seal camshaft edgar t westbury steve huck mikes models

In the meantime I decided to make a start on the cylinder block casting (see the cylinder block page). When Steve very
quickly delivered the goods in extra quick time. So today I left the casting and went back to the camshaft.

The first job is to make the turning fixture and after selecting some suitable sized stock the first task was to square it up so
it could be marked up for 4 holes to secure the two upper blocks, and the two centre marks for the live centres to locate in.

It always surprises me how long I take to get a simple job done! I suspect 90% of my time is spent in setting up to do the work!
Well that and to keep checking my workings..........

The sum total of progress however was to square up the three pieces (base and two upper blocks) and using my new granite
surface plate and height gauge, mark out the base. And thats as far as I got.....

Hopefully tomorrow will bring a little more progress. I would like to at least finish the fixture! Time, as always, will tell........

Edgar T Westbury's Seal 15cc 4 cylinder petrol engine - update 3rd March 2009

After several weeks getting the Myford ML7 lathe refurbished I have been desperate to get back to the Seal engine build.
Taking my own advice for a change, I wanted to get one of the worst (in mind at least) aspects of the build out of the way
early on, that of the camshaft. I have made the fixture to turn the cams on the lathe to a design by Steve Huck's [link] but
now comes the metal turning itself!

Looking at the plans as supplied I cannot get my head around the dimensions given regarding making the camshaft blank.
Feeling a little under the weather I thought that the best way forward would be to make up a machining aide memoir (similar
to the approach I used when designing and making the Chess set featured in Model Engineer, issues 4345,4346 and 4347 :
2009) and try and make sense of the drawing. Eventually I thought I was there and would check my dimensions against a
broken camshaft given to me by the seller of the casting's set.

I intend to make two camshafts initially. The first will be made from stainless steel and used to see if I can get away without
hardening the shaft as recommended by one or two HMEM forum members. The second would be made from steel which I
would subject to the powder hardening process. I fully intend to make other camshafts for this engine later on when trying to
improve performance. I hope to learn a lot more about small/miniature cams and their performance over the coming years.
Don't ask me why but the subject does 'rock my boat' as they say. Anyway I chucked a length of ½" diameter stainless steel
which measures 0.499" and since I am working to a tolerance of +/- 0.001" I will not take a surface cut. Because of the
tolerance limit I have set myself I thought I would take time to check that the Turner lathe I have has the tailstock in line
with the chuck. You may ask why I haven't done this before and the simple answer is lack of experience. I also believed
(wrongly) that the accuracy would be as good as it got when leaving the factory so leave well alone, in case I mucked it up. Its
only the rebuilding of the Myford lathe that has given me the confidence and perhaps techniques, to check something I should
have done as soon as the lathe was received.

I have always suspected something could be out of line from some long cuts done earlier. When using 2 DTI's to check
alignment I couldn't believe it was over 4 degrees out over about 7 inches! The remedy was simplicity itself, with the
tailstock moved to the correct position by using the adjusters, before being locked off. I decided to run the lathe up and run
the saddle up and down a couple of times and recheck, finding everything now running true. I kicked myself for not doing this
earlier. If I am fortunate enough to ever buy a new milling machine I will carry out checks on everything before even
switching it on! Fear of the unknown has a lot to answer for!

With the confidence that the set up of the bar was running true in the 4 jaw chuck and in line with the revolving centre in the
tailstock, I set too turning down one end to the 0.250" diameter required. Steve Huck [link] when designing the camshaft
turning fixture, recommended that I should leave extra at each end of the camshaft to be removed at the end of the cam
profiling. So I allowed enough to clear the centre with the turning tool and then using the DRO moved to what I thought would
be the correct position to cut the gap between cams. All was going fine, if slowly until it came to cut (or in this case leave) the
second inset leaving the cam blank alone. Checking before I made any cut something did not seem right. I checked the
measurement and compared them the broken camshaft and whilst the width of the cam was correct, the gap between them was
not.
No matter how hard I tried I kept tying myself up in knots. I got so confused that I gave up and decided to call it a day. It
was only when laying down this afternoon that by using graph paper to scale, that I could work out what the dimensions should
be. Blonde moment over I have made a new sheet so when I fell well enough to have another go, I should at least know where I
have to cut. I don't say I will get it right, but I know now what needs doing but I thought the same this morning so don't get
too excited! To be contd.

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 below].

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. [see photo below]

Wednesday 25th Marh 2009

At last I felt well enough today to get back out into the workshop. Nothing feels better than a successful or even semi
successful session. It even gets better in that I was working on the Seal engine for the first time since the start of the
Myford refurbishment.

It took quite a while to sort out the turning fixture for the camshaft with no parts fouling each other. I had to reduce the
diameter of the front disc that registers the degree of rotation of the camshaft. Then there was a problem of getting the
cutting tool to have sufficient travel without fouling anything. This all took time but eventually everything went around
without anything going bang!

The cam blank I am using now was not made to match the fixture (my mistake) so I am going to complete the machining as a
practice and confirmation piece. Confirmation that the process I am using will produce the correct camshaft.

To help me avoid mistakes (since I am cutting 6 cams at a time) I decided to mark which cam was which, on the offset
turning fixture. This, together with the cutting charts produced for me by Steve Huck's meant I had a chance of cutting
the right cams in the right order. As an added safety measure I also marked all of the cams with a permanent marker. If
those cams which had to be left remained covered with permanent marker ink, I wouldn't have a problem!

For those of you who have read Steve's cam article in both Model Engineering in the UK and Model Engine Builder in the
USA (and available as a download on www,mikes-models.com), you will realise that 'the first cut is the deepest', as the
song goes. Initially I need to remove 0.078" from all the Cam blanks, but in order. After that it's a case of revolving the
camshaft by 5° and making the cuts on the chart. I had printed out a set of charts already and filled the x boxes with a
highlight colour then laminating them. However I decided to print a new set off and use a highlight pen to colour in the
section that was being cut so I could keep count.

