Goody Bags

In the interim I ran the operation really slow with a 0.005 doc. This really helped out but other than taking forever I was only able to cut 1 part before the bit got too dull. I think the dewalt router just runs too high of an rpm, even at the lowest setting.

Before buying a new bit and wasting the cash can the shapeoko cut long passes of 1/4" thick mild steel using the default rates, lowest rpm setting on the dewalt trim router and w40 as coolant and some compressed air to clear the chips.

I often cut steel on the Shapeoko and in fact, I spent most of the day today cutting some 1018 low carbon steel (Ref 1.25 dia). I was boring 5/8" holes in 1.0 inch long slugs and milling a 7/8 C’Bore 1/8" deep. Major cutting tool manufacturers will list the cutting rates for their tools for a general range of material. (HSS, Carbide and Coated Carbide, etc.)

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I have not personally cut steel but I know you can as long as you are very careful and use a small tool. I would look at this for inspiration:

I usually use the shapeoko to mill hdpe, rubber, and a little bit of aluminum. I started experimenting with steel and I’m working on a 1/4" thick 4x6 part that has a couple of pockets and a contour cut. I started with a new bit but quickly burned it up (I had the RPMs set way too high) before I could finish contour cut. I tried my only other 1/4" end mill but I think it was too spent to use on steel.

Tiny millsstamps

I found that I kept chipping the corners off of endmills when trying to slot / contour cut in steel, especially when ramping (at higher DOC and feedrates, anyhow). Corner radius endmills solve that problem if you don’t mind machining .010/.015" into your wasteboard for full depth cuts. I like these ones from Lakeshore Carbide: CORNER RADIUS END MILLS

Following these guidelines, I can easily get a full day out of a cutter, or if I use the higher number…about a half-day. It’s what I’ve use for 40+ years of machining and 5+ years on my Shapeoko.