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Oil fired crucible furnace

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vtsteam:
Yes Andrew they do machine well -- better in fact than I had thought (and mentioned) earlier.

I believed that they were rough on a HSS end mill and said so at one point, but I think that was just trapped silica sand particles and scale on the surface, not the underlying metal itself. I did use a hand grinder to try to remove the outer skin before milling, but didn't get everything.

After milling I drilled  the same piece through, the drill cut beautifully -- very clean sharp holes, and those nice little uniform bits of swarf mixed with graphite, and a good rate of penetration.

I have no carbide tooling other than a bunch of odd shaped inserts I bought at the Bernardston engine show. I really need to make some kind of milling holder for them -- some kind of fly cutter -- so I can clean off castings without wrecking my HSS mills.

I also don't have an HSS milling cutter sharpener fixture -- just a bench grinder.  I do have a big box of used end mills someone gave me -- hundreds of them, so I would like to be able to sharpen them. I also have a boxed new green wheel.

Takes time to get from A to B like this.

vtsteam:
Can't melt today because of rain. Here are some informational pix from the melts so far.

First set is of three broken ingots, left after pours. I'm not sure which pour goes with which ingot. But they are definitely 3 different pours (or attempts to pour).

vtsteam:
The next two are the two crucibles used. The one on the left was retired after 3 melts/attempts. It was used with a flux of soda ash (sodium carbonate).

The one on the right was used without flux. Also 3 melts. You can see the difference in the slag in each -- especially at the bottom. This crucible is coated with rough slag, but is still usable. The wall thickness is greater and it has retained its shape. In the side view the ceramic looks much better. The slag on the exterior also looks different.

vtsteam:
Finally, some not very exciting pictures of slag scraped off of the second (unfluxed) crucible. Texture and appearance is like very sticky cottage cheese when molten. It is very tenacious and difficult to scrape, even hot.

MetalCaster:
The residual slag is suppose to be scraped out of the crucible immediately after a pour, but I have found that to be easier said than done.

That slag is tough stuff.
I don't have anywhere near the slag you do, perhaps 1/20 of that or less.

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