Beginner and a 10v

After the brief saga of getting the 4 jaw mounted. Tonight I mounted the standard up in the Chuck set for a really light facing cut. 300rpm or so.

Snapped the leg clean off on first touch! I’m slightly astonished as I’d already faced the feet and I assume that would be a greater lateral load!

Ive locktited it’s. Wonder if that’ll hold up to machining.

I can’t quite envision how else to hold it bar the feet. Especially for the boring operation. A feel a glass of beer and a think are in order.

Sorry to hear of your problems Nick and I'm sorry that I cannot offer any advice, except maybe to order a new part.

Hopefully there will be others who can be more helpful.

Brian

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

Maybe a photo of how it was mounted when it broke so people can offer advice on what exactly went wrong?

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

Usual way is to hold by the top flange in the 4-jaw and skim the feet adding a bolt through teh casting so it does not get pulled out of the chuck due to long overhang of the feet. Then clamp the feet to the faceplate to face the flange and bore the trunk guide.

Were you holding the feet in the 4-Jaw, if so jaw pressure probably snapped it.

Loctite unlikely to hold and I have my doubts about whether the usual choice of JB Weld will be upto it.

Have a look at page 5 and 6 of Harold Hall's site for some guidance

Edited By JasonB on 11/02/2021 07:15:36

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.

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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.