EASTON & ANDERSON

GRASSHOPPER ENGINE BUILD

Part five by Jason Ballamy

For the base of the engine I had intended to use a length of 125x65x15 parallel flange channel that I had. Having now got pictures of the actual engine I had to rethink my methods, therefore, to make the top of the base from 5mm steel plate and the sides from 1 1/2" x 5/8" alloy.

You know when you are building bigger engines because you can't cut right through the part with a hacksaw, so the angle grinder with a thin cutting disc was used to complete the cuts and give me a piece approx 5" x17".

After some very basic layout using a pencil and marker the sheet was fixed to the mill table on some MDF packing. The first job was to add another hold down in the middle of some waste followed by cutting the two holes for the pump and cylinder base using a boring head and their associated fixing holes.
The final bit of profiling was done on the rotary table as the crank hole needs to have a rounded end where it meets the cylinder base.

The cylinder of this engine is raised above the bed casting by what can be described as an upturned can with flanges top and bottom and a few webs thrown in for good measure. So starting off with a couple of squares of 5mm steel plate approx 3" square these were put in the 4-jaw and suitable holes bored.

They were then held by the newly formed hole to turn the outside a little over finished diameter having first sawn the corners off.
A piece of scaffold tube became the donor for the central tube
Here are the basic parts, the old rusty pole turned out quite nicely and there is also a brass top that will form the cylinder bottom cover so no risk of rusting.
The two rings were then held on the rotary table to mill some location slots for the reinforcing webs
And matching grooves cut along the tube. As I don't have a tube centre for the R/T tailstock the angle plate up against the end of the tube reduces any risk of it tilting.
The webs were machined from various offcuts of 1/8" plate, here they are all held together to have the radius cut using a home ground radius corner cutter from a blunt slot drill, I prefer this type of cutter to a ball nose one as they remove metal quicker.
And here are all the parts ready to be silver soldered together.
A soak in the pickle and it was then back onto the lathe to have all the finished surfaces machined to size.
And here it is with a bit of paint on. I'd like to say the elongated top holes are a special design feature but they are the result of not having the work on centre when setting out the PCD.
The end frame pivots in a pair of bearing blocks, as they suited being silver soldered together I made the various parts from steel with a bit of machining allowance on the height.
The semi-circular recesses in the main blocks were cut by clamping the two blocks together and drilling then milling down the joint.
And here are all the bits soldered together
After a quick clean-up the tops were sawn off and then milled down to thickness. The holes in the base were tapped and those in the top opened out to clearance size.
I could then bolt the halves together and bore the holes for the bearings.
The final step was to add some thin brass to get the correct look around the fixing holes, drill and tap for the oil cup and then add some studs and bronze bearings.
Finally a bit of paint and we are one step further to completion.


See part one here     See part two here    Part three here    Part four here   Part five here     Part six here      Part seven here     Part eight    Part nine   Part 10     Part 11   Part 12   Part 13    Part 14    Part 15   Part 16