JC attempts the MEM Corliss

[JCvdW]

Today the crosshead and crank pins were made. The outside faces of the pin heads were faced on the lathe. The MT2 collet chuck was moved from the milling machine for this purpose.



The crosshead pin is made from 303 stainless steel. The crank pin is made from brass.

All three pins ready for the screw driver slot to be machined. The crosshead screw is screwed tightly into a piece of 6mm round bar for this.



Following in the steps of the men who went before me, the slots were cut with a slitting saw. The pins were held in the vice with a square collet block. The saw was centred relative to the collet using the bisecting function of the DRO.





For the first time, the complete drive train can be linked together.



A long way to go still, but at least is it starting to resemble a steam engine! 



Can't wait to mount the completed parts on the base to see the interaction between piston, crosshead, connecting rod, crank and flywheel. First have to replace the temporary mild steel axle with a 303 stainless steel axle though.

[RReid]

Following in the steps of the men who went before me, the slots were cut with a slitting saw.

That picture really caught my eye since I was doing virtually the same thing yesterday and have more to do today once I get to it. 304 SS in my case.

Anyway, I'm continuing to enjoy following along!

[crueby]

Great progress, its all looking very good!
 

[vcutajar]

Nice family shot.
Nearly finished.

Vince

[Larry]

Looks great. Have been following along. I still need to finish my base plate.

[JCvdW]

Thanks guys for following along!

The 303 stainless steel shaft took two attempts to get right (First attempt was too short!).

Then the tolerance between the flywheel hub and axle was too tight. After sliding on nicely, the hub jammed solidly on the axle. Probably due to some debris in the grub screw holes. It took assistance from an engineering shop to remove the axle without causing any damage. Sanding down the axle diameter by about 10 micron solved the problem.

With the axle complete, all the parts were bolted onto the baseplate.  The bearings were mounted first with flywheel and crank fitted to the axle. The crank was then connected to the piston inside the cylinder block. The crosshead guide and cylinder block assembly was then moved around slightly to find the smoothest action for the connecting rod and crank.

The location of the resulting mounting holes for the cylinder feet are slightly off compared to the drawings - clearly all the component dimensions are not as accurate as I thought.

With everything bolted down, the friction of the Viton piston o-ring inside the cylinder could be assessed again. By pushing on the piston from one side only during the out stroke, the flywheel could be made to turn. This implies that the momentum of the flywheel is sufficient to overcome the o-ring friction during the return stroke. Once the valves are installed and pressure is applied on both strokes, o-ring friction will definitely not be problem. I think I am good to go as far as the o-ring is concerned.

[youtube1]https://youtu.be/RN6FWzQDnoY[/youtube1]

[crueby]

Excellent!!   

[cnr6400]

your engine turns very smoothly with thumb pressure. Looking great!

[steamer]

Oh I promise you.   Bob (Maryak) would approve!

Dave

[vcutajar]

Looking good.

Vince

[JCvdW]

Thanks guys for the encouraging words!

I decided to start working my way back from the eccentric to the valve gear. First up, the eccentric sheave. I like the oilers that Vince added to his Corliss, so space will be provided to mount one.

A bronze disk was turned on the lathe, and split into two with a slitting saw.


 
The two sawed surfaces were skimmed on the milling machine, the ears were machined, 2mm holes drilled and the 3mm thread for the eccentric rod was tapped.



The two halves were then bolted together, the centre was found and marked on the mill using the mill DRO.





With the sheave centred in the four yaw chuck, the hole was bored on the lathe.



Taking a cue from Vince, a jig was made to securely clamp the two halves, and mounted on the rotary table to mill the outside diameter of the sheave. After removing the bulk of the material with a 6mm end mill, a 2 mm end mill was used to finish the outside surface.



A bit of sanding with 400 grit sandpaper completed the sheave.



Next up, the eccentric disk ...

[gbritnell]

Nice job on the eccentric strap!

[propforward]

Very nicely done - I like your small tap holder. I must make one of those.

[JCvdW]

Thanks guys for the kind feedback!

I can't believe that a month has passed already without any progress - life got in the way.

Before making the eccentric disk, I made a wooden base. After cutting mitres for the corners, rebates for the base plate were cut on the milling machine. Probably the most accurate woodworking I have ever done  .



Sides glued together with corners reinforced.



The aluminium base plate is a snug fit. Not sure if it would need to be screwed to the frame.

[vcutajar]

i missed your updates JC.  Nice to see one.

Vince