Ohio Locomotive Crane

[Kim]

Very nice collection of wheels and locks, Chris.  Profiling all those wheels will take some time!   

Are you finding that using the 3-jaw is keeping the wheels concentric enough for the shaping step?  I thought you might use the 4-jaw to center the axle and wheel before turning the profile.  But the 3-jaw may be close enough.

Kim

[crueby]

Hi Kim,


This particular  chuck seems to be running quite true for these larger sizes. Its got the same spindle thread as the Sherline chucks, but was made for larger Craftsman lathes. I've  got both a 3 jaw scroll one and a 4 jaw independent  chuck. Both are much larger diameter than the Sherline ones, and require the riser blocks to be in place. I cheat a bit by having two lathes, one set up all the time with the risers, so I can  just swap back and forth in seconds. They have taller jaws and the 3 jaw has a separate  set for reversed jaws, so it has the right jaw shape either way.


Bottom line,  was expecting  to need the 4 jaw and have the shaft piece aligned with a dial indicator,  but the 3 jaw is running true, so thats quicker.


Chris


 

[Kim]

That's excellent!  A real time saver, to be sure! 

Kim

[crueby]

That's excellent!  A real time saver, to be sure! 

Kim

Sure is! Just profiled the second wheel, and it only took 15 minutes, no centering of the 4-jaw to deal with, and now I know the number of turns to go in at each step so a lot fewer stops to measure things.

Got the second wheel assembled onto the axle blank (the axles are a little long, will be trimmed later) and the shop elves rolled it into the other room and tossed it up onto the table to test it on the display track. Once adjusted to width, it rolls back and forth very nicely, interesting how the tapers on the rim and the flange make the wheels self center. The elves are practicing their not-quite-a-unicycle act...

[cnr6400]

  I hope Stu Pervisor isn't taking a nap on the line down a bit from the shop elves getting that wheelset rolling!  (it looks great BTW) 

[crueby]

I hope Stu Pervisor isn't taking a nap on the line down a bit from the shop elves getting that wheelset rolling!  (it looks great BTW) 

Stu would have helped, but he hasn't  figured out how wheels work yet, still reading the manual!   

[crueby]

Lots more progress on the wheels:

The elves were racing them, but couldn't work out how to pass each other...   
Started in on the thirs set this morning, got one wheel done...

then had to take a short break and call in the elven emergency squad when the belt on the lathe wore out and broke (it was ticking as a strand of the internal cord stuck out the last couple days)

The spare went on pretty quickly, so not much delay, will get back to wheel number six shortly...

[tghs]

good deal, I've made it a habit "now" to have spare belts for all my machines..

[crueby]

good deal, I've made it a habit "now" to have spare belts for all my machines..

Well worth it to have spares on hand - saves a lot of waiting for replacements!

[crueby]

The Elven Roundy Wheels Company has been busy, set three of four is complete:

For some reason the crane CAD model keeps getting replaced with a roller coaster design, though... 

[crueby]

And the wheels are complete!   

Before starting in on the truck frames, I want to make the gears that go on the inner two axles. These gears will be driven by a set of gears in the middle of the car body frame, taking a vertical shaft down through the center of the turntable, out through a pair of bevel gears, and driving the middle gear. This allows the crane to travel on its own, without a yard engine. At first, when I saw the pictures, I figured that the gears on the wheel axles would need to be a lot wider to accomodate the rotation of the truck frames on corners, but I looked up the normal track radius for standard gauge track on main lines and in yards, and sketched it up in CAD to see what the max rotation angle of the trucks would be in relation to the main frame. This showed just a couple degrees maximum, well within the thickness of the gears, and the crane is not a high speed machine. So, all the gears were back to the same thickness, like the catalog showed.  Here is a CAD view of that whole assembly:


After a little math to determine the gear sizes, I would up adjusting the number of teeth on the gears by a couple teeth. This is since the scaled down real gears work out to a M1.64 size, and the nearest set of involute cutters I have is M1.75. Quite close, but still needed to tweak the tooth count slightly to keep the proper center distances. Made up my tables of rotary table movements for cutting the gears, and made a list of the diameters needed for the gears. While I'm cutting the gears for the axles, I might as well cut the other few for the center gearbox - not going to cut the bevel gears now, will do that later on. There are LOTS more bevel and spur gears needed for this model! So far, I've cut off some elfish poker chips for gear blanks, taken them to thickness, and drilled the starter holes in each one. Still need to bore them out to the final ID (1/5" for most, 5/8" for the axle pair), and then mount them on an arbor to take them to finished outside diameters for each gear.

[Kim]

That's really interesting, with the gear-driven axles and all. Seems like they'd have just driven one of the trucks, and not both.  But as it is, it also seems like the gear on the truck axles would need to have a slight curve to them - just a bit convex so that the gears didn't bind when going around corners.  But maybe the 1-2 degrees isn't sufficient to cause an issue...

Very interesting!
Kim

[crueby]

That's really interesting, with the gear-driven axles and all. Seems like they'd have just driven one of the trucks, and not both.  But as it is, it also seems like the gear on the truck axles would need to have a slight curve to them - just a bit convex so that the gears didn't bind when going around corners.  But maybe the 1-2 degrees isn't sufficient to cause an issue...

Very interesting!
Kim

Hi Kim,


I wondered about curving the teeth on the gear on the axle. It would help the tips clear more,  but not the faces down the sides of the teeth. I'm  hoping that just having a slightly larger mesh distance will be enough to let it swing that little bit. It would need more for tighter c7rves on a narrow gauge loco, like on someth8ng like a shay or heisler.


 

[cnr6400]

  A little extra backlash in a spur gear set, ie enough to allow the trucks to turn, shouldn't hurt at all, apart from being a bit noisier than usual. I used this simple approach in several gear systems I designed in the day job years ago for office equipment where the driven system had to move around a bit. Budget didn't allow special gears with curved teeth or sprung idler gears between drive and driven components, and the extra noise was masked by nearby fans and solenoids.  The slight loss of motion quality and efficiency by imperfect mesh was not important for these particular systems. They weren't clocks!

In the full size Ohio crane with deep gear mesh on big gears, and no noise or motion quality or efficiency concerns , I'm sure it would not be any real issue. It also was not a clock. The full size crane got from A to B in any case, and was probably never intended to set any speed or efficiency records - or keep good time ! 

[crueby]

A little extra backlash in a spur gear set, ie enough to allow the trucks to turn, shouldn't hurt at all, apart from being a bit noisier than usual. I used this simple approach in several gear systems I designed in the day job years ago for office equipment where the driven system had to move around a bit. Budget didn't allow special gears with curved teeth or sprung idler gears between drive and driven components, and the extra noise was masked by nearby fans and solenoids.  The slight loss of motion quality and efficiency by imperfect mesh was not important for these particular systems. They weren't clocks!

In the full size Ohio crane with deep gear mesh on big gears, and no noise or motion quality or efficiency concerns , I'm sure it would not be any real issue. It also was not a clock. The full size crane got from A to B in any case, and was probably never intended to set any speed or efficiency records - or keep good time ! 

Good to know!  The cranes wouldn't travel very fast most likely, these were used in factory yards and such. I would imagine that for long distance travel as part of another train, they might disconnect these gears, otherwise the bevel gears would be spinning quite fast. So far I have not found an operators manual for this crane type.