Wednesday 4th March 2009 – Seal engine update
I thought yesterdays brain clogging problems were over. However, whilst I managed to sort out the dimensions for the camshaft by use of graph paper, when it came to machining I was still unconvinced it was correct
I thought I would help myself by marking, in permanent marker pen, the general location of the cams, so I could see if I was going wrong somewhere. In the event these marks caused me even more difficulty! I did a dry run as it were and ran through the sequence written on my notebook. Whilst it finished where it should, the gap between cam blanks seemed too large. So I got the defective camshaft (it broke in the middle) sent by a previous owner of the castings, and when comparing the marked out bar with the camshaft the spacing was fine, but the gaps seemed to large [see photo].
In the end I was so confused I just gave up and thought I would cut the cams as per my dimensions. You may have guessed that after cutting the first two cams everything was as it should be and the cutting of the remaining blanks went without a hitch. I do not know why I got so tied up with the layout (I suspect it’s my medication!!) but it was not only time slow, but also confidence sapping. I just didn’t believe my own workings and it didn’t even look right on the dry run but right it was. Some optical illusion!
After cutting the camshaft blank I did compare it with the broken camshaft and there is a little variation on the damaged camshaft which may have also disrupted my approach to the work.
My next session will entail making another cam blank but in steel that I will try and harden. I may also need it if I make a mess in applying Steve Huck’s cam turning technique. Now I have done the first blank I am sure the next one (and future camshafts) will be done much quicker. My aide-memoir worked even if I didn’t believe it and I will write it up properly, laminate it and put in the Seal box of bits for the future. I don’t want to got through the last couple of sessions again. No point in learning a lesson if you don’t remember it.
My next task was to stick the 360° paper template onto the cam turning fixture and then I called it a day. photo]
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!
