How to Hand Sharpen a Twist Drill

A skill that every machinist must possess is the ability to work manually with a

twist

drill

. I know you can buy tools to do this automatically, but unless you want to spend a lot of money, you'll find them to be quite cumbersome and time-consuming. use it, you are much better off just learning how to do it by

hand

. Think you can master some bass. Master some basic skills. You will do as good a job and much faster than with a purchase. Not only that, but once you master some of these skills, you can also apply them to polishing lathe bits.

Oh basically I need a couple of tools to

sharpen

the

twist

drill

, obviously you'll need a bench grinder, this is just a simple craft grinder no. big deal, you'll also need a protractor so you can check the angle of the point with a point on the drill and you'll need a six inch ruler to check the length of the cutting edges on the ruler or on the drill to start. The first thing we want to do is a drill that I destroyed on purpose because all my drills are sharp. I couldn't find a dull one to use so I screwed it up on the grinder.

Here now, I will do it. We will show you how, through a step-by-step procedure, how to return it to its original condition. The first thing we want to do is talk about point angles. Basically, there are two different undrilled point angles that you can purchase from us. Included angle of one hundred thirty-five degrees. It is intended for harder steels such as tool steel and high carbon steel, and another option is a one hundred and eighteen degree included angle which is more of a general purpose drill. Can be used on mild steel or non-ferrous metals. I like to polish all mine at 118 degrees.

It seems to be a good general angle, so the first thing we need to do, just

sharpen

ing a drill, is set the angle of one of the flutes, since I'm going to use an included angle of 118 degrees, we're only graduated on one side. so it's 59 degrees, we're going to set our protractor to 59 degrees and then that's the angle that we're going to grind the first edge at, basically we'll just say this before we continue, this is a tool rest that I don't use as a tool rest and you shouldn't just rest it either your

hand

s in this use as consider it's not a palm rest while you're grinding it will sit on top of the rest on the wheel if you hold it here like this you have a lot of control over all the axes you know you have to rely on setting your place rest to get the angle, holding it in the air gives you complete freedom to move the tool and correct different angles.

When setting this 59 degree angle, just hold it above the center, a little bit above the center of the wheel, guess the starting angle, use the entire face of the wheel and grind a good ruler on that first first lip, and you'll get something. It looks pretty good, we'll check the angle here and see where we are, we're a little bit flat so I bring one more crater on the outside of the right one, some of us are getting pretty close now, one thing I want to point out another thing I want to point out is that Not only do you have to get the toe angle right, but you also have to get some angle clearance when you cut it;

In other words, you should look at it from whatever side you want. that edge should lean back a little bit, don't do that if you just do it square to the axis of the drill, the edge will rub behind here and it won't cut, you have a rock that burns and it comes back a little bit, three to five degrees is generally pretty good. I would say just hold your girl above the center line of the wheel and you will get that angle. This is probably the biggest mistake people make when trying to drain. grills is that they don't have enough clearance behind the cutting edge, just check our 59 degrees here again, yeah, that's right, we have a pretty good clearance angle here and if we look at the cutting edge, we just land, you'll see what happens Center a little bit that's good, this first one we don't care about the length, what I want to do is establish those two basic angles, so we'll call it well, footless, brown, the other side we'll do the same. on the other side set our 50 90 and gopher and before we get too far, the image that's here yeah, it looks good before we get too far, we want to keep track of the length of this, we want it to be the same length as first. one that we land on, that's important because if we make one edge longer than the other, the drill will wobble and when it wobbles it will drill an oversized hole, which is generally not good, so we'll just take our sixteenth rule here and We're just going to measure the length of each edge, yeah, about nine and a half seconds, this is about a quarter of an inch, so we have a little bit more left.

They know they didn't close to remove that 59 degree angle again. Make sure we're okay. It still looks good, we'll check the link and make sure the length is the same as what we have so the kids will hear over a quarter of an inch on this one and about the same on this one. Okay, now we have both cutting edges the same way. is a good thing, but this drill is not ready to drill yet because if you look at it from the side you will see that if you try to drill this thing, it would rub here and this is the heel of this fruit, okay, we have to take a Secondary Clear Angle to come out of this back area and that's what we're going to do next, so bring it up again just like you were going to do here, it's got a 59 angle and then lift it up a little bit higher on the wheel, but take a secondary angle.

Okay, you can see we start there and we want to walk, keep this line parallel to the cutting edge and walk until it's almost even with the cutting edge of the opposite fruit, here get pretty close here a little bit. more, okay, here we go, I felt like this now, turn, do the same thing on the other side, you see, just rest my fingers on this rest, so you just use the entire face of the wheel trying to get there. Yes, the trick to learning to grind by hand is to be able to learn to put the tool back on the wheel in the same position and take it off to look at it, as long as you don't change your hand position you can set it.

Go back down and we'll be in the same position, okay, looking away, it's a little bit more you, okay, now we've got both of us really looking from the side, you'll see there's a nice secondary relief here, okay, exercises bigger. so sometimes it's good to even add a third angle, just take a third, just remove this rear bead here just to make sure nothing drags behind the cutting edge, there's nothing critical about that, just keep it even higher on the wheel , take a little bit more like this, okay, now we have a drill that will cut it, make a nice hole, a little drill, a nice hole to make it round and concise, but if you look at the center here you will see this heat that they call the tip of chisel, okay, that's the net of the drill, this part doesn't cut, it just pushes the metal on the non-cutting side, so what we want to do is reduce the size of this chisel tip as much as possible and the shape of do it. is to call the thin web, there are many ways to do it, sometimes we can work in this area, get some of that out to the point a little bit on both sides.

I like to use what is called alto. the traction notch gave it to do that, it's basically kind of a little bit of an angled combination at the same point here, but I do what I do to make that happen while using the side of the wheel with speed to grow. in the corner so that it touches on all sides and turn the drill a little bit so that it makes a small notch just up in the corner, here the same on the other side, turn it now, you can see that we have very little chisel point.

On the left, this makes the exercise easier, but makes it much more self-centering and that's it. I mean these exercises were done, it took me a couple of minutes here, if I wasn't doing the demo it would have been done in less than a minute. I said it's just basic skills, a little knowledge to get started, you can sharpen your own drill, that's all.