View Full Version : Help with face mill + inserts

02-06-2009, 02:49 PM
I just ponied up the money for a 2" face mill - seems like it'll sure save time when squaring up stock and removing a bunch at once.

Just from a quick test, here's the pattern I get; does it look like my mill's in tram well enough? (It looks alright to me, but I don't know for sure)


(sorry for the bad pic, the one without flash wasn't in focus)

Also, the face mill came with carbide inserts which seem pretty standard. Does anyone make HSS inserts like this? Seems kind of like HSS might give me a better finish on aluminum.


Is there anything special to know regarding cutting speeds with face mills, or is it just the standard formula with a 2" cutter? (ie 3.8/2 * cutting speed)

Thanks for the help,


02-07-2009, 10:15 AM
I have a 3" face mill that looks similar to yours. It appears that your mill is perfectly trammed so you are getting a hint of "trail" cutting. Some folks advocate putting the tram out a bit so you get a clean cut. Mine is 0.001 out over a 4" swing. Experiment with trail cutting vs lead cutting to judge surface finish.

I find that putting a smear of kerosene (low odour ) on the aluminum before the final cut works wonders for the finish. WD 40 also does a good job.

Surface ft/min can be be up to 2000 with carbide on Al. I just cleaned up a lathe cross slide (cast iron) front edge for a friend and ran the mill at 200rpm for the first pass on power feed (roughly 4"/min) and then bumped it up to 400rpm for the final 0.005" pass. Looked good.


Just Bob Again
02-07-2009, 10:54 AM
I like HSS inserts. Only company I know that makes them is Warner. Few dealers, you have to order them direct. LMS sells some, but only a couple sizes. Or, use polycrystalline diamond coated. PCD. Expensive but great finish.

02-07-2009, 01:25 PM
If you check across your milled surface with a straight edge and see little or no light in the middle of the slab, you are in tram. Many folks like to get a better finish by tipping the head so that the lead side of the cutter is about .001" low. It will eliminate the trace made by the trailing edge but on wide slabs will make a slight concave that is noticeable. It all depends on what results you want. Your part looks good and flat as the trailing edge leaves a trace visible.