Here we go again . . . MK4

[routercnc]

Finished the 2nd pair off, cleaned up, holes drilled etc.


These are the corner pieces on the gantry-


Not that exciting so I thought I'd also post another way I just tried out of tapping the threads in those parts (well starting them at least) which is much quicker. I started with one of these tapping chucks from RDG tools - designed to either replace the drill press chuck or for use in the tailstock of a lathe. It has a tommy bar and the chuck is free to rotate and slide inside the morse taper housing:


Link below (they are also on e-bay)
http://www.rdgtools.co.uk/acatalog/2...ent-88025.html

Although you are supposed to tap out the existing chuck and replace it with this one I didn't want to keep swapping them over. I'd looked these over at a show so knew that the MT3 taper comes off the chuck leaving a 12mm straight rod - perfect :


Because the 12mm rod was greased I put it inside a plastic bag (to stop the grease going onto the chuck jaws) and then put in lightly in the chuck - just enough to hold it but still allow it to rotate and slide up and down:


Here it is well into tapping the M5 thread:

This takes seconds to do and you can feel the bite / back off and reduce the risk of breaking the tap.

Note that the drill press is NOT powered - I'm using the tommy bar to rotate it manually.

This worked really well, was very quick, and created threads which were perpendicular to the face. I finished them off by putting the parts in a vice and using a cordless drill.

I think the plastic will not last long, it started has started to tear already, so one option is to make a metal adapter tube which is clamped in the drill press chuck at the top, and contains a long bored out 12.05mm dia or so hole in the bottom to hold the greased rod on the end of the tapping chuck. If the bore is a good fit and there is grease in there it should stop the chuck falling out when you raise the drill press.

To have something set up permanently I might even modify a cheap drill press/stand (the ones where you put a mains drill in) to house a long rod attached to the drill chuck - a bit like the Arc Euro ones but their's only goes to about 6mm or so tap size whereas this goes to 13mm.