steveslock wrote:take a drill bit meant for drilling through the hard plate of a safe then try it on mild steel. Tell me how well it drills the steel even though it is harder than mild steel?
That's completely irrelevant to the original problem. The simple fact of the matter which you and your fan fail to understand is that if the drill bit is to complete and survive the task it must be harder than the material it drills.
Speed and pressure have nothing to do with drilling a hole? I'd better get out the old machinist hand book...
I didn't write that nor even imply that. However, no amount of speed or pressure will enable a tool steel bit to
drill through a piece of tool steel. What you are advising is physically impossible. A tool steel bit against a piece of tool steel will at best drill a hole via abrasion and the bit will be totally destroyed. It can be no other way. Wood will also drill wood you can see that by using the bow and drill fire lighting method. You do get a hole but you also abrade the wooden drill and light a fire in the process. What you are advocating is essentially the same as drilling wood with a wooden bit and saying to me "look, look here you can drill a hole just press harder". No shit. Excessive pressure doesn't in any way help the drill bit
properly work. It helps you make a whole but that is not by cutting.
Do get the machinists handbook out and read what is says about drilling tool steel. I am certain it doesn't say just use a HSS drill bit, run your drill slow, dump a heap of lube on it and press as hard as you can. That is how an ignorant jackass behaves in a workshop.
piotr, my only reason for posting was to give him some advice to get the hole drilled. If he is drilling a 100 holes then by all means send it out and chuck it up in the bridgeport. For a couple holes, put the thing in a full size drill press take your time and get-r-done.
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The advice is simply get a tungsten carbide bit. The weight you put on top of a hand drill when working on a bench that is at correct (ergonomic) height is adequate to drill through 0.025" tool steel. The purpose of a drill press isn't so that you can push the drill bit harder into the work than you can with a hand drill (if you think it is then you need to go back to your machinists manual). There is an optimum amount of pressure that needs to be exerted and exceeding that won't help you
drill it will only help you make a hole by abrasion (and generate lots of heat). An adequately powered hand drill with a tungsten carbide bit will drill through .025" tool steel and more.