I managed to get into the workshop this morning so carried on with the pair of flywheels for the two Seal engines. The need to ensure they do not 'wobble' when running is important so I decided to follow the advice of Edgar T Westbury in his article published during 1947 (!) in the Model Engineer magazine and make a mandrel to run between centres.
I decided to turn the mandrel out of BMS (mild steel) and set the taper by adjusting the top slide over to give the 10 deg inclusive angle. After getting the bar to run true in the 4 jaw chuck, the bar was turned down to just under the 0.25" diameter required to match the end of the crankshafts. The thread I used was 1/4" x 40 tpi (model engineer thread) so I checked the Drills Taps and Dies reference book in the Home Workshop series (no.12) by Tubail Cain where he recommends a 5% to 10% reduction in size to allow for the Die to cut correctly.
Once the mandrel was made a elongated nut was mad to hold the flywheel against the taper. Once the nut was threaded I drilled out around 1" in length away from the nut. It was then back to the 4 jaw chuck to centre the mandrel, and fit the flywheel.
I was pleased and disappointed at the same time when I ran the lathe because the flywheel ran true! Pleased because of the work done and disappointed because of the work done in turning the mandrel! On reflection I decided that it was still the right thing to have done and really confirmed the trueness of the flywheel.
So that completed all the turning machine jobs and whilst this one is scrap I at least now know the best procedures to produce the flywheel. So the next time I will ready to go full steam ahead and get the two flywheels made.
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Mandrel for turning Seal flywheels
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Mandrel and ‘practice’ flywheel
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ME 1/4″ x 40 tpi
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Cleaning up the flywheel between centres to stop ‘wobble’
About Mike Freeman
Hello, my name is Mike Freeman and I am a retired Chief Fire Officer from the United Kingdom with a keen interest in model engineering, silver caddy spoons and sea fishing. I live in the pretty fishing port of Brixham, South Devon, in the United Kingdom.
I am a sufferer of degenerative osteoarthritis, which impacts on the amount of time I can spend in the workshop, and is the reason why you will see seats and a stool in some of the photo's. I have only recently added the above sentence after a discussion with one of my Doctor's from the excellent pain clinic, based in Torbay. This does affect concentration one of the reasons why I double then re-double my measurements and set ups.
Before completing nearly 30 years of public service I and my wife Sandy, owned and ran, a small restaurant in Okehampton Devon. Prior to marriage I worked for my father in his various businesses, in the early days these were garages, which he bought in a run down state, then built them up before moving on, to start again.
I took every opportunity in those early days, to work in his workshop's
learning 'on the job' rather than as an apprentice. This, I suspect, is the reason why my building various model's in the early days, turned into model engineering, when funds allowed the required equipment to be bought.
My workshop comprises one half of a detached double garage. It has a
stud wall separating the two halves and unusually perhaps, its own
shower/toilet/washbasin compartment! (the true reason for buying the
bungalow - don't tell the wife!!!)
It is fully insulated with a ceiling and fluorescent lighting supplementing the one window. Several double electrical sockets are dotted around in
relevant positions.
Equipment consists of 2 lathes (1 Myford ML 10 and 1 Chinese variable
speed motor with etched glass DRO's), 1 milling machine (RF25 far East) floor standing pillar drill, Proxxon bandsaw, Warco bandsaw, 6" wire brush and polishing mop motor, 6" coarse and fine grinder, Proxxon mini drill, various benches and an engineers vice. I have just acquired a third lathe, a Myford ML7 which I am at present evaluating so I can decide which of the Myford's I will keep.
I have only just bought the Chinese lathe and had it fitted with DRO's prior to delivery. And what a bonus they are! So good in fact that I decided to buy another set for the Milling machine. Whilst my engineering experience can only be described as limited, I find the use of DRO's has affected my accuracy levels which have improved tremendously (although that's not saying much!) and would recommend their fitting to any model engineer.
Prior to retirement I built for my son's 17th birthday a Locost car. This
was a tremendous project and a great feeling when it passed its test. The book it was based on suggests it can be built for £250. Ours was nothing special in the sense of all new parts but still cost about £900 to build!
