Mark's Build of Rupnow Vertical IC Engine

[mjonkman]

I have started my build of the Rupnow Vertical IC Engine. Figured I'd start my own thread to cover my build vs adding to Brian's thread. It will probably take me a lot longer to build then Brian took.

I ordered most of my materials from McMaster Caar - the cast iron bars as well as the rectangular aluminum stock - downside is have to buy 1ft most of the time. I also purchased the bushings from McMaster though they are a little longer then required by a 1/16" in most cases. I figure it was pretty simple to just face off the end to get the right length. I think they were between $0.50 and $0.60 a piece - so I got a couple extras just in case I screw up

I figured I'd try and do the head first - figuring if I could accomplish that I'd be able to get the rest of the project built. To be honest it took me 3 attempts to get it right. The first one got majorly delayed when the head of my Bridgeport seized up and required a rebuild. While it turned out that the actual cause of the "seizure" was a dog point set screw for aligning collets had been removed by a previous owner then placed in behind another set screw to fill the hole. It worked loose and had been slowly rubbing off and when I had the mill running at high speed it fell out and jammed between the spindle and spindle nose. Once I got the mill back up and running this past weekend, I managed to ruin the first head. I was completely fixated at entering the bolt hole pattern into the DRO and didn't realize that I was 90 degrees out on the start of the first hole. So you guessed it the bolt hole circle was not in the correct place. I also missed the counter bores for the valve piece when I was doing the bottom of the head. The drawings are pretty busy, one really needs to concentrate on reading the fine print (not mocking the drawings - just a complex piece with a lot of information in there)

The second attempt suffered from me trying to be cheap - using only the barest minimal size to hold in the lathe and then attempting to part of the extra 1/2" of material after completing the first end. Figured hey, 1/2" of 2" aluminum bar that could be used for something else. So I thought that I'd part it off. Not wanting to leave chuck marks in the work piece it wasn't super tight in the chuck.... dumb, dumb dumb - parting tool grabbed and ripped the piece out of the chuck. Hangs head in shame.

The third time was a charm. It did get a bit hairy at the end. I don't have an angle vise so I had to think of another way of cutting the angle. I also don't have a chuck for my rotary table though I do have one on the end of my indexing head but that creates a very tall stack. Tall means less rigidity. I simply used a v-block with the head on parallel to drill and counter bore all the holes on both sides. Then I used a left over piece of round stock with the 3 holes drilled and tapped to hold the head. I then tilted the Bridgeport head appropriately and machined off the angle area. Not thinking ahead, I didn't take into account the amount of clearance needed to move the table to the left to get access to the tap drill bit required for the 10-1 mm tap. With the vise in the middle of the table I ran out of left travel, not wanting to reset the vise etc I simply loped off the drill bit and resharpened it. It got the job done, hole is drilled and tapped. In hind sight, I probably could have held the drill bit in a 3/8" collet and not needed to cut it off - I thinks only a 1/64" less then 3/8". I always think of the easier way - after the fact. I did make one minor mistake when I drilled the hole for the spark plug I went through and hit the other side of the slot (see last image). I don't think it will harm anything.

Some valuable lessons for myself. Really wished I hadn't screwed up on that second head but learned its better to just sacrifice small pieces instead of trying to save a few cents. Better to think twice and double check all the operations before committing to a setup.

Thanks Brian for providing the drawings. Looking forward to building out more of this engine.

Looking for a bit of advise as well. My thought on doing the main body of the engine was to square up the ends of the aluminum. Put in all the holes and so forth ending with drilling the 1" holes. Then go over to the bandsaw and removing the bulk of the waste and then back to the mill to finish up - am I being cheap or should I just mill the excess away?

