Vertical Engines - The Wheel barrow CartFor vertical engines I tend to avoid a steerable front axle altogether by building a 'wheel barrow' style cart, which has wheels at one end only and handles and feet at the other end, but the 4 wheel design works equally well. Careful positioning of the axle minimises the weight felt at the handles when moving the unit, but some liftable weight needs to be left to keep the unit stable when it's sitting on the ground. With this wheel barrow style there is a fixed axle at one end with wheels and the other end has legs and feet that sit on the ground when the engine and cart is level. A raised set of handles allows the unit to be tilted up and wheeled away, just like a wheel barrow. Design the handles so that this wheel away height is comfortable and not a source of back strain.
Horizontal Engines - The Billy CartFor horizontals I make a very simple axle pivot using a large bolt with double lock nuts and a couple of thick washers. I always use 50 millimetre RHS (Rolled Hollow Steel) for my structural members. For those who don't know what I'm talking about, this is 2 inch square section steel tubing with walls 2.5 or 3 mm thick.
I make a base frame out of this that is bolted to the engine base and make it large enough to carry the cooling tank if the engine uses one, or just a bit larger than the engine if it's hopper or air cooled.
After selecting the wheels I'm going to use (I generally use old cast iron flat belt pulleys or sack trolley wheels), I position the axles, also made from 50 mm RHS with appropriately sized round stock welded to them to carry the wheels, so that they will not interfere with the operation or starting of the engine, also making sure the axle track is wide enough to clear the flywheels and adequately support the outfit.
A bit of experimenting needs to be done to get the right orientation of wheel diameter and axle height in order to keep the base frame level. I weld one axle to one end of the frame, generally on the flywheel or heavy end, and attach the other axle to the opposite end frame member using the large bolt I mentioned before. I simply drill through the centre line of both pieces of RHS and fit one or two heavy washers between them as a bearing plate, double nutting the bolt on the underside. The bigger the washers the better, but ideally they should be about the same width as the frame/axle members. With the axle under the frame this seems to carry the weight quite well, but the washers add a little to the height so this is another factor to consider before welding it all together in regards to keeping the whole thing level. It's sometimes necessary to add spacers between the fixed axle and the frame or I have used slightly larger wheels on the fixed axle to achieve the same effect.
All that's needed then is some kind of towing/steering handle, which I usually make from 25 mm RHS and a way of attaching it. I'm still experimenting with handle attachment methods, but the simplest is just a couple of flat tabs welded, edge on, to the front of the movable axle and drilled for bolts so it can pivot up and down. I'm trying to devise something that can be easily attached or removed so I can use a common handle and just transfer it from cart to cart as needed. That way when I go to a show I'll only need one handle for all my transporters.
If you ever had a toy wagon or billy cart as a kid you'll see where I got my inspiration from and it seems to work well. The only other comment I'd make is that when selecting wheels consider the kind of ground they will have to traverse as bigger wheels handle rough ground much better than small ones and use wider rims for bigger weights so they don't sink on soft ground, but all the while keeping them in perspective with the engine they're under otherwise they look strange.
Mounting details for cooling tanks vary widely as some use tanks with bases that sit at the same height as the engine while some are elevated. Just use what works for you and supplies the cooling water with fairly straight and short pipes. I hope I've explained this in an understandable way and that you find it useful.
Chassis is 120 X 100 X 5 box section, with 100 X 100 X 5 for the cross beams, and 50 90 X 5 beams for the axles, which are mounted underneath the beams, fixed for the rear axle and moving for the front.
The axle beams have 40 X 40 bar welded into each end, turned down to 1.25" dia to suit the taper-roller bearings on my ex-USAF wheels, which have alloy centres and moulded tyres. The wheels are not exactly vintage, but I am more concerned about mobility than appearance ! Moving a ton of engine and trailer is not best done on small rusty wheels, and I got three sets of wheels at the USAF auctions for about £30, including the bearings.
The turn tables are 10" diameter discs of 1/4" thick plate, flame cut and turned smooth. The support face of the main chassis beams is 120mm wide, so the turntable has a lot of support behind it. The swivel pin is a 30mm steel bolt, with phosphor-bronze bushes in the chassis cross-beams. Greasing facilities are provided.
The cross beams also have heavy-duty U-bolts (not big ones, but small ones like wire rope cleats) at each end, for lashing down to the trailer. The U-bolts I have fitted are 1/2" diameter steel, and can take 5 tons loading.
The articles on this page are Copyright 1999 to Brad Soward and Peter Forbes respectively and may not be reproduced except by direct permission of the authors and the publisher Steam & Engine of Australia.