JC attempts the MEM Corliss

[JCvdW]

Started on the two bearing blocks for the flywheel. I decided to machine both bearings together from a single block of bronze which I had cut from a piece of round bar. I will later separate the two bearings with a slitting saw.



I bored the axle hole on the lathe using a long 5mm end mill as boring bar. I also faced it off to have one side of the block perpendicular to the hole. The axle in the hole then served as reference to machine the base of the bearings parallel to the axle.



I now have to create the curved top of the bearing...

[JCvdW]

I shimmed the top edges of the milling chuck with the blade of a feeler gauge and then milled the curved top of the bearings by rolling the bearing block on the axle.



Using a Magnifying Glass application on my mobile phone, I could accurately position the cutter to mill right into the corners of the curve.



After some further sanding with home made sanding sticks, I am quite happy with the result so far.

[crueby]

great work!
 

[Johnmcc69]

 
 That did turn out nice!
 Cool idea about the "Magnifying Glass"!

 John

[JCvdW]

Thanks John en crueby for the kind remarks!

After drilling the mounting holes, I split the two bearings with a slitting saw, and machined to size.





Now for the Crankshaft Support to mount the second bearing ...

[JCvdW]

I started making the Crankshaft Support by machining the rounded corner. Not having a cutter for this, I used a ball nose cutter the same way a CNC machine would do. I calculated the incremental X and Z coordinates that will result in a rounded corner. It certainly worked better than trying to round the corner with a file.









 

[JCvdW]

Finished machining the Crankshaft support today. Motivating to see the first bit of a subassembly!

[vcutajar]

Nice.
Starting to take shape.

Vince

[JCvdW]

Thanks for the comment Vince!

I started on the Guide, by fly-cutting some mild steel stock, and soon realised that the smooth finish I obtained when fly-cutting the cylinder block was beginners luck!



This provided the perfect excuse for a diversion - to build a power feed for the X-axis of the mill. https://www.modelenginemaker.com/index.php?topic=10327.msg235437#msg235437

The power feed is now complete. I am very happy with the fly cutting results (after also realising the importance of grinding the correct shape on the high speed steel cutter!).

This inspired me to have a second attempt on the cylinder block. The result is a block of mild steel with much more accurate dimensions compared to the first one, and with a much smoother cylinder bore prior to lapping.  I am now at the point where I can drill the steam ports again. Holding thumbs!

[JCvdW]

This weekend I successfully drilled the 20 1.5mm steam port holes in the cylinder block using my sensitive feed micro drill chuck. What a relief! I used three new drill bits on the 20 holes, just to be on the safe side. The micro drill chuck is tightened by hand, allowing the drill bit to spin in the chuck if it catches when breaking through.





I then drilled and reamed the four 6mm holes for the steam valves. I was not aware of the difference between a hand reamer and a machine chucking reamer, and started out using a hand reamer in the milling machine by mistake. I reamed a test hole in my discarded first cylinder block and obtained a smooth and straight 6 mm hole. So far so good. But as Murphy would have it, when reaming the first hole in the second cylinder block, the reamer broke. Fortunately without too much damage to the hole.

This forced me to read up on reamers, and to watch some Youtube videos (which I should have done earlier!). I bought the correct machine chucking reamer today, and reamed the remaining three holes without incident. Nerve-racking, but I guess this is the whole purpose of the exercise - to learn.

[crueby]

Gotta be a big relief to have those holes done, that engine has a lot in the block. Time to sit back and admire it!

[propforward]

Top work. Fly cutting is immensely satisfying for some reason, but also really nice and precise work porting that block, you must be pretty happy with that. Off to look at your power feed now.

[vcutajar]

Nice one JC.  A lot more holes needed in that cylinder block.  It will end up looking like Swiss cheese.

Vince

[Roger B]

Splendid, I liked the CNC (count number of cranks) rounding method 

[JCvdW]

Thanks for checking in Crueby, Stuart, Vince & Roger. Words of encouragement are always much appreciated!

I made a small M2 tap wrench and tap depth stop as suggested by Joe Pieczynski:

[youtube1]https://youtu.be/XNmd1-v62tw[/youtube1].
After a few holes in my practise cylinder block, it was time to tackle the real one.

Four holes tapped. Twenty eight more to go ...