Latest 'build' in progress -- Smitty 101

[bearcar1]

Well, after being laid off from work I turned to the shop to pass the time away until employment would come around again and I settled onto this engine. I purchased the drawings about 17-18 yrs. ago and always had it in the back of my mind (I have a mind?) to build. The drawings were inked by a Bob Smith of Scribe and Co. based out of San Diego, CA. The plans are very well drawn and I have not found any errors whatsoever in my examinations of them. However, not being one to leave anything alone, I have made some major changes from the original plans and have more in the works. This engine will become a four column, double acting, upright, with a bore of 1.000" and a stroke of 1.800". It will sport a Stephenson valve gearing arrangement that will be changed by a small handwheel. (at least that is my plan) The brass flywheel is 3.000" in diameter and is 1.250" in width. The original plans called for narrower flywheel than shown and did not call for the outboard bearing block that I added in order to support the extra weight. The crankshaft is a piece of .250" silver steel riding in bronze bushings. The original merely had it running in square aluminum bearing blocks. The next step will be to machine the cylinder and columns and fabricate the bottom cover. There's plenty more to come so stay tuned.

 

[Maryak]

BC1,

Nice start, good luck with the rest of the build.

Best Regards
Bob

 

[bearcar1]

Thank you Bob, I am taking a break for a few minutes here. I pretty much have all of the stock for this engine in my stash of bits and bobs. The valve itself is going to be a 'spool valve' type riding in a bore in the steam chest which I just now realized I do not have a piece large enough to make it from. Drat. It should prove to be an interesting exercise on the lathe as up until now I have really only dealt with the traditional "D" type arrangements that are more commonly used. The bottom cylinder plate calls for being made from a single block of brass but after looking at it for a while I have decided that it would be a whole lot easier as well as more economical to fabricate it in two separate pieces and silver solder them together. So far so good and I will most likely have it erected later this evening, providing I don't foul up somewhere.

BC1

 

[Philjoe5]

Looking good so far BC1 :bow:. I too am starting on an upright, double acting, oscillating rotary valve engine. It's based upon a horizontal engine which I've built. I like the bearing block design you have. What is the overall height of your engine?

Cheers,
Phil

 

[bearcar1]

Here is the progress so far. Like some great skyscraper rising from a a hole in the ground so is this engine taking shape. It is 8.625" in height. Coming next will be the valve sheaves or straps as they are sometimes referred to as, and the eccentrics. I'm planning on using a simple fixture plate in the mill vise to shape the valve straps. Tomorrow is another day.

 

[bearcar1]

Well, This A.M. has been interesting but here are the results thus far. The two eccentric discs and the valve strap blanks have been made. Now my plan is to attach the straps to a piece of Aluminum bar being held in the mill vise using a steel filing button the width of the strap on the small end and a larger version with a shoulder to fit the larger hole on the big end. The idea being to use a .500" diameter end mill and remove metal until the cutter just nips the two steel buttons. Back down to the shop and hopefully I will have been successful in this adventure by this evening.

BC1

 

[bearcar1]

This session went rather well. I was able to finish machining the valve straps as planned as well as the valve plate that will drive the valve rod. The next thing that I think I want to tackle is the conrod bearing. It is a split bearing with a threaded spigot on one end to accept the conrod. After that I think I will move on to the crank webs and get them out of the way and silver soldered up. Enough of this levity for one day.

 

[bearcar1]

Today was a strange day to say the very least. I finished up the Conrod bearing and had brought it upstairs to photograph. The wife wanted to go to the store and I decided to tag along for the ride. Now here is where I went into the twilight zone. We went to the store and had an enjoyable time in the market and upon returning home I went to pick up where I had left off on the engine. BUT! I could not for the life of me locate the part that I had spent the better part of the morning machining up! ??? NOWHERE! NADA! ZIPPO! Nowhere. :shrug: th_bs The *only* thing I can think of is that I must have put the damned thing in my pocket absent mindedly :-[ and went off on our road trip and the piece fell out of my pocket somewhere on the adventure. I was very upset :rant: to say the least but succumbed to the dismal fact that I would have to start over again and make another part. I even had the conrod installed on the thing. Anyway, here is number two for your viewing pleasure. This evening I am going to work upon making the crank webs, at least get them cut out. These will look similar to the counterweighted items found in lawn mowers. I am going to add some cheeks as the originals drawings only call for .250" brass pieces. Now I'm going to go make certain I still have this piece and secure it in a well lighted, secure place, lest it decide to vaporize itself.
BC1

