[macdarren]

I recently got my Taig mill with a cnc package. I am still working out the details for my enclosure and some of the motor settings and limit switches but I have been playing with trying to get a nice smooth surface on my Al work plate.

So far I have tried fly cutting but that didn't work so well I could see places with variations in the pattern and I could actually measure these areas as being higher than the rest of the surface. I tried a 3/16 end mill that seemed to be working ok but was way too slow. I went to using a 2 flute HSS 3/8 endmill. I can get a pretty decent surface but I have to do about 60% over lap and I can still feel slight valleys on the surface, this diminishes with more overlap and gets very noticeable with overlaps less than 50%. I am thinking maybe there is a better tool for this. My goal would be to get a surface that at least feels flat to my finger and measures pretty flat with my dial indicator. One thing I have also noticed is I occasionally get a little ridges...I would have thought with high overlap that would surely not happen. I do notice them more as running parallel with the cutters path. I have tried a few things like always milling from the same direction, and I can still never get them all the way gone for the entire surface of the plate (about 9x5 inches)

Is there a better tool to use for this, some sort of surfacing mill maybe? Do I have something out of adjustment? Have checked and double checked the mechanicals and I get pretty consistent backlash of about .002 on the x and y with about .0009 on the z. The column seems to be very near perfectly perpendicular to the table and tight. The tables do not seem to have any looseness or play. Only odd thing I have found is that the along the x axis the table seems to have a slight rise. One end maybe .002 from the low to the high but all of the rise seems near the very left most position (say the last 3 inches)....not sure how normal that is but I was kinda thinking a nice work plate finish pass would compensate.

Thanks
Darren

[TOTALLYRC]

Hi Darren,

The first question is did you tram the mill? If it is out of tram this will cause the ridge from pass to pass as the bottom of the cutter is not parallel to the plane of the x and y axis.

The cutter can only do so much and it is up to you to give it the best chance possible.

Mike

[macdarren]

Mike,

Yes I did tram the mill per nick carter's instructions, I got it as close a I could measure with my dial indicator however I will go over it again (maybe borrow a slightly better indicator as mine is good only to .001 and might even be a little sticky) just to be sure nothing has shifted.

Darren

[5artist5]

I am in the same boat on the indicator. Mine only has .001 ticks, It's pretty easy to see when the needle is where .00025, .0005 or .00075 though. May not be all that accurate at the actual value of those readings but I believe it to be +-.00025 of what I guess it reads.

Still once I have some other eqipment such as a decent vice and some better clamps, I am upgrading to a nice .0005 test indicator for sure!

[TOTALLYRC]

A good .0005 or .0001 indicator that only comes out when doing the real fine work is a nice investment and pays for itself the first time you need it.

A sticky indicator needs to be send out for repair. I have a buddy of mine who did it for years and he does mine for the cos of a lunch.