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Steam Powered Face Shovel Excavator
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Email: dogsbody@steamhobby.com     Home: http://steamhobby.com


1. Credits & Specs
2. Overview
3. Base Mechanics  
4. Platform Mechanics  
5. Materials

See Also:
Steam Tractor Tank
R/C Steam
Tractor Tank
Steam Locopede
R/C Steam
Locopede
Turret Tank
R/C Steam
Turret Tank


1. Credits & Specs
  
I made the mistake of performing a Google search entitled "meccano steam".   A bad idea, since it let me find someones build of a large & wonderful face shovel excavator model.   Powered by steam.  Made of Meccano.  Lots of Meccano.   A 90+ year old metal construction set/system involving girders, beams, plates, wheels, gears, axles, and huge numbers of nuts & bolts.

The design was originally built by Patrick Lewis, England, and featured in the October 1970 issue of Meccano Magazine.   John Bader, England, presented an updated article in the June 2002 issue of Constructor Quarterly.    I would have remained in blissful ignorance, if not for Chris' Meccano Restoration site.   Alas, it awoke a childhood love of Meccano and meshed with my current steam cravings.

Chassis & BodyMeccano
Power: Meccano 1929 Vertical Steam Engine
Fuel: Liquid Methylated Spirits (Denatured Alcohol)
Boiler Pressure: 15+ PSI
R/C: Not yet.
Runtime: 15-20 minutes
Weight: 20 lbs (empty)
   




face shovel excavator


2. Overview

As on Chris' version of the face shovel, I used 1970's Meccano yellow, blue & zinc.   This is a large model & needs lots of not inexpensive brass parts for the power train, lots of not inexpensive hinges for the tracks, and lots of not inexpensive girders, wheels, axles, etc...   Fully assembled it weighs just over 20 pounds -- mostly steel and brass.

To build the FSE, first I tracked down the editor of Constructor Quarterly and purchased a reprint of the June 2002 issue (CQ56). 

Next I bought a used & abused 1929 Meccano Vertical Steam engine off eBay.   These are rare & don't come up often, so I wasn't picky.  The paint had been stripped from my find allowing the frame to rust quite badly in places.  

A tear down, wire brushing, sanding, cleaning, and repaint with Chevy blue (sometimes called Old Ford blue) engine enamel cleaned things up.  The paint contains ceramic and is resistant to heat, fuel & oil, plus it matches the 1970's Meccano blue very well.

The exhaust pipe from the engine cylinder was cut off at some point, and vented directly into the firebox.   I extended it back to the top of the boiler.   Also, no gears were included so I purchased a replacement set.
rear view


1929 Meccano Steam Engine closeup



The face shovel has a total of 18 controls.   All but the engine enable/reverse control (red handle on the steam engine itself) are visible below.   There are 10 primary controls, and seven sub-controls for braking.   This might seem like a lot, but eventually you realize they're all needed.


left side view of control


Here they are highlighted.   The reversing gear control (A), bucket door release (B), track steering clutch (C), track drive control (D), three sets of clutch, ratchet brake, and friction brake boom controls (EFG, HIJ, KLM), two-to-one gearbox (N), slewing drive control (O), engine clutch (P), and superstructure locking brake (Q):



The transmission seen from the right side:

right side

Details of the boom and bucket arms:

boom arms

3. Base Mechanics

First I built the track steering gearbox, which makes the tracks either move in the same direction (for forward/back), or opposite directions (for turning).

I ran into problems though, since the newer parts I bought had slightly different dimensions.  In addition, I found myself unsatisfied with the clutch mechanism.

