I haven't taken the table off to replace the ballscrew bellows and fix/adjust the backlash adjusting mechanism but the machine does move so I've given into the temptation to try to start using it already.
I started by trying to surface a big piece of steel and figured out both that I need to get some decent tooling and I needed to square up the head. I had thought just setting the head to zero according to the indicators would get the head pretty square with the table but apparantly not. When I tried surfacing the steel I got a terrible surface finish and could feel channels in it from the end mill not being square with the table.
I found that my nsk dial indicator set mounted well to an empty 3/4" tool holder via sticking the magnetic base to the end of the tool holder--go figure, it was actually quite rigid and a good set up. I set up the indicator so that rotating the spindle would spin the indicator around in as large a diameter circle as possible without hitting the t-slots--about 5.4".
At start the difference between the high reading and low reading was huge--something like 70 thousandths. I first adjusted whatever you call the side to side rotation of the head which was the most off. Then I adjusted whatever you call the front the back rotation of the head. I went through several itterations of that with my nsk .001 indicator which has a nice, easy, smooth movement. When I got it down to one thousandth run out (difference between the highest and lowest reading) I switched to my starret .0001 indicator. At this point I had the bolts which lock down the head half tightened(otherwise the readings change when you lock down the adjustment). I was getting a fine enough adjustment now that I would overshoot and probably went through another dozen itterations before I got it dialed in but I did in the end get it dialed in. In the end I had 2 tens run out (.0002") that was variation in the table surface not alignment of the head.
After squaring the head I tried surfacing the piece of steel again and was getting a good surface; however, I destroyed my chineese end mill about 1/4 through the job. I did a bad job "touching" and got my z offset wrong--that much I know. I probably had my speed and feed wrong too. I need to get myself a handbook since I don't know what I'm doing. I also went straight to the internet and ebay to try to find a good yet affordable tool for surfacing. I ended up getting a 2" diameter 90 degree Iscar face mill that uses tangimill inserts and a pack of new ic328 lnat15 inserts for it at a steel on ebay. I would have prefered IC908 inserts as I'll be wanting to surface aluminum too but oh well--the budget is very tight and I still have to order a nmtb40 arbor for it.
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