The Home Machinist!

Beautiful work! Looks so much better as an assembly.

beautiful work on the throttle jack!

Hello My Friends
Thank you Love4steam and Dan. Been busy with other things the last few days but hope to get something done on the throttle rod down the side of the boiler and the compensating lever today.
Jack

well heres a little somethin from a couple of weekends ago jack

Hello My Friends
Here is some more concerning the throttle and linkage. There are three clevises that connect the throttle rod to the compensating lever, and the small throttle lever down at the smoke box. In the top photo we have a prototype drawing and a length of 1/4" square brass. I will compare the drawing to what we have to work with and make adjustments. Things don't always scale perfectly when building a model. First the future clevis was turned down to 5/32" with a small round nose lathe bit. Then over to the mill and it was cut down to 5/32" as you can see here in the bottom two snappies.

Then a 5/32" end mill was used to cut a recess so the barrel could be silver soldered in. The barrel was drilled half way through with a #1-72 clear drill and the remaining half was drilled with a tap drill. Then it was silver soldered in place. After silver soldering it went for a swim in the acid pot and then was metal finished using the jewelers buffer. Then it had a .140" slot milled in it for the compensating lever, and smoke box throttle lever. Now it's time to start the pivot bolts. These are #1-72 and should be a very snug fit in the clevis. Here the flats are being milled using the spindex.

The pivot pins were all threaded #1-72 and then drilled for the cotter pins. The cotter pin holes were drilled .024. For this a locating fixture was clamped down to the small drill press. Just a simple fixture that was made up and has been used many times for drilling small pins and such. They were all center drilled and then drilled through and the holes chamfered. Then we have a look at the pivot pin fitted into the clevis. One side of the clevis is clear drilled and the other I tapped #1-72. I like the set up better than a pin that just slides in as it makes for a much tighter fit when the pin is in place and the castellated nut is done up. Then a snappy of the clevis and pin fitted to the smoke box throttle lever. Next up will be the castellated nuts. They will be 1/8" across the flats just as the pivot bolts. They will have .020" slots for the .015" cotter pins that I will make. I got some .015" soft stainless wire from McMaster that will be fashioned into half round and then formed into cotter pins. I just love making this little baloney. None of it is really difficult, mainly just busy work, and it all adds greatly to the eye candy on a model.
See You In The Funny Pages...
Jack

Hi Jack:

I see that you soldered a bit of round into the end of the fork to make the clevis. Is there a reason why you didn't just make it one piece and round off the end in the sander or with a file?

Amazing stuff!

Hello My Friends
Thank you rmac, your compliment is much appreciated. There are a number of reasons to make this part in two pieces. Firstly the barrel can be center, tap, and clearance drilled in the lathe. This ensures that the holes are centered in the end radius when the part is finished. You could round the end with files or a belt sander. They probably wouldn't be as crisp and tidy as they are here. To me this is just the fastest easiest way to get the results I wanted. There are other perfectly good ways of doing this, but as I said to me this is quick and easy. Sometimes I will use the file or disc sander if the part is, lets say some brake ringing hidden underneath. Under there, who cares. I will still try to get them looking nice, but get er' done. Now these little clevises are very prominent, right out in front of god and everybody. So I want them be top shelf, nice and neat and crisp. Spend your time where it matters most. Just my two cents.
Happy Model Building.
Jack

Ah ha. Didn't notice that it was threaded. Thanks for the explanation.

Mind numbing detail work. You truly must love doing these kinds of tasks. A rare breed, indeed.
I really appreciate seeing your work and methods.
Thank.
RussN