Vertical Mill operation 101

I just got my first vert. mill in operating condition and I have a large project I want to do on it. I have and used a lathe for a number of years, but again this is my first mill, so how deep should you cut in mild steel with a 3/4" dia HSS end mill (1 HP motor) in one pass? How about if I were using a carbide mill? And what about fly cutters? Is there a "rule of thumb" for this? THX!

In the welding section?

Might get more response in General New

Well, depending on what kind of mill you have, 1/2" and smaller endmills may often be more efficient than the larger 3/4" size. If you try to take a deep cut with a regular 3/4 em, you are going to get a lot of chatter. If you have a lot of material to move, consider getting some "corncob" or roughing endmills. They cut so much easier and last way longer when used properly. The key to taking heavy cuts with them is to keep them cool and feed them agressively. (within reason, of course.)

Start slow and easy and experiment with what your mill will allow you to do.

How deep of a cut can you take? Your machine will let you know. Don't start out with carbide. They are more costly to break. Use the brown chip rule...if you are using HSS cutters and your chips are brown, you are not going too fast. If they turn blue, slow down!

John ..Sorry I just saw "cutting & fabrication" ...I didn't put it together with the first word WELDING! *G* ...I'll move it.

Regal13 ...Hey that color guide-line on the chips is great! THX! ...I was trying to operate my mill like a lathe, and "smoking blue chips" is a good thing. THX for the lesson!!!

Good Info

11Echo

The above information is correct. If you have a BP or clone in the 42" size, I would use a 1/2" HHS bit. the roughers do a good job for fast stock removal. As mentioned above, start slow and let you mill let you know what it will handle. I would rather have a cut a little on the light side than a little on the heavy side.

I have a couple of carbide bits I use on occasionally in very hard material. Generally, I use HHS. Carbide breaks easily and, in my opinion, without coolant, you will not gain much.

Try your post in General New and you will get loads of information.

Grits

With 1 HP its going to be slow with a 3/4" endmill. I would stick with 1/2 and under on a mill that small.

From ME Consultant you can run a 3/4" 4 flute full width and .25 depth with 1HP ~550RPM. Your results may vary.

Make sure you are using either a ER collet chuck or a end mill holder to hold the mill. A cut like that can slowly pull the bit out.

You can run carbide faster and higher feed but unless you have power feeds on the axis or have something too hard for HSS I wouldnt bother. A good 1/2" carbide end mill will run about $40. I hurts when you OOPS!

Carbide is happy running dry. Many times happier than running with coolant.

Power Feed

Amen on the power feed. If you have an R8, make sure the cutter shank and the inside of the collet are clean and dry. They will have a tendency to slip downward with a heavy cut. In my opinion, if you are just getting use to a mill, start off with HSS. Your lathe experience will help a bunch. It is still just speeds and feeds. As Mac mentioned, it hurts much worse when you ding a carbide cutter.

Grits