02-11-2014, 07:42 AM
Unless I missed it, you haven't said what cutting speed (rpm nor sfm) you are using. I assume feed rate is by hand also.
Is the cutter a solid high speed steel one or a carbide insert type? As Mike stated, carbide can run quite a bit higher speed than HSS tools. I'm not sure the average uncoated insert in a budget-oriented milling cutter would be able to take 706 sfm (which is what 900 rpm on a 3" cutter is), so you might start at about half that speed. Getting the flame cut kerf off with a disk grinder would also help preserve cutting tools. If the flame cut slag is still there when you cut with carbide, it would not be unusual to see some sparks and that's not always a sign of impending doom.
Lastly, expect hot chips. It's going to happen if you expect to get material off at a reasonable rate and becomes a matter of managing the flow. As in, stay clear of it.
Is the cutter a solid high speed steel one or a carbide insert type? As Mike stated, carbide can run quite a bit higher speed than HSS tools. I'm not sure the average uncoated insert in a budget-oriented milling cutter would be able to take 706 sfm (which is what 900 rpm on a 3" cutter is), so you might start at about half that speed. Getting the flame cut kerf off with a disk grinder would also help preserve cutting tools. If the flame cut slag is still there when you cut with carbide, it would not be unusual to see some sparks and that's not always a sign of impending doom.
Lastly, expect hot chips. It's going to happen if you expect to get material off at a reasonable rate and becomes a matter of managing the flow. As in, stay clear of it.