Removing drive screws from SBL QCGB

[joebiplane]

I Got a QC gear box for my 9" Model B to upgrade to model A... but I need to change the thread chart presently on the gear box...( wrong bed size)
I did a Logan last year and it posed only minor difficulty.. but the SBL drive screws appear to be made of KRYPTONITE... I ground the heads almost flush and was able to get a # 2 center to remove the heads but the studs refuse to be drilled or milled.
Is there a 3/32 bit that I could use to grind into the hole and grind out the stud without ruining the holes so I can install the new drive screws to attach the new chart after I repaint the Lathe ?

Plan "B" is to relocate the chart a "tad" and drill new holes

 

[WoodArn]

Drive screws are hardened (as you found out). Check the inside of the gearbox to see if the holes for the screws are through holes. If they are, you can use a punch to knock them out. If not, you'll probably need to move the new tag over a bit.

You need to grab and twist.

 

[Tony Wells]

Funny, Jim, I've used tile nippers also. Once or twice I've successfully cut a screwdriver slot across the head and backed them out, but usually they are pretty tight so that doesn't always work. The nippers allow the screw to rotate as it is pulled out, do it works well.

 

[kd4gij]

You will need carbid drill or endmill. A diamond bur would work also.

Marty