Mark's Build of Rupnow Vertical IC Engine

[mjonkman]

Herbie

Thank you Herbie, I was quite happy with the way the frame turned out overall. Though I did realize that I did make one mistake that I didn't catch until after the cylinder support was made. There is a pocket for the head of one of the screws that holds the cylinder onto the cylinder support and somehow I misread the location and its off by a good chunk. Nothing major I just have to redo the pocket and probably make a little plug to fill in the original hole so that I don't see it every time I look at the engine (its hidden so no one else will ever see it except me and I'm kind of a perfectionist... and seeing the extra hole will bother me to no end. Not enough to want to remake the piece as that would be a huge undertaking but enough to want to plug it and make it sort of "disappear".

I'm really waiting for the day that I actually make one complete part for this engine without making a mistake. This is by far the most complicated thing I've ever built but I'm not used to making so many mistakes. Maybe I can blame it on the heat and humidity.. its been like 105+ degrees with high humidity around here most of the days I've been working on it in my non-air conditioned shop

 

[Brian Rupnow]

Mjonkman--don't beat yourself up too bad. There is a LOT of information crammed onto those drawings.---Brian

 

[Herbiev]

Im blaming all my mistakes on the cold . Hovering around 14 degrees Celcius here.

 

[Brian Rupnow]

I make mistakes when working from my own drawings. On some of these parts, it really is a case of "information overload". I find that it helps to use a highliter to highlight every dimension that has anything to do with ONE particular machining operation. You can use two or three different colours of highlighter for different machining operations, and if the print gets too messed up, run another print. Paper is cheap. Never trust your memory.--EVER!!! Before you move the mill table for your next cut, look at the drawing. I have been burned more times than I care to talk about by "remembering" what the drawing said when I looked at it for the previous operation. I know it probably sounds strange that I can screw up the machining on a part that I designed, but trust me---"Designing and detailing" parts and "machining" parts are two totally and distinctly different operations. When I get up from the computer chair and walk 5 feet into my "machine shop", I never try and remember the dimensions of a part I have just designed. I print it out and take the print with me, and work exclusively from the print.

 

[Brian Rupnow]

Mark--Have you hit a bump in the road? I check daily for news of an update.---Brian

 

[mjonkman]

Hi Brian

The only bump in the road has been in time. I've done a lot of work for my job on the weekends in order to be able to take a week vacation next week - funny how it is, you can take a week off using your vacation days but just make sure that you put in enough work so that everything is still done as if you didn't take time off :-(

I did do a bit of work on Labor day weekend and then didn't get back to it till yesterday. I'll update my build log tonight.. lots of pictures at least of some operations.

 

[mjonkman]

The high level overview to bring ya all up to date. I had a little bit of time on the Labor day weekend to get some work done on the engine. I was able to create the cylinder and the crankshaft. However I was too aggressive with the hydraulic press when I pressed in the crank pin and I actually bent the pin. It didn't go in cockeyed, it went in straight and then when I gave it one last little bit it started to bend over - I was quite disappointed. This past weekend I was able to make a new crank pin and press the old out and the new in without incident. I also made the connecting rod and started the piston. So that is where I'm at as of 9pm last night. Now for the details.

Cylinder

Being a bit of a cheap person, I didn't want to cut off a chunk off my 12" long cast iron bar to make the cylinder and while my lathe is a fair sized - South Bend Fourteen, its not big enough to slide the bar into the spindle. So I carefully set it up in the 3-Jaw chuck and got it running fairly true. It was held quite solidly, I faced the end off lightly and then center drilled and put the tail stock center in to support the bar. Then I took a light cut to true up the outside diameter far enough back to install my steady rest. While I didn't need the steady rest to turn the outside I wanted it in place so that I had extra support while running the parting tool to cut the fins as well as doing the initial boring using drill bits. I realize I could do all the boring after parting off the cylinder but I liked the idea of doing the drilling while it was still intact and I could torque down on the chuck and not worry about marring the surface finish.

