Overcrank Single Cylinder Engine

[Brian Rupnow]

Tapping went okay. Now I'm off to build some ends for the cylinder.

 

[Brian Rupnow]

Yowsir,Yowsir!!!----That'll do just fine!!!-----------Actually the piston rod is just a blank peice of rod that I stuck in the hole. ;D ;D

 

[Brian Rupnow]

Time for a piston and rod----

 

[Brian Rupnow]

Here we have a piston and piston rod assembly----Screwed and glued----but not tatooed. And yes, it does have a quite a bit of wobble to it when the chuck rotates. The clean-up machining of the piston will fix that.---Sorry about the out of focus picture.

 

[Jeremy_BP]

The cylinder looks beautiful! I guess the tapping gods were smiling.
Very fast build, at this rate the engine will be done in remarkable time.

 

[Brian Rupnow]

This morning I finished machining the piston to about 0.6255 (when I get into that fourth digit its more good luck and guess work than anything)---added the oil grooves, and faced both ends of the piston a bit "in place" on the rod. I had deliberately made the piston about .040" too long to leave a bit of material for this facing process. I then lapped the piston into the cylinder using some of the lifetime supply of lapping compound which I accumulated when building the Kerzel engine. I noticed that the loctite didn't Loc as much as I had expected. so I took a sharp centerpunch and dimpled the exposed end of the piston rod to keep the piston from ever unscrewing off the rod.

 

[Brian Rupnow]

Now its time to get the valve stuff out of the way---

 

[Brian Rupnow]

It may be difficult to see, but I have completed the steel valve plate that the valve slides against, and the cover plate which is made from a 1/16" clear lexan welders shield. (It is the clear cover that fits over the tinted glass on an arc welding helmet.) Of course there is a large part called the "steam chest" which is not completed yet, nor the actual slide valve itself.

 

[Brian Rupnow]

And now the steamchest---

 

[Brian Rupnow]

I haven't quite finished with the "steam chest" yet, but its close. The only thing standing in my way now is some finish filing on the saw cut edges. I love some of the weird and wacky set-ups I get into with this small stuff. In the picture of the peice standing on end in the vice, I am just getting ready to drill and ream the hole for the valve rod. My general procedure is to lay out the profile on the peice I am going to cut, then set it up in the mill vice, indicate off two edges, and put all the thru-holes and slots in. Then saw out most of the profile on the band saw. The only reason that I didn't cut it out completely before drilling and reaming the hole for the valve rod was that I wanted that long side of the bar to act as a "witness surface" to make sure I got it set up vertically before drilling the hole.

 

[JorgensenSteam]

Brian-

I don't think I could build an engine at that scale.
I don't have the patience or the skill to work at that size.

You build is looking great.
You should be running in no time at the rate you are going.

Pat J

 

[Brian Rupnow]

Thank you for the kind comments, Pat. It does get somewhat challenging modelling at this scale, but at least I don't hurt myself lifting the parts up onto my mill table!!! : :

 

[Brian Rupnow]

I have to build the valve rod now, because in its semi-completed state it will be used as a tool to finish turning the bosses on the steam chest.

 

[Brian Rupnow]

Wouldn't you know it---I also have to make this part as well in order to finish machining the steam chest!!!

 

[Brian Rupnow]

Now this, Me darlins' is why I needed the semi completed valve rod and the semi completed nut to finish machining the steam chest! I left the nut extra long on one side, and left the valve rod extra long as well on the 3/16" diameter end. I inserted the valve rod into the steam chest, then screwed it through the nut. The .094" dia. end was setting in the .094 c'bore in the other side of the steamchest. This allowed me to set it all up in my lathe,use my long dead center in the tailstock with just a dab of lithium grease, and use my cut off tool to machine the round bosses on each side of the steam chest.---The "nut" was my drive dog to transmit torque to the steamchest and make it turn. After the diameters were turned I removed my set-up from the lathe, walked over to the belt sander and ground off the extra long boss on the steamchest (where the tailstock dead center had been). Then popped the other boss back in my lathe and used a file to turn a nice radius on that ground off boss. Now all those bits are finished.---Trust me---They are NOT BIG!!!!

 

[Brian Rupnow]

A few more bits to finish off the cylinder---

 

[Brian Rupnow]

I worked my butt off today-----and its a big butt!!!! I finished all of the peices related to the cylinder and valve. They are only little peices, but there is a lot of work in them. I have to set up the rotary table tomorrow to drill the holes in my exhaust stack. Tomorrow morning will be spent making up oiled paper gaskets for both ends of the cylinder and between all of the various valve plates. Once that is done, I should be able to shift the valve by hand and have the piston travel fully back and forth in the cylinder. If that works out all right, I will post a little video of it. There is no point in me proceeding with the rest of the build untill I know this part is going to function properly.

 

[Brian Rupnow]

Ever since I started this project, I have been referring a lot to the build I did on my version of Elmers 33 mill engine. I have used the identical valve set-up, because it works so well, but have increased the cylinder size from the original 1/2" bore x 1" stroke to 5/8" bore x 1 1/4" stroke. Here is a picture of the new cylinder along with the Elmers 33 for comparison sake.

 

[JorgensenSteam]

Brian-

Its looking really good.

Pat J

 

[Brian Rupnow]

Thanks Pat---Today should be exciting!!!---Brian