Author Topic: Chris' Build of a Lombard Hauler Engine  (Read 295319 times)

Offline zeeprogrammer

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #840 on: February 26, 2017, 02:24:45 AM »
Chris...being American, you do know that we learn best by making boo-boos. I haven't seen a boo-boo from you for a long while...if ever.
 ;D

BTW...in one of your shots is a shelf with a bunch of little itty-bitty things on it. You know the question.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Offline 90LX_Notch

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #841 on: February 26, 2017, 02:30:10 AM »
Brilliant work on the braket Chris.

-Bob
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Online crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #842 on: February 26, 2017, 02:37:33 AM »
Chris...being American, you do know that we learn best by making boo-boos. I haven't seen a boo-boo from you for a long while...if ever.
 ;D

BTW...in one of your shots is a shelf with a bunch of little itty-bitty things on it. You know the question.
I don't do boo boos. I do major brain farts! Most hit the scrap box or the trash can before the camera can focus. Most recent were te botched spokes on steering wheel, remade with new part. Also blew it on first front wheel.


As for little stuff in pic, which one? Most shelves in the room are like that!

Offline b.lindsey

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #843 on: February 26, 2017, 03:11:21 AM »
That boiler support is a very intricate part Chris, you make it look easy!! Nicely done.

Bill

Online Flyboy Jim

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #844 on: February 26, 2017, 03:45:38 AM »
I like that support Chris. Definitely looks like a cast piece.

Great explanation on the differential..................not if I only understood it.  :Doh: Couple more times through and I'd should have it.

When you did the 3D drawing of the frame, does that give you all the pertinent measurements?

Jim

PS: I saw that same shelf as Zee and wondered the same thing. I don't know if others do it, but I always look in the background of pictures to see what I can see. Obviously Zee does.  ;)

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Online crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #845 on: February 26, 2017, 04:05:06 AM »
I think you guys must be looking at the upper shelf on the wall behind the boiler tube? If so, that is a row of miniature scrimshaw pieces, all fossilized walrus tooth sections. Those were all done by the wonderful artist William Carrera. I collected those years ago, also commissioned him to do scenes on a pair of full length walrus tusks I had. I used his work to learn scrimshaw techniques to do on my own collection of whales teeth (all legally collected before the ban went into place!) I haven't done any new scrimshaw in about 10 years, still have about a dozen teeth left to do.

Online crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #846 on: February 26, 2017, 04:07:31 AM »
Oh, and yes, the 3d drawings give me the dimensions of all the parts. When I get the differential parts drawn, I will post some exploded views. Another simple but elegant mechanism. I was surprised how far back the diff mechanism goes.

Online crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #847 on: February 26, 2017, 08:24:17 PM »
Today was a 3D modelling day - started in on the differential. I spent some time working out the number of teeth on the various gears to make it work out with the gear cutter sets I have, the spacing needed for the upper/lower shafts, and the space available inside/under the frame. I wound up increasing the gear ration slightly from the original machine, which is fine for a small model that I dont want to have run too fast given that the small engines seem to like running a little faster than the originals.

So, here is what I wound up with:

The top blue gear (23 teeth, module 1) will sit in the middle of the crankshaft, drivien by the engines. The large orange bottom spur gear (72 teeth, module 1), forms the shell of the differential itself. The four teal inner bevel gears (24 tooth, module 0.7) ride on shafts in a plate held inside the large spur gear, and drive the light green output bevel gears (60 tooth, module 0.7) on either side. The light green output shafts will be held in bearing block sets on either side, and hold the drive chain spur gears at the outer ends.
To support the orange spur gear, the blue center plate has a shaft sticking out either side that rides in holes in the inner ends of the green shaft.
Now, here are some cutaway views:
The first shows the green bevel gear and output shaft on one side removed, so you can see the blue center plate and its axle.The orange spur gear has a rim on one side that the plate is bolted to. The plate slides in from the other side of the gear. The output shafts bear on the hub of the center plate to keep it centered.

