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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.

My purchase of a Clarke bandsaw has meant my Warco bandsaw has to go. It has been a great servant to me and is still working fine. If it wasn't for the fact I wanted a vertical cutting ability I should not have replaced it.

Included in the sale are a couple of new blades so its all ready to go. If you are interested then please email me. It will need to be picked up from Brixham in Devon. Below are some photo's of the bandsaw. I have fixed the price realistically at £50 so first come, first served.

I managed to get out into the workshop a couple of days ago and carried on with the manufacture of the two brass flywheels I am making for the pair of Seal engines. My session started well enough until I misread the dimensions and removed too much metal from the face! I decided however to carry on with making the flywheel so I could iron out any other problems and also make the tool for the flywheel starting cord. The pictures below show the progress and tool profile.

It is a big advantage to grind your own tools and the profile soon ground. I used the plan to get the correct profile. I took the cuts very carefully and got to depth but the next time I shall use the parting tool to remove more material and then turn to the profiled HSS tool. This should make the process even easier.

I will now have to prepare another blank. Fortunately I still have enough material but will have to be careful.

During the last cut of the last brass bar I was cutting for the first use of the bandsaw the blade broke at the weld! I was fortunate enough to have bought a bi-metal blade on eBay so I could carry on.

Phoning Machine Mart proved to be a less stressful experience that I expected. After being put through to 'some one in technical' I spoke to to their engineer who explained that whilst it was the blade, they needed to see if the machine caused it or whether it was a faulty blade.

My description was quickly accepted and the engineer said they would replace the blade even though it was classed as a 'consumable'. So that was good news. I went onto say I was pleased with the saw but the stand was rubbish! He said that a friend of his had bought the same model and held the same views as myself, he built a new stand for it. That convinced me that I should go the same route so as soon as some good weather comes, I will take my Mk Jaguar out of its comfy home and fabricate a stand in the resultant space.

20 minutes after finishing my call to Machine Mart I had a return call where I was told that the man responsible for retail blades would not open a pack of five for just one blade so they decided to send me a pack instead! Common sense but its nice I didn't have to fight for them. So well done Machine Mart and that's a gold star.........until the next time.......well done

Its early days yet since I have just received the Dremel Speedclic cut off system today. However initial observations are favourable. It is an 'expensive' system on the face of it so I will need to see its overall durability, the efficiency of the cutting disc as well as how long they will last before coming up with a final rating.

I purchased my set with a pack of spare discs from Axminster tools and on inspection the quality of materials is very good, but no less than you should expect for its price. The true cost of Dremels cut off disc system will depend upon both the durability of the click mandrel as well as the life of the cutter so some time will need to pass.

On opening the package the mandrel seems strong enough and of course I tried to fit one disc without reading the brief illustrated instruction sheet that accompanied the package. It soon became obvious that you don't put the disc on and press it down whilst turning in one direction so I am ashamed to say I had a look at the destruction's. You simply pull down on the top mandrel collar and place the disc inside before giving it a twist (making sure the Dremel painted side is facing away from the mandrel and tool), then release the collar and your done.

I always run any new disc up to speed for a short time, no matter what its size. More than likely this is not needed but its something drummed into me at an earlier age. When trying the disc on a 3mm bolt it proved both quick and accurate. I like the large size of the disc but on some small work it may prove to big. My answer will be to run one or two disc down to a small size then replace with new and keeping these smaller diameters for other occasions.

One major advantage obvious even this early on is the changing methodology. No more loosing very small screws!

On the face of it the expense is worth it, but I reserve judgement until I know how long the disc will last.

Dremel Instructions and Speedclic

Just had  a short session this morning and continued with the flywheel project for the Seal engines being built. However after getting the outside turning round and facing off I was left with 2.6315" diameter (need 2.5" finished size) so was pleased with progress. I don't know what specification the brass is made to but it machines great!

