Morse taper drill bits or reduced shank......

[RaceDiagnostics]

.....which is best.

I'm looking to buy some larger drill bits, ~ 12 to 20mm. Does anyone have thoughts on whether reduced shank for fitting in a chuck or MT2 fitting into the tail stock is better?

 

[Matchless]

straight into the tail stock would be far better but you may need a jump up from 2mt to 3mt for the larger sizes, cheap enough on fleabay,

 

[Munkul]

MT will always be "better" but reduced shank can be handy for hand drilling at a pinch.

 

[Dr.Al]

straight into the tail stock would be far better but you may need a jump up from 2mt to 3mt for the larger sizes, cheap enough on fleabay,

What he said ↑

MT will be more accurate and less likely to slip. If memory serves me correctly, you can generally get up to about 23 mm in MT2, then they're usually MT3.

I bought a cheap set of reduced shank drill bits and use them when I don't have a sensible size of MT drill bit, but I'm gradually getting more sizes of MT bit and will probably eventually replace them all. The advantage of reduced shank ones is they're cheaper (but buy cheap buy twice...)

 

[Stupoty]

MT will be more accurate and less likely to slip.

Yeah I have had a few cheep reduced shank drills that arn't very concentric, I did re-turn the reduced shank which made it better (luckily the shank wasn't very hard), the original runout made it awful in any fixed drilling equipment like drill press or lathe.

 

[slim_boy_fat]

Iirtc, they're known as 'blacksmiths' drills.

 

[brightspark]

Iirtc, they're known as 'blacksmiths' drills.

there ok but they don't do your drill any favours putting 25mm drills in a half inch chuck. specially when the drill wont go slow enough as it hasn't got a back gear

 

[brightspark]

I have a number 2 mt on the lathe tailstock and have a no3mt reamer I needed to use so bought an adaptor . no 2 to 3mt and used it there not good neither as the no 2 turned in the tailstock even though its in good condition as I cleaned it out with a taper reamer plus your limited by length of bed what you can drill as it looses you about 6 inch have these but only used one once a get you away job

 

[Kram]

If its for lathe I dont bother with large ones. First they are plain hss not cobalt, and 4x more expensive. The lathe doesnt have enough rigidity or slow speed power, above 12mm you'll need 1mm increments, wears them out quick. Ive got a 17mm and lathe is not happy with it!
The cheap option is to peck drill with cobalt hole saws, or better with a rotabroach /mag drill bit,

Small mt1 drills will save a lot of time. 4 or 6mm hole then swap boring bar then 4mm diameter cuts until you get to size.
Lathe doesnt have rigidity for big drills, or deep holes than 60mm. It will do it but painful.

Another very useful one is boring head. Clamp big work to cross slide or an angle plate, boring head spins the tool instead of the work.

 

[mechman]

Iirc mt3 went up to 1. 250" dia (old money) just thought 1/2" drive sockets used to go up 1.250" AF also, Hmmm.