Here is the latest update on progress, yes I have actually made some !!
I will keep the words to a minimum and let the photo's explain.............Any questions just ask.
Phil
Since the last installment, the flywheel in its part finished state won me a big silver cup at the Bradford Model Engineering Society annual exhibition.
After I brought it home from there it was totally stripped down again to allow the inside face of the eight main segments to be fettled up a bit with some filler and smoothed off ready for painting. Then it was put back together for the last time for the final machining operations to add the 200 teeth for the barring engine ring gear, and the 18 grooves for the rope drive on the outside face.
Here it is having the crank side face machined, this will be a datum face later on.
Now the outside diameter is being cleaned up true for the first time in the lathe, this will also be a datum and still needs another finishing cut later on.
The segment joints need to be relieved in the area where the barring ring gear is to be fitted.
This shows the blanks for the eight segments laid out on my flywheel drawing to make sure they will fit OK.
The gear blank segments are clamped in place and then drilled for countersunk screws to hold them to the flywheel.
Obviously two screws is not enough, so I ended up with five in each.
Then mill away the bulk of the material to get it round inside.
Then round outside.
Then back onto the lathe to face the thickness to size and finish the inside diameter to size ready for its teeth.
To save the single point gear tooth cutter having to remove too much metal. I drilled some of the tooth away first, this meant 200 indexes on the rotary table. You do not need any interuptions while doing this.
Then swap the high speed head for the slotting head.
And start another 200 indexes to cut each individual tooth. I made a dead stop on the Y Axis so I could not go too deep by accident.
Boy did I breathe a sigh of relief when I got to this point.
Then it went back in the lathe to finish the outside diameter for the final time, I have fitted an inverter so I can run the lathe down to about 10 rpm, the final pass on a slow feed took about half an hour.
Note the big lumps of lead to stop the overhanging tool chattering.
Once the outside diameter was finished the 18 rope grooves were added, I made a special form tool for this as the grooves are tapered with a radius in the bottom but start off with parallel sides as per the original drawings.
And finally the finished result, I say finished but the countersunk screws will be filled over prior to painting, I do not agree with being able to see modern fasteners on models of old engines.
My main objective was to make the flywheel as true to prototype as possible, the biggest fear I had was that you would be able to see the joints between the eight segments, so I have been a bit paranoid about making sure everything was checked and double checked along the way. I am very pleased with the way it has turned out and I can put that worry behind me.
I think I might make the barring engine next, see you in a year or so
