Making Your Own
It is not difficult to make up a decent trolley for your engine, but some factors have to be taken into account before you start ordering wood or steel.
Wood was traditionally used for smaller trolleys and carts, as it was available and workable by most agricultural engineers of the day, and probably more importantly it was repairable by the local chippy (carpenter) While hardwoods from the far east are desirable for appearance and strength, the traditional woods such as Oak, Ash and Pine will give a good account of themselves if proportioned and finished off properly. The requirement to support a heavy engine whilst in operation and also during transport mean that only the best knot-free timber can be used.
New timber will look very artifical, even if stained to a dark colour. Older timber can often be found at demolition recovery sites, used in various parts of buildings. The best type of site is usually an old factory, as houses did not use heavy sections of timber. Mahogany or Teak are probably the best to go for, as they are naturally dark woods to start with, and have long fibres without knots,giving greater strength. The modern substitutes are probably as good, and most good timber merchants will be able to offer a selection. Another source is a good old fashioned pattern maker, who will have all sorts of sizes handy to look at.
Steel and iron are almost universally used for the heavier engines, both for ease of fabrication and also availability. Some thought has to be given to the appearance of the finished item, and it has to be sympathetic with the age and appearance of the engine which is to be mounted on it. RSJ's and angle iron in the larger sizes are OK, but I personally have a preference for box sections in both square and rectangular sections. There are opinions both for and against, so the individual will have to make his own mind up on that.
Sources are many and widely situated in most urban areas. Scrap yards will sell structural steel that has been salvaged from buildings, demolition companies will also offer the same service. The cost of buying secondhand does not always give value for money, and I have found that buying new not only gives the buyer the choice of the correct size he is looking for, it also get you more modern materials without the large rolled-in names of the mills that made the stuff 50 years ago. If you want that feature in your trolley, then go for secondhand. Most yards will cut to size if you ask nicely, and a bandsaw cut is preferable to flame cutting, and saves a lot of cleaning up afterwards.
Before rushing out and ordering/buying your materials, give some thought to a few parameters:-
a) Weight of the engine and operating forces when running - do you want to drive something by belt for example.
b) Where will it be used: in a field? on hard standing ?
c) How will it be transported, and how will it be secured whilst travelling ?
d) What means will the trolley have for moving it about: a draw bar ? handle ?
e) What weight considerations do you have to consider ? will your trailer cope with the extra weight over and above the engine ?
f) What ground pressure will the trolley exert when fully loaded with engine, fuel and water ?
g) When it has sunk into the ground to the axles, how are you going to get it out ! Etc., etc.
If using timber, the main bearers will have to be cross-braced in at least two places, either by timber beams or by steel axles which are not rotating. The engine will provide a lot of support, but only if the fixing bolts are decently sized and properly fitted with large washers to spread the loads. Mounting the engine direct to the timber is OK if the base of the engine is flat and the loads are spread over a wide area. Otherwise put a piece of flat steel bar between the engine mounts and the timber, so that point loads are taken by the steel, not the wood. Wood screws have no place on engine trollies, other than for nameplates. All bolts should have 10 gauge steel washers under heads and nuts where holding in wood. Hardware suppliers sell roof joist washers in 10 gauge steel, they are usually 2" square with a 1/2" centre hole. These are ideal for the larger bolts, and there are smaller sizes available. A standard steel bolt head or even a coach bolt head will quickly work its way through the surface of timber beams in a mobile situation, even with good hardwoods.
Steel is much easier to fabricate, while not quite as antique-looking! It can be bolted or welded, and generally it is far easier to get things done in steel than in wood, unless you happen to be a carpenter of course. The main selections you will have to make are the size and shape of the beams (angle, channel or box) and the weight of the section you choose. A word of warning on steel sections: A box or channel or angle that is too thin will collapse without warning if stressed beyond it's safe loading, while timber will usually break in a more controlled fashion, especially that with longitudinal fibrous make-up, so always choose a wall thickness which will give you the margin of safety required.
Welding is probably the best form of assembly for steel, as it does not require any maintenance or checking of bolts afterwards. If you cannot do it yourself, a small (cash) amount will usually get some assistance from most frabricators. Ensure that you have worked out positions correctly, as welding is pretty permanent once done.
