Drag knife compensation

Someone asked about calculating a path for drag knife compensation, so I had a go at writing an  OffsetForward method for my Curve class. See the code here.

Part 0018

Part 0015

Part 0014

 One of these flutes was still very sharp, so it should cut ok.

 I did all the CNC work from one side, cutting small, 2mm deep, pilot holes, with a 3mm diameter slot drill, where the 5.5mm holes need to be. Clearing all the metal with the 6mm slot drill took 2 hours.

 I cut the holes to 5.5mm afterwards on Dad's pillar drill.

 For the counterbores, I countersunk them, on the pillar drill, oversize, then did the counterbore with a 10mm endmill.

There was only just enough room to cut the 2mm slot, but there was enough room, see video.

HeeksPython adding python interface

HeeksPython now calls autoexec.py on start up, which can add menus and windows to HeeksCAD.

end holes

These parts are too long to CNC drill the end holes, so I had to make a drilling guide first.
I used a 3mm milling cutter to pocket and profile the shape in the Delrin, then I used the pillar drill and put the aluminium part in the portable vice and held the Delrin guide onto the end of the part to do the drilling. I only used the guide to drill a small depth, then I drilled them through later.

Ungluing accident.

 

See my coolant delivery system in action in the video.

I had a problem with this part. The sawn piece was a tight fit in the pocket in the wood sub-table, so it didn't glue well, so it came unstuck soon after the start of machining. You can see the bent path left in the metal, in the video. I remachined the wood and chiselled the side of the pocket bigger and everything else went well, but there is a bit of a gouge out of the top of the circular post feature. Maybe it won't matter too much? The surface finish doesn't seem any different ( the one on the left of the picture is the most recent part ), despite lowering the feedrate to 50 mm/min instead of 100 mm/min. The tool looked slightly worn after the ungluing accident. It doesn't look much more worn after all the machining, so I think that 200 mm/min is better than 300 mm/min. Hopefully the next one I make won't have any mistakes in it.