Chris's Marion 91 Steam Shovel

[derekwarner]

This is an interesting snap, as it confirms [I think ] a moment or point of balance of the machine

I understand a big mass of boiler room & machinery is to be placed aft ..but the balance point is still a long way back from the action, and the center axis between the sets of crawler tracks

Derek

[Steam Haulage]

Derek,
Have you any concept of the weight of these machines?  I have been studying them for as long as Chris has been on this design and build and have not seen any trace of balance problems on working machines of whatever origin, US or UK when digging. That is true for all the power options which were available, steam, diesel, electric, petrol. The maximum weight of the dipper (bucket) in the Marion 91 was not particularly great being in proportion to the weight of the house and its machinery.
Chris' model is a scaled version of an actual machine which he has been able to visit, measure and study in detail.
Jerry

[Admiral_dk]

Great to see the Master (Elf) behind his creation with a proud smile   

Thanks to you both - Ron and Chris.

[crueby]

Hi Derek,
I think this picture will help, a render of what the final inside of the machine will look like.


At the point where the backstay from the A-frame attaches to the frame under the floor is where the boiler starts, so its wieght is behind that point. Also, there are two very large water storage tanks, one on each side of the boiler, that are used to refill the boiler during use. The coal pile is behind the boiler, on the right end of the picture. All of that will add an awful lot of wieght to the back of the machine, bringing the center of mass well behind the front tracks.

The machine started out with a working weight of 120 tons, when it was mounted on railroad wheels. The addition of the tracks must have added to that, since they added the track frames and tracks front and rear, the large supports out the side, and another large gear block underneath.
Looking up the weight of crushed stone, I see one reference to 2700 pounds per cubic yard, and this shovel had a 2-1/2 yard bucket installed, so that would be in the neighborhood of 5400 pounds, which is quite a lot to have it that far out in front of the machine in the bucket, but even calling it 3 tons, that is a whole lot less than the 120+ ton machine behind it. Obviously it worked out, since the machines were a huge  success for many years!
You do have a point about the balance - before I added the gear train and hoist engine, I had to have a big block sitting on the rear deck to keep the model from tipping itself onto its nose from the weight of the boom assembly. Now, even without the boiler, it balances well behind the front tracks, and needs a fair bit of lift on the rear deck to tip it.
As for side to side, the front tracks have a span of over 21 feet, to keep it from tipping to the side when the boom is swung over.

 

[crueby]

Great to see the Master (Elf) behind his creation with a proud smile 

Thanks to you both - Ron and Chris.

Thanks Admiral!   

[Brian Rupnow]

Really great picture. Now I can understand the constant references to elves much better. I have an old children's Christmas book with pictures of elves in Santas workshop, getting toys ready for Christmas. I think I may well have a picture of Chris' grandfather or great grandfather in that book.--Model looks really sensational too.--Brian

[crueby]

Hi Derek,
I think this picture will help, a render of what the final inside of the machine will look like.


At the point where the backstay from the A-frame attaches to the frame under the floor is where the boiler starts, so its wieght is behind that point. Also, there are two very large water storage tanks, one on each side of the boiler, that are used to refill the boiler during use. The coal pile is behind the boiler, on the right end of the picture. All of that will add an awful lot of wieght to the back of the machine, bringing the center of mass well behind the front tracks.

The machine started out with a working weight of 120 tons, when it was mounted on railroad wheels. The addition of the tracks must have added to that, since they added the track frames and tracks front and rear, the large supports out the side, and another large gear block underneath.
Looking up the weight of crushed stone, I see one reference to 2700 pounds per cubic yard, and this shovel had a 2-1/2 yard bucket installed, so that would be in the neighborhood of 5400 pounds, which is quite a lot to have it that far out in front of the machine in the bucket, but even calling it 3 tons, that is a whole lot less than the 120+ ton machine behind it. Obviously it worked out, since the machines were a huge  success for many years!
You do have a point about the balance - before I added the gear train and hoist engine, I had to have a big block sitting on the rear deck to keep the model from tipping itself onto its nose from the weight of the boom assembly. Now, even without the boiler, it balances well behind the front tracks, and needs a fair bit of lift on the rear deck to tip it.
As for side to side, the front tracks have a span of over 21 feet, to keep it from tipping to the side when the boom is swung over.

