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Re: 2-1/2", 65 ton New Mexico Lumber Co Shay (Lima C/N 1762)

Posted: Sat Mar 25, 2017 8:26 pm
by jamespnelson
Cutting cylinder heads from a piece of 3-1/2" diameter stock today on my cheap< shameless (and free) horizontal band saw. I picked the metal up at my local scrap yard ($0.50/lb for steel), which ends up being less than a dollar a piece. Its an impressive Woodruff key; some sort of old shaft, I'm guessing. Large as it is, its still smaller than the diameter of a Shay's crankshaft (5" for mine). The lower cylinder head was cast integral with the cylinder and crosshead guides, and I'm building that up from pieces, as there was no way practical way to reproduce the casting. I'll post some pictures of that soon: the parts are back from the laser cutter and are beautiful.

Re: 2-1/2", 65 ton New Mexico Lumber Co Shay (Lima C/N 1762)

Posted: Mon Mar 27, 2017 7:53 am
by Brian Hilgert
Those cheap bandsaws are great. My RongFu cuts straighter than the larger Ellis that I have. In fact, the Ellis is in storage because of it.

Looking forward to seeing your progress.

Re: 2-1/2", 65 ton New Mexico Lumber Co Shay (Lima C/N 1762)

Posted: Mon Apr 17, 2017 7:50 pm
by jamespnelson
Got the crosshead/lower cylinder head assemblies welded up today. The prototype used a large casting for this, but I couldn't cipher how to duplicate it. I had the bottom and two side pieces cut with a laser so they would all be identical, and cut the round piece from a piece of 2-12" OD, .125 wall steel structural tubing. I turned the heads and predrilled everything including the packing gland fittings, and tapped the holes before welding. Not even sure I need to do any grinding; the joints are lovely. Only fused the outside for aseptic reasons, but ran a bead in the inside for strength. I also got most of the bottom bracket done today; just need to finish up the inside portion. Post a picture of that when its done.

Re: 2-1/2", 65 ton New Mexico Lumber Co Shay (Lima C/N 1762)

Posted: Mon Apr 24, 2017 8:32 pm
by jamespnelson
Crossheads
Crossheads
Finished the crossheads today. Making the deep pocket was tedious to say the least. I had the covers laser cut as a convenience (and it was 0.125" sheet like the crosshead guide parts, and it wasn't any extra). I tapped the piston rod hole 1/2" NF so i could make any as needed minor adjustments to the rod length once I assemble the engine. In retrospect, I'm going to drill and tap a set screw for that as well, as I'm not sure I want to rely on thread lock on the reciprocating mechanism. Any thoughts on that?

Bottom bracket is also done, but I didn't think to snap a picture of that today. I'm starting on the crank next, as I have all the materials for it at this point, and the web portions are all cut. While I do that the steel for the crank bearing brackets will be on the horizontal band saw. It's 1-1/2" by 5" stock and takes a while to get through, and I need 4.

Re: 2-1/2", 65 ton New Mexico Lumber Co Shay (Lima C/N 1762)

Posted: Mon May 15, 2017 11:29 pm
by jamespnelson
My cylinder castings arrived from Cattail Foundry this afternoon. Fortunately for my postal carrier, this is the last of the castings I need for my project (I think). They came out very nicely; kudos again to Emanuel King and his crew at the foundry. I had 4 made: there is a long lead time on these, and if I cock one up, I don't want to wait another 6-8 weeks for a replacement.

Re: 2-1/2", 65 ton New Mexico Lumber Co Shay (Lima C/N 1762)

Posted: Wed Aug 09, 2017 12:03 am
by jamespnelson
Question for the group: I'm turning the eccentrics, and wondering how folks have done this. I've turned the major diameter, then cut and finished the diameter to accommodate the straps. I used my 0.125 cut off tool
To do this. I've also laid out my slots to cut off each eccentric (3 on this billet in the picture). Next is drilling and reaming the offset. I hane a 1" crankshaft, and was of course going to drill it undersize then ream. I was planning to cut off the sprue and chuck the workpiece in my 4 jaw chuck and indicate the offset for drilling. What I'm concerned about is cutting off the individual cams with my cut off tool after drilling. The interrupted cuts from the bore would be tough on the tool. My other thought was to drill it much smaller, say 0.25" then cut it off, and use a 0.25" rod in my mill chuck to locate the hole and then drill and ream there. The smaller hole would be easier on the cut off tool. Any other thoughts or methods? Appreciate any input.

Jim

Re: 2-1/2", 65 ton New Mexico Lumber Co Shay (Lima C/N 1762)

Posted: Wed Aug 09, 2017 3:04 am
by Harold_V
Do you have a mill? If so, consider locating and drilling the holes after the blanks are parted and finish machined. Real easy to do, especially if you use a DRO, although one is not required.

With the pieces faced parallel, locate one on the mill table, sitting on a pair of parallels. Make sure you clear the area you'll drill and ream (I'd advise boring instead, as you have greater control and a guarantee of a round and properly located hole). Dial the perimeter of the blank, using a DTI. Once you establish center, all you need do is offset the table (or saddle) the appropriate amount and create the desired hole. Done.

H

Re: 2-1/2", 65 ton New Mexico Lumber Co Shay (Lima C/N 1762)

Posted: Wed Aug 09, 2017 7:22 am
by shayloco
jamespnelson wrote:Got the crosshead/lower cylinder head assemblies welded up today.
Nice fabrication work!
-Larry

Re: 2-1/2", 65 ton New Mexico Lumber Co Shay (Lima C/N 1762)

Posted: Wed Aug 09, 2017 10:04 pm
by jamespnelson
Harold,

Yes I do have a mill. Excellent suggestion. I was hoping to be able to locate all the holes at once on the lathe, then open them to finish on the mill (and avoid doing 6 repetitions of the operation). [/quote]
Get creative and it won't be a big deal. Consider making a setup with several parallels. Two of them will form the datum points. Clamp them to the table such that when you insert a piece, it sits much like it would in a V block. You'd locate them approximately 90° from one another, and they'd have to be taller than the parallels you'll use to place under the pieces, so the pieces can touch the parallels used to orient the part. Once you've found center of the first piece, and moved to location, you won't have to do anything more aside from change pieces. That's assuming the diameters of all the pieces are quite similar, or if a minor variation of hole location isn't critical.

H

Re: 2-1/2", 65 ton New Mexico Lumber Co Shay (Lima C/N 1762)

Posted: Thu Aug 10, 2017 1:44 am
by Harold_V
jamespnelson wrote: I was hoping to be able to locate all the holes at once on the lathe, then open them to finish on the mill (and avoid doing 6 repetitions of the operation).
Get creative and it won't be a big deal. Consider making a setup with several parallels. Two of them will form the datum points. Clamp them to the table such that when you insert a piece, it sits much like it would in a V block. You'd locate them approximately 90° from one another, and they'd have to be taller than the parallels you'll use to place under the pieces, so the pieces can touch the parallels used to orient the part. Once you've found center of the first piece, and moved to location, you won't have to do anything more aside from change pieces. That's assuming the diameters of all the pieces are quite similar, or if a minor variation of hole location isn't critical.

H