More Drilling AEB-L Post HT

AVigil said:
What does that mean?
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I think what JT means is that he uses his plasma cutter to zap (“pop”) a small hole, then (after HT) he mechanically drills the hole using carbide burrs and/or carbide straight flute bits.

JT: this raises lots of questions for me:
  • Do you do that secondary drilling operation using the carbide burrs on a drill press or mill? (I only have the drill press)
  • My not having access to a plasma torch, can you (or someone else) think of ANY way to create a starting divot that a 1/8 inch carbide tipped bit can grab onto (to avoid the walking)
  • I know i can drill the 1/8 inch hole: why not use a 1/4 inch burr to enlarge that 1/8 hole to 1/4? (Versus your straight flute bit)
  • I have read the solid carbide bits are brittle and prone to breakage. How do you avoid/minimize that breakage?
Inquiring minds want to know... :-)
 
Try a diamond urr in your Dremel. Doesn't take much of a divot to keep the drill bit from wandering.
 
This is how I do it. You can use a drill press, I use a small mill/drill that’s about like a drill press with an x and y
 
JTknives said:
This is how I do it. You can use a drill press, I use a small mill/drill that’s about like a drill press with an x and y
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thanks JT. the smoke and chips are pretty close to what I see when I use a carbide tipped bit. How many holes to you typically get out of those solid carbide bits? do they dull quickly?
 
Cushing H. said:
So you are suggesting slow speed, slow feed,and nearly continuous supply of coolant?
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Hello, I use “cool tool”, a drop and cut a little, then another drop , you can use the pipe threading oils but they stink like all hell and avoid the ones with Sulfur as it’s a known,Cancer Causer. I don’t think drilling a few holes will kill you though. Even 3n1 oil will help you drill harden steel..
 
Cushing H. said:
thanks JT. the smoke and chips are pretty close to what I see when I use a carbide tipped bit. How many holes to you typically get out of those solid carbide bits? do they dull quickly?
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JT need to sharpen that drill bit or use new one , to much heat there...
This is 67 HRC HSS steel full with carbide ............easy to drill no heat at all and no coolant .I like slow speed for this task it is about 900 RPM on video.Blade was clamped so I can hold with one hand phone .........
 
Natlek - that behavior is almost exactly what i see using a carbide tipped drill, slowest drill speed, and no oil ... except ihave that “walking” problem that creates a deflected bit. I
 
Natlek said:
JT need to sharpen that drill bit or use new one , to much heat there...
This is 67 HRC HSS steel full with carbide ............easy to drill no heat at all and no coolant .I like slow speed for this task it is about 900 RPM on video.Blade was clamped so I can hold with one hand phone .........
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I call bullshit on to hot, I run carbide fast always have. Yours is just as hot, you can see smoke coming off your chips. Not sure on that rpm but it was probably 1,500-2,000. I don’t have time to pussyfoot around when drilling holes. I will take a few pictures of the drills I use and thy get better the duller thy get. I have a 1/4” one that’s lost it’s corners and it drills better now then when it was new. back in the day in the machine shop we would run carbide as fast as the machine would go if cutting hardened stuff. Same with the lathe. On the lathe I would use ceramic inserts and crazy rpms. Just a shower of sparks coming from the cut.
 
Cushing H. said:
Natlek - that behavior is almost exactly what i see using a carbide tipped drill, slowest drill speed, and no oil ... except ihave that “walking” problem that creates a deflected bit. I
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I will show you a bit I really like for your issue.
 
JT, this bit you're going to show us, is that for drilling large holes from a small pilot hole? OR, will it also start a hole in a blank with no pilot hole?
 
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