Slotting advice - milling

Brock Cutlery

Brock Cutlery

Joined
Jan 10, 2015
Messages
1,673
Hey Gents, I want to try something a little different for me. A silver ingot (soft metal) bolster. It is .3 inches thick.
I generally use my mill to slot hard woods like ebony or ironwood, but on this one I want to ask, what is the right way to cut that closed slot?
Do I take off thin layers until I am through? Do I drill straight through and then draw the slot out?
On the wood, I just slowing drop down and mill across in layers until I am through.

Advice greatly appreciated. Wood is pretty forgiving, but I'd rather not break a bit or walk the line all around the piece.
Thanks!
 
Just plunge all the way through leave yourself some extra at the ends to square up with a file. Using a 4 flute mill will give you a better finish. If you have to make the slot wider than your end mill just cut one side on the widening pass don't go back and forth you might over shoot the slot width.
 
i drill two holes at the ends of the slot with a drill bit slightly smaller than the endmill. i do that because on my mini mill, if i try to plunge with an endmill sometimes it wanders and makes a cut wider than the slot needs to be. then i have to start over. i then cut the slot with multiple passes about .015 each pass then square up the ends with a file which is blind (no teeth) on the flat sides. that protects me from making the slot wider by accident.
 
another detail since you are using an expensive piece of metal. my first pass i do .003" , second one .005", third .010" and then .015" for the rest of the cuts. if you try a deep cut on the first pass, the endmill may wander and make too wide of a cut if you crank the table too fast. . if you cut in small increments at first, the wall of the slot will keep the later passes from wandering and making it too wide.
 
yep i like to undersize mill to help keep the bit from wondering off then once to full depth i widen the slot to spec. if you go over lucky for you you are using softish metal and can peen it a hair to close up any gap. ended up doing this once with copper and the kitchen knife guys loved the hammered look so now i have to hammer most all my knife fronts just cause they like the look
 
butcher_block said:
yep i like to undersize mill to help keep the bit from wondering off then once to full depth i widen the slot to spec. if you go over lucky for you you are using softish metal and can peen it a hair to close up any gap. ended up doing this once with copper and the kitchen knife guys loved the hammered look so now i have to hammer most all my knife fronts just cause they like the look
Click to expand...
One Small Boo-Booo turns into a design element...Go Figure:cool::thumbsup::thumbsup::thumbsup:
 
butcher_block said:
yep but also for the info of the thread you can peen and then sand flat so it looks like you never messed up
Click to expand...

The hammered rabbit hole looks like a much funner option Butch. Now you got me googling hammered bolsters. Some cool looking stuff. I think I like the copper look better than silver.
 
butcher_block said:
yep but also for the info of the thread you can peen and then sand flat so it looks like you never messed up
Click to expand...
I have peened a couple with the ball end of a small hammer to get a good press fit...sometimes it works other times best to start over.
 
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