Angle iron (really this is angle steel these days!) should not be used for anything heavy or where the chassis is long with an engine in the middle. It can be used with timber infill to advantage, and adds considerable strength to a pair of timber beams if laid on top with the other flange along the sides of the timber and bolted through. Even the larger angles do not make for good trollies, unless you have a large quantity laying around waiting to be used up, in which case other factors override appearance.
RSJ, (rolled steel joist) Channels, Universal beams and Columns are close to ideal, as they provide a good foundation for long chassis beams, and also give a flat surface to bolt the engine to. Holes can be drilled in the vertical flange without significant weakening of the beam, and for most engines there will be a size to suit most weights and pockets. Remember that flanges of RSJ's and channels are tapered on the insides, so you will have to use taper wedges for the bolts and nuts, these are commonly available at most good hardware suppliers, and are cast and galvanised as supplied. Beams and columns are usually rolled with parallel flanges.
Box section is my personal preference, but it is not to everyone's taste. Box does have some advantages: it can be used to carry fuel and water if the sections are large enough, it is stiffer than a channel as it has two vertical flanges instead of one, although the material thickness is usually less for box than channel. It is also usually cleaner on the surface than channel and angle, particularly the electrically welded version.
While not being able to cover every possibility, the following rough guide should be adequate to give an idea of required material sizes.
Minimum size 3" X 2" on edge for small engines such as the Lister D and Wolseley WD series. Maximum size that looks reasonable is probably 6" X 4" on edge, and that would be OK for up to about 5cwt - 8 cwt of engine weight. Consideration must be given to safety factors in the larger weights, particularly if the engine is transported by road on a trailer. Provision for bolted lashing points must be made, and wood screws must not be used for any security fastenings.
Minimum size 3" X 2" X 5/16" section, laid on edge so the 3" face is vertical. Similar ratings for the timber, but can be increased by 60% if timber is used in conjunction with and inside of the angle as a filler. Maximum size is about 6" X 4" X 3/8" section, but it doesn't look very nice, and I personally would use this as a stiffener for a piece of timber. Up to 10 cwt if used with timber infill, otherwise about 6 cwt by itself.
Minimum size for chassis beams would be 3" X 2" X 1/4" section, carrying up to 4 cwt. Larger sizes up to 8" X 6" X 1/2" section would be safe up to 25cwt. While timber infill could be used, it would not add a lot of additional strength in relation to the cost of machining it to fit inside the channel. If you need more stength, go up in size.
Minimum wall thickness first:- This stuff comes with 16g, 10g and upwards in wall thicknesses. The absolute minimum is the 10g wall, and only on light weight trollies. The 5mm wall is the preferred size in the smaller sections, then up to 10mm in the big stuff. Minimum material dimensions are 50mm X 50mm in 5mm wall, or 75mm X 50mm in the 10g wall. This will be OK for the Lister D, Wolseley WS and Petter M size of engines. For my own CE twins and others in the 10 cwt weight range, I have used 100 X 120 X 5mm wall section.
Box sections go up to 250 X 200 X 10mm wall, so there is no practical limitation on the weight carrying capacity of your trolley !
Handles and lashing Points
Means of movement must be thought about at the construction stages, and the trolley handle should be of sufficiently heavy construction to take all the pulling and shoving that will come when you are positioning the engine on the rally field. It should also be quickly detachable, so it does not lay in the grass and trip someone up or stand up in the air and poke you in the eye !
A single tube handle with a T bar at the end is about as neat and simple as it gets, and a yoke at the axle end can be made up easily from a bit of folded bar or similar material. If a quick-release pin is used (and kept greased!) then the whole assembly can be off in a few seconds. If the axle steers, then the size of pin and coupling to the handle must be quite substantial to withstand the forces that will be present. A piece of 1-1/4" Hydraulic seamles tube makes a nice handle for most small to medium trolleys, and 1-1/2" is good for most things that you are likely to drag around manually, ie up to about half a ton. Put a gusset each side of the main bar to absorb and twisting on the T.
Lashing points are very important, both for tying down to the trailer for transportation, but also for recovery if the thing gets stuck in the mud at the rally! More than one engine owner has had his pride and joy damaged while being dragged out of the rally field by an unsympathetic tractor or digger driver. I prefer to use U-bolts from wire cleats, as they are more substantial thatn most other bolts, they come galvanised or can be bought in stainless steel from rigging companies, and they also can be bolted through a chassis, which means easy replacements if you bend one.
