Angle for Sharpening Drill Bits: 118 vs 135 and Why It Matters

The bit skates across the punch mark before it ever bites into the steel. You lean harder. The point walks off target, and the hole comes out oversized when it finally catches.

Nine times out of ten the culprit is not the drill press or your hand pressure. It is the angle for sharpening drill bits ground onto the tip.

Most twist bits ship in one of two point angles, 118 degrees or 135 degrees. Get the wrong one for the material, or let the two edges wear unevenly. Every symptom above shows up again.

Why the angle for sharpening drill bits changes the whole cut

A drill point angle is measured across the tip, between the two cutting lips. A narrower angle like 118 degrees comes to a sharper point. A wider angle like 135 degrees is flatter and spreads the cutting edge out more.

Drill Doctor’s own comparison calls 118 degrees the universal standard for most jobs, since the sharper point resists walking. It does not need a split tip to center itself. The company is blunt that 135 degree bits get more credit than they deserve for everyday work.

A 135 degree bit only self centers because of its split point. That design grinds two extra facets into the chisel edge, so it starts cutting immediately without a pilot hole. It also needs less downward pressure to bite.

Point angle discipline is not unique to drill bits either. It is the same idea behind our broader guide to sharpening tools for chisels and knives.

Lip relief and the chisel edge nobody checks

Point angle gets all the attention, but lip relief angle matters just as much. It is the clearance ground behind each cutting edge so the bit can bite instead of rub. Too little relief and the bit rubs and burns instead of cutting cleanly.

Shop convention calls for a modest chisel edge lean, often cited as 12 to 20 degrees at the tip. Not everyone agrees with that figure.

One veteran machinist disagrees. He argues factory bits run closer to a 45 degree lean. That would put the true chisel edge angle nearer 135 degrees than the common rule of thumb.

We are not picking a side in that debate. The practical takeaway is simpler: symmetry matters more than hitting one exact number. Two lips ground to different angles or lengths will drift off center, no matter the relief figure.

Sharpen the basic edge first if yours have not seen a wheel in years. Our guide to the actual sharpening process on a bench grinder covers that step.

Picking 118 or 135 for the material in front of you

For wood, plastic, and soft metals like aluminum, 118 degrees is the safer default and needs no special technique. Regal Cutting Tools puts it simply: 118 degrees suits soft metals, and 135 suits hardened material like stainless steel. Reach for a genuine split point bit when the material fights back.

A plain 135 degree grind without the split loses most of its advantage. Without those extra facets it wanders just like a blunt 118 degree bit would. The split point, not the angle number alone, does the centering work.

A bench tool that holds either angle for you

Grinding a consistent point angle by hand takes practice most home shops never get enough of. If you would rather set the angle once, a dedicated drill bit sharpener holds it for you. For a wider view, our how we judge drill bit sharpeners on accuracy guide covers the rest.

Prefer to keep using your existing bench grinder instead of a dedicated machine? See turning a bench grinder into a bit sharpening station for that route.

If the 750X does not fit your bit range or budget, our separate look at Drill Doctor’s full model lineup covers the rest of the family.

How to check the angle for sharpening drill bits without guessing

Grab a drill point gauge if you have one. Line the notches up with each cutting edge and read the angle straight off the tool.

No gauge on hand? A protractor head on a combination square gets close enough for shop work. You can also run the numbers with our free angle tool before you touch a wheel.

Either way, check both edges, not just one. A gauge only helps if you use it on the whole point.

Mistakes that undo a good angle

Most sharpening problems trace back to the same handful of errors, angle number aside.

• Grinding the two lips to different angles or different lengths, which throws the hole off center.
• Letting the chisel point grow wide from repeated regrinds without ever thinning the web behind it.
• Choosing a relief angle so steep the edge chips, or so shallow the bit rubs instead of cutting.
• Assuming a plain 135 degree grind self centers the way a true split point does.

For coverage beyond drill bits, see what else we cover in the shop tools category.

FAQ

Is 135 degrees always better than 118 degrees?

No. Plenty of home shop drilling never needs a 135 degree split point at all. Save it for stainless steel and other hardened material.

Do I need a split point for wood or plastic?

No. Split points solve a metal drilling problem, starting the cut without a pilot hole in hard material. In wood and plastic a standard 118 degree point centers fine on its own.

What lip relief angle should I aim for?

Aim for the modest lean most shops use rather than a steep one. Getting both lips equal matters more than hitting one specific number, since mismatched lips cause off center holes regardless of the relief figure.

Can I resharpen a 135 degree bit down to 118 degrees?

Yes. It is a common practical fix once a split point wears out, and it is exactly what Drill Doctor recommends as an alternative to buying new bits.

What is the right angle for sharpening drill bits used on stainless steel?

135 degrees with a genuine split point, since a plain grind at that angle will not self center the way stainless work demands. Pair it with a slower feed and steady, even pressure.