Drill THK Rails? (searched already)

[legendboy]

I bought a set of SHS15 rails and blocks on ebay without looking at them close enough.

These rails have mounting holes drilled and tapped on the bottom. I am wondering if it is even possible to drill out the tapped hole + counter sink so I am able to screw them from the top?

I imagine these rails are extremely hard. Maybe too hard for an operation like counterboring?

I am mounting them to a 2" thick dura-bar flat table.

Any ideas appreciated!

[blackbeard52]

I have done just that. Carbide is the only way to do it. (Machinist techies dont bash me) I used masonary bits from a local hardware and they cut through it but use plenty of air to cool to prevent annealing. Drill through with 3/16 and counter bore with a larger bit. there will be a taper in the hole ....Just a suggestion.

[legendboy]

I put them back on ebay and bought the correct rails. Hopefully i recoup my $