I need this amount of organisation since there are 47 rotations with cuts for the exhaust and 49 rotations and cuts for
the inlet cams. So as you can see there is a lot of work to be done. Now multiply that by the 3 cams I will be making (this
practice then two engines) and you will see this is not going to be quick!

More importantly though is the fact that I'm back!

28th March 2009

Well today was a good day. The first of many I hope. I wanted to complete at least one blank camshaft in steel. I expect I
could have made 1 ½ blanks if I hadn't made a mistake with the taper end of the camshaft.

I had completed all the fussy bits and then took too much off the 1/8th" tail. So that was parted off and will be kept as a
comparator piece (scrap really!). I was a little miffed that I managed to get all the parts within 0.001" only to make a silly
mistake at the end (literally).

At least the structure I put so much time into for machining seemed to work. Indeed the time I took to make the nearly
completed camshaft blank [see photo] was much reduced for the second attempt. This particular camshaft is made from BMS
(bright metal steel) and will be for my hardening experiment. I have another two blanks to make over the next couple of
days but these will be turned from stainless steel. Not sure if it's the best material but it is surely harder wearing than
BMS.

The only task remaining to complete today's example is to drill the small hole in the opposite end from the taper. This is to
allow a small steel pointer to be used when turning the camshaft in the fixture designed by Steve Huck (thanks again Steve!).
I will drill the hole when I have all three blanks machined to the same point to make use of the set up time involved.
I decided that the best way to approach the task of producing the cam blank was to machine the awkward part first. The
first job was to centre the bar in the 4 jaw chuck with the minimum showing. Then the bar was turned down first to 0.250"
diameter. Using the digital readouts the start and end of the taper was lightly scored on to the bar, along with the
measurement of the length for the thread.

It was then another turning job to bring the diameter down to suit the 2BA thread which was then threaded by use of the
die held in the tailstock holder. Once this was carried out the thread was then reduced to size. The next procedure was to
turn the 10° taper just in time noticing that the tap setting should be only 5°. I must admit to a little apprehension when
sizing the job up especially blending the taper to the threads. In the end though there wasn't any difficulty and the thought
was far worse than the deed (as I have found with many engineering tasks done for the first time).

Once the tapered end was completed the 4 jaws were released and the bar drawn out, centered again, and then parted off
with sufficient length to make a complete camshaft blank.

The bar was reversed in the 4 jaw with only enough bar showing to allow the dti to be used to centre the bar. After facing
off the end was centre drilled so a live centre could be used in the production of the camshaft. This was the first time that I
thought about how I was going to turn the cams in the next stage. In particular because the taper end was very small and
certainly too small to centre drill and use against the live centre, but likewise I couldn't grip the nice taper end in the 4 jaw
chuck. So I decided to produce a brass bush that would protect the shaft with the taper [photo] leaving the larger diameter
faced end to be held with the live centre.

Once the bush was drilled and reamed, it was parted off and the bush and shaft placed in the 4 Jaw chuck, using the dti
again to get it running true. I decided (with fingers crossed) that I better check the shaft was true across its length and I
was really pleased to find no discernable difference between ends. Now the test would be if my new chart with the
dimensions on (chart is too posh a term for the scrap of paper - see photo) would work.

Starting with the end nearest the chuck, the digital readouts proved there worth as I set the position of the saddle into the
correct position. With a new insert in the parting off tool I took the cut to depth. Set the y axis reading to zero and moved
the saddle to the end position and cutting to 0.005" of the finished size. This left a middle piece to be removed, again to
within the 0.005" of finished size. I now carefully moved the saddle between the two cam edges using the parting tool to
turn down the last 5 thou to finish across the gap.

Then the saddle was moved towards the tailstock and into position for the next cut to within 0.005" before cutting the end
position, removing the centre part last. This was repeated until all 8 cam blanks were cut. The tool was changed and the end
nearest the tailstock then turned to finished size using the half method. Since learning about the half method I can nearly
always get to the 1 thousandths of an inch allowance I give myself. Well unless I go stupid as I did earlier on in the day, but
that wasn't a failure of the methodology, rather the stupidity of the operator!!

And that was enough for me today. At least I made progress. Hopefully tomorrow I will be able to produce another blank (I
would like to get both done really but that depends more on health issues than time ……)

29th March 2009

Well other than loosing an hour because of British Summer time, and watching Jensen Button win the Oz GP (well done to both
Jensen and Lewis Hamilton for a great drive in a poor car - amazing from McLaren!)at 0600 hours, I managed to get out into
the workshop for a second successive day! Brilliant…….

Onto the build though…….. I managed to get both stainless steel camhaft taper and threaded ends done, and also cut out the
blank cams completing one piece. So tomorrow I hope to complete the cutting of the cam blanks out of the second. Completing
this phase before profile cutting the cams. The second photo below shows where I got to before stopping for the day
…..ignore the left hand side of the shafts since they have yet to be cut to final size. Also there will be a cross drilled hole in
the left hand side to accommodate Steve Huck's idea of a marker when I profile the cams.

When the camshafts are finished to size the left hand side is much reduced (and loosing the cross drilled hole).
I think that when I have managed to make the cams that will be a big psychological problem over. The next 'big' job will be
the crankshafts but I may have a go at bringing the castings to size first before making the crankshafts. After that its all
down hill! Only 16 valves, 8 cylinder liners, 8 conrods, 8 pistons…………….oh *&^%% hell what have I done!!!!!

3rd April 2009

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 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.