How to use a roughing end mill

[CuttersCov]

Hi all,

I need to remove cold rolled steel with the dimensions of .75" by 1". If you think of taking a piece of square stock and milling it into an L bracket you get the idea.

I'm just a beginner and at school we only have 4 flute end mills.

I was thinking I could get a roughing bit to remove the material much faster.

Any hints on what I need to look at? How much faster will it be than a regular end mill? (I'm currently only taking off about .025 per pass and it takes about 2 hours to do one piece.

Thanks,

Matt

[dkowalcz]

At .025 depth I wouldn't think a rougher would be much help, you need enough depth to get to where the scallops are a benefit.

Check your speeds and feeds - 75 fpm for HSS on steel is what I usually use for manual machining. Feed about .001 per tooth to start, then adjust by feel. If this is on a bridgeport clone, then you can probably go .100 to .200 deep per pass easy, even if it's a pretty clapped out "school mill".

I've had good results with the SuperCeed brand name for hogging cutters. They do work much better than the finishing endmills for roughing out material, and the scallops are fine enough that the finish is usually acceptable without a second pass with another endmill.

[CuttersCov]

It's .025-.030 per pass using the side of the cutter going the full .75 deep. The mill is half an inch diameter which would only take off 1/2 inch plus depth worth of material whereas if I cut from the side it takes of 3/4 of an inch plus depth. Not sure if you understood what I meant or I misinterpretted what you said.

But by scallops I assume you mean those little teeth on the flutes? I ordered one today from McMaster 1/2" 4 flute roughing mill. We'll see how it goes, what I am wondering is how much faster it will remove metal. I think I was running the current set up at about 400 rpm. Even if I get the same rpm, but can speed up the automatic feed another 2 settings that would be great. I calculated 8 more hours worth of milling just on these pieces and even if it gets cut down to 5 hours I'll be happy.

-Matt

[dertsap]

it isn t wise to cut at the depths that you are ,you shouldn t mill to a depth greater than half the dia of the tool , a ruffer won t like cutting at that depth either ,if you take .1 depth , and 1/2 dia engagement you should be able to knock off that material quickly with a simple endmill , i don t think that it will be much more to your benefit to buy a roughing cutter , price vs an extra few minutes ,

[timlkallam]

Use a band saw or slitting saw to rough it out then use an end mill to clean it up.

[ViperTX]

I'm with timlkallam......otherwise it's a pretty time consuming process..

[CuttersCov]

Ok, my results.

I up ended the pieces I was working on so that the roughing end mill could be sunk even deeper and with the roughing mill's entire "side" cutting I was taking cuts an inch tall and .150 deep. Don't know what the feed rate was I ran the autofeed at setting 2 (whether that's 2 fpm I don't know) The chips were almost like saw dust (chips didn't change color) and what would have taken an hour before only took 15 minutes. I have more to do in the next week so I'll be able to give a better comparison.

Note: Band saw was a good idea but for the pieces I was doing it wouldn't work.

-Matt