I second Brian's statement about the stress/cringing while cutting the grooves using the power feed - worked extremely well. Stupidly I made a slight mistake - my lathe is direct reading (diameter vs radius) and I calculated the depth of cut as radius and thus only made the grooves half the depth. However I realized the mistake on the last groove and just reversed the steps backwards to recut all the grooves to the correct depth. To cut the grooves I used a dial indicator against the saddle to move accurately on the longitudinal axis - keep the spacing uniform. I was exceptionally happy with the results.

I rough bored the cylinder to the appropriate depth by step drilling to about 7/8". Yes I could have gone closer to 1" but I erred on the side of caution - at least in my opinion. Once rough bored I decided to cut the cylinder off on the bandsaw as I was getting some harmonics on the lathe. Having snapped a blade off on the cylinder head I'm a little gun shy on the parting tool.

Once the cylinder was cut off from the raw stock I set it up in the 4-jaw got it running true. Faced the cylinder to length and turn down the shoulder and then bored it out to 1". I don't have a 1" reamer and I was reluctant to purchase one (cheap again). I bored it with the largest bar I had the fit the hole and then used a brake hone to lightly hone it and knock off any tool marks. I managed to bore it fairly true <0.0005" taper at 1.000" inside diameter. My neighbor - auto mechanic and funny car engine builder for the past 50+ years liked the internal finish of the bore.

Then it was over the mill and drill and tap the holes for the cylinder head and attachment to the cylinder support.

 

[mjonkman]

With the cylinder made I started work on the crankshaft.

I started with a piece of mystery steel - probably 1018 that I faced off and then machined to final diameter and finally cut off in the horizontal bandsaw. Then I faced to final thickness. Sorry didn't' take many pictures of that process.

Once complete I set it up in the vise on the vertical mill. I supported it on 2 parallels and a v-block.

I drilled and reamed the center hole to spec and then the crank pin hole. I then drilled and reamed the two radius holes for the main throw / counter weight. Reamed because I like the finish over the drill plus I planned on using dowel pins in these holes on the next setup.

After completing these two holes I realized I didn't have dowel pins but found a broken end mill and by the looks of it a broken reamer instead. The goal here was to use these two pins along with my small parallels to set the piece upright in the chuck and be perfectly level. Then I could remove the pins and the parallels and have everything setup correctly. I then milled the waste area away with a roughing end mill and cleaned up with a 4 flute carbide end mill.

I turned the crank pin (sorry no pictures). And created the main crank rod and cut the key seat with an end mill.

I polished the crank throw as best I could with varying grits of sandpaper until I was happy with the surface finish.

I then assembled it and gave it a bit too much of a press and the end result was a crooked crank pin !@#%.

 

[mjonkman]

I remade the crank pin and pushed out the old with the hydraulic press and carefully pressed in the new one. I didn't take any pictures.

I then started on the connecting rod. Cut out the rough size - bigger then required but honestly I should have gone wider as you will see later.

I squared up the two long edges and got them parallel and squared of the one end. I drilled and reamed the two bushing holes on the two ends. Then drilled and reamed the four holes for the radius between the straights and the round ends. As you can see if I had gone wider I would have been able to drill and ream all the holes instead the last 2 had to be cut with an end mill. But there was just enough meat there to hold the two dowel pins I wanted to position there.

Using these two dowel pins and my small parallels I was able to set the angle cut up as a flat cut on the mill without any screwing around with angle blocks, sine bars or any of those fun to use items. Then I just milled to the scribe lines and radius bottoms with a 1/2" end mill. Wash rinse and repeat on the other side.

Then I turned two guide pins that fit the two bushing holes. The 1/4" ends fit a plug in the top of my rotary table. So after setting up the table on center I simply popped in the appropriate guide piece, a sacrificial plate. Attached the connecting rod and clamped it down. Then using the offset for the two holes I was able to simply cut the radius in a few passes. Wash rinse and repeat on the other end.

