Seems to me that mounting on a face plate might be the safest method of holding that part?

Good though Loctite is, it is unlikely to be up to that repair, and epoxy is unlikely to do it either. It might be possible to braze or bronze weld it, but I think really it would be better if you can get a new part.

It is a while since I did my Stuart 10V, it came with my Unimat 3 nearly 40 years ago. The way I did the standard was with the faceplate. I don't remember the details of which end I did first, and if I was looking at one now that would partly depend on how clean the casting was. The older castings may have been better than recent production. If I could, I would be inclined to try making a mandrel fitted in the three jaw that just fits the bore of the standard. A bit of epoxy might be needed to ensure a good grip. That would allow turning the top of the flange, then by turning the job around, the feet can be faced. With the flange trued, it can be mounted on the faceplate. I faced the bottom of the feet on mine with them whirling around unsupported, so a sound casting should be OK like that. You do want to take light cuts and not inadvertently start the machine with the tool about to foul one leg. It was all a bit tricky on the Unimat since it is only marginally big enough to machine a 10V. I also did the bulk of the machining for a double 10 on the Unimat, so I've done three of those standards.

John

You might find it useful to read the fairly comprehensive advice and study the photos of machining setups in the little book 'Building a Steam Engine from Castings' by Andrew Smith (the modern version has been revised by Pengwern). It's widely available for less than a tenner. Try TEE Publishing, for example.

The previous replies to your questions mention the standard ways of doing the job you are tackling, and these are much more likely to avoid the common pitfalls.

My own inclination would be to order a replacement casting from Stuart Models, and put this one down to experience.

Its a nice engine and a good starter project.

Nick, also take a look at this thread at the bottom of the page and over onto the next. Infact have a read of it all.