Well I managed to turn all the journals to size without a major mistake (so far!) and only have the profiling to do on the milling machine. I did check the journals on the granite block and was pleased that they all came around the +/- 0.001 tolerance I set myself. However it is important I feel, to maintain one measurement instrument since there are differences between say a digital caliper and micrometer as discussed on this blog previously.

Now that the 'important' machining is done I can concentrate on the overall profile of the crankshaft. When done I will mark out the second blank waste area's and will drill away the waste before milling as I did this first one. Still, progress is progress.....

Whilst not up to doing any machining I thought I would take the opportunity to draw up a better dimension aide memoir. I did however manage to reverse the set up ready for the next  session.

In this, and future posts, I am adding links to where I source my tooling (new or second hand) in response to the many enquires I get as to where I bought a particular item. So the links will take you to suppliers or auction sites relative to the item highlighted and hopefully help readers directly.

Crankshaft.

After quite a bit of work on laptop the produced a set of dimensions were transferred to my master build notebook and also the white board alongside the Milling machine. I first tried using my dividing head to hold the blank for machining but because that  meant using a chuck I decided that my Vertex Rotary Table would be easier. It also meant using my as yet un-used, tail-stock, as the first method of securing the blank. I took good care to make sure the blank was level in both planes and then added an angle plate with vertical flat bar to secure part of the blank with an engineers clamp. Finally, a small jack was secured under the blank allowing a very stiff fix to take place.

Once the top side was completed the bar was revolved 180 deg. and the remainder of the blank milled to shape. This was then transferred to the lathe for the next stage in the process of producing the two crankshafts.

Quite a bit of time was spent setting up the lathe. I decided to tackle the turning by fixing a driving dog (to be made up) to the face plate. Using a new large centre at the head stock end and a live centre at the tail stock meant a smooth turn could be achieved. The final task was to ensure the tail stock and head stock were in line before turning the whole face plate one complete revolution to ensure nothing caught.

I have a Glanze replaceable carbide tipped parting tool and thought I would try to use the parting tool to machine the crankshaft. The carbide insert hadn't been changed for some time but I thought it would be best to turn all down before finishing cuts would be made using a brand new insert.

The surface finish gained so far shows promise for final cuts. So far I have turned one end to just become round before turning down the three different sizes required of that end. So far , so good.................

After converting all the plans dimensions to decimal using a excel spreadsheet, they were transferred to both steel blanks. To ensure they were as accurate as possible a small angle plate combined with an engineer's square clamped in position ensured the markings were at right angles to the longest side. To allow sufficient 'waste' material at each end I used a 0.250 slip gauge to set the height gauge to zero. I also referred frequently to the gauge as I went up the blanks, to ensure no accidental slippage occurred as I went higher. It is still surprising to me that you can pick up expensive and accurate second hand tooling on eBay. I have added a few in this article that lead to the auction site for those who have asked where I buy my tooling.

Also using this method of marking out allowed any errors in end squareness of the blanks to be eliminated. Whilst it may seem a lot of work to mark out in this fashion the lines are a great safety measure for me as I progress to the milling and turning stages, especially since they will not be needed initially because of the use of digital readouts on both lathe and Mill. So they provide a constant check whilst machining.

Not sure it was needed but I 'normalised' the steel blanks

I knew I shouldn't have gone out to the workshop, feeling a little under the weather after being brutalised by my younger brother Stephen (he maliciously tripped me up  when I was already wobbling - my life is spent being 'wobbly' all the time). However he also suffered some damage to his ribs, from laughing so much!!!

I have to make excuses for a very poor couple of hours at the milling machine somehow. Those who have been following the build of a pair of Westbury Seals here (or on my main website) will know I made a fixture for making the con rods and that the methodology for machining was in development. Well the radius turning for the ends worked well, and I shall keep that, but profiling the rest of the con rod didn't achieve either consistent, or satisfactory results, so it is going to be left until after the crankshafts now.