After some sanding and light filing/polishing I pressed in the 2 bushings. Only to realize that I should have tested the bushings on the crank pin. It was two tight of a fit - ie it wouldn't go on. So back to the lathe, setup the crank in the 4 jaw chuck and spun it up and used some emory cloth to polish up the crank pin and reduce it by half thou for a good fit. Lesson learned check the stupid fit before you take it off the lathe in the first place

Finally the engine showing all the parts made to date.

 

[mjonkman]

Finally I started on the piston last night. I turned it on the lathe, boring the main skirt, finishing the outside diameter to just about 1.001". I then polished with emory cloth to get it to being in the bottom of the cylinder and be a light press in the top end of the cylinder (remember cylinder as a few tenths taper from boring). I figure I can lap out the taper - at least that is my hope.

I cut the groove, parted it off in the lathe and then faced to length. Both ends of the piston will enter the cylinder with limited pressure.

And that is as far as I got on it.

 

[Brian Rupnow]

Great work and great write up Mark. Thank you.--And if it's any consolation, I too have fits with press fits!!--What is your plan for the gears. I have a couple of guys in Australia building this engine, and they are having a rough time with the gears. It seems that all or at least most of the gears over there are MOD style gears, and nothing matches the DP gears that this engine requires. Are you making your own gears or buying a set and modifying them to suit?--- Brian

 

[mjonkman]

My plan is to make them myself. Bought the gear cutters a couple months ago from Travers.

The folks in Australia might look on eBay for cutters. There seems to be cheap sets - the problem I had was they are all metric bores and my horizontal mill spindles are all imperial sizes.

Mark

 

[mjonkman]

I finished up the piston a week or so ago. Basically held it in a 5C square block collet holder. So that i could machine the slot for the connecting rod and bore the wrist pin hole perpendicular to each other. I had to trim the connecting rod bushing to the proper length and give the connecting rod a light lapping - 420 sandpaper on my surface plate in order to get it to move smoothly in the slot.

I have not yet lapped in the piston to the bore of the cylinder - haven't quite gotten up the nerve to do that yet

Last weekend I had to make a table top out of ash for a young lady who lives around the corner from me, so that took up most of my weekend.

I did some work on my home foundry this week. I built a crucible lifter/ pourer for my A12 crucible - similar construction to Myfordboy's version (see on youtube). I've also made my first official casting pattern and will hopefully cast the flywheel out of bronze. This will be a lot of firsts - first real pattern, first use of the lifter and first melt of brass/bronze and first real part cast. I've broken down and melted about 50 small engines and even some aluminum mower decks and created at least a 100lbs of aluminum ingots but never actually cast a real part. Unfortunately it has rained all week here (of course its my vacation) so I haven't had a chance to try out the stuff since I made it. I still have to finish painting the pattern.

The pattern is made out of mahogany as I was able to get some cheap mahogany at a local wood supplier - boards were not "sellable". I jointed and then planed and finally resawed the mahogany (to get it thinner while not wasting the extra 3/16" of material). Because I was too lazy to change out my bandsaw blade (takes about 20min) I did a rough cut of the pieces but did not even attempt to create a nice circular blank. I glued up some rough pieces to create the general shape I wanted. The split between the two halves was done by gluing a piece of craft paper in between so once I was done turning I could split the pattern apart with a chisel.

I left it for a few days while I made the crucible lifter (why does it always take so long to build a tool when your in the middle of a projects ).

I turned the blank on my second oldest son's small wood lathe. Since I have to store his two lathes in my shop I may as well use them. Apparently he can't have them at Fort Sam Houston during AIT. And I highly doubt the army will pay to move em around so maybe I get them for quite a while. In a way its too bad because he started turning at age 12 or 13 and by the time he was 16 he was turning fantastic hollow forms - urn shapes and the like that have 1/8" thick walls and only a small 1-1/4" hole in the top - way way beyond any of my abilities. (sorry I digress).

