Extra long bits

I picked up some 42mm long x 3mm single flute end mills a month or so ago on eBay and finally got around to trying them out. They do a pretty good job! I’ve already broken one of course while cutting out 8/4 walnut with it - but that long and that thin cutting wood that hard and I wasn’t in the least surprised…

These are the bits I picked up…

3 Likes

Sweet, what kind of feed rate/DOC are you using?

One trick I found for deep cuts is to do the parameter cut as a “pocket” just a bit wider than the bit width. The longer the bit the more pronounced any runout will be, so having the extra space keeps the bit from hitting the sided and binding as it cuts deeper.

2 Likes

I used the standard 32in/min, 0.04in… That’s about half the speed I normally go with walnut, at least since installing the new wide maker slide. Had to go a lot slower with the old setup.

1 Like

Interesting - I’ll have to try that out next time! Haven’t decided what to make of it yet, but the bit I did break happened after an hour of cutting (after both inside cuts were made), and only about 10 minutes into the outside cut, while it was still only 0.2" or less into the material. None of these cuts were too critical on dimensions, but I did notice they were a bit wider than nominal once it was complete. I should probably measure that runout and compensate…