 

That question got me wondering how much that the tracks added in wieght - according to a web search, a set of heavy duty rail tracks are around 5 tons each, so 10 tons for the pair. According to the Fusion 360 model, the tracks, supports, drive shafts, gears all total about 28 tons (huge castings all round). That means converting from rail trucks to crawler tracks added around 18 tons (give or take a few tons depending on how good my measurements were) to the original working wieght of 120 tons, so total of 138 tons working weight (includes water/fuel) of the machine. Quite a lot, though still 1/3 the wieght of a laden 747 jet! (hmm, how many swallows to carry it, they could grip it by the husk...)

[cnr6400]

Swallows of what, to carry it?        (husk or no husk, >hic<)

I certainly don't think there will be any stability issues with the model. There sure weren't any with the full size big shovel units in normal use. I have seen old photos of shovels in trouble from overload, ground collapsing under the tracks or the rails under railroad ones, collisions with other vehicles, and being stuck under landslides or rockslides, but never due as far as I know to instability of the machine itself.

Glad to see Bucket Bob and Ratchet Ronnie the elves are behaving themselves in the photo with you! 

[crueby]

Swallows of what, to carry it?        (husk or no husk, >hic<)

I certainly don't think there will be any stability issues with the model. There sure weren't any with the full size big shovel units in normal use. I have seen old photos of shovels in trouble from overload, ground collapsing under the tracks or the rails under railroad ones, collisions with other vehicles, and being stuck under landslides or rockslides, but never due as far as I know to instability of the machine itself.

Glad to see Bucket Bob and Ratchet Ronnie the elves are behaving themselves in the photo with you! 

This is about the worst one I have seen - it is a photo of whats left of a steam shovel after a rock fall at the panama canal (picture from the Isthmanian Commision annual report of 1912). The remains are NOT the shovel in the background, they are the little bits of twisted metal sticking out where the red arrow is pointing! The guy at the right seems to be saying 'Dang, my lunchbox was in the cab'.      Now, in the report they go into details on accidents like this, they just mention the machine and time lost, never mention the crew that was in it...

[crueby]

Okay. Been fussing, fettling, finessing, fiddling, fabricating, faltering, fanning, fastening/unfastening, filing, fidgeting, fingering, and generally farting about with the last engine all afternoon/evening trying to get the fecking thing to run. 

Finally, figured it out! I'm flabbergasted. 

Got the timing down to the point were it would go nearing a full turn by itself, then keeps stopping. In both directions. Was starting to think I had fluffed the final crankshaft eccentric offset or something. 

Turns out the silly passageway in the right cylinder valve slider is blocked with a drop of hardened loctite!    It looks clear from both ends, but you cannot see all the way through due to the end walls. Finally got out a bit of wire to run down it, and on the left valve it slides right through. On the right one, half way in and bonk, stops dead. Shined a flashlight in one end chamber, and I can see a red glow.

Sigh.

Must have dribbled in there when I plugged the drill hole in the end, went in the passage far enough it did not show.     


Now, on the very first engine the same passage had some chips in it, and I had made a mental (yup) note to check the rest but apparently missed one. The plugged one.   

At least the issue is known, but it is way past time for a break, will sort that one out tomorrow and put the steam chest back together. Again.

At least the lunch run was a fun one!

[Admiral_dk]

Oh man - things like this can really baffle you for a long time and when a really bad case comes around, you nearly goes bonkers in desparation and it is not only engines 

Glad you discovered the reason as it help your sanity quite a bit     

Best wishes

Per

[MJM460]

Well done on finding that one Chris, it was well hidden.

At least you now know that everything else is perfect and double checked.

Another significant milestone in a great project.  I look for each post every day.

MJM460

[crueby]

Hours yesterday fiddling and investigating, minutes today to fix the third engine's valve and reassemble it - then it just took off running!  To clear the blockage in the passage, heated a bit of wire and pushed it through the drop of hardened loctite to soften it and push it out. Oh, and wat5ching the video I heard the clicking sound, remembered that I had loosened the bottom caps on the con rods so I could apply low pressure air and turn it over by hand to see when the valves opened/closed - the con rod would snap over the fraction of loose space against the crank as it changed direction. Just went and tightened those again, clicking sound is gone.

<a href="https://www.youtube.com/watch?v=_QLoV7DMMSg" target="_blank">http://www.youtube.com/watch?v=_QLoV7DMMSg</a>

So, now can get back to final assembly!

 

[cnr6400]

It runs great Chris! congratulations.  Glad the problem was relatively simple / not involving re-making parts.

[Kim]

Amazing work, as always, Chris!
Kim