Model Engine Maker
Engines => From Plans => Topic started by: toolznthings on May 02, 2016, 06:51:37 PM
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Hi All,
Going to try and resurrect a build I did just over a year ago on Brian Rupnow's double horizontal with some changes. As memory serves me I'll get started. ;D
I did the cylinder block first from mild steel and there will be a picture of it later since I started taking pictures after it was complete.
The base plate was next and I made it a little larger than the plans. Rough sawed from aluminum plate with stock left for milling. Holes for the bearing towers were done first with dowel pin holes at the manual mill.. Holes were added to fixture for milling where they will be hidden on final assembly.
Made a couple of roughing passes and one finish pass on the cnc mill.
The finished base removed from the setup plate. The single large mounting hole was my part zero location.
Next on the build was the crank shaft assembly. I went to a 5/16" size shaft and turned the ends to be silver soldered to .250", with the correct distance between shoulders to establish the crank throw assembly spacing. The cranks throws were milled on a fixture using shoulder screws for location. The holes were spaced and drilled and reamed .250" on the manual mill leaving mill stock.( No picture of the milling. )
This is the simple soldering fixture for the throws, maintains width / parallel.
Next step was a larger fixture to align the throws to the remaining shafts doing one side at a time and positioning a stop block to get the 90 degree throw.
Another view and pictures of the finished crank.
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Another great build you are sharing Brian! I'll be enjoying this. :ThumbsUp:
That crankshaft turned out fantastic. Thanks for showing your techniques. :cheers:
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What yogi said. Very nice crankshaft!
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Toolznthings--I am always happy to see someone build from plans I have posted. Good luck, I will be following along.---Brian Rupnow
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Nice work Brian, I will be following along and interested to see your setups and parts machining.
Dave
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Unless Toolznthings first name is also Brian, there is some confusion going on about who started this thread!!----Brian Rupnow
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Yes, Toolznthings first name is Brian; met him at NAMES this year, seems like a nice guy!
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Thanks , Dave !
Yep ! I'm the other Brian. Sounds like we have an echo going on here. :Lol:
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The bearing stands are the next parts to be done. The two outboard supports will be made from aluminum and will use a miniature ball bearing. ( McMaster # 57155K325 ) The center support will be brass with a removable bearing cap and bored to fit the center throw of the crank shaft.
I machined the thickness of all the blanks to .375 and stood them vertical in the mill vise and face milled the bottoms square to the sides. The outside aluminum stands were bored for the bearings. The center stand was bored with the bearing cap in place. Rough drilling here to get ready for boring.
The blanks are now ready to have the outside contour done on the CNC mill.
Part zero was the bearing bores and the finished bottoms were indicated in parallel to the x-axis using a piece of aluminum for a fixture. I keep several plates for doing this kind of fixture and add holes as needed. Re-face until they can't be used any longer.
After all stands were milled I added the tapped holes and dowel pin holes to the bottoms of all three stands working from the finished bores.
A trial assembly with the crank shaft. The small ball bearings are visible in the picture. I choose the bearings one with the outer flange.
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Machining the connecting rods .....
The connecting rods will be made from 6061-T6 aluminum bar stock. The wrist pin hole will be bushed with 660 bronze bushings and the crank end will have 660 bronze split bushings. I started with wider stock in the mill vise and CNC milled the .900 width about 1 " deep.
A fixture was made to support the first milled profile with a pocket to align the .900 width and the next contour was milled.
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Connecting rods .....
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Connecting rods, still .....
The next step was to START ALL OVER ! I realized later that evening that the hole for the socket head screw holding the part on the fixture was in the wrong place in the rod. Obvious as seen laying on the print. Practice makes perfect . :cheers:
The fixture with the correct hole position.
Finishing the rod thickness at the manual mill.
On to the manual mill to finish the rod end caps and and bores for the bearings. You can't see the parallel under the rod in this operation.
The finished rods with a trial assembly on the crank. The bronze bearings in the rods are split with each half a tight fit in the rod and rod cap.
( I may not have noted in my previous post that the crank shaft diameters were increased to 5/16" in diameter. )
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More machining ....
The piston assembly is next on the build. The piston head will be 660 bronze with a minimal bore fitting o-ring and the rod end will be cross drilled for a 1/16"
dowel pin.
