Good Morning Jason

The 2 measurements are as follows:

1. ctr of crankshaft to top of cylinder cover is 4.278"
2. diameter of flywheel is 9.050"

Having to take these measurements gave me the first opportunity to roughly put the bits of the engine together and see what it'll look like

The ratchet on the barrel arbor should not be loctited!

In the majority of fusee clocks the ratchet is secured by a taper pin through the arbor.

You wind a fusee clock by the square on the fusee. The square and ratchet on the barrel arbor is only used when setting up the clock by providing a pre tension on the mainspring and hence fusee line. Around 3/4 of a turn should be sufficient. This is done so when the mainspring is unwound there is still some tension on the fusee line otherwise the line will come loose and not re-engage in the grooves on the fusee when winding back up.

Hope that's clear! (as mud!!)

Regards

Derek

Thanks for commenting Dave and Art!   --Tim

Thanks Dave!
Yeah, I was looking through your die filer build just the other day!  Looking at your file support and hold down.  That's a very interesting way to do it. for sure!  Don't know if I'm going to do that yet, but it looks like it's something that could be added later if I choose to do so.

Kim

Next, the job is set up on the faceplate for boring the pivot hole. The revised design for this now has a taper seating both sides so that the assembly is more firmly clamped, with a smaller parallel bore between the two tapers. Having finally persuaded the the centre pop to run very nearly true, using a wobbler and DTI, I pulled the single clamping dog up hard and then carefully balanced the job with my faceplate balancer. The bolt just showing behind the casting is there just for balance. In vindication of the use the balancer, I was able to run this set-up at 1000 rpm without vibration.

I faced the back of the boss to size and, as there was already an off-centre hole, I started to open the bore up using slot drills rather than twist drills, then bored it true before finishing with a tapping size drill.

I then bored the taper, realising early enough to reset the topside to 15° instead of the 20° I had started with. The original design (as revised) calls for a 40° included taper. I cannot think why, apart from that the Prof seems to have standardised on that angle. A shallower taper will clamp better and will still be self-releasing. I have revised the revision and settled on 30° included, and increased the diameter a tad to boot. There is still plenty of meat round the hole. I had already made the clamping bolt with its tapered seating to use as a gauge, and tweaked the topside angle until the hole blued up properly.   

A useful idea from the Mark 3 is to tap the central hole so that the part can be mounted on a stub mandrel for boring the second taper seating.