Sizes are: about 3/8" material for the U bolt on small to medium engines, 1/2" for up to 10 cwt and 5/8" for the big boys. Make sure you can get your lashing straps or chain through the eye of the U before you get it all assembled. There is a lot of margin of safety in these sizes, and I always reckon that it is good insurance to err heavier than lighter.
Axles and Wheels
Solid axles are my personal preference, but then I have access to turning facilities, so can get most anything made up without any problem. Tube is OK for light engines, say less than 3 cwt or 150 kg approximately. Tubing tends to fail catastrophically, see my comments above, so use solid wherever possible. One inch is a good size, as most wheels are around that bore that you would use for a small engine cart. Larger bores can be accomodated by sleeving the wheels or the axles to suit. Don't forget to drill the greaser holes through if you sleeve the wheel hubs. 1-1/4" bar turned down to 25mm or one inch at each end will make a decent axle for most small to medium engine trolleys.
Bearings are not usually fitted to engine carts or trolleys, but they do make an enormous difference to the mobility of the whole assembly. I have given up plain hubs for ever, as the effort required to the bigger engines is just beyond a single person, especially in grassy fields ! My own larger engines run at about 10cwt or half a ton, and with cast wheels and plain bearings, they are almost impossible to start away from standing still. With wider rims and taper bearings they are much easier to get moving, and the wider wheels do not sink into the ground as much. Cast spoked wheels are very decorative, and in the smaller sizes are probably quite safe to use again without crack detection. Larger wheels I think should be checked for fractures, just in case.
Wheel styles are not of great interest to me, although if I had an engine with original trolley and wheels I would make sure they stayed together, come hell or high water. My present trolleys have ex-USAF aluminum (aluminium) cast centres with moulded on outer tyres. They are twelve inches diameter by about four inches wide, and run on large taper roller bearings. These were bought as a job lot, ex-USAF from Molesworth, and I got about eighteen wheels for £35 - not bad ! They have other benefits: the height of the trolley is lower with the smaller diameter wheels, and the whole thing looks more stable. The wheels do not break up the surface of the concrete floor in the workshop, and do not sink into the asphalt outside on hot days.
Turntables and Steering
If you want your trolley or cart to steer, then you have to make some hard choices about where and how it is all going to work, before you start buying bits and pieces. Steering axles with Ackermann steering geometry are very nice, but unless you pick up a trolley from the military sales already made up, it will be a swivel axle for you !
A swivel axle is the simplest means of steering a cart, and requires that the front axle be able to pivot about the centre of it's own axle, around a pivot that is fixed to the chassis. The pivot has not only to keep the axle on the straight and level, it also has to keep the axle straight in the vertical plane as well, while you are doing your dammdest to pull the axle off the front of the cart. A swivel pin of at least 3/4" is required for even small engines, and the pin must be well located on the chassis to prevent movement. Larger engines will need something a bit better than that, and I have gone for 30mm diameter pins with 40mm bushes for them to run inside, leaving a 5mm wall for the bush material. Greasing arrangements have been made. Turntables are 6mm plate, 270mm diameter, flame cut and then turned smooth on the OD. One is fixed to the moving axle, and one to the fixed axle support on the frame. Once again, arrangements for greasing are provided. On really large trolleys, I would go for Ackermann steering, as it is much better at keeping the whole trolley level at extremes of steering lock.
If the steering axle is to have a decent amount of lock, the wheels must pass underneath the frame somewhere. If the wheel set is all the same diameter, then the rear wheels have to be spaced up from the front ones to allow clearance under the axle for the moving axle and wheels. There is no need for huge amounts of clearance, just enough to allow for flexing of the frame and axles when moving over rough surfaces. My own axles are about 20mm different in height from the trolley chassis, the rear one having a spacer between it and the main frame to make up for the turntable height of the front axle, thus keeping the whole thing level. The turntable has to support the front axle over it range of movement, so try to get as much beam under and over the turntable plates as is decently possible.
Fixing the Engine to the Trolley
Use only high tensile bolts, do not use set-screws with threads all the way down unless you absolutely have to, they look awful. If bolting through a box-section, use anti-crush tubes inside the box to prevent the tube collapsing under the compression loads of the bolts. A stub of steel turned down to take your starting handle can be bolted or welded on where convenient, and a padlock facility would prevent the handle going for walkies !