 

[Maryak]

BC1

Sorry to read about the missing part. :'(

It's almost a given that it will re-appear after you have finished making the replacement. ;D

Best Regards
Bob

 

[bearcar1]

One would certainly think that wouldn't they Bob. I have searched literally everywhere for this piece. I even went so far as to sweep and vacuum the rugs and floors from counter to wall, looked under the seats in the car and under the floormats, in the driveway, even went and retraced our steps to/from and inside the stores. That puppy is GONE. If it does show up later I will probably give it a huge heave ho in an attempt to launch it into orbit for all of the aggravation it has caused me. But, if that is the worst thing that happens on this winding road to mechanical nirvana, then I will count my blessings and move onto other challenges.

Today, after wolfing down about a dozen hard boiled eggs with horseradish (and yes they were colored eggs) and returning home from the mother-in-laws stickpoke I was able to get the crank webs layed out on .250" brass plate and rough sawn oversize, to shape. Tomorrow holds the tedious job of final shaping and possibly attachment to the crankshaft, we shall see.

 

[bearcar1]

The crank webs and cheeks are done and boy do my hands ache from filing to final shape. I layed them out and cut them to rough shape last evening from .250" brass plate and the cheeks from .125" brass sheet. The original drawings did not call for the cheeks but I did some initial weighing of the piston which I had made from a piece of bronze, leftover from another project :shrug: and the piston rod and decided that a bit more weight would be a good idea, just in case. I can always either mill material from underneath the cheeks or leave them off entirely if it comes to that but I am in hopes that will not be necessary in the end. Tomorrow is silver solder day and that should prove to be entertainment at its finest. Then it is on to the knuckle that will be used to join the piston rod to the connecting rod. I still need to locate a small chunk of brass for the steam/valve chest as I can see that is going to be a hold up in this project.

Till next time
Cheers

BC1

 

[deere_x475guy]

Your coming along nicely bearcar1 and the parts look good. Good luck with your silver soldering.

 

[Maryak]

BC1,

Nice webs and counterweights. :bow:

Best Regards
Bob

 

[bearcar1]

Gentlemen, I thank you for your words of approval, it is most appreciated and after seeing the work that you fellows do, it makes it that much more gratifying. ;D Tonight I did some initial woodworking and did some gluing up of a base for the beastie. I selected White Oak and at this point am undecided whether to leave it natural and merely seal it or use a slightly darker color wash on it. Decisions, decisions.

BC1

 

[bearcar1]

To further the development of this engine build I silver soldered the entire rotating assembly together today. It went surprisingly well. The original drawings came with a simple method of keeping everything in line by stacking four identical square plates together and drilling two holes in them that match the spacing of the crankpin to crankshaft. These then would be setup on a flat surface several inches apart from each other and rods placed through the holes, capturing the crank webs in the process. I opted to forego this as: 1) I did not wish to sacrifice some good plates in order to do so and: 2) thought of a simpler (for me) method that would be faster as well. I faced off a piece of 1.000" Aluminum round and drilled a deep hole through the center. Then I parted it off into two separate pieces. I placed one of these 'barrels' onto the crankshaft rod followed by the two crank webs followed by the second Aluminum 'barrel'. I found that two .250" cutter bit blanks between the webs shimmed with a small piece of Aluminum can stock (I was afraid that brass or steel would get stuck somewhere I did not want it to be) gave me the correct width I needed for the conrod bearing. The webs had been drilled and reamed to .250", this coupled with the Aluminum 'barrels' kept everything square with the crankshaft and the two cutters were long enough to capture the crankpin and crankshaft together and kept them inline. Several small "C" clamps were used to hold everything firmly in place. I soldered up the crankpin first and let the pieces cool back down. Once this was done I removed the cutter/shim combination and proceeded to solder up the webs, allowing each to cool back down before continuing to the next. This was my insurance that nothing would become overheated and allow a joint that was previously soldered to slip. (don't you just hate it when that happens?) Once it was all cooled down and I could handle it, I chucked one end of the assembly in the lathe and proceeded to take a couple of passes across the edges of the webs in order to assure their concentricity. Then, the piece was affixed back into the bearings and they were then bolted securely to the base. This prevented any unwanted lateral movement from being introduced when I cut the crankshaft out from between the webs. A new blade in the hacksaw did the deed well and a follow up with a sharp file to get everything flush did the trick. Due care being taken not to scar up the inside surfaces of the webs. When I was satisfied with that I found that the conrod bearing was a bit tight on the crankpin and I eased the inside solder joint with a three sided scraper. The one thing that I had not planned on was that the additional cheeks I added would interfere with the outboard columns so I reduced the thickness of both of them by .060" and all is right with the world now. th_wav I have begun to fabricate the 'knee joint' coupler between the con rod and the piston rod. This will be a custom one off part as the drawings simply show those two parts having a flat machined on one of their sides for about .500", in a scissors joint type arrangement, with a bolt securing them together. I really don't like that arrangement much so am going to set about a more substantial set up. Wish me luck.

