How To Sharpen Drills

[Rig Pig]

I genuinely hope you continue to get away with side loading your grinding wheel, but it really is dangerous. Have a look at the instructions on the wheel manufactures web pages if you don't believe me!

 

[Shedendman]

carborundum stones for general sharpening and silicon carbide green stones for sharpening tungston carbide

Cheers,now what about cooling the edge i dip mine in water now and again for HSS is that good enough?

 

[JonnyAlpha]

Back on the question is the video guide I added correct? and here's his second video on making the wooden jig.

 

[brightspark]

Cheers,now what about cooling the edge i dip mine in water now and again for HSS is that good enough?

yep fine as long as the tips dont get hot and discolour

 

[Rig Pig]

The jig looks ok but as others have said with a bit of practice it's much quicker just to do it free hand.

If you have plenty of spare time to build a sharpener have a look at the Quorn

 

[J.B. Welding]

Definately not P.C. but the best thing I have ever used to sharpen a drill bit is freehand on the side of the chopsaw disk. Super fast so little/no heat build up and big flat surface. some makes of disk work better than others. No pressure required just a light touch. Again common sense prevails when doing such things- being able to utilise what is at hand can get you out of a tight spot but of course a full appreciation of the risks and dangers will help focus ones concerntration. I blew my mates mind once when I sharpened his drill bit out on site with a 4 1/2" grinder in one hand and the drill bit in the other. Once you get a feel for the angles involved it will become second nature whatever grinder you use, remember to wear s.specs!!!

 

[brightspark]

i suggest u have a read through this article on drill sharpening by harold hall along with all his other projects . hese a well respected engineer . hand sharped drills are ok for the majority of stuff but not if u need acuracy using small drills http://homews.co.uk/page354.html

 

[J.B. Welding]

Thats a good article b.spark, I don't know where you find 'em! I remember, as a young apprentice, seeing the old boys sharpening up drills freehand and wondering "how is that possible?". A real case of practice makes nearly perfect. I appreciate for a perfect centre and true to size hole a jig would be the way forward, micrometer style countersink tools are also a dream to use for chatter free, perfect depth countersinking.

 

[baconbarm]

Ive probably sharpened a billion drills over the years, I used to make road tankers for a living and would need to drill thousands of holes in each tanker from 4mm to upwards of 20mm in stainless steel, using a variety of power tools.

For a beginner-

each edge has a slope, make sure the cutting edge is the high end (seems obvious, but ive seen it done the wrong way many a time)

Once sharpened, spin the drill between your thumb and fingers and look to see if both edges are identical in size/ pitch.

If you want to have a practice, I would say an 8mm drill is about the easiest to play around with- their a big enough size to easily see whats happening as you sharpen.

 

[Wedg1e]

I blew my mates mind once when I sharpened his drill bit out on site with a 4 1/2" grinder in one hand and the drill bit in the other. Once you get a feel for the angles involved it will become second nature whatever grinder you use, remember to wear s.specs!!!

I've done this when time was tight; even a badly-shaped drill with a sharp edge at an incorrect angle will drill holes better than a blunt or snapped one!

 

[gordon stephenson]

While I agree with Rigpig about not using the side of the wheel for normal grinding, I use the side of the wheel for drill dressing, the very light pressures involved in my opinion do not constitute a danger, (And I have also seen firsthand the catastrophic results of an exploding 18" stone when not used correctly).

 

[AndyStobbs]

I'm having a bit of difficulty seeing how the angle affects the hole size. The entire fluted section of the drill is the correct size. Surely if it fits in the hole then the hole is the right size?
I can see how it might end up oversized but not too small.

 

[J.B. Welding]

When using a twist drill bit over and over, drilling a consistant thickness of steel, it is important to remember to drill through the cut hole more than you might think necessary. This will stop the bit wearing on the sides just at the end creating a taper. If you are drilling through thick stock with a taper worn drill you may note that the bit starts to bind on the sides once you are into the hole say a inch or so. The only way to repair this is to cut the end off the drill bit and resharpen it. Generally a hand sharpened bit will produce an oversized hole due to running a bit off centre, not to be worried about unless you are working at a tiny tolerance spec.

 

[Flapdisk]

i suggest u have a read through this article on drill sharpening by harold hall along with all his other projects . hese a well respected engineer . hand sharped drills are ok for the majority of stuff but not if u need acuracy using small drills http://homews.co.uk/page354.html

Interesting to see that he sets the jig up to sharpen on the side of the wheel

 

[gordon stephenson]

Also what a lot of people don't know (and most of the time dosen't matter) is that good twist drills are made with a very slight back taper, I was taught when serving my time that a 1" dia drill will have a back taper of 1/2 to 3/4 of a thou per inch of length .ie: It will be slightly smaller diameter at the shank than at the original cutting edge to allow for clearance when drilling deeper holes etc.

 

[printcom]

My missus brought me one of those Drill Doctors for xmas, I am not sure that I would have spent the money on it but to be honest it does a bloody good job. I wouldn't want to be without it now especially for the small bits.

 

[JonnyAlpha]

Whilst looking for a cheapish VFM Bench Grinder I noticed that some, like this one, have what looks like a groove in one of the rest for drill sharpening, anyone used one, are they any good. Clearly not as good as a bespoke drill sharpening die :-)

 

[Pete.]

Not all grinders wheels are risky to grind on the side. I have a dished wheel on my grinder that is designed for it.

 

[daleyd]

When using a twist drill bit over and over, drilling a consistant thickness of steel, it is important to remember to drill through the cut hole more than you might think necessary. This will stop the bit wearing on the sides just at the end creating a taper. If you are drilling through thick stock with a taper worn drill you may note that the bit starts to bind on the sides once you are into the hole say a inch or so. The only way to repair this is to cut the end off the drill bit and resharpen it. Generally a hand sharpened bit will produce an oversized hole due to running a bit off centre, not to be worried about unless you are working at a tiny tolerance spec.

If you were working to that tight a spec I would have thought you should be using a reamer?

 

[Burdekin]

One of my first jobs as an apprentice in the apprentice workshop was to re-sharpen all the drill bits. I can't remember how long it took me, probably a week or two but after that I certainly knew how. It is actually really easy to do especially if someone shows you the correct way.