Nick –

The relevance of the various lever ratios is simply that of the steering force needed.

I might have give the steering a small castor angle, but studying the photographs closely suggests the original was all-square: no camber, no castor, vertical king-pins but some toe-in. The design had some good ideas but was rather crude even by 1908 standards.

The springs are separated from their seatings on the king-pin brackets by spacer pads, so it would be simple to give the spacers a small castor angle.

It may be possible but more difficult to give some camber.

Toe-in is easy as I gave the track-rod opposite-handed threads for its clevises.

Any king-pin inclination would need completely new assemblies.

However, let's not get hung-up on this. The model represents a rather basic steam-wagon built in 1908, basic even for its time, of probably little more than jogging pace flat-out; not a "modern" car of even 1918 vintage!

'

Werner –

An interesting example!

My wagon is to 4-inch scale, so a hefty beast. The problem with a miniature lorry is that the driver has to sit on it to be able to reach the controls, adding to the weight on everything including the steering.

My mass is a little over half the maximum for my wagon by one-third scale, for a 3-tonne full-size capacity.

I don't know the Clayton's original carrying load, but I think it was about 5 tonnes (well, tons but there is little difference). In two-inch scale the scale maximum load becomes about 23kgs (50lbs).

So an average adult on a 1/6 scale model of a 5T lorry would give the poor thing several times that load!

Even a 10T original would still have a scale maximum of only 46kgs.

If your friend has to sit on his Clayton wagon to drive it (I have seen that done, on a grass sports field to make it even more difficult for the vehicle) it is hardly surprising the steering was so hard! Fine if driven from a trailer that removes all the driver's mass from the vehicle; but not easy or elegant to arrange.

Howard, Noel,

It was the 'Standard' wagon that was of 5T capacity, Mine is the smaller "Light Delivery Van' (as the catalogues had it), of 2-3 T load.

So at worst, 2 tons scales to [40/27] = 1.48cwt; approx. 11.9 stone.

So it should carry my roughly 9 – 10 stone – probably not very evenly distributed. Distributed on the lorry platform that is, not on me. Oh, all right….. and on me. Though this assumes I can find somehow / somewhere to have the springs heat-treated.

Whether it will have the power, is another matter….. At best I can't expect more than 1/4HP from the engine, if it manages 400 rpm; a compound fed un-superheated steam at 90psi boiler-pressure, through a loop of pipe exposed to the fresh air. (That's how the original was designed!)

.

The steering-geometry is all there and done… years ago, too. I copied from archive photos that do show the original E.S. Hindley & Sons' draughtsmen were not too worried about such niceties as king-pin inclination etc., and made it all-square. The most I can do without radical re-working is giving it a little castor-angle by wedge-shaped spacers between the axle-beam and the springs. Hindleys' own advertising stated range but not speed, but I'd be surprised if these things managed even a heady 8mph on their smooth steel tyres with remarkably crude brakes, so true steering geometry was probably not all that critical.

.

My original question was anyway about the control end: the appropriate number of steering-wheel turns for a vehicle of this type; to guide designing the steering-box.

I think the only way to measure the steering torque on a model like mine, would be to steer it via a spring-balance!

The full-size steering-wheel had a vertical auxiliary handle, as on a traction-engine and often clipped on to modern HGV equivalents. This does suggest a good deal of "mangling" was needed to manoeuvre the wagon in tight spots such as factory yards.

'

Miniature road steam (and indeed i.c. or electrically-powered) vehicles have it hard because the ground they run on is always at twelve-inch scale; be it a well-mown sports field, a farm meadow or smooth asphalt. I have seen a two-inch scale under-type steam-lorry charging around a sports field with its well-built driver perched improbably side-saddle on it, and wondered at the model's ability at all even on mown grass, on wheels less than three inches diameter.

The full-size Hindley wagons must have been a nightmare in bad conditions such as on wet or icy setts; where their steel-tyred wheels with no strakes or tread of any sort would have given no lateral grip – probably, sometimes little driving grip. The boiler was to the maker's own patent to enable it to operate, so the patent document and the advertising said, on hills up to 1-in-8; and the road serving their own factory was itself very steep. So getting one of these, especially the larger ones, fully-laden up a steep hill in Winter was no joke.

No mention of driving the thing safely down-hill though, either. For their brakes were ridiculously crude even by Edwardian HGV standards too: just one curved iron or steel block, a bit like that on a railway wagon, on each rear wheel, pulled against the rearward "side" by a screw worked from a large crank-handle between the crew seats. It was little better than a parking-brake.

There was no brake on the flywheel, exposed but below the chassis and of no auxiliary PTO purpose.

…..