BC1

 

[cfellows]

Nothing more pleasing than a well crafted crankshaft! :bow:

Chuck

 

[bearcar1]

Yes Chuck, I am rather proud of my crankshaft *ahem* ;D It had seemed a tad bit fiddly at first but as the fabrication sequence proceeded it seemed to naturally start coming together. To this point the engine has been one of the most enjoyable that I have ever built as it has a straight forward and rather simplistic design. Well suited for a shop class type of project or that first engine from barstock attempt. Although if one were to have a look see at the original drawings and compare them to this engine, the only similarities would be in the overall design as I have taken quite a few liberties with this one and changed just about the entire layout other than the column supports and the cylinder, which by the way does not have any trunk or crosshead rails. It utilizes a long spigot as part of the bottom cover that extends down and has an unthreaded cap that is held in place by two, 2-56 hex head screws. This longer fitting acts to guide the piston rod and absorbs the side loads that are placed upon the piston rod while it is in motion. In the end of this spigot a wide countersink hole has been bored and this is where the piston rod packing is wound into. When the cap is torqued down it compresses the packing in and around the piston rod thereby establishing the seal, unlike the usual threaded packing glands that are more commonly employed. This I think is a throwback towards the designs that are utilized by our brothers in the UK on their engines. Today I am attempting to fabricate from scratch the knee joint to connect the piston rod with the conrod. :fan: yum. TallyHO!!!

BC1

 

[bearcar1]

with sweat pouring off his brow like a spring rain he emerges from the depths of the dungeon buried deep below his castle fortress............... Whew! I thought I was living one of those dark novel readers for a moment and then I realized it was all my imagination Actually, I just came up for a bit and to display the progress on the knee joint for this engine. I won't bore you with what has already been said in regards to how this part of the engine is handled but will begin by saying mine started out as a piece of .500" square brass about two inches long. I cut a small bit roughly .750" off this piece to be used as a mating part. I then held the longer piece in the mill vise and machined a mortise slot .250" wide and .250" deep. I then turned my attention to the shorter piece and after setting it square in the mill vise, proceeded to mill off two adjacent sides to form the tenon to match the slot in the previous part. Not terribly difficult but care had to be taken in order for them both to fit and still be able to be axially equal. That is, when I put the two together in preparation to soft solder them back together they would not be offset to one another. After soft soldering them together and a bit of a go on the sides with a file to remove excess solder, it was off to my trusty SB that awaited me along the wall. I don't own any square collets but after this, I am definitely going to invest in a small set of the standard sizes. I centered the whole affair in the 4-jaw chuck and then performed the ritual center drill, followed up with the number drill for the 10-32 threads that were to follow. I drilled just deep enough so as not to break into the connecting pin hole that was yet to be drilled. I also made a small center pop mark on the parts to indicate the common side. (these things come to you sometimes in a flash of brilliance) The next step was to thread the part and turn the spigot that would accept the piston rod. Are you with me so far lads ??? I removed the part from the chuck and turned the part end over and gripped the part by the newly formed spigot and repeated the same steps for this end except I did not turn a spigot but a tapered form that would be a bit more appealing than a square-ish looking edge. After removing from the chuck and carefully laying out the position for the cross pin I placed a center pop on the side of the cajoined pieces using a magnifying glass as this part needed to be spot on center. Now I don't know about any of you but I have in the past used quick set araldite (epoxy) to hold pieces for machining and I did that in this instance as well after facing off the end of a scrap piece of Aluminum rod in the 4-jaw chuck. Once the adhesive had set, I used a wiggler in the tailstock and a DI mounted on the tool post to center up the pieces in preparation of drilling the cross hole. VERY carefully and SLOWLY I center drilled, through drilled, and reamed the pieces to .125". To release the parts from captivity of their quick and dirty 'faceplate' I used a propane torch. The adhesive let go with this persuasion and before the pieces had an opportunity to cool down I applied more heat and separated the two pieces. The following photos show the radius that I am filing on the piston rod piece and have quite a ways to go still. I felt the conrod piece need to be deepened just a tad and did so, I need to clean that up a bit still as you can plainly see. These have been the most labor intensive parts to machine on this engine so far and I'm not done with it yet. Tonight's agenda is more filing and test fitting, followed tomorrow with more fiddling and fitting more than likely. I can hardly wait.

