MY CORLISS

ENGINE BUILD

Part 14  by Vince Cutajar

I bolted the crosshead guide and the rear cylinder cover together and held in the lathe with a live centre. Skimmed the edges of the guide and cylinder cover to make sure they were both the same.


Next I played around with a new toy, an Italian (but made in China) 125mm milling vice. Cleaned it up a bit and removed the rotatable base and then indicated it on the X3 table in preparation for milling the slots in the crosshead guide.


Marked the length of the slots and then clamped it in the vice. To properly locate the slots with reference to the holes on the flange, two 3mm drills were used.


Two holes were stepped drilled to 15mm right through the guide.


The holes were then opened up with a 16mm end mill.


First slot cut with the 16mm end mill.


And the lower slot was cut the same way. The finished crosshead guide just out of the vice - still needs deburring and cleanup.


Next to be made, were the piston, connecting rod, crosshead and gland nut. I departed from my usual way of doing things. I have a habit of starting a part and continue on the same part until it is finished. For these four items I determined that I needed to use the dividing head and a collet holder in the lathe a couple of times. So to save some time with tool changes I worked on most of the items at the same time. First off will be the gland nut. The plans called for it to be made out of mild steel. As the connecting rod will moving sideways in it I decided to make it out of bronze. A piece of bronze was clamped to the dividing head and a 16mm hex section was milled out.


The material was next transferred to the lathe in the three jaw chuck and the rest of the machining done. The thread was 10 X 1mm to match the thread in the rear cylinder cover. It was parted off and then I needed to clean up the face of the nut. The rear cylinder cover came in handy to hold it in the lathe for facing.


The next item was the crosshead. The same piece of bronze was again chucked up in the lathe. A tapping hole for a 4mm thread was drilled and this same hole used for the live centre.Started reducing the diameter to fit in the crosshead guide.


Next to be done was the crosshead.  This was brought down to size until it was a snug fit in the crosshead guide.


Then off to the dividing head which was still indicated on the mill table. Two sides were milled off to size.


I was intending to use the slitting saw to part off the guide from the parent material, but was feeling lazy, so I used a hacksaw and then milled off that side to size.  Obviously to do this I had to remove the dividing head (which was not required anymore) and installed the vice.  The crosshead was then patiently fitted in the guide until it would slide nicely in it.

Next the connecting rod was done on the lathe using a collet holder.  For the rod I used a piece of 6mm stainless steel.  After this was finished, a Teflon washer was turned in the collet holder.  This will be used in the cylinder head under the gland nut instead of packing. 


Work on the piston was then started and initially I was going to make it with mild steel but then I remembered that the cylinder was also mild steel. Luckily I managed to find some cast iron. I roughed it out, cut the packing groove and also a parting groove and then brought the diameter to size until it just fit the cylinder.


Parted it off and was lucky that I did not need any finishing on the parted face.  Some more fitting ensued using fine sandpaper until it would slip smoothly in the cylinder.



Part 12+1 here part 15

 
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