Drilling 1inch hole in 1.5 inch thick A36

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I am drilling a hole in A36. It has been difficult with multiple sharpenings per hole. I don’t mean the final hole, I mean per step I need to sharpen 2-4 times. I am using a Silver and Demming set of bits. Using lathe is not an option due to the length of the piece.

Details
Final diameter 1inch
A36 alloy 1.5 inches thick
Using small manual mill
Turning at minimum speed which is 315 RPM

Two questions
What is the proper way to drill, how many bits to use to finally get to 1 inch?
What is an easy way to get a pilot hole drilled all the way through?
 
Wow that is kind of a crap shoot in A36 which is a mystery mix. It can go from soft easy drilling to Hss bit eating monster in a 1/8” of cutting. I use coblt drills when working with A36. Start at 1/4” and increase by 1/8” if you have them, 1/4” max and use a lot of lube and peck drill don’t just plung through, with lite to medium pressure. Let the drills do the work. You don’t say what size the mill is, or if you have a drill press. Which ever one has the most power is what I would use.
Good luck
CH.
 
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The mill head is a Smithy, but it has been converted to mill only with 10x10 yuasa xy table. I think it is 3/4 horse.

I am taking smaller steps and it is working better(1/32 steps in many cases). I need a keyless chuck.
 
315 rpm is too fast to drill a one inch hole in most any steel. Do you know anyone with a mill that will turn at a slower speed?
Usually I drill a 1/4 to 3/8 inch hole all the way through and then drill with the one inch bit and use lots of cutting oil at 60 or so RPM.
I would use a keyed chuck myself as they usually have stronger gripping power than a keyless chuck.

edit: and I would use a cobalt bit if I had one...
 
What is your maximum collet size ? Carbide insert drill could handle the 315 rpm .
 
Yes, what cathead said; when possible it is good practice to drill a pilot hole that is the thickness of the web of the final drill. In production, a RPM of over 300 would not be too fast in soft steel; using 80 ft./ min. as a starting point, according to my machine shop teacher, you take the cutting speed and multiply it by four and divide the result by the diameter of the moving part ( this is not exact, but a person can do it in their head), the result in this case would be 320 RPM. I wonder if you are using cheap import drills?
 
Does the mill head have a back-gear function? 315 is was too fast!!! Figure the surface feet at the edge of the bit. It's cooking ,ie getting very hot! I have a very old flat belt machine with #4 Morse Taper. This beast has a back gear and auto down feed. I drilled a hole 2 1/4" thru 1" A36. Very slow but a pretty hole. Not reamed quality but better than you would have thought. I watched it and applied cutting oil as needed. 1/4" pilot and then full size.
 
Suggest relief holes like for hole cutters.
About 1/4", 2-3 spread around the perimiter.
They make a huge difference.
 
Most hardware stores sell carbide tipped drills also . Not very expensive when compared to multiple sharpenings . And then you can re-use it too .
 
If a person in the shop where I apprenticed drilled at such a snail's pace as has been suggested, he would have had a very pointed conversation with the foreman, along the lines of "speed that up!" 60 rpm is only about 15 feet per minute cutting speed, that would be slow even for carbon steel tools. As I previously said, about 80 FPM is a starting point for HSS tools on mild steel.
 
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