 

[bearcar1]

Today found BC1 picking up and continuing from where he had left off last evening. That was the final shaping of the knee joint pieces. Here I thought that this would be a simple enough process, make up a couple of filing buttons and settle in for a few hours of manual labor, but NOOO! When I got it all shaped and it was looking good to me I attempted to fit it up and immediately found the pieces to be too large th_wtf1 to fit up under the cylinder. Now I have to admit that I had not really given a great deal of thought process into the makings of a one-off knee and had failed to measure the space that was available to me. Well oh boy howdy! I'm here to tell you there isn't a great deal of room to be had. It did not really matter originally as this was supposed to be a simple scissor type joint fastened together with a nut and bolt. Well I went to plan "X" as I had not really made a plan "A" so that meant that a plan"B" would be useless. :shrug: I had to remove about .125" off of the beautiful and freshly made conrod part and then had to turn off the spigot that connected to the piston rod side, as well as reduce the thickness of the shelf on that end. So much for 'custom' work. OK, with that accomplished, I trial fit the whole affair back into place and found that the shelf that I had just recently thinned down was interfering on the heads of the two hex headed bolts securing the packing gland to the cylinder. Now what was I going to do. scratch.gif Well, I took the part to the mill and machined two slots in the shelf to allow clearance. After again fitting the pieces up I found that now the bottom face of the conrod side was brushing against the crank webs. Gimme a break! th_bs I took the whole thing apart, *again*, and proceeded to turn off .025" off of the diameter of the crank webs and once again put it all back together. A test turn revealed that I still had clearance troubles at the inside edges of the web bottoms. Dammit! I remembered seeing full scale cranks having edges that were beveled and decided to try that. Took it all apart *again* and went to work on the webs with a sharp file and after putting it all back together "we had lift-off" as they say in the aerospace industry. Hallelujah! :bow: It all spins quite nicely now but there isn't a great deal of room to spare, maybe .020" on each end of the stroke. woohoo1 I forgot the camera in the shop and do not feel like going to retrieve it so will post some more pics later. I'm going to be shifting gears just a bit and work on the wooden base and nameplate pedestal as I am lacking a small chunk of brass to make up the steam chest from. This will hold me up from finishing the engine portion of the build. Then I have to deal with fabricating the reverse gear mechanism, drag links, idler links, etc. You can bet your bottom dollar, I'll be doing my homework on those as I sure as Hell don't want to go through another day like today :big: Rof} but then again, that would take all of the fun out of this hobby now wouldn't it?

BC1

 

[bearcar1]

I just realized that I had promised more photos for you lads. Here, for your viewing critique, are the latest in this quest for steam power. One thing is certain, digital cameras are SOOO unforgiving in terms of showing quite starkly, every little flaw and spec that the human eye would normally dismiss. Anyway, I had used a rag to wipe off some oil smudges and it deposited all sorts of little pieces that I did not notice myself until viewing these. I apologize for that :bow: I mainly wanted to show what it was that has kept me in a state of th_wtf1 the past few days. Now for those of you who are just not too bright :shrug: yes, that is a small center drill point acting as a pivot pin. I have yet to machine a shoulder bolt to fit. Also, I wanted to show the Oak picture frame type base complete with pedestal for displaying the engine name plate and builder's tag. This will more than likely be all of the photos for a while as I am still in search of a brass chunk that will suit my purpose of machining the valve chest. Until I locate a piece that is to my fancy, this collection of pieces is headed for a place on the bottom shelf, not the top one mind you ;D . I have been busy machining the adjuster that links the reversing plate and the valve, but nothing fancy to report there and that step will be completed in short order. Enjoy (I hope)
Cheers

BC1