Resusitating Some Chinese Iron

I haven't fallen off the edge, or given up. I have my scraper with carbide blade. The sharpening system is functional. I even got a bigger granite plate. My efforts have been going into making the straight edge that I will need for fitting the dovetails. I got a hunk of Durabar and started carving. Visual inconsistencies showed up in the metal while machinin the bar true. That was thrashed about in http://www.hobby-machinist.com/thre...o-peel-off-of-virgin-metal.43907/#post-376831

The bar is squared up as much as my machinery is capable of. The angle that allows the straight edge to enter the dovetail is cut. I am now hogging out the lightening pockets. The photo shows the pockets already drilled. I should get an end mill holder today, so that I can proceed to the removal of the rest of the pocket. I have had persistent problems with the mill being sucked out of the collet when taking heavy cuts. I am hoping that the holder with its set screw will keep the depth from increasing. I expect to stress relieve and final machine the straight edge next week.
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Nice man, I too have run into inconsistencies in the metal while machining, it's most apparent when surface grinding, it will skip over the surface with no sparks in some spots.
 
So everything is roughed out, the pockets milled, and the straight edge has been stress relieved.
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So on to the fun part, scraping. But first I needed to clean off enough space on the bench to do the scraping. One of the things cluttering up the bench is a Y-axis extension. Mini mills are notorious for not having enough Y travel to do anything useful, especially when the factory machining is so poor that you don't even get the advertised 4". Most extensions move the column back and extend the base dovetail to the rear. That used to work OK, but the later base casting have been thinned out in the rear. I had a nice chunk of 1 1/2X2 1018 steel that I could mount on the front. I installed dowel pins to keep the steel in one spot, then drilled and tapped for mounting bolts. I will put epoxy between the base and the extension before I re-machine the base dovetail. Pins, epoxy, and 8mm cap screws should keep the extension in place.
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that's awesome man, good job, did you send it out for stress relief?
 
I went the kitchen range route. I put it through 3 hours of oven clean. I'm thinking that I am real close to recommended temperature for durabar and soak time was close to 2 hours per inch of thickness. I'll hang it and ring it a few times then see what comes of the scraping. If it seems to be moving, I'll put 'er back in the oven for a few more hours. I'm not sure how much I'll get done right away, what with Easter and out of state company. Living in Florida pretty much guarantees that you'll get visitors around spring break time.
 
That's how I did mine, it worked for my small straghtedge, supposedly 932 degrees is what they can get to
 
I finished the milling on the base last night. I wish that I had gotten cast iron for the extension, but that was decided a few months back when I was dumber. Now I need to mill the saddle. I was only going to do the X-axis when I started this project, so I have already milled the table and X side of the saddle. Now ai need to get the saddle on the mill so that the Y dovetail is milled at the correct angle. I am thinking that I'll clamp the mini mill table to the mill and align it to the mill's x travel. I'll then attach the saddle to the mini mill table and clamp it. That should make the saddle as accurate as my mill. I don't see another way to get the saddle on the table. Any suggestions?
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And now I get to clean up all the cast iron dust!!
 
Baithog said:
....snip....

And now I get to clean up all the cast iron dust!!
Click to expand...

Take all of that cast iron dust and small chips and add them to your fertilizer spreader and spread all over the yard. Adds a boost of iron to the grass!

BTW- Nice job!
 
I did some scraping on the base and saddle. I'm still not happy with the points per inch, but it is as flat as I can measure. I cut cast iron gib abd scraped its bearing surface. Put together, the Y-axis is not air bearing free and smooth as silk. It is smooth and it is an easy push by hand to get full length motion.

Next I need an actuator. I have the choice of acme screw. It would be a !/2-10 2 start with anti backlash nut. The other option is an imported class 7 ball screw. Both are in the 5 turns per inch range. The ball nut will take some creativity to get into the limited space, but should take less torque to turn it. The Acme nut is more compact and marginally cheaper, but sucks up torque with increased friction. I am leaning toward the ball screw mainly because I prefer to use motor torque to machine rather than being sucked up by the screw/nut. Any wisdom? I suppose that is more of a CNC forum question.
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are you doing a cnc conversion? the only issue with the ball screw is you may have to use the gib locks when not using that axis to machine.
lookin good man
 
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