Building one of Rudy's steamers

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Deanofid

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Hi all;

After quite a bit of deciding and un-deciding on what I want to build for my next engine, I finally made the choice of one of Rudy Kouhoupt's engines. I've always liked Rudy's work, but have only built one of his projects in the past.
Settling on something to use my free time on sometimes seems to take half an age, for me. I work in the shop most days, but not always on something that is just for fun, like an engine. I usually work from my own scribbles, and having nice prints, as Rudy always drew, is kind of nice!

So, here's the start of the project. This engine is one that was featured in one of his books, and I think also in a machinists magazine. The prints are copyrighted, so I can't put them here, but if you want to build this engine, it's in his first "Shop Wisdom" book. He didn't give it a catchy name, like some builders do. He just called it "A Horizontal Stationary Engine".


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The first thing I'll make is the base and sub base. To start, the ends are milled off square to clean up my hack saw marks. The sub base is thinner and will be a little wider than the base, and both pieces need to be milled to width. Since the sub base is too thin to mill unsupported, I clamped them both together for this step. Being thicker, the base provides extra support needed for milling the two. When the sub base is brought to size, it's removed from the sandwich, and the base is milled further to bring it to the proper width. The piece of scrap metal near the moveable jaw is just for a little extra support for the whole thing.




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When the base has been brought to size, it's time to drill it full of holes. The holes can be laid out using a scribe and straight edge, but I usually find that if I have a lot to do it's better to center spot them all using coordinates on the milling machine. The letters marked on the piece are to remind me of the different hole sizes needed. The X on the left end of the piece is to mark my reference edge.




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Next the base with the spotted holes is clamped to the sub base, and while drilling the holes through the base, the sub base gets its holes spotted at the same time, except for a few that are outside the dimensions of the base.




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Now all the holes that are to be threaded are tapped. I use a tapping block anytime I can, especially when tapping small holes, like 2-56, or even up to size 8. It keeps the tap straight in the hole. Starting a tap crooked is probably the best way to break one. All you need for one is shown in the picture above. Just drill through holes in a disc for the sizes of whatever taps you are worried about breaking, (which is to say, all small ones!).

For aluminum, I use paraffin wax instead of a tapping fluid. It makes a big difference in the tapping effort, which means less torque on those tiny taps that break so easily. Just rub the threads of the tap on it to fill the flutes. Also, it doesn't leave a mess to clean up, like liquid tapping juice.



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Since the next step for the base and sub base is to mill away the contours, the crank throw slot, and the exhaust slot, the pieces will need some kind of support that holds them up above the top of the milling vise, or off the milling table, depending on how you do things. A cheap source of sacrificial packing for jobs like this is wood. Here, a piece of dimensioned poplar is being tapped for screws that will go through the base pieces to hold each one securely to the piece of wood. Most types of wood that are not too soft will take threaded holes just like metal, and they're really easy to tap. As long as the wood will hold the threads without stripping out under moderate tightening, it will work fine.
Wood screws work better, of course, but you can't always find the tiny sizes needed if all you have is small holes in your work piece.




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Here you can see how well the wooden packing piece works. The contours have been milled away in the base.




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And here the crank throw slot has been milled out. When all the milling is done on the two base pieces, the piece of wood can be fly cut to use another day, or can just be tossed in the fireplace. When your jig pieces only cost 25 cents, you don't feel so bad about using them!

Similar milling is done to the sub base, and is basically the same thing as just done here, so I won't show that piece.




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So, here are the two base pieces, drilled 'n milled, and just needing a little filing and sanding to finish them up.

I deviated from Rudy's prints a little out of necessity. The sub base was made from slightly thicker material because that's what I had on hand. The crank throw slots were made square bottomed because I didn't have a large enough end mill to make them fully radiused. If it happens that the crank throw slots need the radius later on for some functional reason, I'll file them out at that time.

Well, that's the start of it. Maybe I'll get a little more done tomorrow. Depends on work...

Dean





 
Dean,

Looking forward to following along on your build. Great start and a super write-up.

Dennis
 
Ditto the coments above. I really like Rudy's engines and he designed at least one of every conceivable type. His set of 10 small display engines c/w display case was most inspired and a great early project. They featured in "Live Steam" some years ago. I have started the horo engine with hackworth valve gear. Will post details when I return to construction. Keep up the good work & I look forward to more of your posts.
Cheers,
 
nice start.
I use the wood idea when cutting plate, or profiling on the cnc, I have been known to set "0" a little low.
(I have a few reamers made from small end mills)
-B-
 
Dennis, 4wheels, and -B-, thanks for having a look. I appreciate your comments.
 
