Glacern 2.5" Face Mill

[wrmiller]

Got my face mill and inserts and thought I'd give 'em a try on some 7075 drops I bought. When doing bidirectional milling I notice a slight difference in finish and I have a very slight step where the passes overlap. I can't catch a fingernail on the edge, but I can feel the boundary with my finger. Maybe that's the difference in finish? All I know for sure is that if I just kiss the metal with a #2 Nicholson file the line disappears.

But it is annoying to look at. Maybe if I make both passes in the same direction it will be less noticeable.

The pic is of the last pass at .010 DOC and about 2500 spindle rpm.

 

[Sandro]

It's normal to get a slight step. You can try making both passes in the same direction, it might help. It's also possible that the next time the step and finish will be different.

Sent from my D5106 using Tapatalk

 

[dave2176]

I would love one those. I think the moral of the story is to have an assortment of face mills so you always have the right size to do it in one pass. ;-)

Dave

 

[coolidge]

Several variables there Bill, deflection in the tool, spindle, head, column, load difference between first pass and second pass, did you climb mill one pass that may unload your backlash, and is your head trammed properly. Try machining that same block doing forward and back passes on Y you will really see some sawtooth steps then if your head isn't dialed in.

 

[sanddan]

It sounds to me that the tramming in the head is off in the "nod" direction. I have the 3" version of that face mill and it will give a "no step" finish between the 2 passes. I had to tweak the tramming on my mill except I was getting the step in the x travel direction. The finish on your part looks great. What insert are you using?

 

[wrmiller]

If it is off, it isn't by much. As I said, I can kiss it with a fine file and it (step) disappears in one swipe. I haven't tried two single direction passes yet. The finish is really nice, can't complain there. the inserts are SEHT43AFFN. Don't know much about inserts yet, but they are the polished, razor sharp inserts for aluminum. Ran WD40 in the Fogbuster for lub..

 

[wrmiller]

Ok, still playing with the face mill. I discovered that the inserts (supposedly from Germany) will sit differently depending on how they are indexed. After twiddling with the thing for a while, I found a setup that didn't rock slightly on my surface plate.

First attempt was a half-width pass on the front (towards me) of the piece, followed by a second pass, in the same direction, on the back half of the piece. The step near the front of the piece is barely there. I can see it better than I can feel it.



This last attempt was the first pass at about 3/4 width, left to right, on the back half of the piece (climb cutting?). The second pass was done in the same direction on the front of the piece. Result was NO step. Didn't change a thing on the mill or setup, just the sequence of the passes.



Still a little wavy on the surface finish (my cheap little camera does OK for what it is), and you can't tell in the pic, but the finish is almost mirror like. Not bad for a pile of iron from China.

 

[coolidge]

Left and right will show errors in the nod of the head, now run several passes front to back on Y to check tram left and right, maybe 1.5 inches per pass. Also I think the 935TV would face that in a single pass (Coolidge takes off running)

 

[dave2176]

Also I think the 935TV would face that in a single pass (Coolidge takes off running)

Now we are back to needing multiple face mills so that the piece can be milled in one pass. After all you wouldn't want to use your 8" face mill on a 2" wide piece.

 

[wrmiller]

Oh I already know my X-axis tram is slightly out: When cutting from left to right the trailing inserts will just cut this 'fuzz' after the front inserts are off the piece. It ain't much, but it is off a touch.

Single pass eh? So you're going to get that 4" face mill?