I continue my work on the slot for the grub screws (aka set screws) with the rougher. Went full depth (6.35mm) and step over between 0.2mm to 0.4mm with feed of 50mm/min at spindle spinning at about 1500-1800 rpm (more than 1/2 of the knob turned on the speed control). I proceeded with 0.25mm step over for the rest of the job as it sounded better though I didn't have problem with deeper step over.
Both slots were finished with a Sherline HSS Endmill (a bigger 5/16" for the grub screws slot and a 3/16" for the tool slot). Same speed and feed but step over at 0.1mm at full depth of 6.35mm. Lots of oil was use resulting in my table being almost flooded (I'm exaggerating, I know...).
Next ops, centre drilling of the 2 grub screw hole. This was done using the XBox controller with the help of MDI to position the drill. I dropped the feed to just 5% (extremely slow) and bring the drill down with the XBox controller. Quite fun. Too lazy to code for this simple job. I started with a smaller drill and went with the #21 before using the spindle with a MT1 dead centre to guide the 10-32 tap. Worked rather well. I've 2 very square tap holes that I'm proud of :-)
The completed flycutter was tested on a piece of T6061 aluminium plate. I'm happy with the result.
|Completed both slots with finishing pass using HSS endmill at 0.1mm step over at full depth.|
|Test fit with 1/4 square left hand tool. Perfect!!!|
|Using the squareness of the vise by laying it down on its side. A square was used to make sure that the business end of the flycutter is parallel to the x axis using the mill table as a guide.|
|Dimples created by center drill to mark the grub screw holes.|
|Drilling with smaller drill to start the holes.|
|#21 drill for #10-32 tap.|
|Tapping using a dead center in the spindle as guide. The dead center was pressed against the hole at the top of the tap to maintain pressure.|
|Deburring with a larger drill.|
|Test fitting with grub screws.|
|Done!!! Time to test it out.|
|Lazy to put on the ER16 spindle for the 10mm shank. An adapter is used instead. Not a good solution but good enough for the test. HSS tool blank was used instead of the brazed on carbide shown in the earlier pic as I'm cutting aluminium.|
My next project is the drill chuck adapter for the ER16. Once that's done, I'll be swapping the MT1 for the ER16 headstock. That will, however, start after I assembled the 5410 mill from the leftovers of upgrading the current mill from 5410 to its current state (a hybrid of A2Z Y base, Sherline 18" table, and Sherline's 2010 column).
I'll end this post with an unedited (in fact, I don't know how to edit videos) clip of the flycutter in action. Pardon me for the quality (or lack of).