A little more done today;

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The bearing blocks are supposed to be made from 3/8" aluminum flat bar, but all I have close to that size is 1/2", so I'll rough out the blocks and fly cut them to the proper thickness later. Once a couple of blocks are squared up and brought to length, they're put into the mill vise side by side and the center part for the bearings is milled away.





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When the bottom half of the bearings are to size, they are basically just a rectangle with a notch in the middle. The next step is to mill an angle on each end of the two blocks.
The print doesn't give this angle. Instead, it shows the dimensioned points of all the corners of the piece. To me, it's easier to set this up if I know the angle, so I made a simple drawing of the piece and measured it. Then set a simple adjustable protractor to that angle and set the surface of the part that needs to be milled away to the protractor blade, like in the picture above. This method works well for non-critical angles. Of course, the person building has to decide what is critical, and what is not. Usually, decorative angles like this are not.





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Then made a few passes with the fly cutter until the flat that forms the angle met the bottom surface of the lower bearing block. I took only about .015" per cut with this setup so the fly cutter didn't knock the piece out of postion.





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The bottom and top pieces are shown in the picture above. The top pieces are the smaller ones.





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The pieces still need their mounting holes drilled and tapped. The print for this piece shows four 4-40 tapped holes in this piece, two in the bottom and two in the top, all tapped 1/4" deep. Instead of drilling four separate holes, I just drilled two all the way through the piece, since both sets of opposing threaded holes are on the same center line.
When I had the holes drilled, they were tapped the 1/4" deep called for in the print, two from the top, two from the bottom.





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The bearing top caps are much the same as the bottom parts, except they have clearance holes instead of being tapped. There is also a tapped hole in the center of the top caps for oil cups, shown being done in the picture above.

Enough milling for a bit. Next up I'll do a couple of oil cups for the bearing caps.

Thanks for having a look,

Dean
 
Looking good Dean Thm:

Regards, Arnold
 
Thanks for checking in on it, Arnold. Appreciate that!

Was able to do a little more on it today.

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For the oil cups, I turned up a piece of 3/16 brass rod. Note the cutter being used is completely flat on the top surface. It's what you need for cutting brass. The flat top keeps the cutter from trying to grab the brass piece, and makes for a fine finish. It's a standard configuration for HSS cutting tools used for brass turning.





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The end of the piece is threaded 4-40 with a die. This will go into the tapped hole in the bearing top cap.





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Then the piece is drilled through. For tiny bits and a fast spinning piece, peck it like a chicken! Small bits need to be cleaned out often.

This drill bit has been honed just for use on brass. It correlates to the way a tool is made for brass turning, explained above. The very front of the cutting edge is stoned flat, and it will cut brass like crazy and never grab.
If you've ever had a drill bit grab and pull itself into brass, you know what I'm talking about. If it happens on a small bit, it will snap it right off. On bigger bits, it will usually spin them in the chuck. If you dedicate a set of bits for brass, and take the sharp cutting edge off of them, you can feed them into brass almost as fast as you want, and they will not grab. They just cut away, pretty as you please. I have a set of bits just for brass, and have ground the cutting edges on all of them flat using a stone. You can do a set in about 10 minutes.





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Once all the work on this end is done, the piece is parted off. I dropped the first one on the floor, but amazingly I found it!





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The last step on the oil cup is to reverse it and put it in a chuck so I can drill the well for the oil. Again, a drill bit with a honed-flat edge is used.





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There it is. Dirty fingers for scale. Didn't have a quarter handy.




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This is where I end up today. Proper studs and nuts have yet to be made for mounting to the base, and a finish fly cut will be taken on the assembled pieces to smooth up the joints between top and bottom bearing caps.

Thinking about making the bearings and crank next. I have no square stock to use for the bearings, so I'll have to cut squares out of round stock. Maybe tomorrow.

Dean
 
Nice Dean. Nice pics and tips.

I'm interested in the tips about drill bits and brass but I'm still very new to jargon and methods. Can you tell me more about how you modified the drill bit for brass? When I look at the pic of the drill bit...I can't tell what you did.

Also, I was reviewing your thread. The first pic of the post on bearing blocks shows an end mill roughing out a large groove. I'm learning about milling. Did you cut that at depth? Or take several passes to get there?

Thanks.
 
zeeprogrammer said:
I'm interested in the tips about drill bits and brass but I'm still very new to jargon and methods. Can you tell me more about how you modified the drill bit for brass? When I look at the pic of the drill bit...I can't tell what you did.

Hi Zee. Thanks for having a look and commenting on the thread.