 

[Brian Rupnow]

Mjonkman--thank you so much for starting your build thread. Please edit your profile so that the location of where you are in the world shows up when you post. That head is a real trick pony. It looks very simple, but as you have found out, there are a lot of "traps" in there for the unwary. I'm not exactly sure that I understand your question about the frame. If you look at the build thread I have on it, you will see the different steps I took and the sequence of machining of the main frame in post #81. I started with a rectangular block, put in all of the holes including the two 1" holes in the face, then walked out to the bandsaw and carved away as much material as I could, then back into the mill to "finish" the saw cut sides will an endmill. ---Just a word--I never mill away material that can be cut away on the bandsaw. I always do 90% of my material removal with the bandsaw, and clean up the sawcut surfaces on the mill. This saves an incredible amount of time. ---This is great to see you building my engine.---Brian

 

[mjonkman]

Hi Brian, your answer was what I was looking for in terms of using the bandsaw to cut off the excess. One of those nervous twitches in thought process after blowing things up with my second attempt at the head under to goal at that time of trying to save a bit of material (and of course time, mess etc). I'll update my profile.

Sincerely
Mark R. Jonkman

 

[Brian Rupnow]

Thanks for the update to your profile, Mark. It is always good to know where folks are. I can phone anybody in continental USA or Canada if they get in a bind and need some one on one help with their builds. I can't offer that assistance to the guys in Australia or New Zealand, but they are a pretty sharp bunch down there, and seem to build the things I post without any assistance.---Brian

 

[mjonkman]

This past weekend I worked on the frame of the engine. I'll be honest, this was far more challenging then the cylinder head in my opinion - but maybe its just the shear amount of machining hat needs to be done.

I started with a block of 2"x5" aluminum, cutting off a 4.25" length. I actually bought the large block of aluminum as well as the chunk needed for the cylinder mount plate from OnlineMetals not McMaster Caar as stated in my first post.

I faced the ends of the work with a long reach 4"+ x 3/4" end mill to get them roughly square as my bandsaw left an angled edge. I was really testing to see how the mill would cut with new bearings and a really long end mill - got just a little bit of chatter but otherwise remarkably smooth square cut. However I used a face mill to properly flatten and square up the work piece on all 6 sides bringing it to final thickness and height but leaving almost a half inch extra on the width planning on removing that later and keeping the excess as part of the scrap removed from the right side.

 

[Brian Rupnow]

Thanks for the update Mark. My thoughts on the frame were that it wasn't technically complicated like the head, but it certainly had a tremendous amount of work in it.

 

[mjonkman]

After squaring up the stock I laid out the major features using blue layout dye using the bottom left front as my 0,0. I then drilled and tapped/reamed the 4 holes on the front. I bored the blind hole for the bearing using the boring head, stupidly starting from the .404" dia hole and increasing to ~0.875". I'm going to be honest, I've hardly ever used the boring head and the few times I have used it have been on "rough" holes that just needed to have the bore increased. I struggled a bit with the blind hole. As I approached the final diameter, and started taking lighter cuts, the boring bar I was using tended to start pushing a ridge of aluminum forward - like an uncut ring while still cutting. This tended to cause some chatter as well and kind of messed me up. I took a real light final cut with a very slow feed rate hoping to minimize that "ridge" and avoid chatter - which it did quite nicely *except* I didn't account for the spring in the cut and blew past the final diameter by a .003". Instead of a light press fit I now have a sloppy fit. Instead of dwelling on it, I just continued to increase the hole diameter till it was about .005" less then 1" and made a press fit bushing to go into the hole. I bored the inside diameter of the bushing for a press fit for the bearing and a fairly tight press fit for the outside. I installed it and for safety added some green locktite. The more experienced will know my mistake, that fairly tight outer fit affected the inside diameter after pressing in and what was a slightly more then light press fit is a really tight press fit for the bearing. May need to bore out a .001" or so. Lessons learned. I finished up drilling and tapping all the required holes as well as the 1" diameter (0.5" radius) for the vertical to horizontal edge interface on the two sides. I step drilled to 31/32" and then I used a 4 flute 1" end mill to finish to 1". I did it for 2 reasons - my 1" harbor freight drill bit has seen better days (its actually been twisted on the shank) and I find I can get a much nicer finish using an end mill to plunge cut to the final 1" diameter. Probably broke some machinist rules on that one but it worked for me and the finish of the hole was extremely nice.

