Chris's Marion 91 Steam Shovel

[crueby]

OK Chris, when are you going to start building this one?

Have a great day,
Thomas

NO!  NOT!!  Did you see how many tracks?


Besides, Zee needs a project!   

[Ye-Ole Steam Dude]

OK Chris, when are you going to start building this one?

Have a great day,
Thomas

NO!  NOT!!  Did you see how many tracks?


Besides, Zee needs a project!   

Hey Chris,

I'm thinking quarter-scale.....

Have a great day,
Thomas

[crueby]

OK Chris, when are you going to start building this one?

Have a great day,
Thomas

NO!  NOT!!  Did you see how many tracks?


Besides, Zee needs a project!   

Hey Chris,

I'm thinking quarter-scale.....

Have a great day,
Thomas

Gack....
I am going to need to borrow your shop. And your welder. And a crew of workers. And a spare field to build it in...   

[galland]

Say Chris,  After thinking the 5760 was a monster (2,560 tons) I found out it was the baby of their large units. Their big one was the 6360 and was 15,000 ton and the largest land vehicle ever built. Just amazing.

    Gary

[crueby]

Thats a BIG baby!
Its amazing that anything that size can move. I've got a copy of the Marion shovel movie DVD from the HCEA, it has footage from the Model 92's up through these giant monsters, amazing to see them in action.
 

[crueby]

Today I made up the arbor for the smaller gears, and got the blanks turned down to diameter. Since the holes in the hubs are all different sizes for the different shafts, I used the largest screw I could for the cap (10-32) and made up a set of little sleeves for the rest of the blanks. These sleeves are a close fit to the gear holes, and are slightly shorter than the gears are thick, so they do not touch the cap before the gear. The cap on the arbor and the center of the arbor end are relieved slightly, so that the cap and the arbor contact the gears out at the rim for best holding power. These gears will not have spokes, so all that is left on these is to cut the teeth.

Here is the setup on the mill, with the rotary table set up vertically, and the cutter centered on the gear. Each gear cutter is good for a range of number of teeth, the first one takes a nbr 2 cutter from the M1 set.

Now, it may appear that the arbor is longer than necessary, and it is a bit - I am planning on using the other end for the larger gears that need spokes, and the narrow end can go into the chuck a bit. The length needs to be enough for the headstock to clear the 4-jaw and rotary table when it is at the finish of the cut, I've been caught on that before and now make sure the arbor is long enough for the smaller gears. I like using the 4-jaw for these operations since it seems to grip better than the 3-jaw scroll chuck. I'll leave this arbor in place through all of the operations on these gears, to ensure that the arbor stays dead centered - it in place since it was turned and drilled. The end of the arbor had to narrow down for the smaller gears, otherwise the cutter would hit it before the cuts were completely through the gear blanks. For the larger gears, I'll keep it at full diameter.
We have our first run of the fall for the RC submarines at the local indoor pool tonight, so I will start cutting gears tomorrow.
 

[kvom]

The Saturn missile transporter was also built by Marion and is the largest self-propelled vehicle.  The 6350 apparently was powered externally.

[crueby]

The Saturn missile transporter was also built by Marion and is the largest self-propelled vehicle.  The 6350 apparently was powered externally.

I believe that they used that transporter for the shuttle as well, it still is there at Canaveral. It even featured on an episode of Dirty Jobs, cleaning and greasing the tracks.

[Brian Rupnow]

A long arbor is a good thing. I have, in my collection of "Oh shits" a #4 cutter that was ran into the hardened corner of my vice because the arbor I was using was too short.---Not pretty!!!.

[steam guy willy]

Was doing a little research on the Marion Shovels and found a website with a bunch of photos of a 5760 shovel being assembled. It is amazing and huge. If anyone is interested.        www.stripmine.org/5760_slideshow.htm

      Gary

Hi Gary its a good job they all have those hard hats !!!!!!!!!!!!!

[crueby]

Was doing a little research on the Marion Shovels and found a website with a bunch of photos of a 5760 shovel being assembled. It is amazing and huge. If anyone is interested.        www.stripmine.org/5760_slideshow.htm

      Gary

Hi Gary its a good job they all have those hard hats !!!!!!!!!!!!!

If you want a BIG model, someone has a pair of dragline buckets, real, for sale on ebay, though you better have a really big truck!

[MJM460]

I was thinking about driving those things.

A drag race from the lights would not be very exciting, but you would always have right of way!

Looking forward to learning about beat cutting, you have quite a pile of blanks there.

MJM460

[crueby]

I was thinking about driving those things.

A drag race from the lights would not be very exciting, but you would always have right of way!

Looking forward to learning about beat cutting, you have quite a pile of blanks there.

MJM460

Oh look, that guy in the car is cutting me off..... SQUISH!   

[crueby]

Got a start on the gears this afternoon, starting with the smallest one. This one determined how small the end of the arbor needed to be, just smaller than the valleys between the teeth.


This view shows where the cutter moves to at the end of the cut, and why that section of the arbor needed to be smaller too:

So, the first three gears are cut, all Module 1 but different diameters/number of teeth. The fourth would be done, but a brain fart interfered and I had to remake the blank for it...   

I am using the Sherline rotary table for cutting the gears - the handwheel on it is set up to be 5 degrees per full turn of the handle, and the handwheel is marked down to a tenth of a degree. What I did a few years ago was figure out the formulas for making a list of handwheel settings based on how many teeth in the gear - it tells me how many full turns and what number to stop at so that I can just follow the list without having to do any math on the fly. Its easy to do a gear that divides into 360 degrees evenly, but for example a 21 tooth gear works out to be three full turns of the wheel from the current position, stopping at handwheel markings: 0, 21.4, 42.9, 14.3, 35.7, 7.1, 28.6 . Those are the handwheel markings, not the number of degrees on the edge of the table, and in this case the sequence repeats every 7 teeth. Having that list makes it really easy to follow the sequence, checking off each move and cut as I go, with less likelyhood to miscount anything. Some of the lists for very large gears get very long, others are very short, like for a 16 tooth wheel its 4 turns and stop at 0, then 4 turns to 25. Spreadsheets can be very handy things!
Its still important to make sure that the cutter is set to the proper height, centered on the blank (and locked down), that the proper cutter is picked for each gear (each cutter in the set is good for a certain range of number of teeth), that the table is moved in to the proper depth of cut for each size gear (and locked down), that I remember to check off each move/cut as I go, and to keep distractions (TV, phone, talkative elves, etc) kept away.  Other than that, gear cutting is a breeze!   

[Craig DeShong]

Did pretty much the same thing when I got my dividing head.  40 turns of the handle is 360 degrees.  Also 6 plates supplied with a plethora of different hole configurations.

I gave up trying to figure out the documentation and wrote my first program  since retirement to tell me the disk circle to use and the handle turns- disk holes to advance for any number of gear teeth I might want to cut.

Old skills are still pretty handy once in a while.