That's when my memory kicked in and I remembered the ball nose cutters I have and one was in the correct size of 0.250". A quick check of the radius showed it to be near enough so my previously turned valve guide was mounted in the chuck and when considering how to get to depth the second part of my memory decided to wake up. I have a clamp that I attach to the tailstock and then use a DTI, secured to a small magnetic base, to rest against the clamp so ensuring complete accuracy with depth. Why I didn't use it yesterday for the tappets I do not know!!!

I did not use the ball nose milling cutter directly on the valve guide but drilled it out first just undersized and using the cutter to clean up and cut the bottom radius.

Another plan issue showed itself yesterday when completing the two camshaft bushes. Neither the article or the plans show the angle of the oil holes required in both bushes.  Nor does it give the diameter of the hole.

My solution was to use the new digital angle ruler bought from Axminster tools on the plan (see photo). This gave a reading of 33 degrees and measuring the plan showed the hole size o be 1/16".  I had a bit of a blonde moment however when working out how best to drill the hole and its chamfered entrance. I thought the best was would be to use my Proxxon drill and stand. So I set the head over to 33 degrees and yes I know you will know but when depressing the stand of course it goes only directly up and down!

Blushing I got out my angle vice and after setting the digital angle meter to zero on the base of the drill stand, I adjusted the vice to the required angle and form then on it was simple.

The next session should see most of the valve guides for this first engine completed. After that as soon as the 1.8mm drills arrive I can complete the two nuts required for each valve before carrying out a new experience for me, case hardening the tappets and nuts. I will cover the experience in a separate section of the website as I have had some advice from a member of the forum I use.

If you don't know it then I can highly recommend the Home Model Engine Machinist forum, especially if you are a novice as they are both approachable and knowledgeable.

As always here are a few photo's that may help explain my ramblings.....

So after completing the valves the next items I was going to tackle was the two 1/4" hex nuts per valve. That was until I found I didn't have a suitable drill for the tapping. According to my charts I needed a 1.8mm No. 50 or 0.0709" drill. When going to my numbers drill box the only one missing is ............yep No. 50. So that job was put to one side and instead I decided to make the two camshaft bushes. The first went well enough and was reamed 0.250" and was pleased when it fits the camshaft nicely.

The second bush however produced another problem when checking the main block casting. This one was bought second and had some work done by the previous owner. All the work when checked previously was of a high standard, however the two holes bored previously were not the same. One, the timing end was spot on but the second was slightly oval! So worked stopped on the bush because it will need to be oversized, and the casting set up on my angle plate on the mill and the hole bored circular. When the finished 'round' hole was measured the bush will need to be some 35 thou oversize.

I can't see this will cause any problems yet, but will keep my fingers crossed.  I will be using some hardening powder for both the nuts and the tappets, for the first time so that will be interesting. I have had it for a couple of years now and never used it before so if anyone has any tips additional to the 'normal' instructions I have, that would be very helpful.

Making the last camshaft proved the adage that “practice make perfect”. Not that I am in any way saying that the camshafts are perfect, far from it! But the last camshaft (I hope) took the least amount of time and for a change very few problems. Each time I nearly made a mistake I managed to stop myself from continuing, which is not an insignificant result believe me!

I now have a camshaft to harden as an experiment, and a completed camshaft for each Seal engine. Their production was not without incident and a little heartache at times, but I must go on record and thank Steve Huck for all his considerable help with cutting charts and giving me confidence when I had doubts, so thank you Steve.

The issue of errata on plans is something I have mentioned before. If you consider the ‘fit for purpose’ test as in the UK then the Seal plans I have would not pass. If the plans were new then an error or two may be expected, however this design by Edgar T Westbury is over 60 years old. Is it too much to expect some obvious errors to be removed from the plans SOLD to the public? Let alone some major issues over the camshaft design. I know I lost some sleep over what was right and what was wrong. One thing I hope to come out of the Seal build is a comprehensive list of ‘issues’ relating to the plans and they will be posted on my main website as well as my Blog for future builders. Additionally a copy of errata will be sent to the publishers of the plans, with a hope they amend their plans. We shall see.