Another reason to stop is the revelation (to me after 4 years or so) that always using my scrap box (I call it recycling to be politically correct) for all my parts is not really the way to go for critical parts. Hugh, my nearest model engineering neighbour, supplied me with a link to his metals supplier. So I am going to order some aluminium flat, with known properties for the con-rods. That allows me to put them to one side, waiting for the metal to arrive (smart excuse eh!). I am simplifying my procedures as well. Milling to shape using 'normal' techniques is the best way to go only using my fixture to radius the small end and mill the indentation in the centre of the con rod body.

I tried to be to clever really, and use the rotary table in the same way I made the 4 chess knights. So when the correct stock arrives, at a known grade, and closer size, I am sure it won't take long to get them done.

Now over the the crankshafts. I got myself tied up in a knot over the requirement of HT steel for the crankshafts as described in Westbury's article and plans. This brought no end of trouble in cutting a bar of  HT steel in half (again being to clever for my own good  bought a bar of sufficient diameter to get two cranks from). In the end I went back to Hemingway's site (supply plans and a kit of castings as well as bar stock) and ordered two crankshaft blanks from them.

They arrived quickly enough and I put them to one side to concentrate on the con rods, however as you know from above this has now changed. A couple of years ago now I machined a piece of flat steel bar and was amazed when releasing it from its clamps, to see it bend like a banana! HMEM (the forum I use) members explained how cold rolled steel (that was what I was using at the time) had so many stresses when rolled that before use the metal should be 'normalised'. This is achieved by heating it to a cherry red colour, then letting it cool naturally, so releasing all the stress. Whether the steel as bought was normalised or not, ( knowing my recent luck, or rubbish working....) being bent like a banana,  is not good for an engine.

Since I had never carried out the simple procedure before, it seemed sensible to heat it up so that's what I did. Whether my cherry was dark enough I don't know, but its been done. So when I next go out to my home from heaven I will face off the ends of both bars so they are square, then drill 3 holes for the lathe centres to run in. One for the two central end shafts and the others for each throw.

I never seem to learn that the body is a better teller of  my potential workmanship than my head!

Well I managed to get out into the workshop this morning to continue on with the Seal con-rods, that's after quickly turning up a bush for the centre of a de-burring wheel. I was impressed with one I saw earlier this week on a visit to nearby model engineer, Hugh's workshop. After trying it out I continue to be impressed, even if they are a little expensive!

Anyway, on to the con-rods. I managed to reduce my steps during the night on machining with the small rotary table. Nevertheless it still took quite some time to refine the measurements and angles required. I think I am nearly there now and whilst I need to improve on my finished sizes (I always allow too much for final finishing. I should be  much braver!) I was pleased that the machining itself went without mishap. No grabbing the metal and climbing t who knows where!  The securing method of the fixture  made seems to have enough grip.

There is still some refinement needed but whatever else I believe I will achieve some accuracy with repeatability. Time as always, will tell. Here are some photo's but I must repeat, they are not finished!!!

One other simple but effective modification was attaching some rubber sheet (bought via eBay - use my link on the main website if you want to help with the running costs of the two sites, it doesn't cost you a thing.) which I used to replace the naff and tired clear thin plastic sheet used before. It works a treat so I may buy some more for the Y axis on the Milling Machine. See what you think.

Well the 25th January was the day I finally got back into the workshop to work on metal. In particular the pair of Seal engines. I have had either a real or perceived, problem with sourcing high tensile steel or its equivalent in the UK. I had previously purchased some round bar or the said material and thought if I bought the correct diameter I could saw it in half then get two blanks from it.

A saga then developed in trying various methods of sawing this &()*&^%$$ bar in half. Various suggestion's were made from forum members and email from followers of my two engineering sites (www.mikes-models.com as well as this blog). In the end I thought it may be easier to mill the bar down to get just one crank from it, whilst trying to find other suppliers of HT Steel in flat and not bar.

After securing the bar I used a new end mill with good quality cutting oil and off I went. I was pleased to see that the milling was certainly removing material so at least it would machine. I set about removing sufficient material so I could get a flat surface on 4 sides to allow it be be secured better in the milling vice. However after getting the 4th side done the cutter was worse for wear. I certainly could not afford to replace the cutter at the current rate of material so took it over to the grinding station and had a go at resharpening. Something I have never even attempted before, and was really surprised to find that the sharpening did actually worked! It may not have been to a toolmakers standard but it did cut better than before sharpening.

