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Building a milling machine

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NormanV:
One casting that I have been having trouble with is the spindle mount, it is basically just a 4" hollow cube. I tried twice to mould it in sand but both times the centre broke away. I then made a core box and tried to make a core using sodium silicate. Somehow the CO2 did not penetrate and it was unsuccessful. I then tried a baked sand core but that failed too.
Then I had a "eureka" moment, I had some ceramic fibre insulation board left over from making my furnace and I cut a piece to size to use as a core. I was concerned that as it is so light it would move as I poured the molten metal in so I anchored it in the sand with a couple of woodscrews in the back. It was a successful pour and the fibre board was very easy to remove from the casting.
I also needed a cover for this part to keep the oil in for the bearings, as a bit of fun I cut my initials from thin ply to decorate the front of the cover. I half expected the sand to break up but that cast well also.

NormanV:
I've also been working on the front casting. I had made it oversize to ensure that there would be no gaps and I had to reduce the width by 3mm to make it fit. I started with an angle grinder but soon discovered that a "Surform" plane removed the metal very quickly and I was able to keep the sides straighter than I could with the grinder. No pictures yet.

NormanV:
More progress on the front casting. I got it down to width and fitting between the sides nicely. Then came the first critical part of the build. The front surface has to be flat and the only means at my disposal was to scrape it. I have a large angle plate that could serve as a surface plate and I set to scraping. I spent the whole of yesterday on it and made some good progress. It went from touching on two diagonally opposite corners only to about 30% of the surface touching the surface plate. This morning I started afresh but soon realised that with the amount of metal that I still had to remove I had a good week of scraping ahead of me. I am not that patient! I phoned a local engineering company and the agreed to mill it flat for £30. I thought that that was a bargain and now the job is done.

NormanV:
Had a frustrating morning, I drove 30 miles to my nearest fastening supplier and found that they were shut! However on my way back home I passed a farm supplies shop and they had all that I needed. I'll go there in future as they are only 15 miles down the road.
With the screws that I bought I was able to fit the front casting to the body complete with a piece of 4" x 1/2" CRS that is going to act as the vertical slide. This had to be at 90 degrees to the mounting for the top tube and this was achieved using a "rafter square". Not the most precise piece of equipment but near enough at this stage as I will put shims under the top tube to set it accurately on final assembly.
There was an awful lot of drilling and tapping today, there is a total of 56 fasteners on it so far.

Arbalist:
This is progressing nicely!  :thumbup:

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