Today I managed to drill, then tap the oil filler holes on both cylinder blocks of the Seal engines.  The set up time for any machining  task is normally much longer that the metal removal and today's task was a fine example of the little extra effort in making another engine.

The first job was to set the adjustable angle vice up on the milling machine. The plans call for the oil dipstick filler hole to be at an angle of 20 deg to the engine blocks head. The way I set this angle was to use the digital angle meter I have. A much valued tool and a recommended addition to any workshop. It was first zeroed on the milling table then with the casting standing on a pair of parallels, the meter placed on its top and the vice adjusted until the correct reading was seen.

I decided that I would reduce the speed of the drill and use three different sized drills before starting the tap. This method ensured that the threads would be cut in line with the drilling. However I find it easier to move  the casting to the bench and finish the thread, BUT only after it has been started in the same position as the drilling.

Hopefully here are a few pictures that will make the text clearer.......

Having completed the first Seal camshaft you can imagine my bitter disappointment when checking the profiles against the plans to find that they were miles out! No matter how many times I looked at them, turned them around and even when stood on my head, it wasn’t right!

I rechecked the methodology; re read Steve Huck’s article, to find out where I went wrong but all to no avail. The camshaft looked nice, but looking nice was not going to cut the mustard for a successful engine build, let alone the two Seal engines I am making!

When I couldn’t make any further progress in finding the answer I emailed Steve Huck and after many, many, emails, photo’s and explanations we came to find the answer.

Steve makes it perfectly clear in his article (reproduced on this website, by kind permission of Steve) that when making the cuts you turn the camshaft 5 degrees AWAY from you, i.e. clockwise. So what did I do? Well I thought that moving the cam 5 degrees towards me would make an easier cut and my 360 degree wheel had two scales on it (see photo). So when I made the 270 degree cut I should in fact have been making the 90 degree cut! So in fact I was 180 degrees out.

To make sure no one else makes the same mistake Steve has amended his cutting chart (see downloads) including a portion of the 360 degree wheel he uses, and makes it even clearer that the cut must be AWAY from you. Not that he didn’t say it clear enough in his article, no the fault was all mine. You may think this shows me up more than a little, well you would be incorrect to think such a thing.

Indeed it only goes to show my genius! Why? Well the two engines I am building will run contrary to each other so one needs in fact to run backwards. When analysing the pattern I had achieved Steve emailed me to say that the camshaft I had made was exactly what was needed to run an engine in the opposite direction.

So in fact what you may think of as a mistake was in fact planned on my part………….. to make the second engine  work…….tee hee…

So now I can make the two ‘proper’ camshafts with confidence. After all the research, and with the help of Steve to find out what happened to produce my ‘special’ camshaft, I have a far better understanding of a subject I thought I knew something about…….In the end, a good outcome.

I get many emails but I had a nice one today from Rob Wilson who was complementary on my site but also without prompting, sent me two articles relevant to the building of my Seal engine. Both articles were in PDF form and one covered the build, detailed by Edgar T Westbury himself, in Model Engineer magazine 1947.

The second was an article on setting boring bars heights on a lathe and this is one I have not seen before so I hope to earn something of benefit when boring the crankcase on the lathe. Its this sort of unselfish help that seems to be common to model engineers as a group. So thank you Rob and keep visiting.