I flipped the part over, picked up the same two edges and moved over the other side of the .404" hole and then double checked center with the coaxial indicator - it showed less then a 0.0005 off center. This time I bored the bulk of the hole with a 3/4" end mill to the 0.313" depth and finished off with the boring head. Being far more cognizant of doing a lot of spring cuts near the end. Had a similar problem with the lighter cuts pushing up a ridge (which didn't occur when taking .025" off the diameter -0.0125 depth of cut). Only when taking 0.0025" depth of cut. But after some fiddling it worked out pretty nice and the bearing is a light press fit, I can push it half way in with my fingers.

 

[mjonkman]

With both front and back features completed - those that required drilling, tapping or reaming. I drilled and tapped the features on the top of the frame as well as those on the bottom.

Then I used the bandsaw to cut off the waste on one of the two sides, leaving about 1/16" - 1/8" of material to clean off after. I just did the one side thus leaving one side that was still parallel and true. That way I could just put it back on the mill and use the 2" face mill to clean up edge down to its final dimension. For some reason I opted to do the side with the extra waste (0.5" I had left behind in width originally). Then had to go back later when I did the second side and cut that off on the bandsaw and bring the base to its final width of 4.5" wide.

Then back to the bandsaw to cut off the second side's waste and brought it down to final dimension with the face mill. I used the radius as my guide to coming down to final dimension as well as using the depth micrometer from the far edge down to side of the vertical to make sure that it was correctly dimensioned. I had to go in an extra .002" to pick up the radius. Thus the final dimension of the vertical section of the frame is about .004" narrower then it should be - but I highly doubt that will affect much.

Then I face milled the two sides of the horizontal section at the same time resting the bottom of the frame on parallels.

 

[mjonkman]

I had to go to DC for an interview with a government agency so I had to take the day off of work, which gave me the opportunity to finish the frame this afternoon.

I started by drilling and reaming 2 - 5/16" holes to create the radius on the bottom of the slot that runs through the middle of the vertical part of the frame. The reaming was only because I wanted a better finish then the drill bit gives. I then chain drilled the bulk of the waste out of the groove coming in from one side of the frame step drilling up to 1/2". At one point Mickey Mouse made a short term appearance

Then I switched the frame to a vertical orientation and used a 1/2" rougher end mill with a 2-1/4" cutting length to clean out the bulk of the remaining waste - going down in 1/4" steps from the top to the bottom of the groove finishing the bottom with a few light cuts to final depth. Then I backed out the end mill 0.156" vertically and carefully worked the two sides of the groove down to about 0.030" undersized on either side. Switched to a long reach 5/8" end mill which had a 4" cut length - way too long but with light cuts was able to finish out the sides to final dimension. I didn't have a 2" reach 1/2" end mill so I was kind of stuck on using the long reach one with light cuts I got a pretty nice finish. I was worried that the vertical portions might be too springy but it worked out ok. And the frame is finished. I hope I'm not too long winded in my explanations and/or posting too many pictures.

 

[Cogsy]

Picture amounts and explanation lengths seem just right to me. Looking good so far - I'll be following along (and wishing I had the time to be working on mine).

 

[Brian Rupnow]

You did good, Mark!! Now I'm going to give you a hint. I always bore my bearing pockets .001" to .003" oversize on diameter. That's because it is almost impossible to flip a thick piece over and pick up the hole from the off side and still get things perfectly concentric. After all the machining is finished I take a piece of cold rolled shaft that I know the bearings will fit onto, put a skim of green Loctite around the i.d. of each bearing cavity, pop the bearings into place, then immediately insert the piece of guide rod thru both bearings. The bit of clearance between the outer diameter of the bearing will let the bearing "tip" a bit in the housing, the guide rod will ensure perfect concentricity with no binding, and when the Loctite dries the guide shaft can be slid out, leaving the bearings perfectly concentric.----Brian.

