Tapping holes while material is still clamped to my mill table?

[HankMcSpank]

ok, here's my conundrum...see if you can help (all suggestions welcome).

I'm milling very small bits of acrylic - which are just 4.8mm wide, with 6 x M4 threaded holes in them. So, with just 0.4mm material left either side of the threaded hole once the part is cut, what I've discovered is if I cut the part out, then try to tap the holes afterwards - .... SNAPSVILLE!

I'm therefore having to tap the holes while the material is still in one larger piece *and* while it's still clamped to the CNC table/bed (the acrylic is clamped to the table via 5mm MDF, so I drill through the acrylic & into the MDF a further 3mm to allow me to tap the hole hole in the material). This is a crock, as I have to shuttle the bed out to one side to tap the six holes...compounded by my present tap wrench having a standard T bar type handle, making it very difficult to use (the Z plane gets in the way of the handle while threading the holes !)

What I'd like to be able to do, is shuttle the material to one side still, but use my electric screwdriver to tap these small holes (they're only about 5mm deep & this is just acrylic, so the electric screwdriver should be fine at it's slowest speed).

But what adapter do I need to connect my electric screwdriver to an M4 tap?

My electric screwdriver has a bog standard hex receiving socket (I don't know what that measures though!), and I think(?) the square end on a standard tap is 1/4"?


I see it's possible to buy tap ratchet wrenches (with no T bar aspect), but they still look clumpy & I'd rather have the electric screwdriver do the turning!)

Any input most welcome here!

(by the way...in the tool management of my CNC software, I see there are 'tap' tools available as an option to select...what's going on there?!!! My spindle turns at 7000RPM...how on earth can you tap a hole that way!! :confused: )