Part one by Jason Ballamy

Having enjoyed the "reinvented" Stuart Real project I thought that their James Coombes could do with a similar treatment to bring him into the 21st century. So I set to with a copy of Andrew Smith's book which is the cheapest way to get a set of the drawings and redrew it in Alibre to use mostly barstock and to metric standards. Some of the main points I wanted to address were:

  1. Do away with the cast box bed and outrigger bearing support and mount the engine on a "stone" plinth

  2. The sole plate and table on the stuart are just bits of flat 3/16" plate so these to be made to look a lot more like castings and generally more appealing to the eye.

  3. Similar with the plain columns to be replaced by ones with classic bases and capitals

  4. Do away with the soldered conrod which may put people off and not easy to solder it up true

  5. Do away with the clumsy bolt together eccentric rod and replace with a single straight piece

  6. Add decorative bands to the cylinder as I was not going to timber clad this one and do something with the inlet as I don't like that going in via the valve chest cover. And while I'm at it get rid of the chunky exhaust flange.

  7. Generally add a bit more detail but not go as far as things like fluted columns, wedged and cottered straps etc otherwise I may as well just build a Waller Table Engine.

Starting with the sole plate and outrigger bearing base two pieces of 12mm plate were squared up on the manual mill to overall size. Then the soleplate was clamped to the CNC's bed with some packing below so that the four hole sthat will hold it to the base could be drilled and I also thinned down an area where the crankshaft clearance slot will be cut so that you don't see a thick edge around this hole as it would not have been cast full thickness.f

I find mounting the clamp bars the wrong way round is a good way to lower their profile so you can get in closer without too much tool sticking out of the collet holder.

Using the four previously drilled holes the sole plate was screwed to my well used machining plate to have 1.5mm taken off most of it's thickness just leaving raised bosses under the screws and a raised rectangular pad for the bearing pedestal using a cutter with 1mm corner radius to leave a fillet for that cast look. I also cut out the clearance for the crank, drilled holes for screws to fix the columns and counterbored these to accurately locate spigots on the column ends.
Just to show you don't need a CNC to do these things the outrigger base was done on the manual mill, the counterbored holes with have thivk "washers" bonded in to create raised bosses for teh hold down bolts
The quickest way to get the decorative moulding around the edges was to hold the plate at a slight angle to replicate the draft angle and then a couple of deep passes of the side of a ball nose cutter produced the required profile unfortunately the photo was out of focus for that

Next four squares of steel were JB Welded into place and once set were milled down to an even 5mm high. These will form the bases of the columns.

The table was done in much the same way from 10mm material so I'll just post a couple of photos of the underside and then the top.
While it would be nice if people decided to build their own from scratch I've done this and the earlier Real build to show people what is possible and even if they just feel up to incorporating one or two of the features then the threads will have been some use. It also shows that if you pick up a part set of castings or are unlucky enough to muck up or get an unusable casting then there is still hope as just about anything can be made if you put your mind to it and that you don't have to just buy another casting and build another engine the same as everyone before you.

It is also a good way to ease your way into designing completely from scratch as methods learnt modifying existing designs can be put to use when and if a modeller wants to move on to a subject that was never made available or has long gone out of production. Also lets not forget that without those that went down this route in the past we would not have the designs being built today, I'm sure some peoples casting stashes would be a lot smaller if the likes of Clarkson, Mount, Westbury etc had not designed engines from scratch and then shared their work with others.

Part two here.