6" Ruston Proctor Traction Engine - Model Build

As I supported the request for more build threads thru a previous post, I am adding the build of my 6" Ruston Proctor Steam Traction Engine.

Even though the model is a half size scale model of the original, it is only a medium size engine. The original engine weighed 3 1/2 tons and the model will weigh about 650 kg. It has a 10" dia boiler and the rear wheels are 24" diameter. Small enough to transport is a standard 6' x 4' box trailer.

A set of drawings and castings was obtained from Live Steam Models and shipped by sea freight to Sydney, Australia.

The drawings for the model engine were drawn with imperial dimensions and specified inch size plates and pipe, many of which were not available. The biggest change that I had to make was making the boiler. The drawing specified a barrel of 10" OD (254mm) but this size is not available in commercial pipe, unless you rolled a special tube. I decided to use10" NB pressure pipe (273mm OD) but this meant changing the width of the engine. The distance over the horn plate was now wider which effected the width of the rear axle and most of the components.

Because of all these changes and some mistakes and missing dimensions, I re-drew all parts of the engine using Solidworks CAD software and created my own set of detail drawings.

I had worked for most of my working life as a mechanical engineering draftsman but have had little experience actually running a mill and a lathe and was advised by a toolmaker to start with the front wheels as they were a good introduction to the different machining techniques.

Milling the slots in the front wheel hubs for the spokes.

To bend the wheel spokes, I used a press which I converted from a 12 tonne pipe bender and machined an angled plate to press against.

Home Made 12 Tone Press

The angle base plate for pressing bend in spokes required a little trial and error to achieve the correct angle to overcome the spring-back in the spoke angle when the press was released. This arrangement produced a consistent bend angle in all of the spokes.

The holes in the spokes being stack drilled for the rivets which attach them to the wheel rim.

Wheel assembly mounted on a temporary axle which is bolted to the mill table. All spokes assembled in the wheel hub and the wheel ring centered about the axle and mounting holes drilled.

I did not have an accurate way to measure the bore for the wheel hub, only an outside micrometer, so made a Go/NoGo plug gauge. Then used the plug gauge to transfer the diameter to the bush. With the dial indicator I could machine the bush slightly bigger for a press fit.

The plug gauge became a universal tool for measuring and was also used as the axle which I used to assemble and drill the spokes on the mill. (shown in previous photo).

Pressing bronze bush into wheel hub

Hello Paul,

Thanks for starting this build thread, I am building a 6" Burrell traction engine, been on it for 4 1/2 years. hopefully be running next year............................

I have put pictures on here now and again, gear cutting, making wheels , general machining and assembly etc.

I will be following with interest.

Good luck with your build,

Richard.

Hi Richard, The 6" Burrell is a nice engine although much bigger than my 6" Ruston. Have been working on mine for about 3 years. Hopefully only 1 more to go.

Machining the yoke which supports the front axle on my Sieg SX3 mill.

Boring hole in yoke to accept a pivot pin for the front axle after a bit of fettling on the rough casting

Milling 2 side plates for the spring retainer on a rotary table.

The side plates were then welded to and end plate to complete the fabrication below.

The leaf spring retainer for the front axle is complete. My first attempt at cutting a thread on my lathe.

The front axle was supplied as a casting and the ends machined for a running fit on the wheel bushes. and the larger diameter on the axle ends are a modification from the original design for a lip seal.

Front wheel and axle assembly almost finished.  (Wheels are 18" diameter).  I still have to rivet the spokes to the rims and add rubber tyres.  I would like to vulcanize the rubber to the rims but this is very expensive and may have to glue them instead.

Edited By Paul Lousick on 13/11/2015 21:26:33

Paul,

Thanks for starting this ... and please keep the thread going.

What you are building is WAY out of my league; but I shall be following with great interest.

MichaelG.

Thanks Michael,

I have always had an interest in old machinery, having learnt to drive a tractor at 8 years old on a farm. My friends have full size traction engines but I do not have room at my home and my wife cannot understand why I would want a 10 ton monster sitting the back yard. Building a model seemed the way to go.

Paul.

CONSTRUCTION of REAR WHEELS

The rear wheels which are similar in construction to the front wheels but larger and more complex. The wheels are 24" diameter x 5 inches wide. The LH hub can be disconnected from the drive gears and free-wheel by removing 2 pins. A rope winch can then be engaged to haul objects while the engine is stationary.

I do not have a set of rolls to make the wheel rims so so paid for them to be supplied. The spokes were laser cut and I gave a CAD drawing to the laser company in .dxf format. They were supplied within 0.2mm of the required size and only needed a slight lick with a linisher to finish.

The RH fixed hub was mounted on a rotary table and is located on center by a specially turned bush which fits the hole in the table and the bore of the hub. The mill head was then centered on the bore.

The position for the slots was then marked out on the top surface by painting with a black "Texta" pen and scribing their outline with a sharp pointer held in the mill chuck. Slots were then cut.

Holes for attaching spokes drilled, then tapped, using the mill to guide the tap and keep it vertical.

The mill table was moved from the datum center position to drill bolt holes and countersink. Rotary table indexed to drill the next hole.

Drilling, tapping and counterboring holes in the left hand (free wheeling) hub

Machining the cover for the LH rear wheel hub on my 9" Southbend lathe.

Assembly and machining of attachment holes for LH rear wheel hub.

Laser cut, rear wheel spokes being drilled in a simple jig on the mill table The positions for the holes was stored in the DRO , allowing for quick repeated drilling of all spokes.

Final assembly and drilling of holes to attach the spokes to the ring on the RH rear wheel.

