Bridgeport Interact Series 1 Mk 2 - Expected Cutting Performance?

[MeTri]

Hi again,

Over that last few days I've been working with my new mill. I've had several problems including power phase in the wrong order, shorted power line and several User errors . Now I think I have the hang of the basics. I run the mill in ISO mode because it makes it more familiar. Right, now to the question;
I've been working with 1/2" hot rolled steel. The first piece I cut a slot with a 1/2" HSS 2 flute cutter at 600rpm and a feed rate of 2.4 inches per minute. That's a chip load of .002" per tooth, which is what I usually use and a depth of cut of 0.050". The machine seemed to go alright. Finish at the bottom of the slot on each pass was adequate, but small ridges were noticeable (likely due to my z-axis flutter. The sides had noticeable chatter, but the machine had sounded alright when cutting.

Next I tried a slot in the same material with a 1/2" Carbide 2 flute cutter. I ran at 1800 rpm with 0.050" depth of cut and a feed of 9.6 ipm. The machine HATED it. chatter like a son of a gun. Horrible chirping sounds (this was with flood coolant on the HSS I had used cutting oil because I hadn't connected the flood coolant yet) from the upper quill area as well as vibrations in the colar just above the QC nut. the colar just above the Quick Change nut has 2 holes in it, as if it can be tightened but the schematic doesn't seem to show that. Either way, vibrations were felt. So I slowed the speed to 1200 and hte feed to 50. The chatter noises were mostly gone, but the finish on the sides of the slot still had lots of chatter marks. Not super deep, but marks none the less. I know slotting is not a machines favourite taks...

So my question becomes, for those of you who have used this machine, what should I epxect as finish and cutting rates? I'm well below the litereature metal removal rates and the feeds and speeds I tried and the ones I learned to calculate in school. I'm wondering if my spindle is in need of refurbishing. I will tighten the spine damping ring and adjust belt tension.

Anyway any experiences of what you have successfully cut would be appreciated. Thanks

Brian

PS I'm having a ton of fun with my machine, chatter and problems included

[MeTri]

Well, just in case it help anyone later...

I was able to cut .150" in hot rolled steel with a 2.5" 5 insert face mill. The machine didn't miss a beat and the finish is good. Feed rate was slow at .5" per minute. The finish is near mirror with the same cutter and material with a .05" depth of cut and 1 inch per minute. rpms were at 800.

I stlll can't get a nice finish on the sides of a pocket. Conventional or climb milling. I'm really thinking it's the bearings in the spindle. I'll do more tests. I contacted the place MachineTek said he has used and they seem to have great prices. I was quoted $850 for thier upgraded bearing replacement, and regrinding the taper. I'll probably send it out later this winter when I'm willing to have the machine down for a while...