The pattern is turned - I wasn't trying for perfect symetrical sides, I was trying for approximate shape with the goal to turn the fly wheel to final shape and size. I had a minor snafu while turning the second side and broke off the spigot I had made on the one end. I had to resort to using my metal lathe to turn the second side (ugghh) because I didn't have a chuck that could hold that large a diameter on the wood lathe. I did glue it back on and have filled in any cracks and damage from the break.

I am trying to do this as a casting because I just couldn't justify the cost of a large piece of bronze and didn't want to make it out of steel. And since I made a foundry furnace last year and had piles of brass/bronze pipe fittings, broken gears etc.. I figured on trying to make the flywheel by casting the blank and then turning accordingly. But we'll see how that goes if and when it stops raining. I still have to final sand and paint the pattern and make the gating system. Based on research the gating system will need to be a bit fancier then say for aluminum - square or rectangular runners that are fairly small to help control the flow of material into the pattern such that it doesn't erode the sand as it goes in. So some work on that front still to come.

Today I'll be working on the gears for the cam and crank shaft. Note - I assume there is nothing special about the cam shaft itself? I got the dimensions off the whole engine drawing but didn't see a separate sheet in my downloads for that particular piece.

 

[Brian Rupnow]

Mark--that is a very interesting post about casting the flywheel. You are right about the camshaft. It is just a piece of plain cold rolled round stock, and doesn't rotate. The cam gear has a bushing in it and spins on the camshaft. --Brian

 

[mjonkman]

I had started on the gears - making the blanks on Friday evening (before my last post). I made 2 blanks for each gear in case I screw up - course I did manage to screw up the last blank - larger gear, misread the depth mic and took .017 instead of 0.007" on the last cut and now the one shoulder is a little short. Maybe I'll use it as my first trial cut.

In order to cut the gears I plan on using my horizontal mill and dividing head. I've never had the dividing head on the horizontal mill and totally neglected the fact that the keys to hold it in line with the slots on the table might work well on my Bridgeport but not are too wide to fit the slots on my small horizontal mill. So I had to make new keys for the bottom of it as well as the tail stock. I spent last evening making the ones for the dividing head but unfortunately the tail stock is not the one for the dividing head - its one my dad picked up at Busy Bee in London On and swapped for a smaller tailstock that I had and was going to modify for my dividing head. Long story, the key slot in the bottom of the tailstock is a different size then the ones on the dividing head so I have to make a different sized set for it. So another evening will be spent on that at some point this week.

The sun came out around 2pm this afternoon and with the threat of rain gone for the remainder of the day I thought I'd take a stab at casting the flywheel. In a short statement, the process was not a success. However, there was a ton of learning and a number of changes that I will implement before the next attempt.

Things that went well

Using the runner system as suggested on a post on Alloy Avenue seemed to work well. Basically from http://www.alloyavenue.com/vb/showthread.php?6173-Gating-Brass-bronze-castings. However I didn't do the math I just followed the pictures. In reading more I should probably increase the height of the runner to about twice what I used and increase the size of the gate.

I used Petrobond sand and that seemed to hold the shape and pack in very nicely. However I really wish I had bought a lot more of it when I picked it up a year or so ago. I thought 100lbs in 2 - 5 gallon pails seemed like a lot of sand. I used almost the entire amount in my flask - which I will admit is a bit big. Next time I get some spare change I'll pick up another 3-4 pails.

What didn't work so well.

My new crucible lifter / pourer that I made last week. I'm not a super "strong" person - I can lift and move around a 100lbs without an issue but when I have to balance a A12 crucible 2/3 full of molten bronze it gets awkward very fast. I did not include any kind of handle to get a grip to twist/rotate the handle to pour the bronze. When I finally managed to get it twisted enough to pour I could not sustain the pour and was unable to restart it fast enough. The end result was that I filled the runner and started to fill the pattern area but it froze before I could start the pour again. I welded a bolt to the handle to give me twisting leverage and added another piece of rod at the end of the handle so a second person can help with the pour. The other issue I found with the new lifter pourer is that the rotating lock on the lower part of the handle. The lock worked sort of okay but I feel that it also reduced my ability to twist the handle to some extent. I will be revisiting that. I think I solid rod protruding out permanently fixed would suffice for a lock - perhaps with a little play to allow slight differences in crucible heights. Still thinking on that. I'm not that experienced to know how variable the height of crucibles will be.

