Pointier drill bits to drill steel ?

Leu Custom

Leu Custom

Joined
Jun 2, 2007
Messages
1,354
What company makes drill bits that are pointier so you can pretty much plop it down straight on the mark you just made in the metal with a punch? All I have ever seen is drill bits from hardware stores which have a very obtuse pointed tip even when it says for drilling hard metals.

Is "walking" causes by the drill bit or the lack of tolerances on the drill press? The operator or a combination of all?

Drilling A2 if that makes a difference to anyone.

Thanks in advance!

Pohan
 
Leu Custom said:
What company makes drill bits that are pointier so you can pretty much plop it down straight on the mark you just made in the metal with a punch? All I have ever seen is drill bits from hardware stores which have a very obtuse pointed tip even when it says for drilling hard metals.

Is "walking" causes by the drill bit or the lack of tolerances on the drill press? The operator or a combination of all?

Drilling A2 if that makes a difference to anyone.

Thanks in advance!

Pohan
Click to expand...

Most all drills i have seen are about the same from the factory. some times we resharpen them a little "sharper" but you end up loosing strength in the point. what you really need is a center drill, like a #2 or a #3. this will solve all your problems. well maybe not all your problems but it will solve your drill walking problems.
 
If you're using a center punch first, I don't think you should have any walking problems. Are these very large holes? You may want a pilot hole first in that case or you may just want to punch it deeper.
 
You can buy "sharper" drill bits (90° included angle), marketed as plastic drill bits. Try US Plastics.

However, a more acute bit will not really help you. It will require more HP to drill the same hole because the cutting edge is longer. It will violently grab upon exit. They are great for plastics but not steel.

I agree with JT; a center-drill is what you want.

Drill bits have a lot of flex. A machine that is 100% rigid will not prevent a drill bit from walking, unless the drill bit is stub-length.

This is one of those situations where 'the industry' has things 99.99% figured out. For tougher materials, it is recommended that you use a bit that is more obtuse (135°), not more acute. Buy a name-brand center-drill; a 4" long #3 KEO is what I use (4" so you don't have to re-set your table height in-between center-drilling and drilling operations). Buy a name-brand cobalt drill; TiN-coated, cobalt 135° split point such as Norseman (recommended here and available at US Knifemakers last time I checked). Use soluble oil as a lube if possible; use the right RPM. I make a spike out of W-1 that has a 2.2" deep x 5/16" Ø hole. I drill 10 to 20 at a time without sharpening or changing bits; I run my drill press at 500 to 600 RPM. I use a Rigid drill press from Home Depot; not exactly a precision instrument.
 
I use Dewalts Index pointed bits, they doa pretty good job of going where you point it. Problem is in the smaller sizes, which is probably where you are having a problem. Good advice from Patriqq
 
for some reason, I have this problem when drilling 3/8" wide holes. Either i'm blind or the bits SUCK! or aren't sharp enough to grab the material on contact.

What number is a center drill that will ultimately end up as a 3/8" hole? Don't want any counterboring or sinking.

Thanks!
 
Short answer: drills made for drilling plastics are often 90 deg. I believe Onsrud has a line.

Long answer: the flatter the tip, the less edge is engaged in the cut, the less force required to make the cut, and the better the hole. 135 have become more popular than 118.

If you want something that walks less, try something with a split point or a helical tip grind.

Punch your punch mark harder?


BTW: center drills are for drilling holes in parts to be mounted between centers such as in a lathe. I think ya'll mean a spotting drill. Center drills can be used as a spotting drill in a pinch, they are stiff.

If using a piloted hole, sometimes it is helpful to make sure it is smaller than the web of the next drill if you want the larger dill to follow the smaller hole.
 
Thanks for the replies guys!

Maybe I just need a new 3/8" bit !

Seemed to be annoyingLESS when it was new!
 
What you want is what is called a "spotting drill" bit.
Too many people use "centering drills" for locating holes, and that's not what they're designed for.
"centering"drills are used to find, well, the "center" of stock that is being turned in a lathe.
The configuration of a "centering" drill forces it to locate itself in the "center" of the stock.
A "spotting" drill is designed to make, well, a "spot" to be drilled!
It's what you are looking for.
Here's a 1/4 and an 1/8, followed by the entire selection.

