Chris's Build of a Stanley 735 Engine

[steam guy willy]

Hi Chris, do your little helpers have their own little pots of swarfega ?!!!

 

Willy

I've learned not to ask...!


Perhaps you could make a beam engine and leave the Iron  Maidens lying around ?!!!   I haven't had any trouble from them recently !!!

[crueby]

Dunno Willy, that elf seems to be enjoying that...   

[crueby]

What? Plenty of room!  Why I must measure several inches across on the monitor... 



-Doug

Hi Doug, I am laying out the stock for the valve tie rods and the piston crossheads, and was looking back at the pictures you posted. In this one, the crosshead guide looks completely different than any of the other plans or photos I have seen, with a squared slot in the guide rather than the usual arced surface. Is this just a partial view of the parts, or did they make the guiide this way at some point? In the plans and photos I have, the outer surface of the crosshead and the inner surface of the guide are arcs on a common circle.
Before I go too far on the parts, thought I had better ask!

Thanks,Chris

[crueby]

This morning got the valve and piston rods shortened to length and the ends threaded to go into the fittings below. The piston rod lower end was most likely one piece (or welded) to the crosshead, but I am threading it for adjustment and assembly ease. The lower ends of the valve rods go into the tie rods that slide in the valve guide I made the other day, and connect to the stephenson linkage.

Aside from gaskets, I THINK that completes the cylinder assembly. Started in on the valve tie rods from square bar, threaded the inside of the ends to fit the valve rods, and turned the ends to fit the valve guides.


The square section will next be slotted to fit over the slide link, where the blue lines are sketched on. I am leaving the extra stock below that for now to have a way to hold it.

[cnr6400]

 

[Elam Works]

...the crosshead guide looks completely different than any of the other plans or photos I have seen, with a squared slot in the guide rather than the usual arced surface. Is this just a partial view of the parts, or did they make the guiide this way at some point?

Chris,

This was the type of guide they used on the 20hp in 1913-14 with a Ø5/8" x 1/2" roller. This particular CAD model being of a 1913 engine that was in the shop for overhaul. In 1915 they changed to a crosshead guide with a convex surface. In 1917 it changed to concave (with crosshead being convex.) This they kept until the advent of the trunk guides on the SV engines, 1925-26. so depends on what year you are modeling or if going hybrid, which type you like.

-Doug

Ref: Design Evolution of the 20hp Stanley Engine.
http://www.modelenginemaker.com/index.php/topic,9311.msg207297.html#msg207297

[Elam Works]

The piston rod lower end was most likely one piece (or welded) to the crosshead, ...

Forged integral. The forging details did evolve over time, along with the shape of the bearing surfaces for the crosshead guide. Until they went to he trunk guides of 1925-26. Those did thread into the crosshead and were locked by a pinch bolt.

-Doug

[crueby]

Thanks again Doug!!  May your shop elves always be friendly and helpful!  (hmm, theres a christmas card in there... )

[crueby]

This morning chain drilled


and milled out the slots in the valve tie rods - used a 3/32" end mill.

then drilled/tapped the sides for 2-56 screws to hold the pivot bearings

and turned the bearings out of bronze. These are the smallest bearings I've ever made, .109 diameter x .113 long. Hope the shop elves don't want a new pinky ring!

Parts in place on the engine:

Next up, the crossheads for the ends of the piston rods.

[crueby]

And this afternoon started on the crossheads. Cut some lengths of 303 stainless bar, and drilled the center hole for the con rod bearing:

then used the dial indicator to center it in both directions in the 4-jaw on the lathe,

to drill/tap the hole for the piston rod, and turn the OD down to size:

Next will move over to the mill, with the rotary table set up vertically, to mill out the recesses in the sides of the crosshead.
While I was at the lathe, turned up a couple of lock nuts for the piston rods:

[Kim]

More good looking little parts!  Way to go, Chris! 
Kim

[crueby]

Thanks Kim, little by little working my way down towards the crankshaft end of the engine. Still marvelling at how much they pack into a small space, and trying to keep track of what order everything has to be assembled in.

[tghs]

you know this rate of progress is really making some of us look bad,, but I am learning and planning things from it all

[crueby]

you know this rate of progress is really making some of us look bad,, but I am learning and planning things from it all

No worries, you are back in that silly universe with only 24 hours in a day...!   

[crueby]

Finishing off the crossheads with a combination of milling out the larger recesses and rolling the edges with a rotary tool/dental bur.

test fit on the engine:

For the crosshead guides, I think I can make them by boring the ID into a short bit of bronze then cutting that into quartered slabs for the four guides, maybe start on that tomorrow.