Chris's Un-Ransome Tree Feller

[Jo]

I could do with some more fire wood 

Jo

[crueby]

I could do with some more fire wood 

Jo

Well, when TGHS gets his boat finished, I'll have him sail you over a bundle of it!   

[crueby]

A lot of milling time this morning, got the valve chest blocks taken down to length/width/thickness, and also fit the mounting block to the big ring in the middle of the cylinder:

Next time I'll start cutting the hollow center chambers into the top and middle blocks, then can start cutting the ports and drilling all the passages.

[tghs]

I could do with some more fire wood 

Jo

Well, when TGHS gets his boat finished, I'll have him sail you over a bundle of it!   

At the Progress I'm making it might be better to ship some acorns over..

[crueby]

I could do with some more fire wood 

Jo

Well, when TGHS gets his boat finished, I'll have him sail you over a bundle of it!   

At the Progress I'm making it might be better to ship some acorns over..

     'kit' firewood!

[cnr6400]

 

[crueby]

The two steam chests have been hollowed out. The cavities do not go all the way through - the shallower one is the top layer, this cavity will hold the slider connected to the linkages to the piston. It will open ports near the ends of the travel, sending pressure to one end or the other of the 'piston' rod holding the slider which has the normal d valve on it to control the piston. That slider will be in the thicker one on the left. The shallow one without a cavity is the bottom layer, it will have the ports for the d-valve and passages out to the piping to the cylinder ends. Confusing? Yes. It will be clearer in a few days when all the parts are made and I can stack them up to show the full assembly. This is the same mechanism used on some boiler feed pumps.


Also drilled the top layer for the valve rod, and made the o-ring holding glands for each end. The middle of the rod has a narrower section, to hold the slide valve as the rod moves back and forth. In a normal steam chest, we usually put an adjusting nut in the slider - for this rod, the adjustments will be at the clevis on the outer end of the rod where it connects to the linkages.

[cnr6400]

 

[stevendavis]

Looks good! 

[bent]

Yup, that looks stout, and functional, and no twiddly twisted rods and such.  Should be a runner!

 

[crueby]

Thanks guys!

[crueby]

This morning got the shuttle rod for the main D valve turned up from some round bar. This will hold the D valve in its center section, and slide back and forth in the hole down the length of the larger steam chest, moving when the smaller valve from the piston linkage gets to one end of its travel. The ends of the rod are beveled in so that steam/air can get to the end of the rod even when the rod is up against the cover plate.


Here it is slid into its hole. Its travel will be limited by the end of the rod hitting the cover plate on the end of the steam chest - that cover plate is yet to be made.


Also drilled a number of passages/ports. The top of the chest has three holes to form the ports for the upper valve slider, the outer ports have a hole drilled to the end of the steam chest plus the center one has a hole running to the back and down to the bottom for the exhaust. The end ports have a channel milled down to meet the hole for the shuttle rod. First drilled the passages


then milled the connecting slots

Here is a top view showing the upper ports and the openings at the end. The fitting on the side is for the steam/air inlet tube. That fitting was salvaged from the first attempt at this engine.

Still to do on this block is to drill/tap the holes to hold the blocks together, as well as to hold cover plates on the ends...

[cnr6400]

  Looking great Chris!

[crueby]

Looking great Chris!

Thanks Jeff!

[crueby]

Late this afternoon the rains/wind moved in which chased me back indoors, so I wandered back into the shop and got a few more things done on the valve chests. Started with milling the ports in the bottom section of the steam chest. Drilled slightly undersized holes, then opened them up and connected them with a mini end mill.

Then drilled the passages, starting with the exhaust passage from the middle port - this one also connects up through the middle steam chest section to take the exhaust from the other slider.

Drilled the passages from the outer ports to the ends of the block, and at the same setup also drilled the holes to mount the pipe flanges - the pressure will be taken out  to the ends of the cylinders with small pipes. On the original attempt at this engine I put blocks on the side of the cylinder to do this, but that was another set of leaks that was hard to fix, so this time taking the easy route with pipes along the length of the cylinder.

So, here is where the steam chest(s) are at the moment. First the lower one with the ports/passages just cut. Behind it, upside down, are the other two steam chest blocks.


And with the middle section turned right side up and set in place:

And the third section right side up and set in place too...

Nice stack of parts!

At this point I made up a list of things left to do on the cylinder assembly, before moving on to the base frame that will hold it. For some reason, the shop elves got very upset when I gave it to them to proofread... Huh, wonder why?