Do you find yourself searching through a pile of old worn-out drill bits looking for a decent drill that isn’t blunt, give up and go out and buy a brand new one just so you drill a couple of holes and finish a job?
This happens to me all too often and I end up with a drawer full of blunt drills that I have every intention of sharpening but don’t practice enough to do it by hand, so I asked myself if a drill sharpener may be the answer, and do they really work?
Drill bit sharpeners work for drills between 3/32” and ½ “Inch diameter, they will sharpen twist drills to a 118-degree point and can sharpen Carbide, Cobalt, High-Speed Steel, Black Oxide, TiN-Coated, and Masonry bits. To sharpen drills that are smaller than 3/32” or larger than ½” using a bench grinder is best.
What are drill sharpeners
Drill bit sharpeners provide a quick and easy way to sharpen drill bits. Most drill sharpeners are self-contained units that can be powered by household mains electricity:
- 110V-120V / 60 Hz
- 230V -240V / 50Hz
They normally have one or more grinding wheels driven by a small motor and have a drill guide that keeps the drill bit being used at the right angle for sharpening.
They are often designed to be mounted on a bench, a work table, or held in a vice.
The grinding wheels are set to the correct angle, allowing drills to be resharpened once they become blunt.
How do drill sharpeners work?
Drills bits with cutting angles of 118 degrees have a more aggressive tip and with a smaller chisel, these are used for drilling holes into softer material such as wood or plastic.
Drills with a 135 Degree angle are flatter, with a longer chisel and these drill bits work better on hard materials such as Stainless steel or tool steel.
The drill bits are held or clamped in a guide which allows for a constant angle to be held whilst the drill bit it is sharpened.
Normally the drill bit is fitted into the guide and the correct depth set this stops the drill bit being ground too far reducing its lifespan.
A good drill sharpener will be adjustable to allow for multiple angles to be chosen and will accommodate a wide range of drill diameters.
Inside the Drill sharpener, a small grinding wheel turns against the tip of the blunt drill and cuts a new sharp edge.
The grinding wheel is made from hard carbide or diamond and rotates up to 15000 RPM.
Grinding wheels can often be supplied in different grades, know as ‘Grit’ this term lets you know how course the surface of the grinding wheel is for example 100 grit has a rougher surface than a 180 grit grinding wheel.
Typically 180 grit drill sharpener grinding wheel is a fine grade, and a 100 grit drill sharpening wheel is a coarse grade.
A finer grade grinding wheel can sharpen all drill bits perfectly well, however, when sharpening drill bits made from cobalt, or on large diameter drill bits above ½” or 12mm, this grade of grinding wheel can have a shorter lifespan.
For grinding cobalt or larger drill bits using a lower grit or ‘Coarse’ grinding wheel is better as this will cut more material and last longer.
For sharpening badly damaged drill bits using a coarse grinding wheel will make the job quicker as it will remove more material faster.
As the drill is pushed into the sharpener, the grinding wheel rotates and will remove material from the tip of the drill cleaning off any chips or damage to leave a clean sharp edge on the drill bit.
Do drill sharpeners work?
Drill sharpeners do work for drill bits that are above 3/32” (2.4mm) and below ½” (12.5mm) diameter.
Good quality drill sharpeners will sharpen over 200 drills before the grinding wheel needs to be replaced.
You can often tell when a grinding wheel needs to be replaced by checking the surface of the wheel, if it looks shiny or has a mirror finish it will no longer sharpen properly.
Also, drill tips that are getting too hot and turning blue whilst sharpening is a sign the grinding wheel needs to be replaced.
I recommend that you avoid cheap drill bit sharpeners, the kind that attaches to a drill, as they tend to be less accurate and do not give a good edge to the drill bit.
Also, they do not rotate fast enough to grind harder cobalt drill bits and tend to wear out quickly.
For drills below 3/32” (2.4mm) diameter or above ½” (12.5mm) using drill sharpeners do not work very well, to sharpen these sizes it is better to use a bench grinder and cut the new drill tips by hand.
You can learn how to sharpen drill bits using a bench grinder by reading our Drill sharpening guide here.
Is it worth sharpening drills?
If you are constantly making things or have DIY projects around your home that require drilling holes then investing in a drill sharpener is a very good idea.
A good set of 5 different diameter Bosch multi-purpose drills can cost $15 (£10) like these from Amazon and once they are blunt they need to be replaced.
I find these last for about 10 holes drilled into hard masonry and then they start to blunt, and replacing them would cost $15, which can become expensive.
A good drill sharpener will cost $100 and can sharpen these drills multiple times.
Not only does owning a drill sharpener save you money quickly, not having to constantly replace blunt drill bits, but you can also save time too
Using a drill bit sharpener only takes a few minutes to sharpen even the bluntest drills whereas having to stop working, go to the local DIY store, or ordering drill bits online can take hours or days.
How much do drill bit sharpeners cost?
There are several brands of drill sharpener on the market, most DIY or hardware stores have a version, the bigger stores will often have their own brand units.
Cheaper drill bit sharpeners start at $15 and you get what you pay for, they often are flimsy and have low quality grinding wheels which wear out quickly and don’t give an accurate point to the drill bit.
The can be difficult to keep clean, as the grinding dust will build up inside and clog the grinding wheel.
Cheaper drill sharpeners don’t tend to have spares either so instead of just replacing a grinding wheel for a few bucks you end up having to buy a whole new unit.
Better quality drill sharpeners between $30 -$70 tend to work better but often are limited to only a few sizes of drill diameter or only grind at 118 or 135 degrees,
For repeatable high DIY/light workshop quality expect to pay around $100 for a reasonable drill sharpener that has the 5 features below.
Here are 5 things to look for When buying a drill bit sharpener:
- Capable of sharpening a wide range of drill bits
- It should have an adjustable grinding angle between 118 & 140 degrees
- Compact and fit easily on a bench or workspace
- Easy to cleaning
- Selectable grinding wheels that can be replaced.
One of the best drill sharpeners currently available for DIY/workshop use which has all these features is the Drill doctor XP, they are not expensive and are available on Amazon