes in the steam chest and drilled them through. I then mounted the chest on the cylinder using the chest for a template. I drilled the first hole in the cylinder. As I drilled each hole I placed a drill or drill blank in the hole to keep things in position.
I am getting so close. Nearly all parts have been made with the excepton of a couple of fittings and drilling holes for the cylinder wrapper. I have loosely partially assembled the engine. Things seem to be fitting quite well.
Finally Finished!
This project has taken a while but I have finaly prevailed. Other projects and responsibilities have hindered progress but I finally got my priorities straightened out. The engine ran very well first time around. I am extremely pleased.