The dog clutches (formed from gears & screws) only engaged coarsely.   Applying too much force to the steering control could easily stall the steam engine.   Thus I redesigned things using 26T bevel gears instead, making the operation very smooth.   The bevel gears mesh nicely when pushed together, and the upgrade is highly recommended.


bottom view of track steering gearbox


Finishing the base naturally involved making... the tracks.   This part of the assembly is a mind numbing experience.   There are 168 hinges, each attached with two screws, two washers, four nuts, and lots of Loctite.   Fun, fun, fun...  Or not.  :-)


closeup of track


A picture of the fully assembled tracks attached to the base.  Can also see the linkage I devised for controlling the engine clutch here:

rear view of tracks


Finally, a closeup of the bearing ring sitting between the base & crane platform.  The fixtures hanging from the platform and hooked under the bearing ring are free running pulleys that stabilize the platform to prevent rocking.


side view of tracks and bearing ring

Overall, base assembly is straightforward.  The text and pictures provided in Constructor Quarterly are more than adequate.  My only recommendation is to use new axles everywhere.   Used axles typically have small bends or buildup that inhibits smooth operation, which I learned the hard way.



4. Platform Mechanics

The crane platform assembly is somewhat more involved, but most elements can be figured out with thought, and careful reading of the magazine.


view of platform assembly

Naturally the first step was putting together the platform superstructure, A-frame, and side plates.  

I approached the transmission opportunistically using the provided photos.   Whatever was obvious I made first.   Some elements must be inferred, and certain areas are only covered by the text.   Ultimately I went through numerous cycles of disassembly & reassembly when working on areas with tight access.  I can't emphasis enough the importance of using new clean straight axles.

One area not well described in the magazine is the track & slewing drive controls.   These transfer engine power to the track steering gearbox, and platform slewing gear (within the bearing ring) respectfully.  

The vertical clutches are described, but not how they're articulated.   See right for my approach here.

drive clutch


4.1 Design Changes

As with the track steering gearbox, I upgraded most clutches to use bevel gears.  The original dog-clutches used a collar grubscrew to engage a #171 standard socket coupling.   They only engage in one position, when grubscrew & coupling slot align.

The bevel gears work much better, engaging at any position and requiring less movement.  They are longer however, requiring more axle space.   Minor shuffling of elements in places is necessary.

old & new dog clutchs



The two-speed reduction gearbox with bevel gears.  It wouldn't fit in the original position, so I turned it 90 degrees.   As a small bonus, the new position makes hooking up the engine easier.


two speed reduction gearbox



The updated boom drum drive.   The boom drum raises & lowers the entire boom (crane assembly).   Plenty of axle room here, so an easy refit.

Also visible is the superstructure locking brake control -- the 38t gear connected through a trunnion.   Somewhat close to the boiler, so don't burn your hand!

boom drum drive



The updated reversing gears.   These support reversing engine power to the tracks, slewing gear, and bucket arm crowd drum.   The reversing gear axle was overfull once fitted with bevel gears, so I switched to #171a Short Socket Couplings.  I also removed the stack of wheel discs forming a center bearing (not really needed anyway).    The gear selectors I made from strips of 3/8" by 1/16" aluminum.


reversing gears





The revised bucket arm drum drive and bucket arm crowd drum drive.   These control lifting the bucket arm up/down, and pushing/pulling the bucket arm in/out within the boom.

Plenty of room for the bevel gear upgrade in both cases.


buck arm drum drive


5. Materials List & Vendors

 
Contact Address:
    Constructor Quarterly
    17 Ryegate Road
    Crosspool, Sheffield
    S10 5FA
    England
  • Meccanoman Online Superstore.   Great selection, often offering both new & used parts.   Accepts new web orders infrequently though, so check back often.
  • Meccanoshop.  Prices tend to be a little higher, but they're always open.   Discounts on bulk purchases of smaller items like screws/washers/etc...    Copies of Constructor Quarterly are sold there also (scroll to bottom of page).
  • Joel Perlin Erector Sets & Meccano.   Large inventory of Meccano parts.   In particular, stocks the hard to find #27S replacement gear/pinion set for the 1929 Meccano Steam Engine.   The pitch of the 27S gears differs from standard Meccano gear pitch, matching the original steam engine gears.
  • eBay.co.uk   Large number of Meccano vendors to be found on the UK eBay.   Keep an eye on shipping costs.
  • Other Supplies (Home Depot, Kragen, etc...)
    • 3-in-1 oil
    • Loctite Thread Locker
    • Chevy Blue Engine Enamel

See also:
Steam Tractor Tank
R/C Steam
Tractor  Tank

Meccano Web Ring
See also:
Steam Locopede
R/C Steam
Locopede