So feeling smug I thought I would rough turn the inside of the cavity (will be the rear of the finished flywheel) and using one of my home made boring bars before reversing the blank and bringing the front to roughly the correct diameter so that finishing cuts could be made all the better when running the lathe at faster speeds than the unbalanced blank would allow. This is when I hit a snag! One that I did not expect or had come across before using the Turner lathe.

The diameter of the cavity when finished, will be 1.75" and when I reversed the jaws, they were too big to go inside the cavity! So my smart thoughts went out the window! I will now have to remove the remaining excess by another method.

I did however resolve a question I had about the small diameter of the valve liners for the Seal. The answer came to me when studying the drawings last night and the reason is the need for the valve spring to sit over the outside of the valve guide. Mystery solved and I will just have to be careful when making them!

When I resume work on the flywheel I will hold the turned part in the 4 jaws as normal. A few photo's below show progress........

On one visit to my local scrap yard I was fortunate enough pick up a large diameter piece of scrapped brass. It had one problem, which I guess is why it was put into some factories scrap skip, a large cut on part of the bar, but fortunately it had enough unaffected to match the 2 ½” diameters needed for the flywheels.

Brass from my local scrap yard

The first task was to decide a machining procedure for the flywheels and after a little thought I decided that I would make a centre mark and scribe a 2 ½” diameter circle in the available space on the brass bar. This mark would be used to centre the brass  in the 4 jaw chuck by using a centre drill in the tailstock, using the pressure from the tail stock to hold the brass in position on the 4 jaw chuck.

Using the tailstock to centre the brass blank in the 4 jaw chuck

I will then face off the blank and turn the outside to a round shape before centre boring the cavity which forms the rear of the flywheel. Once this is done the blank will be removed and then use the 4 jaw chuck to hold onto the inside of the cavity, the front part of the flywheel will be turned and finished to shape. The final diameter however will not be completed until the flywheel is held on a mandrel running between centres as per Westbury’s suggestions, to get the flywheel turned accurate enough to eliminate wobble when used on the engine for real. Well that was/is the plan.

To save me some effort without producing mountains of swarf, I used the new bandsaw to cut away as much as was safe from the scrapped lump.  This blank was then taken to the 4 jaw and I decided it would be safer to reverse the jaws when holding the rough blank. They would be reversed again when the cavity is produced.

The blank was set up as per my machining plan and the first cuts made to the outside and this is where I decided that enough was enough. The next session will see the continuation of the turning of the outside until round before facing and then boring out the rear cavity of the flywheel. Look back and see the progress

Progress so far on turning the first of two flywheels for the Seal engine

Well today I managed to get back out to the workshop for a couple of hours. Since the cylinder liners have now been made it was time to start on the other cylinder fittings, namely the 16 valve liners (yes I am building 2 engines).

Having looked at the plans several times and referred to Edgar T Westbury's article published in Model Engineer (April 1947!) it seemed to me that since the guide must have the valve bore exactly central and to size, it would be better to use the 4 jaw chuck to make them.

I then considered the machining process to make the valve guides and due to their shape  the best way forward would be to produce phosphor bronze blanks. These would then be inserted into a special collet (yet to be made) which would allow me to produce all the blanks in one go (see photo of the first trial blank).

The blanks could then be inserted into the collet, which would be set to run true in the 4 jaw chuck. Then the very small 3/32^nd” central hole can be drilled and reamed before finally boring the ¼” diameter inset which needs a special HSS tool ground to shape, allowing the bottom radius to be turned.

Whether this is the best way to make the valve guides I am not sure, and if you know a better way then let me know before I start the job in earnest. Edgar’s article is very skimpy on making the valve guides and this worries me in case there is an easier way to proceed.......A second question arises in my mind in relation to Edgar’s design. Again I will have to do further research since I cannot see why he would have produced the guide with such a small diameter bottom end. It is only 5/32” in diameter and the valve stem is 3/32” in diameter. Making it larger would have the benefit of allowing a larger diameter valve stem, although that may have an influence on the inlet and exhaust volumes......

I may have missed a very good reason for his design being so, so I decided to put further work to one side on the valve guides until I know more and push ahead instead with the 2 flywheels.

Valve guide on the Block casting