10-28-2015, 09:09 AM
Like you I started woodworking then ventured to the dark side. I have no formal training so any advice is to be taken with a grain of salt.
The router is probably a good analogy, but when was the last time you used a HSS router bit. The trick with a milling cutter is to keep the heat out of the cutter. From what I gather a lot of the heat of cutting is removed with the chips. the work piece will remove heat as well. The burning you see in the maple is caused by the cutting edge rubbing the material, same is true in metal but you won't likely burn the metal, but no chips coming off no heat removal. That sweet spot is making chips heavy enough to carry the heat away from the cutting edge.
From what I've seen depth of cut has little to do with cutter life to the point where you load the cutter to the breaking point. Taking lots of shallow cuts to get to depth just wears the bottom cutting edge, cut as deep as you think you can. A rough rule of thumb I've seen is when making a plunge cut as in a key way go 1/2 the dia of the cutter in depth, or profiling from the side the dia of the cutter in depth. Get close to size then take a light finish pass to get a better finish.
The truth be I hardly ever use a HSS end mill in steel without flood coolant. Its messy but extends the life of the cutter by magnitudes.
Hope some of this helps.
The router is probably a good analogy, but when was the last time you used a HSS router bit. The trick with a milling cutter is to keep the heat out of the cutter. From what I gather a lot of the heat of cutting is removed with the chips. the work piece will remove heat as well. The burning you see in the maple is caused by the cutting edge rubbing the material, same is true in metal but you won't likely burn the metal, but no chips coming off no heat removal. That sweet spot is making chips heavy enough to carry the heat away from the cutting edge.
From what I've seen depth of cut has little to do with cutter life to the point where you load the cutter to the breaking point. Taking lots of shallow cuts to get to depth just wears the bottom cutting edge, cut as deep as you think you can. A rough rule of thumb I've seen is when making a plunge cut as in a key way go 1/2 the dia of the cutter in depth, or profiling from the side the dia of the cutter in depth. Get close to size then take a light finish pass to get a better finish.
The truth be I hardly ever use a HSS end mill in steel without flood coolant. Its messy but extends the life of the cutter by magnitudes.
Hope some of this helps.
Free advice is worth exactly what you payed for it.
Greg
Greg