This is the first part to the Metal Master jr. that I have gotten around to working on.  The bed casting turned out to be quite difficult to cast because of some of the large mass of metal around the head stock end of the bed.  I made several castings before I was able to get the shrink cavities down to a usable amount. The first castings were in green sand but later I switched to Petrobond.

The pattern all rammed up with cores installed, ready for the pour.

This is the pattern and one of the first beds I cast.  The later ones with Petrobond gave a much nicer surface finish

The 2" shell end mill made quick work of cleaning up the rough casting.  After the clean up was finished II milled the bottom  flat and then was able to mount the bed directly to the table.  Because the length of the bed is longer  than the x-axis travel of my mill I had to move the bed and do the milling in 2 passes.  The 2" end mill did allow me to make one final clean up pass on the part of the bed that will hold the way. I recessed this 0.1" below the rest of the casting.

With the Ways clamped in position I drilled for the mounting screws,  after drilling the ways were removed and the holes were tapped.  I mounted the tap in the drill chuck to start the tapping, and after the were about .5" deep I released the tap, raised the quill and finished with a heavy tap wrench and plenty of tapping fluid.  After all this work I did not want to chance breaking off a tap.

The ways are made from  2.5 x 0.375 ' cold finish steel.  I milled a  0.1" deep slot 1.25" wide down the center of the ways to help recess the mounting screws and make it easier to grind the top of the ways.  I mounted a fiber reinforced grinding wheel in the mill and gave the top a couple of quick passes to finish off the top.  The finish turned out very nice and I may not have to scrape the surface when I am finished.

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