Mini Mill Side Milling Help?

[jtrout13]

Hi all,

I just got my mini mill set up, got it stiffened, gas spring modded, and trammed in X and Y directions. I get beautiful finish cuts (0.002-0.005 DOC) when end milling that rival that of much stiffer knee mill. However, whenever I try to mill using the side of the mill, I get terrible surface finish and chatter that almost shakes the machine off the table.

Today, I was using a 3/8" TiN coated endmill, 1500RPM, workpiece 3/8" brass plate, and was trying to take off 0.010 per pass. Z and X gibs were locked, the feed was along the Y axis, conventional milling. Finish looks like something out of a horror movie and chatter is awful.

I'm an experienced machinist, but new to bench-size tools. Do any X2 owners have any suggestions about this? I'll obviously avoid side milling where possible, but there are times it is absolutely necessary. Any help would be really appreciated!

 

[Tin Falcon]

plugging the numbers into a calculator and using a sfm of 300 for brass it appears you need to crank up the rpm about double of what you are using.
As far as finish I have found a light cut of a few thou climb milling improves the surface finish.

In the several seminars I have sat in on with Brian Barker of MACH3. Brian has done his homework and has run a lot of cnc machines. He always recommends using published /calulated speeds and feeds for any machine . smaller machines you need to take smaller DOC.
An x-2 should handle what you are doing.
tin

 

[Omnimill]

I nearly always up and down mill and make a finish cut with the direction that gives the best finish.

Vic.

 

[lensman57]

Hi,

Have you adjusted all the gibs? I had the same problem with my X1 and tightening the gibs a little helped.

Regards,

A.G

 

[Dirtfan1981]

if its 360 free cuttung brass you can crank up the rpm and feed the crap out of it, but brass is soft and grabby. if you get chatter you can dull out your tool or put atouch above center to let rub alittle. i work on multi spindles and we run brass at 400+ sfm