The second view shows the center plate removed as well

which shows the four bevel gears and the axles they ride on. The bevel gear axles do not go into the center hub, they stop just short inside the central plate.

Now, if you are familiar with how a car's differential works, this should be familiar. As the blue top gear turns, the orange gear and its contents also get turned. If the forces on both tracks are the same, then the bevel gears do nothing, and the output shafts both turn together.
In a turn, say to the left, the left output shaft needs to turn slower and the right shaft faster. The freewheeling small bevel gears turn, so that the output shafts can turn at different rates.   

Hard to describe from a static drawing, If you go to this web site, it has some very good animations of the same basic mechanism. The only difference is that instead of a pair of spur gears, the input gear is another bevel gear set, but the inner gearing is the same.
http://auto.howstuffworks.com/differential2.htm
« Last Edit: June 04, 2018, 01:34:44 AM by crueby »

Online crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #848 on: February 27, 2017, 11:45:49 PM »
Some more work on the 3D model today, laying out the support frame and bearings for the differential unit. Here is the rendering of the frame/bearings,

and the unit with the engine beds, which it bolts to.

The final unit will also have a sheet metal cover over the differential gears (though it seems a shame to cover up all that work!).

That should be enough to get started on making the parts, will intermix that with the 3D model of the engine itself...
« Last Edit: June 04, 2018, 01:34:54 AM by crueby »

Offline 10KPete

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #849 on: February 28, 2017, 12:40:26 AM »
Oh boy, oh boy! We get to see you make bevel gears... :popcorn:

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Online crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #850 on: February 28, 2017, 01:09:46 AM »
Oh boy, oh boy! We get to see you make bevel gears... :popcorn:

Pete
Again!   :o


Not my first set, made them for the Shay build. With the extra passes needed, they are like making the same gear three times, three times the chances to bungle something!

Online Flyboy Jim

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #851 on: February 28, 2017, 03:11:29 AM »
Nice drawings and good explanation, Chris. Looking forward to seeing this come together. Pretty involved project.

Jim
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Online crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #852 on: February 28, 2017, 03:16:24 AM »
Thanks Jim,  I did take some time to make that y axis lock you sent the link for, works amazingly well! The stock one was more of a y axis slower downer than a lock.

Offline mike mott

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #853 on: February 28, 2017, 04:30:46 AM »
Hi Chris I'm on Page 5 amazing work, the ship model is wonderful too, I suppose you are familiar with MSW http://modelshipworld.com/
and the wonderful build logs there of some remarkable ship models.

The track parts are very nice I cannot recall reading about the cutting of the slots depth of cut or feed info. Did you cut each slot in 1 cut or were there a number of passes in and out for each slot? I know this is way past , But I just started your log.

Mike
If you can imagine it you can build it

Online crueby

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Re: Chris' Build of a Lombard Hauler Engine
« Reply #854 on: February 28, 2017, 01:22:41 PM »
Hi Chris I'm on Page 5 amazing work, the ship model is wonderful too, I suppose you are familiar with MSW http://modelshipworld.com/
and the wonderful build logs there of some remarkable ship models.

The track parts are very nice I cannot recall reading about the cutting of the slots depth of cut or feed info. Did you cut each slot in 1 cut or were there a number of passes in and out for each slot? I know this is way past , But I just started your log.

Mike
Hi Mike!

I used to subscribe to the NRG's journal many years ago (in the pre-internet days), but I had not seen their forums - will have to go check them out! Thanks for the link.

For the slots in the tracks, those  were cut in one pass, done by hand so I can't give feed rates, just done by feel with a few drops of oil on the metal for each cut. That is why I had them laid flat for cutting the slots and came back to square up the bottoms of the slots, rather than vertical to do it in one go, or the 1/8" end mill would have flexed and heated up too much. The 303 stainless cuts nice and easily with a fresh sharp cutter, which helps a lot, another stainless alloy would not have worked out so well.

Chris