Started by single point threading the piston end of the rod.
I made the piston next and left stock on the o.d. and length and used thread locker and assembled to the piston rod.
Back to the lathe to turn the final diameter concentric to the piston rod and finish face the length. Not pictured in this view I cut the o-ring groove to get a very light fit in the cylinder block.
To insure the correct overall piston length and a set up to drill the cross hole in the piston rod end I made a simple fixture.
The installed o-ring is in this picture. Not shown is the 1/16 cross drill and reamed hole. ( visible in future pictures. ) The purpose of this pinning is to be able to disassemble the the piston rod with out removing the piston itself and losing concentricity.
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Nice work on the crank Brian, and the other parts as well. This is a little different build for you. What type of fit did you try for on the O ring?
gbritnell
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Hi George,
Well I wish I could say it was calculated, but I did a trial and error fit until I felt that the drag was not going to produce to much friction in the bore.
I've done it on several engines and the ring seems to seal well under the conditions these little engines run.
Brian
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Cylinder head / Cross guide ......
Machining the cylinder head / cross head guide was the next step. Machined from 360 brass round bar stock. The .500 x .750 end was machined first and held in a collet to finish the diameter that goes in the cylinder head and to bore the piston rod thru hole.
I made a boring bar from a long length 1/4" end mill.
A set up was made at the manual mill to machine the outside dimensions and drill the mounting holes. Working off the bored thru hole.
The finished parts with the cylinder head.
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Hi, Please can you tell me what the word "hold" means on your drawings, I have come across the word "bare" but never seen hold before,
Thanks
Willy
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Very nice work Brian and wonderful pictures as well. You are making some quick progress on the build.
Bill
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Hi, Please can you tell me what the word "hold" means on your drawings, I have come across the word "bare" but never seen hold before,
Thanks
Willy
Hello,
By the way the credit for that drawing is Brian Rupnow's. So I knew what he meant.
It may not be universal, but " hold " in my world means to maintain a tight tolerance on the feature when no tolerance is given. For me it was a reminder that I needed to pay attention to that particular feature. I'm self reviewing the importance of the parts I'm making and adjusting as I go.
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Very nice work Brian and wonderful pictures as well. You are making some quick progress on the build.
Bill
Thanks for the compliment ! I am " cheating " on the progress since this is a build I did a year ago. Short on overall pictures since it was may first attempt at displaying a build thread at another location.
Brian
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Ah yes, I remember that now. In that case I am really looking forward to seeing the end result :)
Bill
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Hi, Please can you tell me what the word "hold" means on your drawings, I have come across the word "bare" but never seen hold before,
Thanks
Willy
Hello,
By the way the credit for that drawing is Brian Rupnow's. So I knew what he meant.
Hi, Thanks for that, I might use it myself , is is copyright ?? !!
Willbert
It may not be universal, but " hold " in my world means to maintain a tight tolerance on the feature when no tolerance is given. For me it was a reminder that I needed to pay attention to that particular feature. I'm self reviewing the importance of the parts I'm making and adjusting as I go.
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Hi,
You can get the draws free from Brian Rupnow. He posts here and other places. Give him a shout out for help.
Brian
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Valve mechanism .....
Next parts made are for the valve mechanism. The valves are turned from 660 bronze and the large end eccentric and rod end are machined from 360 brass.
The connecting rod was made from 12L14 and single point threaded 10-32 threads on each end.
The eccentric end stock was machined to thickness and the .750 hole was bored to size. There was stock left all around for the CNC operation. Using my fixture plate again I made a clamping bushing to fit the .750 bore and after clamping to the fixture I was able to indicate the bushing o.d. for part zero.
The finish contour concentric to the bore.
Next operation at the manual mill was to drill and tap the 10-32 threads for the rod.
Back to the CNC to mill the contours on all the rod ends.
Band sawed apart and finish milled the thickness and milled the slots and drill and reamed the .125 holes.
The finished parts and a trial assembly.
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Finishing valve train parts .....
I turned the valves in the lathe and finished the the .250 x .312 end and the .125 cross hole at the manual mill.
The beginning of the lathe operation. Turned the valves from 660 bronze.
Back at the lathe I turned the eccentric hubs and added the set screw holes back at the mill.
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Flywheel machining .....
Machining of the flywheels at the lathe. Machined from 12L14 bar stock.
