I get to do an aluminum blank for a fence and I am curious whether I can put slots in it with the router?I am not sure how thick it is, may say 3/16's.
Yes you can use a router on aluminium. Use some kind of a fence, a piece of angle iron or a block of hardwood. Use a new bit, an old dull one will cause you problems. Pre-drill smaller holes than the slot width at each end of the slot. Stay back away from the end of the slot about 1/32 of an inch. Make several passes, at a depth of about 1/16 of an inch, per pass. If you can, make the slot with a bit smaller than the finished slot width. Use a 3/16 bit for a 1/4 inch slot. Use a 5/16 bit for a 3/8 inch slot. This will give cleaner slot edges and allow you to accurately make the slot width that you want. You can do this dry, but a little WD-40 oil will give even cleaner slot edges. Also climb mill the last pass on each slot edge to give a better/ smother edge. Climb Milling is pushing the router backwards of the way you normally travel in wood. Ben