Final assembly and drilling of holes to attach the spokes to the ring on the LH rear wheel. The spokes are attached with temporary bolts which will be replaced by 1/4" dia round head rivets.

This was then welded to the outer wheel rim and the fillet weld ground to produce a smooth fillet. When painted it should look like a fillet in a cast wheel. The

This is great stuff Paul,

Keep it coming

Neil

Hi Neil,

Someone asked for build threads and foolishly I put my hand up and did not realize how much work was involved but I will keep it coming. Lots more yet.

Paul

REAR AXLE BEARING HOUSING

The original, full size traction engine had a sprung rear axle but the model only has a rigid axle. The housing is a similar shape but does not have any springs.

Locating center ho housing with an edge finder and machining outside diameter.

Boring the inside of the housing. This opening was intended to be an oil reservoir for lubricating the axle bush but I intend to fit a screw-type grease lubricator instead.

Drilling and tapping the mounting holes for a spring retaining plate. This will only be a dummy / look-alike on the model engines.

The bottom of the oil reservoir was fitted with a small pipe and a wick which transferred oil to the bush but I am using grease instead because the housing does not have any shaft seals to retain oil and it runs thru and marks the driveway.

Machining of the housing finished and bush fitted. The bore of the bronze bush was slightly undersize after pressing and a bit tight for a running fit with the shaft so I used a car honing tool to open up the bore to the correct size.

Note: The round rod on the left is from the bar stock which I am using for the rear axle. It is ground 1.75", grade 4140 steel. I also had a piece of mild steel bright bar (1020 grade) which I was using for a temporary set-up and found that it was slightly undersize compared to the ground bar.

The reduced diameter on the end of the rod fits into a base plate which is mounted on the mill table and is used when I assembled and drilled holes for the spokes.

Hi Paul very nice work, looking forward to following this build.

Mal.

COUNTERSHAFT BEARING HOUSING with OIL LUBRICATORS

The countershaft is the Intermediate shaft between the crankshaft and the axle which supports the gears. This is a 2-speed engine with 2 different diameter gears on the RH side for the different travel speeds.

A simple turning job on the lathe to machine the bore and location diameters on the outside.

The housing is mounted on a rotary table for milling a flat on the casting and tapping a thread for the lubricator.

Rotary table mounted vertically and centered under the mill. The mill table was then moved sideways to machine flats on the casting flange. The spot faces were made with an end mill and cut by moving the milling table sideways because plunge cutting would not produce a flat surface.

Drilling holes for bolts.

Finished counter shaft bearing housing with oil lubricator. (Flip top lubricators are commercially available and cheaper than making your own). A bronze bush still to be inserted with an interference fit.

(Note: Photo taken under a different light which produced the bronze casting color)

CRANKSHAFT BEARING HOUSING and ADJUSTABLE BRONZE BUSH

The crankshaft is supported by 2 bearing assemblies, one on each side. The bronze bushes are split into 3 parts and are adjusted for the fit with the crankshaft by replacing shims, Alignment of the shaft (forwards and back) is also adjusted by shims.

Crankshaft bearing assembly (alignment shims not shown)

Machining of the crankshaft bearing housing

The housing was a difficult shape to hold in the lathe, so I made a temporary plate which was bolted to 2 of the mounting holes and held it by a 4 jaw chuck. Then turned the location diameters which fit into matching holes in the engine horn plates.

The sides of the supplied bronze casting for the bush was milled to square it up, Then painted with a black Texta pen and the position for saw cuts marked out with the aid a scriber in the mill.

First saw cut thru both sides.

Second saw cuts

The sawn faces of the cut bush pieces being milled smooth

I made a temporary heating hearth out of aerorated concrete blocks and joined the bush together with soft solder. The solder will be melted and the bush separated after final machining.

Final machining of the bronze bush assembly,

REAR WHEEL RIM ASSEMBLY AND MACHINING

The rims on the rear engine wheels are 24" diameter and are fixed to the spokes with 1/4" round head rivets. There is also a brake drum on each wheel.

The wheel hub and spokes were positioned on the wheel rims and tack welded in position. The spoke positions were all numbered so they could be re-assembled in their original position and the rim and ring removed for final welding then ground smooth. I used a 6mm wide grinding wheel in an angle grinder to produce a smooth fillet corner that will look like a cast wheel when painted.

The steel rings for the wheel brakes were rolled from 32 x 8mm flat bar in 2 pieced. (easier than trying to make a complete circle) and plug welded to the inside of the wheel rim. The brake rings were rolled to a close fit with the rims then clamped in position to make an exact match with the rims and plug welded.

Drilling and countersinking holes for plug welds.

The brake rings were turned to be concentric with the wheel axis. This 24" dia wheel was too big for my 9" lathe so used a mates. His can turn 4 foot diameter. That was fun to operate a big machine.

Very very nice to see this thread! Good effort!

Stunned, I am

This thread is definitely a 'Must Read"

MichaelG.

This is good, please keep it going

Thanks for the positive feedback. It is time consuming to compile the posts but I will keep them coming. Paul.

Nice work going to be a very nice engine when finished please keep the photos coming !!!

H

Excellent build diary!

Soft soldering of bearing halves has never worked for me, for some reason. So as an alternative I made a jig that located both crankshaft bearing castings and the crankshaft bearings:

That way I ensured that the bores are co-radial with the circular location features on the castings and that guarantees the whole shebang lines up when bolted to the hornplates without the need for line boring in situ.

Andrew

Paul: You may like to look at your PMs

Nice work! I do like a nice traction engine.