Mountings for fuel and water tanks are easily provided, but make sure they are man enough to carry the weights, particularly fuel.
Welding and Finishing
I have a home welder of 140 amps, and some nice chrome alloy rods. I will probably get the whole thing welded at our local fab shop, as I am not that good at stick welding. Practice makes perfect they say, but I appreciate a good weld when I see one, and turn my nose up when I see a series of welds with blow-holes and slag all around. If you can do it yourself, great !
Finishing is the hardest part, as it all needs dismantling to do a decent job, yet is it always rushed so that the engine can be shown at the local rally or crank-up ! Take your time with it and leave room and time to strip it all down and paint/powder coat properly. I use powder a lot at the factory, and have had quite a bit of experience with it over the last ten years. There are both indoor and outdoor grades available, and the outdoor grades are the ones you need ! Don't use a garish colour that you will regret later on, try and use a colour that mixes with your engine collection without standing out like a sore thumb. Black and dark grey are quite nice, dark greens as per Lister can be very classy, as will dark blues. Reds and Green in the stronger colours tend to be a bit OTT in my opinion.
Weights of Materials
A few figures on weights of steel sections may help with working out weights on your trolley:
|Material||Description||Web Thickness||Flange Thickness||Weight per metre||Configuration|
|Rolled Joist 102 X 44mm||Lightweight RSJ||4.5mm (0.177")||6.10mm (0.240")||7.5kg (16.5lbs)||H section on it's side|
|Rolled Joist 102 X 102mm||Standard weight RSJ||9.5mm (0.374")||10.3mm (0.405")||23kg (50.6lbs)||H section on it's side|
|Rolled Joist 152 X 127mm||Heavyweight RSJ||10.4mm (0.409")||13.2mm (0.520")||37kg (81 lbs)||H section on it's side|
|Rolled Channel 102 X 51mm||Lightweight Channel||6.10mm (0.240")||7.60mm (0.299")||10.42kg (22.9 lbs)||U section on it's side|
|Rolled Channel 127 X 64mm||Heavyweight Channel||6.40mm (0.250")||9.20mm (0.362")||14.90kg (32.78 lbs)||U section on it's side|
|Rolled Channel 152 X 89mm||Heavyweight Channel||7.10mm (0.280")||11.60mm (0.299")||23.84kg (52.45 lbs)||U section on it's side|
|Rolled Channel 178 X 89mm||Heavyweight Channel||7.60mm (0.300")||12.30mm (0.484")||26.81kg (58.98 lbs)||U section on it's side|
|Unequal Angle 75 X 50mm||Medium weight angle||6.0mm (0.236")||6.0mm (0.236")||5.65kg (12.43 lbs)||L section, large side vertical|
|Unequal Angle 75 X 50mm||Medium weight angle||10.0mm (0.236")||10.0mm (0.236")||8.78kg (19.31 lbs)||L section, large side vertical|
|Unequal Angle 100 X 75mm||Heavyweight angle||8.0mm (0.315")||8.0mm (0.315")||10.60kg (23.32 lbs)||L section, large side vertical|
|Unequal Angle 100 X 75mm||Heavyweight angle||10.0mm (0.393")||10.0mm (0.393")||13.00kg (28.60 lbs)||L section, large side vertical|
|Square Box 50 X 50mm||Medium weight box||5.0mm (0.196")||5.0mm (0.196")||6.97kg (15.33 lbs)||Hollow square box section|
|Square Box 100 X 100mm||Medium weight box||5.0mm (0.196")||5.0mm (0.196")||14.80kg (32.56 lbs)||Hollow square box section|
|Rectangular 100 X 50mm||Medium weight box||5.0mm (0.196")||5.0mm (0.196")||10.90kg (23.98 lbs)||Rect section, large side vertical|
|Rectangular 120 X 80mm||Medium weight box||6.0mm (0.236")||6.0mm (0.236")||18.40kg (40.48 lbs)||Rect section, large side vertical|
|Rectangular 200 X 100mm||Medium weight box||6.0mm (0.236")||6.0mm (0.236")||22.70kg (49.94 lbs)||Rect section, large side vertical|