The camshafts are not complete as yet, since as they have some finishing left but the machining is completed. A bi-product of completing this stage of the build is the much diminished fear factor of producing camshafts, since the 3 completed camshafts and the 50% practice camshaft (on a blank I ‘corrupted’ early on) has given me some experience.

So its now onwards and upwards, with the next major items being the two crankshafts……….ohhhhhh……..

Well I managed to get back into the workshop this morning and decided that I would start on the last camshaft for the Seal engine since the lathe was still set up for the cam turning fixture. With the half turned practice blank that will make nearly 4 camshafts now made. Two proper camshafts made from Stainless Steel and another made from BMS which I intend to try and harden. If it works I may use it as a comparator in one of the engines. If it doesn't work, well I will have learnt from that as well.

I am going to write a large lettered poster for the workshop saying “If it looks or feels wrong then it IS! Investigate as to why before continuing!”  I may produce a dozen copies and post them all around the workshop and maybe have it tattooed to the inside of my eyelids as well.

I did have a few set up problems with the camshaft fixture turning true. I must be learning something though because it took me less time than usual to find the culprit. My tail stock also swivels around the locking point located centrally. I couldn't see to begin with why, when I was off setting the tail stock, the live centre did not follow, indeed it was going the other way! It was only when I lent on it that it revolved! Doh.

Hopefully tomorrow I shall complete the camshaft and then I can get my lathe back.

Well another lesson learned and mystery solved. It brought to mind all the times when 'something' wasn't right and in the past I have not investigated fully. Its only since the rebuild of the Myford ML7 that I have been far more investigative with good benefits resulting. So the new motto will hopefully serve to 'help' me. Time will tell.

Today I managed to finish turning the second camshaft as can be seen in the photo below although I have yet to complete cleaning up the camshaft. It is only held in the chuck to allow it to be filed and sanded. It is not unsupported for turning, just using the Myford as a very expensive vice!

The second camshaft took a lot less time than the first, but I did annoyingly catch one of the lobes with a nick. I blame SWMBO who came in at a very inopportune time! I managed to keep my muttering under my breath until she left. Then I said a loud tut tut. Fortunately most of the mark was removed with further cutting but part of it is still there, and I know its still there!

Hopefully tomorrow will see an end to cam cutting for a little while, although I still have one more to make. At least I now have a pair of camshafts and that should allow me to tackle the main castingsnext , namely the cylinder blocks. Anyway here is the photo of the latest camshaft, half way through tidying up.

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.

 1. Is the cam profiles on the published plan correct?

2. What is your understanding on the firing order for the profiles shown on the plan? 

I am aware that the firing order was changed in the Aug 1947 magazine to 1, 3, 4, 2. rather than the order shown under the cams in the photo, however should the profiles also have changed?

 I have seen two photo's of completed plans that seem to match the plans profiles, and I want to confirm the firing order. An early reply would be very much appreciated.

Also If anyone has any comment about how the engines should be handed or built so they will power the boat with two contra rotaing props that would also be helpful.

Kind regards

Mike

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!!!!!

28^th 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 1/8^th”  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 ……)

Today I managed to get the practice cam turned enough to satisfy myself that the system will work so a start has been made on the first of the two real camshafts.

I was hoping to make faster progress but I got distracted by the arrival of another set of castings. When inspecting them I was very surprised to see quite a bit of difference between them. My first set always seemed a little out, especially the cylinder block and head (see photo below). Seeing the second set has confirmed that the size difference is not the same with the second set. Also the sump casting is a lot bigger compared to the rest of the first cylinder block and hen comparing the two sump castings you can see just how much difference there is.

I don’t know if there is another supplier of castings for the Seal other than Hemingways, [link]but if they come from the same source there must be another set of patterns! At least I now know the differences between the both sets and what work I have to do to put them right.