I agree with what Jesse has said, and will add a couple more comments. I thin the web of the drill when drilling hard stuff. On the standard sharpening of a drill, the center part of the drill just rubs against the material, which promotes work hardening if care is not taken. I also find a heavy center punch on location tends to help. A sharp drill makes the job go a whole lot easier. I no longer buy HSS endmills under 1/4". Over all in the smaller sizes, carbide is a whole lot cheaper for what I do, and carbide will go through the spring steel very easily. My personal first choice would be to punch the hole. I remember plans for a small hole punch in ME in the mid to late 50's. It has been on my to do list for a number of years. Regards, Doug JESSE LIVINGSTON wrote: >Spring steel can usually (noticed I said USUALLY) be drilled by running the >drill very slowly, using plenty of thread cutting oil and keeping a steady >and relentless pressure against the drill bit. If the drill ever makes a >turn without removing metal the steel will instantly case/work harden and >all forward progress will cease. This same system works on stainless steels >that work harden when drilling. > >Unka Jesse > > > -- Doug Edwards Stueart@xxxxxxxxx Building a 70 ton Willamette in 1.6" http://www.rad45.org/Supplies.htm Building a 80 ton Climax in 1.6" MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.