"Application Prevents misalignment caused by using regular drills for centering."


http://www.fastenal.com/web/products/detail.ex?sku=7000098&ucst=t

http://www.fastenal.com/web/products/detail.ex?sku=7000096&ucst=t

http://www.fastenal.com/web/products.ex?N=999604413&Nty=0
 
Ideally the spotting drill has a flatter point than the drill you're starting. That way your drill starts from its center and not the edges. That will improve accuracy, reduce damaging chatter, and prevent that screwed up funk that can happen around the start of the hole.

... Thus spotting drills should be less pointy than your drill. A thin web and split point and large size and short length keep it from walking. You can spot a 1/4" hole with a 1/2" spotting drill - you're just trying to create a cone so you only go down a tad.
 
I tried a name-brand USA-made spotting drill and was highly disappointed. The bit just seemed to "rub" its way into the cut. Thats why I started using center-drills as "spotting drills". I use a 60° center drill to start a 135° drill bit, contrary to recommendations. I find that an extra-aggressive (within reason) feed with plenty of coolant is the way to avoid the problems that Nathan listed.

You probably won't want to use the spotting/center drill to blow through your blank to final size. These bits have no or minimal flutes, so chips have nowhere to go after a certain depth. Plus they are expensive and difficult to sharpen.
 
patriqq said:
I tried a name-brand USA-made spotting drill and was highly disappointed. The bit just seemed to "rub" its way into the cut. Thats why I started using center-drills as "spotting drills". I use a 60° center drill to start a 135° drill bit, contrary to recommendations. I find that an extra-aggressive (within reason) feed with plenty of coolant is the way to avoid the problems that Nathan listed.

You probably won't want to use the spotting/center drill to blow through your blank to final size. These bits have no or minimal flutes, so chips have nowhere to go after a certain depth. Plus they are expensive and difficult to sharpen.
Click to expand...

Ah yes ! Thanks for the clarification. Wasn't sure if i was suppose to use it for the entire hole or to start the hole. Maybe my entire problem is i need to get a new drill bit !
 
If the hole location is crucial, run a pilot hole first and then without moving the table or chuck drill the hole to the desired size.

If you are looking to drill a "round" hole, which drill bits do not do, drill undersized and follow with the appropriate ream.

I use dreamers, which are a combination bit that has an undersized drill at the tip followed by the required ream. They work great for drilling handles for pins which require a perfectly round hole.

Fred
 
The bits I have been using are round enough for me. It's just sometimes especially if the bits seem a bit on the older side, that drilling a hole in the middle is impossible ! :eek:
 
Leu Custom, are you trying to drill a 3/8" hole all in one shot? It kind of sounds as though you are. You might want to start with a 9/32" hole first and then switch to your 3/8" bit and open it up.

-d
 
deker said:
Leu Custom, are you trying to drill a 3/8" hole all in one shot? It kind of sounds as though you are. You might want to start with a 9/32" hole first and then switch to your 3/8" bit and open it up.

-d
Click to expand...

Yes I am ! I have drilled several hundred hundred holes in 3/8" over the years and i guess depending on how good the drill bit is sharp wise is whether it's good or not !

Maybe i'll try a small pilot hole with say a 1/16" or something then go bigger!
 
Centerpunch hard to make a good divot at the mark, use a sharp 135 degree bit, make sure the point is in your centerpunch mark divot. Use lots of oil and a slow spindle speed. Get a DrillDoctor sharpener if you are going to be a lot of drilling, I resharpen my bits regularly, I never have walking problems

-Page
 
Here's my two cents on the topic. A center drill is fine to start or spot a hole, its just alittle grabby, so be carefull , or just use a clamp to clamp the piece of steel down. split point drills are the way to go, they are thinner at the chisel point so they tend to walk less (the point finds thew center punch mark easier, also less force to drill as the center of the drill has no speed and if the point is thinner its easier to drill the hole.

I routinely drill 3/8 or larger holes in A2 or D2 no problem, think your drill is dull.
 
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