I then thought it may be time to invest in a milling tool with replaceable carbide inserts and approach the bar cutting this way. So that is why the title of the article is all about con rods!!!! I have yet to receive the tool so put the bar back till later (again!!). When looking around for something else I saw the con rod that came with the set of castings I bought second hand from another engineer. It was one that obviously did not pass his quality control (I have no doubt there will be others from me!) so I used this defective con rod to work out a machining procedure. Since I have 8 to make (a pair of engines, remember) I considered it to be worthwhile making any fixtures I produced to be in steel.

So now I can start on the process of making the con rods. I should also offer a health warning that my method has yet to be proven so beware..... After reading Edgar Westbury's comments in his 1947 article, and searching the net for other approaches I decided to ignore them all and look for my own. I decided that the form of the con rod would lend itself to the method I used when making the knight's, as part of a metal chess set, I made for the retirement of my younger brother Stephen from the Devon and Cornwall Police force.

The central tool in my method requires the use of a rotary table (my smaller 3" diameter table) and a special long 'T' nut with two securing positions located at the small and big ends. I intend to drill the blank undersized (to allow later reaming to finished size) then hold them securely to the rotary table.  They sit proud of the table by means of the height of 'T' nut and spacers between the blank and the 'T' nut.

Hopefully my next session will prove the methodology. If I get it correctly then it should mean the con rods all match (within myskill limits).

Look back to find out how I get on, and if you know of a supplier of steel in the UK for the crankshafts please let me know. I have contacted Hemingway's (supplier of the official castings and material's for the Seal) but I am waiting for their reply to see if they will sell the crankshaft material to me.

Nice just to be in the workshop again so

I have turned 4 pistons for the first Seal engine and following advice I have turned them 1 Thou under size. The 2 sets of rings per piston take up the rest.....

A full wrote up of the build can be seen on my main website so here is a picture of the progress to date:-

I set everything up last night ready to make a start on cutting the 1.5" diameter round bar of high tensile steel, in half. I was full of hope that with the carbide tipped saw blade that cuts wood and metal, this would be a successful. However two issues quickly arose, firstly the width of cut was increasing beyond the width of the blade, and secondly, it was very brutal and I suppose to a degree I chickened out!

So I decided to see whether a 4" slitting saw with side cutting teeth would do the job. I hadn't tried this previously due to how to hold the work and secondly, all the handle work on the mill. These issues were resolved because the power feed was working well and I now had a method to hold the work (the use of tapped holes in one end to secure plates too). Well it worked to a degree, after adding additional table clamps to stop some lateral movement. However it was again very slow going and I was not convinced that this would be successful in a reasonable amount of time (and blades!!).

So I have decided to approach the problem in a different way. 1, search out a local engineering firm to see if they can help cut the bar. 2, research whether the need for High Tensile steel is still valid bearing on mind how much materials have changed over the last 63 years since Westbury designed the Seal. and finally 3, look to take on another element of the build such as con rods or pistons while I sort out 1 and 2 above.

So if you can be of any help then please email me.

Today I managed to get the surface fly cut back and also the base but have left 3 thou for final lapping of the top and bottom. Hope its enough! The home made power feed worked great and certainly helped me with the physical side of turning x axis. So that was some good news!

Fitted the valves and couldn't resist trying a couple of springs just to see...don't know why we do it...get ahead of ourselves...anyway I will now sort out a cutter to cut the valve seats.

Decided to test out my idea for cutting the HT steel in half bought for the two crankshafts. My method is to tap the end of the bar (within the allowance of the finished length of the cranks) and secure two pieces of flat bar to it. These are then clamped to the saw table. This will allow both to be secured and remain there once the cut has been made.

Decided to try and make the two from one bar of HT (its very expensive in the UK) bit have left it for the next session when I will be fitter (don't want pieces flying around he workshop!

If it works all right I will start to make the crankshafts next.