After finishing one side of the flywheel and the o.d. by holding in the three jaw chuck it was sawed off leaving stock for the opposite side. Aluminum soft jaws were mounted on the lathe chuck and the second side and thru bore were finished. Adjust-Tru chuck insured concentricity with the previous turned o.d.
Turned soft jaws are never a guarantee that the chucked part is running dead true. I always check indicate to be sure.
Facing to thickness in this photo.
Profile finished and boring for the crankshaft.
Next operation at the CNC mill was to machine a set of aluminum soft jaws to hold the turned flywheel in the vise. Indicating the bore for part zero.
I then proceeded to pocket mill the areas between the spokes. The first tool drilled a 1/2" hole for the plunge cut to start the milling operations. After the rough cut I made a finish pass to complete the operation.
The set screw hole was added at the manual mill and completed the flywheels.
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Very nice Brian!
I'm still quietly watching.
Dave
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Thanks Dave it's appreciated !!
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More machining ....
The spacer that goes under the cylinder block was made from aluminum and was squared up at the manual mill and the mounting holes were drilled thru. I decided to add some decoration to the sides of the the block at the CNC mill.
Using an engraving bit I did all four sides. A later photo will show the results.
This is what I came up with for the air supply manifold. I was trying to find a common air hook for this engine and three others I have built. Every engine ended up with some kind of self made hose barb that I really did not like. I was with my wife in a local craft store and saw hoses for air brush guns and decided that would work. I made some test turnings to figure out the thread fit and seat for the hose end. The thread was .375/.370 o.d. x 28 TPI and a drilled hole .234 diameter back 1/4" and a thru hole and length to suit.
I made a setup with a small regulator and valve on a wood block with the air brush hose.
Drawing of the manifold and manifold bolt/fitting to attach the manifold to the cylinder block that I designed.
Made from 360 brass the contour of the manifold was cut at the CNC mill.
The final thickness was face milled at the manual mill and the holes for the air channels were drill. Each hole was counter bored .250 x .062 deep for brass plugs that were silver solder to close off the channels. The air hose adapter was made and silver soldered in place.
Picture of manifold before plugging the ports. Fine glass bead blasted.
At the lathe I turned and threaded the manifold shoulder bolts / ports and made a setup at the mill to cut the hex head.
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:popcorn: Still following.
Good progress and very nice looking parts! :ThumbsUp:
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Finishing up the build .....
After doing all the necessary finish work on all the parts final assembly is next. Bench work to remove tooling marks, fine glass bead blasting, adding oil holes, and painting the flywheels after polishing.
The " wrist " pins were made from 12L14 .125 diameter ground stock and grooved for 1/8" e-clips. Some of the parts not pictured before can be seen in this layout. Brass pads were turned to go under all the set screws so as not to mark the crankshaft and allow for easy adjustment and disassembly of the flywheels and eccentrics.
Finished the assembly and mounting on a wood base with a diamond drag engraved tag.
Credit to Brian Rupnow for the design and drawings. THANKS !!!
The little oil cup ( center bearing stand ) was a left over from 30+ years ago when my wife and I made them for Cole's Power Models. An experience not forgotten.
Thanks everyone for all the views and comments !!
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Here is the video of the engine running ......
https://youtu.be/kuS3So7rg-Y (https://youtu.be/kuS3So7rg-Y)
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Brian,
The finish on this and all your engines is super. I really like the satin finish on the brass parts. You're going to have to dive into the I.C. world before to long.
Keep up the good work.
gbritnell
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That's a great looking engine, Brian. And thanks for the super build log.
--Tim
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A marvelous build of one of my favourite engines. Fit and finish are superior to my original prototype. Congratulations on a great build.--Brian Rupnow
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Thanks all for the kind comments, very much appreciated !
Brian ( the other one ;D )
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Very nice Brian!
I do agree with George, the finish on your parts is fantastic; I'm a fan and user of super fine glass bead and love the satin finish that they leave.
She runs pretty darn nice too!
OK what's next?
Dave
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Hi Dave,
Thanks ! Not sure what to post next. I have some more completed builds to pick from.
Brian
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Great running engine Brian! :ThumbsUp: :ThumbsUp: :ThumbsUp:
I love how it is running so slow, it's just ticking over. Well done!