I think I need to get the bronze a little hotter then I did to keep it pouring and flowing better. I don't have a thermocoupler setup yet.

I need to modify the flask design and add some handles for lifting at least the cope off the drag.With 50lbs of sand rammed up it was hellish to lift it off. Two handles one either side would have really helped.

Get some foundry gloves so I don't keep ruining my welding gloves - my cheap welding gloves from Lowes burst into flames while skimming the crap off the top of the molten bronze.

Give myself enough time to ram up a good mold before starting the furnace. Thought I would have enough time to do both at the same time. But it took me 3 attempts to get a more or less decent - but not perfect mold. Unfortunately it was getting dark and I was getting exhausted so I went with that and it would have worked.

Also the extra piece I had added onto the pattern to allow for work holding also became a bit of an issue. I was ramming that part up in the cope and then continuing it on up as a riser to help prevent shrinkage. I could never get the pattern to pull out correctly without tearing the sand perhaps because I couldn't ram it down hard enough. Perhaps a piece of copper pipe to cut out the riser vs working around a pipe would have helped.

But I think with a few modifications and more daylight I think I can be successful. Definitely need a 2nd person to help with the pour or I need to start working out at the gym Lot of learning going on.

 

[Brian Rupnow]

Mark--thanks for the update. You're a braver man than me. I have never tried casting metal.---Brian

 

[mjonkman]

Not so sure about "braver"... "stupider" might be a better word

I wanted to create my own foundry furnace because down the line my goal is to create scale models of real engines (gas, steam, stirling) etc without jumping through hoops with crazy setups to do the same out of bar stock. I have seen some fantastic weldments etc to get beautiful models without casting but I like to dabble in woodworking as well as metal working so this is one part that lets me do a bit of both. After this engine is complete and I need to finish up a Stirling (Jan Ridder's coffee cup Stirling) I started a while back and another steam engine I started with my eldest son (waiting on him to have time to help finish it - want it done as a joint effort) then I'll be making patterns for my next engine.

Choices currently are

1) Maytag model 92 (I bought a 1931 at auction a few weeks ago, so I have an original to work with)

2) Rider Errickson Stirling (started making some patterns but screwed up a complex composite piece pattern during glue up)

Saner heads prevailed on Saturday and I avoided going to an auction where a IHC 2HP Famous Vertical was sold. I would have had to bid on that puppy and I had no where to store it and no way to get something that big home. But its one cool engine that I might like to model someday.

It may be a week before my next update on the engine.

 

[mjonkman]

Sorry no update this week and possibly next week or two. Major issues to deal with at my full time job.

 

[Brian Rupnow]

Work has this nasty habit of popping up and interfering with one's hobbies!!!

 

[mjonkman]

I got a chance to get back out to the shop late Thursday afternoon. The first thing I did was make myself a pouring shank for my crucible. This one is just simply a ring to hold the crucible and a small vertical riser and then the handle. With the ring correctly sized and shaped it seemed to hold the crucible extremely stably so I decided to forego temporarily a locking mechanism to prevent the crucible from falling out (aka I was in a hurry and wanted to get on with the show )

On Friday morning after getting my "apprentice" working on his project - he's building a Jan Riders' coffee cup Stirling, I started getting ready to create a new mold.

Some of my issues with creating the mold stemmed from the fact I didn't really have a way of lifting the cope off the drag perfectly vertical because I had no way of gripping the cope. Therefore I added some draw pulls to the sides of the cope and drag to make them easier to move. This worked well *except* I put them 90 degrees to the lock between the cope and drag which gives better grip but means that I can't set them on edge to clean out loose sand. Will adjust before next go round. I need the handles because in this scenario there is 50lbs of sand in each half of the mold.


