3/4" Scale J1e

[Greg_Lewis]

I had a similar problem with a chuck vs. rotary table, and I just made up an al. plate to fit between the two, thus holes for the t-slots could be offset from holes for the 3-jaw.

[JBodenmann]

Hello My Friends
Greg's suggestion to mount the three jaw to the rotary table was my first choice, but I didn't have any material laying around that would work. So a different route was taken. Here is something that the set up was used for. The Barco alarm has a couple globe valves that need handles. Some small 1-1/2" scale handles are on hand but they were far too large. These were .290" in diameter. Some new ones were made that are .215" and .187" in diameter. Brass round stock was chucked in the rotary table after turning the end to .215". A center drill was used to poke eight positions and then they were drilled with a #59 drill, .041". A 1/32" end mill was then used to elongate the holes by .020". The center of the handle was then cut down, lowering it by .015" leaving the outer edge and a raised center. Then over to the jewelers buffer to smooth the sharp edges slightly. The little fellow was then parted off. This was then repeated to make a handle that is only .187" in diameter. This scales out to 3" in 3/4" scale. The bottom photo shows three valve handles. the large one is .290" in diameter. The other two are .215", and .187" in diameter. The small one is as small as I am prepared to make one. The two smaller ones should do for any 3/4" scale valves. The holes through the center are #60 which is the tap drill size for a #00-90 thread. This is actually oversize for 3/4" scale but anything smaller would be far too delicate. As if #00-90 isn't too delicate already. When all the parts are finished molds will be made from them. The small handle here is just one part for the low water alarm. There are actually two on the alarm. And the alarm is just a small part of the J1e. It just seems to go on and on.
See You In The Funny Pages...
Jack

[JBodenmann]

Hello My Friends
The Barco alarm is now ready to have some feet fitted up. First the mounting feet were made along with some stand offs which were fastened to the feet with some #0-80 round head screws. These stand offs are just to locate the feet when they are glued on. For this some Gorilla glue two part epoxy was used. Then the alarm was stuck to the boiler jacket with hot melt glue. Then the feet were set in place with some glue dabbed on them. In Andy's thread I was blabbing about making mistakes and having to re do things and that is exactly what happened here. After... of course after, the glue set I noticed that the two feet on the upper side of the water alarm were too long. I made all three the same length thinking they were the same. The two facing the centerline of the boiler should be a bit shorter. I didn't notice this detail until things were stuck together. So they were snapped off, shortened and then re glued. Not a big deal but I really hate doing things twice. Now the boss on top for the access plug can be glued on and filling and sanding can proceed. This will be done with the primer in the bottle cap and toothpick routine. Dabbing on primer and letting capillary action do its thing. This will be done several times until all the filets are satisfactory. Then a couple coats of spray can primer. After all is looking good the parts will be used to make molds. Now on to the next detail, the booster engine and its associated piping.
See Late Alligator
Jack

[JBodenmann]

Hello My Friends
Now it's time to start a little trinket that I have been wanting to make for some time, the trailing truck booster engine. This will be a dummy engine and not a functional one. First off here is a cool photo that was found online. It looks like they have a booster fitted up to a dyno. Everyone has come to have a look. There are obviously some of the office staff, along with some guys from the shop. That would have been something to see. This is an interesting photo as it shows the front end of the booster with its ribbed bearing housing and the small access doors for lubrication. There was probably some sort of spring pad lubricators in there. This ribbed housing will be a fun little puzzle to make. This is the booster I will be making. Then we have a side elevation drawing. Note the difference in the access door location. I will not be making this particular booster, but another I have a fairly compete drawing set for. Then we have progress so far, a start on the main housing. Also to be made are the flexible joints that connect the booster to the steam and exhaust piping. These large insulated lines run forward under the cab across the fire box and under the running boards. They are a prominent feature of the New York Central Hudsons. The supply line is on the fire mans side, and has an air operated throttle valve right aft of the smoke box. The exhaust line is on the engineers side and runs forward to the feed water heater in the smoke box. Gaggles of fun little baloney to make.
See You In The Funny Pages...
Jack

