01-06-2014, 12:03 AM
(01-05-2014, 09:46 PM)Hawkeye Wrote: I spent some time this week trying to find some bar stock big enough to mill one long dovetail section that I could then cut into individual toolholders. My usual scrap yard was closed, so I tried the Other One. No joy there. I tried several metalworking shops, but none had anything close to what I need. I figured I'd make a few the 'hard' way - one at a time.
I have some 2" and 1 3/4" square bar, so I cut about 4" of 1 3/4". Squared off the ends and used a 3/4" x 6" cutter in the U2 to step down on either side of the dovetail. I tried the shaper to rough out the undercuts but had some trouble and went back to the vertical mill. Cutting dovetails with a single-insert carbide is quite slow.
I finally got the dovetails to a slip fit into both of the slots on the toolpost. The clamp worked very well.
Next, I milled the slot between the dovetails for the height-adjustment pin, then drilled for the adjusting screw. Almost had the hole tapped all the way through when my nice spiral-flute tap broke off.
Two days work shot. This piece will have to wait until I build a spark-erosion EDM machine. There's nearly 3/4" of good-quality tap in the hole.
Mike
I use a die grinder or Dremel tool with a diamond bit (Cone point or tree type point) and carefully wear away the centre section of the tap until I can break out the rest with a prick punch. Rarely have I ever had a tap that will not succumb to this treatment.
Walter
starlight_tools, proud to be a member of Metalworking Forum since Apr 2012.