My estimate of my model's power was from the usual [nPLAN/33000] Horsepower sum, but it makes a lot of assumptions even with a generous Diagram Factor (the 'n' in the formula) – I think I used about 0.7 for that.

I can manage 100W? That's comforting – probably a bit more as I am in fair fettle for 70!

I'll try to remember that when I'm next hauling myself very slowly from the depths of the cave "digging" project I help on – trying to find the cave we hope to find below a mass of boulders. Two hundred feet deep and still going down…. It's a long way back out, a series of short but strenuous climbs then a final 35ft vertical ladder ascent to the sunshine. It would be interesting to know what power I am expending on this, even if taking the "Work Done" as simply lifting vertically my GVW including nearly a stone of damp clothing and kit, ignoring a great deal of friction, very heavy breathing and other "mechanical losses", but I don't really know how to calculate it!

Thankyou Duncan!

At best I can climb 1 ladder rung (9" spacing) a second.

So assuming about 10 stone for me + clothes and kit, this gives about 144W or 0.2HP… So maybe I'm a bit fitter than I feel! I'm still in fairly good fettle, though I am only 70.

In reality it's probably a bit under that, but it still seems right hard work.

(I converted the units to metric then divided the W by 746).

…..

An entertaining digression but getting back to the OP –

We've established my steam-wagon, like its original, has very crude steering geometry; but my question was on steering-wheel size and full lock-to-lock turns.

The photos and experimenting with a tape-measure suggests a wheel of about 15" diameter full-size, so 5" diameter on the model. The present one is only 4" dia. And it is fitted with a small, peg-type crank-handle.

While number of turns, comes to about 5 on the present worm-wheel radius and DP in the gear-box.

Of the two options, a worm and wheel seems the better than screw and nut. A lot less work and the wheel can be rotated on its mounting when it wears, as if I am ever likely to wear it out. Not cheap, as I'd have to buy the two parts, but saving me a lot of time, gaining a better result and still be right for the era, whichever option the original Hindley wagons actually had in there.

I'd likely use a coarser DP for strength and longevity, and slightly larger worm-wheel, so reducing the number of turns. With care not to go too far and make the steering too heavy.

Thank you but if you look back through this you will find it was pretty well covered! I had wanted some guidance on steering ratios.

Hindleys did not trouble too much about niceties on a steam-wagon not likely to have reached even 8mph on whatever asphalted road it was lucky to find, and I copied a set of photos giving better views than that Dorset Year Book 1977 illustration in the query about pumps.

I also referred to reprints of contemporary manuals for operating and servicing steam road vehicles, not modern motorway cruisers.

I have given the track-rod put a fair amount of toe-adjustment, presently toeing inwards to the front. The whole thing did look all-square with long king-pins and no obvious camber or castor angles. The most I can do now is taper the axle-to-spring spacer blocks, to give the steering a modest castor.

I made the channel beam axle by welding two lengths of folded 2mm thick channel back-to-back and dressing the welds smooth, so it holds insufficient steel to accommodate tapers itself.

.

Despite the apparently poor steering layout, Commercial Motor reviewers of the time (1908) considered it an easily-manoeuverable vehicle to drive, in their road test that involved driving one several times round Finsbury Circus, from E.S. Hindley & Sons' London show-room. Perhaps it was, compared to some of the lumps the magazine was probably offered for review.

Hindley built quite a number of the mid-engined "Light", and the bigger undertype "Standard" and its heavy-duty "Colonial" equivalent, steam-wagons. Hauliers and house-rermovers Pickfords owned a fair-sized fleet of the "Standards" before abruptly moving to another maker, Foden I think.

The Hindley wagon catalogue also reckoned it so simple that any ordinary man can learn to drive it in a short time – so I think I'm in with a chance!

Edited By Nigel Graham 2 on 26/06/2023 14:23:25

Edited By Nigel Graham 2 on 26/06/2023 14:24:27

Well, it is interesting but doesn't help my original query because I am constrained by what someone in a drawing-office in the village of Bourton decided 112 years ago; but that feature of Sentinel steam-lorries is used as an example in one of my reference books.

The steering-gear on my model at present is a worm and wheel but is temporary, as it a bit small and weak for the application. I don't know what the originals used because the works are encased, but the shape of the gear-box and what suggests a shaft end on its face, would be appropriate for either worm and quadrant (not full wheel) or screw and nut.

The lack of drawings enforced a lot of lateral research for this project, and this revealed some manufacturers used Ackermann steering fitted screw-and-nut gear, others used a worm and quadrant, some fitted a full worm-wheel that can be rotated to a new quadrant when it wears.

.

My first car was a Sharps Commercials 'Bond Minicar', whose single front wheel suspension – plus engine – was on a near-vertical column rotated by worm and quadrant as on some early road-rollers.