The Home Machinist!

Hello My Friends
Thank you Russ. You are correct, sometimes this is a bit mind numbing and I wonder about my sanity from time to time Here is a bit more on the throttle linkage. The castle nuts were made yesterday. 5/32" leaded steel was used. First they were center drilled and then drilled and tapped #1-72. For tapping tiny threads like this a pin vise is aligned by a shaft held in the tailstock. Then over to the milling machine and the spindex. Six flats were milled to 1/8" over the flats. After that they were given a zoom using the jewelers buffer. This is not at all nessessary but improves the appearance. Then back to the spindex and the slots for the cotter pins were milled. A .020" slitting saw was used for this. Then back to the lathe for parting off. Before doing this the chip pan was cleaned out and vacuumed. These tiny nuts were smaller than most of the chips in the pan. Also, when they were parted off, a small rod was placed in the nuts to catch them as they came free. Only three were needed, but I made six as they are so easy to lose.

This is timely. I need to make a couple of 1/4" - 40 castle nuts and was pondering the best way to do it. Thanks.

Now that the castle nuts are made we will be needing some cotter pins. Some .015" soft stainless wire was purchased from McMaster and made into half round. This is easy to do as the next few photos will show. One end of the wire was clamped to the steel table. It was then run over the smooth surface of the small drill press and some vise grips were clamped to the other end and left hanging to keep some tension on the wire. Then it was simply draw filed until it measured .007". Half round, easy peasy.

Now after making tiny bits and pieces we are getting to the fun part, putting things together. Here we have a clevis with it's pivot bolt and castle nut with a cotter pin stuffed in. Too much fun! In the bottom photo here we have the start of the compensating lever that fits in the throttle rod half way down the boiler. The Nickel Plate Berkshires had a very cool casting for the pivot pin support with a removable pivot pin, but the New York Central Hudsons just had a single pin sticking out through the boiler jacket with another castle nut holding things in place. More to come.
Jack

I suppose a watchmaker would be in awe of these gigantic parts you're making.

Hello My Friends
Small...big...it's all relative. 3/4" scale is small when compared to say, 1-1/2" scale or 3-3/4". But it's absolutely huge compared to Z scale, which I dabble in. For some models you might need a fork lift, for others tweezers and an optivisor, which I find myself using quite a lot these days. It's all good! Here is some progress on the compensating lever and pivot. The compensating lever was made up from free machining brass which is unsuitable for bearings. The bushings are phosphor bronze which wear well. One of my pet peeves is a throttle with slop in the linkage. So I make my throttle linkages with good bronze bearings, and case hardened steel pins. This seems to hold up well. The last photo here shows the lever pivot. The pin is case hardened steel. It is TIG welded to a length of curved .050" steel which will be stuck to the inside of the boiler jacket with JB weld. The pivot pin is .090". The threads are #2-56. It will have a steel shoulder nut set up for another .015" cotter pin. The control rod that connects the throttle lever in the cab with the combination lever and then the throttle lever on the side of the smoke box will be .071" steel. As there are several pins and bushings in this linkage they must be a good fit, as all that lost motion can really add up.
See You In The Funny Pages...
Jack

Hello My Friends
Just a photo of a poor old girl near the end of her life. There are signs of neglect here. Several things that would never be allowed in better times. First off the engine is filthy. Notice the square hole hacked in the steam dome cover. Also the lagging has been removed from the booster exhaust line. This was often done in the final years of the J's. Some even had the boosters removed completely. Other changes from original are the auxiliary reservoir for the power reverse, the top check valve in addition to the normal check valve, and loco valve pilot. Another change is the oversize sand dome which crowds the steam dome, with the casing for the sanders removed. There are also some very sloppily run air lines to the sanders. Obviously a hasty repair as they were normally run under the jacket. There is also a poorly routed bit of piping the comes out from between the sand and steam dome and heads down towards the running board. This may be an air tank res. balance line, as the usual one up at the smoke box is missing. She still has the smoke box clean out plug, which was often removed and welded up in later years, especially on oil burners. And lastly, this engine has a very unusual feature, or should I say omission. I'm not going to give it away, lets see who is first to notice. I have never seen this on other J's, but then I haven't really looked. A picture can certainly tell us a lot can't it.
See Ya' Later Alligator.
Jack

Have to wonder why the shops removed the expansion fulcrum for the throttle. Could have made for an interesting slop in the throttle linkage.

Hello My Friends
UPsteam is correct, no compensating lever.
Jack

JBodenmann wrote: ↑Wed May 05, 2021 12:51 am Hello My Friends
Just a photo of a poor old girl near the end of her life. There are signs of neglect here. Several things that would never be allowed in better times. First off the engine is filthy. Notice the square hole hacked in the steam dome cover. Also the lagging has been removed from the booster exhaust line. This was often done in the final years of the J's. Some even had the boosters removed completely. Other changes from original are the auxiliary reservoir for the power reverse, the top check valve in addition to the normal check valve, and loco valve pilot. Another change is the oversize sand dome which crowds the steam dome, with the casing for the sanders removed. There are also some very sloppily run air lines to the sanders. Obviously a hasty repair as they were normally run under the jacket. There is also a poorly routed bit of piping the comes out from between the sand and steam dome and heads down towards the running board. This may be an air tank res. balance line, as the usual one up at the smoke box is missing. She still has the smoke box clean out plug, which was often removed and welded up in later years, especially on oil burners. And lastly, this engine has a very unusual feature, or should I say omission. I'm not going to give it away, lets see who is first to notice. I have never seen this on other J's, but then I haven't really looked. A picture can certainly tell us a lot can't it.
See Ya' Later Alligator.
Jack

jack can you upload a bigger shot of that B&W picture? im just curious to see the number. thanks

Hello My Friends
Here is a little progress on the throttle lever assembly. A package came from the foundry the other day. Very cool, my throttle castings. It is the casting that fits to the boiler backhead. Then the throttle mounts to it as you can see in the second photo. This was a most delightful little puzzle. I have always liked these overhead throttles. I have made many in 1-1/2" scale for Berkshires and Hudsons. A little project like this is not for someone into instant gratification. First look at some drawings. Then some scribbles with a pencil (I'm definitely old school). Make the masters, and then the molds. Shoot the waxes and send them off to the foundry. Wait...for me often the hardest part. Then the castings arrive and if I haven't screwed up, they will fit together into a lovely little trinket like this. Modern steam had lots of this cool little baloney. I had some help from Doug and his wonderful wire EDM machine. He made the quadrants and the latch. Sometimes I manage to make something I'm particularly satisfied with and this is one of them. Too much fun! I still have some more to do on the throttle linkage. I wasn't too happy with the lever it connects to down at the smoke box, so I will be re making that. Not the first part I have made for the scrap box box and certainly not the last. But you can't let these little set backs discourage you. Chalk it up to experience and move on. After that I'll probably get back to the turret casing. Then I may start on the tender frame. It will be the one piece cast steel water bottom variety. Built up from steel shapes and sheet. Some of these tenders had a corrugated bottom...another little puzzle.
See You In The funny Pages...
Jack

Outstanding! For a size reference, how big is that castle nut in the last picture! What a work of art.

Alex