Hemingway Quorn Mk3

Christianstark

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Just started the Quorn project. I’m beginning with the 2 base castings. I think I’ll be going the rout of JB Welding the 2 pieces together for at least boring the 2 connecting bars. Did some small machining of what I think will be reference surfaces, but took just enough off to clean up the casting roughing. Will post pics tomorrow.
 
OK, so yesterday I was able to deck the bottoms of the "feet" of the base castings first. It was a tad awkward in the milling vise, but I only skimmed off just enough to clear the casting surface, and get everything level in relation to the casted holes. The cast holes are rough, so the only goal was to get them close, and take as little off as possible. The "feet" are the machined surfaces closest to the camera.
IMG_3823.jpeg

The next step was to machine the "inside" surfaces of the castings. I did each one individually by orienting the foot/feet of each casting to the fixed jaw, and then bumping the part around to get the cast bores as vertical as possible. They are rough casts, but I was able to get it all within an acceptable vertical orientation, and then used a carbide face mill to deck the inside sides. I am planning on JB Welding the 2 pieces together soon, for boring out the main base bar bores, in order to get them perfectly concentric.
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The cast holes are decently accurate, but not perfect. By epoxying the parts together and boring both in the same vice set-up, I can guarantee them to be concentric and parallel to each other at least to a tolerance as accurate as my machine is.
IMG_3821.jpeg
I will JB Weld them together while held in orientation by a decent fitting pin, prior to the boring operations. Later I can weaken the epoxy with a torch, and separate the two pieces. Boring will be done following an order of operations where I can implement cotters for clamping in lieu of splitting the castings. The cotter holes would need to be bored first, and then the cotter brass would be lock titan in prior to boring the main base bar holes.

I have not epoxied them together yet. Trying to make sure I am not painting myself into a corner, so order of operations will be critical for all cast parts during this project. The base castings will look like this when epoxied, and then the orientation bar will be slid out. At this point, the 3 feet will be my primary reference plane till the parts are again separated.
IMG_3822.jpeg
 
Cool, Looking forward to following along on your build.
 
Same, looking forward to it too! Instead of JB Weld, could you use superglue? I often see it for temporary heat-removal methods like this, and wonder if it would make less of a mess and be easier to remove at the end.
 
Same, looking forward to it too! Instead of JB Weld, could you use superglue? I often see it for temporary heat-removal methods like this, and wonder if it would make less of a mess and be easier to remove at the end.
I am glad you chimed in. I have been scared of having difficulty separating the 2 pieces and damaging the parts with JB Weld. I thought about doing Superglue and panduit straps as an additional mechanical stabilization effort so the parts don't come apart prematurely.
 
Another option might be to bolt them together! I think those large-flat places between the holes you could drill/tap/transfer some holes and bolt them together in the 'empty' center section. You'd end up having some extra holes in the castings at that point, but functionally they'd be irrelevant. Plugging them after would be easy enough with the bolt-trick.

IMO, depending on how you are setting them up, super glue might be sufficient. , though I suspect you're planning on drilling the holes in a vertical mill (which, IMO, probably means JUST epoxy/glue would be suspect to me).

SOME sort of solid mechanical connection would be a good 'better safe than sorry' to me, even if it is just clamps outside of the vise (though, that could interfere with any sort of boring head).
 
I like the idea of superglue + mechanical. Mechanical would hold the parts together, while the superglue would prevent against slipping and losing concentricity. I would prefer to leave as much cast iron as possible but if strapping would not be secure, I would be open to bolting. Crowdsourcing ideas is EXACTLY why I chose to make a build thread on this. This is going to challenge my noob machinist skill. I plan on being EXTRA careful with the cast parts.
 
Did some easy through bolt holes. They are for mounting the quoin to a bench, but I went ahead and did them now. They are 8mm holes (.3150") so I will be able to make a fixture plate to make clamping up in a vise easier, and tap 3 x 8mm holes in them. I guess the plan has shifted to Superglue + mounting the castings once joined, to a fixture plate instead of straps or drilling and tapping the parts themselves.Not sure if I need an angle plate, or if mounting on a faced piece of Alu or steel will suffice. I have tons of steel and aluminum in my scrap closet (literally tons of aircraft grade "scrap") So we shall see.

IMG_3824.jpeg
 
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