 

[ZebDog]

I agree pics are always good and explanations are great on how you encounter and resolve problems. Keep up with the good work I will be following this build

 

[Herbiev]

Making good progress there Mark. I love Brian's idea of getting the bearings concentric

 

[mjonkman]

This weekend I worked on the cylinder mounting plate. I began by milling all 6 sides square to each other - taking a skim cut off the surfaces - at least my 1x2 aluminum bar stock was about .012 wider and .01 thicker then 1x2. So squaring it up and cleaning the extrusion marks out and other nicks and dings is where I generally start.

I love the DRO and being able to put in all the locations for the holes that need to be drilled, reamed and counterbore. I like to say I'm so good that I can punch in all the numbers into the DRO and never make a mistake Ya right. Therefore I've decided that from here on out, I will always do a quick layout with dye and the 10 min at the surface plate to make sure that I have something to double check my DRO values against. Won't say why

I did things in a little different order then Brian did. I basically skipped doing any of the boring of the right end on the mill. I did it all on the lathe.

So I started by spot drilling all the holes on the top. Then I drilled the 5 holes on the left end with an H (0.266") bit, then reamed the 5th hole as per the prints. I don't own any counterbores and thus I switched out to a 5/8" end mill and counterbored that hole. Then switched out to a 7/16" end mill and counterbored the other 4 holes. I proceeded to drill the bolt hole circle with a #18 drill bit and drilled and reamed a 1/4" hole in the center of the bolt hole circle.

The reason for the 1/4" reamed hole is I will use that to setup on the rotary table to get it centered.

I flipped the part over, played out the slot on the back and then milled the groove in the bottom. I started with a 1/4" rougher and finished with a 5/16" 2 flute end mill.

I pulled the vise off the mill and setup the rotary table. To center the rotary table quickly I have a slug that I turned that fits into the bore of the rotary table and takes a 1/4" pin. I put the pin into the 1/4" collet and when I can easily slide it into the 1/4" hole in the guide slug in the rotary table then I'm pretty close to being dead on center. after centering it that way, I threw in the coaxial indicator, it was <0.0005" off center. So its a pretty accurate means to quickly center the table under the spindle.

I mounted the workpiece using the same 1/4" pin and alignment hole I drilled and reamed earlier. Then using a 1/2" fine tooth rougher I milled the radius on the end of the part. I only worried about the outside radius. The finish from the fine tooth rougher was fairly decent so I simply stayed with that.

I finished the part on the lathe. I put on my 4-jaw chuck on my SouthBend Fourteen. It has a huge Buck 4-jaw chuck that comes in handy at times like this. Again I used the 1/4" pin held in the drill chuck of the tailstock and the 1/4" hole in the work piece to quickly center the workpiece with the 4 jaw chuck. Again I double checked it with the coaxial indicator and it was pretty much spot on. Did a really minor adjustment on that. I put smaller pieces of aluminum between the jaws and the workpiece to prevent marring. I had a piece with a radius on it that I put against the radius end but that was simply because it was sitting there.

I then drilled out the center hole to about 1" stepping through a series of smaller bits. I finished up boring the hole to size with the boring bar to 1.375". Then I widened out the hole to 2" for the first 5/8". The lathe worked perfectly for this operation. I could take reasonably decent size cuts so it went really fast. The concentricity from the center hole was really close. I think I got it to within about 0.005 all the way around the radius before I finally broke through. I worked better then I thought it would.

The whole reason I did it different then Brian was because I wanted that 1/4" hole to align on the rotary table and to use the same alignment for on the lathe.

