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James Coombesrunning 100 years

Type: Table Engine, single cylinder, double acting, slide valve.
Bore 1 in
Stroke: 2 in
Height: 14 1/4 in
Availability 1978-Today.
Design: Table Engine




THE
"JAMES COOMBES'
A Table Engine



Bore: 1 in.
Stroke: 2 in.


Price
£212

Height. 14 1/8 in.

The James Coombes is based on a table engine that worked for more than a century in a Bristol colliery. The original had a ten inch bore and a twenty four inch stroke, developing approximately 20 hp at 40 rpm.
The model was designed by Mr Andrew Smith who also wrote the book "Building the James Coombes Table Engine".
Stacks Image 98


Contents:

Cast Iron - Baseplate, crosshead guides, pedestal, pulley, crank, cylinder, valve chest and cover, top and bottom cylinder covers, piston, 7 in. flywheel.
Brass - Slide Valve, eccentric strap, valve operating block, glands, conrod bush, crossheads, crankshaft bearings.
Steel - Crankshaft, connecting rod, eccentric sheave, eccentric rod, clevis, crankpin, piston and valve rods, all material for valve gear and beam pivot.
Sundries - Detailer drawings, gaskets, "O" ring, gland packing, fixings pack.







Design

The table engine layout is a method of reducing the floorspace an engine takes up. The cylinder is placed on a table structure, below it is the crank. To pass the movement above the cylinder to the crosshead, above the cylinder, the conrod is much more complex. A rod is connected to a bar that spans the width of the cylinder and two connecting rods, connected to each end of the spar pass up through slots in the table and connect to a bar running through the crosshead. The crosshead runs in slots machined into two triangular support frames. The crosshead slides in the James Coombes design but some feature rollers that run in the support frames. Valve gear is the same as for the Beam engine but with a much shorter eccentric rod. The two supports towering above the cylinder combined with the two connecting rods give this engine a very arhitectural look, some engines were very extravigant in the design of the casting leading to another variant of this engine type, the Cathedral Engine. The running of this engine looks a bit odd to start with, the occilating connecting rods eaither side of the cylinder. After a while it becomes a bit hypnotising.







Stacks Image 117
Full size pumping engine, basis for the No.1



Stacks Image 127
Engraving of a table engine



Stacks Image 142
Planning on building this engine, buy the book it is a must have.






Video James Coombes Running









Common Govenor



As well as a series of common engines, Stuart also created a set castings for a governor to be used on all the range. Detailed plans how to machine the castings to match each of the engines.
Driven by a spring belt the govenor is fully working. It links to a working steam valve.