The building of a Stuart S50 Engine

The Flywheel

22nd February 2018

I started work on the flywheel.

Initially I held the wheel as true as I could in a three jaw chuck.

Careful cuts were taken on the outer surface, about 0.1mm per cut as near to the jaw of the chuck as possible.

Then I took cuts across the face edge and then turned my attention to facing the centre boss and the inside of the outside edge.

Then is used a centre drill to make the guide for a the drill a little smaller than the 1/4" reamer and then drill through and then reamed the hole.

Some tidying up of the boss was also done at this stage but not shown in the photo.

The flywheel was then turned round and the same done to the reverse side, the jaws of the chuck were tightened to hole the flywheel whilst I sat on the reamers and this ensured is remained square whilst gripped on the previously machined surface

Then a mandrel was made up as a good fit to the 1/4" hole in the flywheel and a thread put on the end to tighten the flywheel into place.

The outer surface was then machined and cleaned up with wet and dry to give a near polished surface finish.

This the flywheel running true on the mandrel careful fine cuts, less than 0.1mm,  were made on both side faces.

26th February 2018

The final part of the flywheel is to drill and tap a hole for the 5BA retaining grub screw.

First I set the wheel at an angle which would allow the drill chuck to hold a small centre drill and not hit the wheel.

The centre drill then drill a small centre position which was followed through with the tapping size drill for 5BA.

The the tapping was carried out using the gig as shown. I noticed that with the tap in the T that if I put a drill in the drill chuck that is perfectly held the drill in an upright position and reduced the chance of breakage.

I used all there taps to again reduce the likelihood of breakage of such a small tap.

All the tapping went well and the grub screw fitted well.

The 1/4" reamer was then run through the hole to clear and material which had been pushed out whilst drilling and tapping.

9th October 2018

The flywheel is masked up and the primer applied.