Boring on the lathe with a step drill

I have a 49/64". I'm not sure what the max is, but probably about 1".
I have S&D drills up to 1 in., but the shanks are pristine and I refuse to put them in a chuck.
I'm leery of the MT2-MT3 sockets. I broke the tang off one (larger) years ago and spun it in the tailstock. Didn't do any favors for the taper.

I just ordered one of the big step drills (1-3/8 max) for $6 off eBay.
 
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Those step drills are awesome. Everybody should give them a test, You will be surprised at what they can do. I used a 1/2 one to drill a tom of holes in a truck frame. They will go through faster, and since they have several cutting surfaces, they stay sharp quite awhile. Then can be easily stoned back to a good edge.

They are also great for sheet metal, The body acts as a giude, so the cutting edge is always in the right position for a clean cut, and can't grab like a regular drill. I would love to find a 2" one to cut holes for mounting automotive gauges.
 
I'm glad this topic was brought up. My step drills would have probably remained untouched for years to come. Do you only grip the S&D bits with a collet Mr.whoopee?
 
Do you only grip the S&D bits with a collet Mr.whoopee?

Yes. In the shop where I apprenticed it was a firing offense to hold them in a chuck. We had taper shank drills for use in the lathes. I kept that rule when I opened my own shop.
 
the only problem i see with the process is that Unibits are made for sheetmetal work, where there is little contact between bit and the work in operation.
when you are plunging into a solid piece you are increasing the load on the bit, drillchuck, and tailstock due to the greater surface area in contact with the cutting edge.
the process may work fine if you peck drill or are drilling in softer materials,
but hogging out big bores in tough materials at high rates will be eventful. :eek:

i like the out of the box thinking! :grin:
 
the only problem i see with the process is that Unibits are made for sheetmetal work, where there is little contact between bit and the work in operation.
when you are plunging into a solid piece you are increasing the load on the bit, drillchuck, and tailstock due to the greater surface area in contact with the cutting edge.
the process may work fine if you peck drill or are drilling in softer materials,
but hogging out big bores in tough materials at high rates will be eventful. :eek:

i like the out of the box thinking! :grin:

As I said, that's what I expected. But the material you see me drilling through isn't sheet, and there were zero events. I was expecting all that surface area to be "grabby" and probably stall my motor, but it didn't even come close. It was just like drilling with a twist drill.
 
As I said, that's what I expected. But the material you see me drilling through isn't sheet, and there were zero events. I was expecting all that surface area to be "grabby" and probably stall my motor, but it didn't even come close. It was just like drilling with a twist drill.

This would be similar to using a large twist drill with multiple grooves in the cutting edge to form chip breaks. It substantially reduces the cutting force.
 
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