RE: [CAD_CAM_EDM_DRO] Re: Ballscrew mounting

I think I was the first one to suggest drilling the screw. Did it on my last
project after I broke a couple of carbide inserts when I was turning the
screws and did not plunge deep enough. I had no problem with the bit
walking. I first center punched the screw and then used a center drill (I
think it was a #2 or #3 which ever one has a 1/2" body). No tentative
cutting, just plunge that bit into the screw to avoid the bit rubbing and
work hardening the material.

Tim
[Denver, CO]

> > Sounds like a good plan, Joel. I never considered drilling the ballscrew
> > and inserting another piece with the features already turned on it. The
> > darn screw is so hard it would be very difficult to turn and thread it.
> > Great idea! Question: what do you plan to drill the screw end with? I
> > tried it tonight on a scrap piece of ballscrew and even using a HSS stub
> > bit the hole was still slightly off center. It just didn't want to bite.
> The
> > point at which the tip of the bit hits the material seems to be the
> > critical issue. If it walks at all any other drilling will be off...
>
> Hi Jeff,
> Drilling the screw is not my idea, someone on this list mentioned
> it and it
> seems like a good plan. I guess the screw is case hardened and the center
> should be softer so it makes a lot of sense. I hadn't thought
> about keeping
> the drill centered but a couple ideas come to mind. You could
> use a tool in
> the toolpost to turn a depression of sorts in the end of the screw first,
> that would help center the drill. Or maybe rough out the hole
> with a drill
> and finish it with a boring bar?
>
> Joel
>
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