Lets Get Basic- Drill Bits For Lathing

Hertel brand. Get a basic set of 1/16- 1/2 from Enco on sale plus wait for the 20% off codes with free shipping. I wouldn't buy anything cheaper. A set of these in jobber length and a good Jacobs chuck(US made) or Albrecht chuck will take care of most of your day to day drilling. Anything over 1/2 inch I prefer using my Morse taper twist drill directly in the tailstock. If you have a problem breaking drills( assuming you aren't drill too fast or deep with cutting oil) you have a alignment issue with your tailstock.
 
Very good thread. Trying to make a list which includes drill bits. I signed up to receive emails from Enco several months ago but wasn't ready to buy at that time. Now I am but haven't heard from them in a couple weeks. Is this happening with everyone, or did they cut me off... or put me on their list for losers? :wink:
 
I had a few sets of cheap drill bits that sort of worked but some of the drill bits weren't straight and some weren't ground correctly. The bent drill bits do better in a hand drill than in a lathe or drill press. With an hand drill you can start the point right in a center punch hole and the drill shakes a bit but you get a hole where you want it. In a machine the drill point makes a circle above your piece making it hard to accurately start a hole. Recently I decided to spend the extra money on a good set of drill bits. I wasn't sure what brands were good so I bought a set from McMaster Carr. They don't always tell you the brand name you are going to get but I have bought quite a few things from them and it is never crap.

McMaster Carr ended up sending Chicago Latrobe drill bits and their price on them was cheaper than what the same set would have been from Amazon. I haven't had a chance to use my new drill bits very much but the ones I have used have been straight and well sharpened.
 
Boxed sets of drill bits are the cheap end of the market.
Boxed sets of Chinese drill bits are the really cheap end of the market.
You get what you pay for.

I have found quite a few Chinese drill bits are mis-ground at the tip so they cut off centre, and the holes end up about 0.3 mm oversize. If the tip breaks through at the other side, the hole abruptly drops in diameter to the correct size. I use them for drilling timber these days.

Quite a few drills from the lesser ranked mfrs show a slight bend over all. It's not just the Chinese ones which do this. The bend is probably caused by asymmetries in the heat treatment. A bent or off-centre drill bit is utter death in a CNC.

I have resorted to buying Swedish Dormer drill bits in the required sizes (ie not in sets), and mostly stub length. I trust them. Yes, single Dormer drills cost more, but one Dormer drill bit is less expensive than two 'cheap' drill bits plus a wrecked job.

Cheers
Roger
 
I second Harbor Freight for run-of-the-mill. Used 'em in a small machine shop where we were doing a lot of medical research setups. Good and sharp. Dirt cheap. If you need to make sure you get them in the right place, use a center drill first - then the bit follows right in where you want it. Check the diameter with calipers or micrometers first if you're concerned about the size - most of the ones I've used came in right on par. If you're worried, you can always 'sneak up' on it - use a smaller size first, then go to the size you want - less chance of overdrilling.
That way, you can save your really good bits for only the most difficult/demanding jobs.
 
for lathe work, I'd recommend you get a couple of sets of jobber length drill bits. $50 - $60 import sets are fine to start out with, and as the one you use most often dull, just replace them with high quality ones.

1. number drill set (#1 - #60)
2. letter drill set (A - Z)
3. fractional set (1/16" - 1/2" by 1/64ths)
4. 60 degree center drills
5. 90 degree spotting drills

Brand wise I'm really fond of "Triumph Twist Drill", the Thunderbit line they make is amazing, but pricey.
http://triumphtwistdrill.com/thunderbit/
 
I have bits from various places including everything from Old Starretts to HF boxes.
While "get what you pay for" is a common mantra, I simply ask "what am i paying for?" Or more precisely, "what would I pay more for?"
Which leads me to this: yes, sometimes an incorrectly ground bit will walk. But the grinder doesn't know if it's the cheapest bit or the most overpriced designer bit. A HF bit tip can be ground just as precise as any bit, anywhere, only for very much less money.
And when we talk about how 'precise' a bit is, I simply say, "it's a DRILL bit! If i wanted it precise, the hole would get a different treatment."
If it's precision that matters, a drill bit is the wrong tool, especially all by itself. On lathe or mill, I'd at least start with a center drill. Then the tip wouldn't matter near as much. Then use an undersize drill for material removal. Maybe plunge an end mill for perpendicularity. Finish with a reamer or a boring bar.
That's when precision matters.
Otherwise, IMO, drills are just drills. Nothing special. So i don't spend like they are.

Wrat
 
Checking drills for straight - Get a chunk of plate glass 3/8" or more thick
Roll item in question, mirror doubles visible error. Mark, clamp in vise,
thhoughtful bump with lead hammer.......BLJHB
 
wrat said:
If it's precision that matters, a drill bit is the wrong tool, especially all by itself. On lathe or mill, I'd at least start with a center drill. Then the tip wouldn't matter near as much. Then use an undersize drill for material removal. Maybe plunge an end mill for perpendicularity. Finish with a reamer or a boring bar.
That's when precision matters.
Otherwise, IMO, drills are just drills. Nothing special. So i don't spend like they are.

Wrat
Click to expand...

For a project I was working on recently I needed to put a 3/8 hole in the middle of a 4 inch long 1/2 inch piece of round. We were going to ream it later to get a more accurate size but the hole needs to be pretty close to down the center of the piece. Sure drilling first then boring will get you a straighter hole than drilling but how are you going to bore a 3/8 hole that is 4 inches deep? A reamer will give you a good size but it will want to follow the hole that was drilled. We could drill it crooked put it on a mandrill and turn the outside, or leave it long and turn it between centers put in the ends of the hole but those options are harder than drilling a straight hole to begin with. Drilling a straight deep hole with a bent drill bit probably isn't going to happen. Sure the mandril option or the centers option would probably give us better results than drilling with a good drill bit the good drill bit is good enough and takes less time.
 
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