I had planned on doing the cylinder today but my wife came home yesterday aft with a flyer someone shoved into the mail box that said there was an estate sale 5 houses over and around the corner. I went there after church this morning and saw an old beat up Kennedy box in the garage and some toolbits scattered around it. Asked the young man conducting the sale what he wanted for the whole mess figuring on doing some negotiating - he wanted $10. But for the $10 he wanted me to take everything and by that he reached down and flipped a tarp over that had probably a hundred carbide end mills, 50-60 reamers, carbide burrs, taps, and well basically 3 - 5 gallon pails of tooling. I tried renovating higher and finally I just shoved $40 in his hand. He would go above $25. Still felt like a thief. So I spent the better part of the afternoon sorting the stuff and putting things away. Apparently his father was a tool and die maker that did a lot of work on satellite stuff and a lot of tiny work. There seems to be a lot of little tiny burrs that maybe used in some form of grinder about the size of a dental grinder??

Not all the end mills are sharp but I'm pretty sure I got a lot more than $40 worth of stuff. Now I got yet another Kennedy box to figure out what to do with. Just gave my son (apprentice machinist) 2 of my Kennedy boxes because I didn't have enough room and my new work bench is solid drawers and thus holds most of my measuring instruments. This one needs some new felt and a bunch of cleanup and a new top handle.

Here are the picts.

 

[mjonkman]

Here are some more pictures including some of the estate sale stuff. I think the young man was just happy that someone wanted and would use the stuff. He was planning on throwing the whole works in the garbage at the end of the day.

 

[Brian Rupnow]

Looking really great, and a great buy on the toolbox and all the bits.---Brian

 

[mjonkman]

I wasn't able to get anything done this weekend - life got in the way I guess. I had to do a brazing demonstration at the high school on Friday and I have a young man that comes to my place every Friday for 5-6hrs to learn how to use machine shop equipment. In return for me doing a brazing demo, they taught him to run the CNC plasma cutter and he got to cut a nice little mountain scene.

We finished the gyroscope that Clickspring on YouTube designed on Friday aft and he would like to try and build this engine as well.

He is on a "gap" year between high school and college and his dad told me he is planning on going to China in Feb for a immersive language program. So that gives him only 5 months, one day a week to build the engine. Trying to figure out if that is enough time. It would most certainly give him a huge amount of experience on a wide variety of machine shop equipment. To give a little more backstory, he's been accepted into a program at a STEM (Science Technology Engineering and Math) heavy college/university that likes to do a lot of hands on. They have a big machine shop at the college and he has had no exposure to tools in high school so he wanted to learn. So his dad (my boss's boss) asked if I'd show him the ropes. This isn't a paid thing, I just do it because I like showing young people how to use tools - even though I'm not an expert -> my full time job is writing educational software for elementary age kids.

Brian I'd be interested in your take as to whether it wise to attempt this engine with him or find a simpler project. Or if there is a simpler engine that still gives a good broad spectrum of machining techniques that might be more suitable. The gyroscope project was largely a lathe project. I also need to let go a bit, I've been mother henning him - watching his every move and making sure he doesn't mess up.

 

[Brian Rupnow]

I designed and detailed and built and ran the engine in less than 30 days.--But then, I had 11 other i.c and 12 other steam engines "under my belt" previously. The only other "simpler" i.c. engine I know of (and it's not really that much simpler) is the Webster, which is a free plan download from the internet. I do have a great set of plans for a beam type steam engine I could send you, that runs on compressed air, and is simpler than an i.c. engine. If the kid is really a "new guy", and only has 20 days available to complete this engine, it will be pretty questionable if there is enough time to complete it.---Brian

 

[mjonkman]

Thanks for the feedback Brian.

 

[Herbiev]

I shall be following in your footsteps today on the building of the frame. Thanks for the pics and great write up. It shows what works well and also points out some risky areas to watch out for. If mine turns out half as well as yours i shall be a happy chappy.