You can't see the difference in the pic of the drill in the post above, but I took some close-ups of how to do it, and what to look for.

stockdrill.jpg


This is how a stock drill bit looks on the end. It comes to a very sharp edge where the bit cuts metal (arrow). That same sharp edge that cuts steel so well will also dig in hard in brass and suck the bit into the work.



stonedrill.jpg


To take that sharp edge down, you run the cutting edge of the bit along a honing stone. The idea is to make it flat, which is no good for cutting steel, but cuts brass very well, and stops the grabbing problem. Run the bit in the direction of the arrow towards you, honing in only one direction. It usually takes 3-5 strokes to get the sharp edge off and condition it for brass cutting. (I realize the arrow has two heads, but hone the bit in only one direction.)




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When you are done it will look like this. The shiny part you see is where the sharp edge has been honed down flat. It only takes a very small flat to be effective.

I mentioned that I have a set of bits done this way, but once done, they won't cut steel like they used to, and should only be used on brass. You need more than one set of bits if you're going to do this. One for steel, one for brass. Keep them separate from your other bits.

The milling cut being made for the bearing blocks was done in about four or five steps. It's 3/8" deep. My milling machine is small, and while it will take that full cut at once, there's no use in working it that hard. Also, when cutting to a measured depth, like in this shot, or for cutting a pocket, you want to kind of "sneak up" on it so you don't go over your mark. If you take it all at once, you might go too deep.

Dean
 
Nice work, and thanks for the info on drill bits for brass. I have always had that problem of the bits grabing while working with brass, now know why and how to fix it.

JimN
 
Hi Dean,
Nice tips - nice engine - keep it up.
Cheers,
 
Jim, -B-, and Brian, thanks much for looking in on it. I appreciate your comments.
I have a few more to put up tomorrow, then have to get at the paying jobs. You know how it goes.

Dean
 
Thanks very much Dean. The pictures showing how the drill bits are done were great. I was surprised just how grabby drilling brass is, so this is very useful to me.
 
You're welcome, Zee! I'm pleased if you found something useful there. Was just a little tidbit I learned from a clockmaker years ago. A nice old gent who didn't think he "owned" his tricks.

Just a little more progress today. Spent a silly amount of time turning round stock into square, but it's all fun 'n games.

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This is the piece I started with to make some square stock that will used for the bearings.
I have quite a few pieces of various sized brass round stock that I got a few years ago from a screw machine shop. If I remember right, I got two five gallon buckets full of drops for about $25, and all of it is round and hex stock. If you need short pieces of brass, aluminum, and sometimes 12L14 or 303 round or hex, a screw machine shop is a good place to look. The auto chuckers they use won't feed the last few inches of stock from a full length, so it ends up in the drop box and is recycled. Even if you pay recycling prices for it, or a little more, it's still way cheaper than buying from a metal supplier. Consider that the 3/4" square stock I needed for the bearings is about $2 an INCH if purchased from a web supplier.





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And this is what I ended up with a while later. A 3/4" square piece. Took a while, but sometimes you have to use what you've got.





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After cutting off a couple of pieces for the bearings, they will be put into the bearing blocks.





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Then the block and bearing assemblies are fly cut for an even finish. I had left the aluminum bearing blocks a little over sized when making them earlier, so I could remove a bit of material from the sides in this step.





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And another progress shot. Soon, I'll bore the bearings and start work on the crankshaft.

Dean



 
That's looking good Dean Thm:.

Regards, Arnold
 
Bugger looking good..... that last pic is just downright PRETTY!

:bow: :bow: :bow: :bow:
 
Arnold and Artie, thanks much! Glad to have your comments.


Today started out as crankshaft day, but I petered out before I got it done. Cut out the pieces, and of course, the only flat stock I had to make the crank throws was way over sized, so spent a lot of time milling them down. From 1/4" x 1" CRS flat bar down to 3/16" x 5/8 for the size of the throws.

I took pictures, and had witty banter all made up, but when I went to put the pictures on my computer, the flash card blew a gasket, (or whatever it is they do that makes them quit working).
So, all I have is a couple of pics to share. Oh well. It saved you all from the banter.

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These are the crank throws, done except for a little finish work. The holes have a bevel on one side only. The smaller hole has it on one side, the larger hole on the other, to let the solder form a little fillet when the shafts are soldered in.




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Here's the stuff to start the next session. Maybe tomorrow. There's always a "maybe" or a "tomorrow" in there somewhere...

Dean
 
Sorry Dean. I'm not impressed. Now had that been a 'tan' M&M...well!
On the other hand...had it been a 'tan' M&M...I might wonder why you still have it. :big:

Thanks for explaining the bevels..I was wondering about that.
 

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