Because I had a lot of problems the last go round with the hub that I added to one side of the pattern for holding while turning. While the true problem was probably not being able to lift straight up (no handles last time) I decided to ram up the drag with this half of the pattern instead. It worked. I also used a thicker runner to feed the pattern, not sure whether the runner was too small last time or not. Next time I might do back to the narrow runner since it took a lot of molten metal to fill that thing up.

The pattern rammed up nicely on the first attempt. It wasn't perfect but the pattern area itself was pretty good, the runner had some crumbling along its edges that I tried to clean out. Making the runner even bigger then the wooden runner pattern. I don't have any pictures itself of the rammed up pattern. My "apprentice" might he was doing a lot of pictures, snapchat and videos of what I was doing (hopefully none of those videos see the light of day).

With a good pattern or at least one I was happy with I fired up the furnace. It was a coolish day out and I had a hard time getting it to stay lit. Finally got sensible and put the hot plate under the oil tank and got the oil warm - amazing difference in performance on that. Actually had to cut back the amount of oil going in because it was burning too rich. Lesson learned even if its a comfortable cool day, get the hot plate out as the oil viscosity really affects the burner.

I filled the A12 crucible full of brass shavings that I had saved (as well as spent .22 casings and some miscellaneous brass/bronze fittings that were buried in that pail. Once that melted it left a fair amount of crap on top, guess the small chips oxidized more then big stuff did. After scrapping that off the top and then adding more big fittings and the like I got about 2/3 - 3/4 of the crucible full of molten metal. I let it heat up till it was nice and viscous.

I used the old lifter/pourer - now relegated to crucible lifter to get the crucible out of the furnace and then the new pouring shank to pour with. The only headache was the plinth got stuck to the bottom of the crucible again :-( but didn't seem to effect anything just a bit in the way is all.

When I poured the top half started to lift a bit causing some bronze to seep out the split, I stepped on it to get it back down and continued to pour out the entire contents of the crucible into the mold. A small amount started coming up the riser above the center of the hub - basically to the level of the bottom of the riser extender. But didn't go up into the extender. With the crucible empty and the pouring riser full but not a lot in the other riser, plus the lift of the two halves I was certain that this was yet another failure.

After waiting an impatient 10 min with "apprentice" and wife harassing me about whether it was a success or failure I dumped it out into a wheel barrow to prove it was a failure. Much to my surprise the riser on the hub had fed the pattern nicely and while it had shrunk down in the middle to almost next to nothing above the pattern, it had done its job and the pour was a *SUCCESS*.

The only negative at the end was the when I tried to lift the cope and drag to get it into the wheel barrow the sand in the bottom of the drag broke loose onto the ground. Next time I'll lift with the board it was sitting on.

After letting it cool for a good while - aka cleaned up all the pouring stuff, put away the lifters and pourer and all that paraphernalia. I came back to the casting and hit it with some water to cool it off and then cut off the riser above the hub and the in gate. Both were solid, though I bet the riser was empty a 1/4" or so above the hub.

I started machined it later yesterday evening. I should have done a few things differently but it came out ok. I still need to drill the holes into the face of the flywheel. There is a funny - smearing area on the face of the flywheel and a couple of tiny pinholes on the circumference. But overall it was a complete success.

In order to machine it, held the side without the extended hub in the 3-Jaw on the outside then I machined the face and hub to clean them up. This is where I made my mistake. I did not go to final dimensions anywhere, I just cleaned up this side. I should have taken everything to final dimension or at least within .020" so that when all was said and done it would be just skim cuts to finish off after cutting off the hub extension. Oh well, lesson learned. After roughing the first side I used the spigot or hub extension to turn the opposite side to final dimensions and turned the outside diameter to approximately final size. Then flipped around and tried to finish the first side using the inner hub to hold - it worked but it was a bit flimsy and did at least once pull it slightly out of running true. Next time I either completely finish the first side or use the outside diameter to hold when finishing the side where the extended hub was. This is the first time I've turned a casting like this so it was a learning process. I had the idea correct just not the execution steps in the right order.

Pictures to follow from my iPhone momentarily in a separate post.