Face Mill ?

[79TigerPilot]

I am looking at getting one of Glacern's FM45 face mills and trying to decide between the 2.5" or 3" version. The 3" would be nice but I am concerned it may be too much for my 1hp J-head Bridgeport to push. Mostly be doing 6061 aluminum.

Would appreciate any advice on which to choose.

The Glacern stuff is beautiful. http://www.glacern.com/fm45



Craig

[HorsePowerMetal]

Here is the thing,
Buy the bigger one...usually. Here is why, in the world of machining where production output is of value we like to use tools made with more rigidity and the highest number of inserts or teeth feasible. This allows for a high metal removal rate (MRR). BUT if you’re a small shop, to partially or mostly a hobby shop, buy the smaller one. This is because of the higher versatility of a smaller cutting radius, and less costly maintenance for less teeth.

Facing/ Profiling Feed Rate is found by multiplying the number of fluted teeth by desired chip load per flute by the RPM. Example:

3in dia. Cutter with 6 teeth
6061 alum. Pulling a surface footage number out of the air I’m going to use 500

Desired chip load .0007 per tooth, per rotation per tooth
Your desired chip load will vary with depth of cut

chipload0.0007*Teeth6*RPM600=FeedRate 2.52 inches per min

Metal Removal Rate (MRR) formula = Multiply the depth of cut (Z travel into material) by the width of cut “chip load” and the feed rate to find cubic inches per minute of material removed

This is my first post i hope i did well... and good luck

[HimyKabibble]

Originally Posted by 79TigerPilot I am looking at getting one of Glacern's FM45 face mills and trying to decide between the 2.5" or 3" version. The 3" would be nice but I am concerned it may be too much for my 1hp J-head Bridgeport to push. Mostly be doing 6061 aluminum. Would appreciate any advice on which to choose. The Glacern stuff is beautiful. http://www.glacern.com/fm45 Craig

Craig,

Presumably, you'd be using it for surfacing, not hogging, so power should not be a major concern. It'll run low enough RPM, you can put it in backgear, put your VFD in reverse, and you'll have oodles of torque. With 1HP, you'd theoretically be able to go full width at almost 0.050" depth of cut.

Regards,
Ray L.

[LeftCoastCNC]

A couple other things to consider;

On poorly supported thinner sections, a larger face mill will have more of a tendency to chatter in my experience.

I noticed the 3" has 6 inserts while the 2.5" has 5 inserts... Inserts are usually sold in boxes of 5 or 10 making the 3" inconvenient for a hobbyist.

MRR with the same style cutter will be limited by HP of the machine.

Unless you spend a lot of time surfacing, you would probably not miss the extra .5" of swath of the 3".

[HorsePowerMetal]

Yup, These are all good points.

[79TigerPilot]

I ended up ordering the 2.5" FM45. Very nice looking cutter.

They were out of the R8 arbors so I got one locally but it doesn't seem to fit. Either the arbor is a little over on the or the cutter is a little under. I think it would go if I were to put it on the press and give it a litle force but I don't want to do that. I am going to look for another arbor tomorow.

Can anyone tell me how tight the fit should be between the arbor od and the shell mill cutter's ID for the 1" dia hole.

Craig

[HimyKabibble]

Originally Posted by 79TigerPilot I ended up ordering the 2.5" FM45. Very nice looking cutter. They were out of the R8 arbors so I got one locally but it doesn't seem to fit. Either the arbor is a little over on the or the cutter is a little under. I think it would go if I were to put it on the press and give it a litle force but I don't want to do that. I am going to look for another arbor tomorow. Can anyone tell me how tight the fit should be between the arbor od and the shell mill cutter's ID for the 1" dia hole. Craig

Craig,

You want it to be well centered, so it should be snug, but not really tight. Definitely NOT a press-fit. You could put a lathe tool vertically in your vise, put the arbor in the spindle, and shave a few tenths at a time off the arbor until the face mill slips on nicely. It can't be off by much. For that matter, you could probably just do it with emery cloth.

Regards,
Ray L.

[MeTri]

I'd liken the fit of the face mill on the arbor to that of a large endmill in an endmill holder (maybe a hair looser, but not much if at all). You need to be able to slide it on and off, but there should be zero free play.

Brian

[79TigerPilot]

Thanks for the ideas. I checked the runout on the arbor and it was fine so I hit it with some 600 grit paper, didn't take much and it fits just fine now.

Craig

[packrat]

While a facemill is great for removing stock fast, nothing beats a fly cutter for a great finish. In aluminum even 0.050 deep cuts or more are possible.