[Andy R]

Jack,
It is always interesting to see you make "Gaggles of fun little baloney". I learn a lot.
I see also that you made a custom scale to allow translating whatever is shown on the drawings to 3/4-inch scale.
That's worth emulating!
Regards,
Andy

[JBodenmann]

Hello My Friends
Here is some little baloney that was cobbled together today. The front end of the stoker engine has some ribbed bearing enclosures that the axle rides in. Between these there is a housing for the big gear on the axle, and that is what we are making here. Some 1-1/2" diameter brass was drilled, bored to have a 1/16" wall thickness ,and then parted off. This then had a quarter section cut with the mill and slitting saw.

[NP317]

How were the booster engines disconnected from the axle for cruising at speed?
I've wondered about that.
I THINK I see how, looking at the cross sectional drawings, but I'm not sure.
RussN

[JBodenmann]

Here one half is being quartered, and the quartered section has been placed on the sides. This will form the gear enclosure. There is still a small rectangular piece to be added to the top. This assembly was then put together with small screws and silver soldered. In the third photo some 1-1/8" round brass has been chucked in the three jaw. If you look closely you can see a shim under the top jaw. This will allow the 3/4" hole and the recessed portion of the bearing housing to be turned off center. The bottom photo here shows the off center hole.

[JBodenmann]

Now for the offset turning. This top photo shows a cutter that was made up. The cutter is 1/4" wide and has a small radius at the corners. The next two photos show it in action. The slots are .255" wide. The ribs are .062" wide. The ribs are tapered. In the last photo the part has been re chucked so the ribs run concentric and the ribs are being rounded with a file. Then they went for a zoom on the jewelers buffer to finish things up. As I was making this part it looked surprisingly like the drawing. Then it dawned on me that I probably made some of these parts as the pattern makers long ago did. Shapes are shapes, and to make them the same techniques apply.

[JBodenmann]

Now it's time to slice and dice. First the part was cut in half and then a flat was milled where it fits against the main housing. Things are just piled together in the bottom photo. The parts made today are the gear enclosure and the top half of the bearing housing. These parts are integral to the main housing. Delrin AF split bearings will be made for the trailing truck axle to spin in. Tomorrow the bottom half of the bearing housing will be made. It bolts on from below. Having fun here.
Jack

[JBodenmann]

Hello My Friends
I just noticed Russ' question. Here is how things worked. When the engineer activated the booster engine steam started the engine turning over. On engines with a Johnson bar he had to move a latch that allowed the Johnson bar to move forward more than usual and operated an air valve that opened the air throttle down by the smoke box. On engines like 5344 that had a screw reverser I don't really know how the air throttle was activated. This allowed steam to flow to the booster, at this point the booster engine was running free and the booster cylinder cocks were open. The booster had what was called a timing tank that slowly filled with steam. I don't know how long this took but when the tank was full, steam pressure closed the cylinder cocks and a piston inside the booster moved an idler gear engaging the booster with the trailing truck axle. After that, the rotation of the stoker engine kept the gears engaged. When the speed of the locomotive overcame the speed of the booster engine the idler gear was thrown out of engagement. All this baloney had to be kept in operating order, so as the locomotives aged and were bumped to less demanding service the boosters were removed. Many pictures of Hudsons taken in later years show this. First the insulation covering the large steam lines started to come off bit by bit. Then the boosters. When new the Hudsons were immaculately maintained as they were used on the top of the line passenger service. The Twentieth Century Limited and such. Most always clean and intact. Then they began to be bumped to lesser trains, and then to commuter service. In their final days they often looked rather forlorn. A sad end to these magnificent locomotives. Not one was saved from the scrappers torch.
Jack

[NP317]

Jack:
Thanks for your explanation of the booster operation. Way more complex than I envisioned.
'Sure makes jet turbine engines look simple...
RussN