Spade bits are great if you just want a hole in something. The length of the bit allows you to drill quite a deep hole, and the point does allow you to start the hole precisely.

And, like just about anything else you might need for the minilathe, you can get them from LMS. LMS also sells pre-ground tools if you’re more comfortable starting out that way. Note that they’re 1/4″ square rather than 5/16″, so they’ll require a thicker shim than normal to bring the tip of the tool up to the centerline of the lathe.

The tip of the tool blank should be a little below the center line of the wheel. Remember to use a wheel-dressing tool from time to time to freshen up the surface of the grinder wheels. Doing so will make the job of tool grinding go more quickly and with a better result.

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The good news is that these work a lot better than the star pattern countersink bits. Every hole I did (as long as I kept the drill relatively straight) was a circle.

These ‘twist’ bits are the drill bits I use 95% of the time. They are easy to use, come in good size sets and can be sharpened pretty easily.

For finish cuts, and turning such “soft” materials as aluminum, use more clearance and more rake angles for a better finish. I have seen may references on this reflector to Top Rake, which is confusing to me, as it does not define whether side rake, or back rake is being referred to.

But if you don’t have one or can’t use one for a particular job, then I use a square on two angles (front and right hand side) to make sure the drill looks straight before drilling.

To stop breakout, simply put a piece of scrap wood under or behind what you are drilling. It needs to be secure and have no gap between it and the piece you are working on.

But hole saws are tougher. These ones (which is the style that I have) can take some beating and even a nail or two in case you decide to remodel your kitchen.

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I don’t use them now, but when I worked in the trade I new someone who had them. They were nice to have but after a while your doing so many that your eye just gets good enough to get the middle each time.

Fortunately, HSS does not conduct the heat to your fingers very fast, but you can get burned if you go too long between cooling dips.

Another tip is it helps to keep a good full set somewhere, that way you can always drill the right size hole and don’t get stuck during a job. I have a green Sutton set at work and an Alpha set at home.

Side rake is the angle from the side cutting edge of the tool toward the opposite side of tool (across the top of the tool). It can also be ground for negative, neutral, or positive side rake. A negative rake angle is usually used for brittle materials, such as brass, which are notorious for “hogging in” as you cut.

They work as intended. If you do want a particular size hole then I would put it in a pedestal drill. This will privide the control you need for a precise hole.

Once you get a good set, you can replace bits individually. A good drill bit set is a good thing to ask for as a present (Birthday, Christmas, etc.).

The idea is that the cage around the bit is the right size for your hole, and then you simply drill. With no mucking around about trying to make sure the hole is in the middle.

Softer and stringier materials like aluminum and 1018 steel need more rake to give a knife like edge while materials that break up easily like brass and cast iron use less rake to keep the tool from digging in and grabbing.

Holesaw bits can get quite big. 121mm (4 and 49/64 inches) is the largest ive seen but there could be larger. Holesaws keep the hole section which is the difference between them and the forstner bit.

I’ve never bought an individual holesaw although it seems you can (see here). Having a set gives peace of mind. If you do want to try and buy individual you’ll need one with an individual arbor with pins like this. Don’t buy ones that work any other way!

It can also help to have someone else (who has a technical eye) to check your drill by sight to make sure it is 90° to your work.

Most of the regular cutting tools I make are undercut on the front and left edge of the tool. Since most tools are designed to cut while moving from right to left (towards the headstock) it is not necessary to provide relief on the right side of the tool. Additionally, I usually grind a similar relief, or rake, on the top surface of the tool.

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It can also add a little burnishing action as the work rubs the front face of the bit and will give smoother finishes the side and top rake reduce the amount of cutting force and heat generated and help to control the chip by giving it a different angle to curl on depending on the material being cut.

Plugs can be used to fill screw holes for finishing (instead of putty) or for making items like toys and other fine woodworking. They are extensively used when constructing with the pocket hole method.

We will round the tip to form a tool that is useful for facing and turning. Hold the tool so the tip touches the wheel and with the tool tilted downward. Rotate the tool gently against the wheel to round the tip to about a 1/32″ to 1/16″ radius.

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These bits save time and get better accuracy as only one hole needs to be drilled for each screw. They also tend to come with a little steel ring that acts as a depth stop that is put on with an allen (hex) key.

Having said that the hole usually isn’t the cleanest hole you will ever drill. And for this reason I don’t use them much in the workshop. When I used to work in construction and go ‘on site’ a lot, the spade bits got quite a workout.

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A very general rule of thumb. For heavy, roughing cuts, use less clearance and rake angles. This leaves more material in the cutting tool to withstand the pressures of heavy cutting, plus more “beef” in the tool, means more ability to carry heat away from the cutting edges.

Good to have around although sometimes can’t give the quality of hole required. I have a set of Irwin spade bits at home that hardly ever gets used, but it does come in handy sometimes.

So now you know how to grind the most basic of cutting tools. There are many other types of tools that you can grind including shaping tools, cutoff tools and boring tools. Here’s some additional info posted by Brian Pitt:

Rake angles, particularly back rake, may be built into the tool holders. The old lantern type holders I grew up on usually had a positive back rake angle built in. This was a help when grinding your tools, as you did not have to grind any back rake into the tool itself. When grinding threads tho, a neutral back rake angle is desirable, thus one had to grind a negative rake angle (point of tool pointed downward) to compensate for the positive back rake angle built into the tool holders.

The only time I had an issue with drill bits is when I bought a couple of hex shank sets on eBay (no brand) and they were rubbish out of the box.

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First we will grind the end of the tool blank. Use the coarse wheel of your bench grinder and hold the tool blank angled downwards from the tip to the rear and with the tip pointing to the left about 10-15 degrees.

When you order your lathe, be sure to order about 10 5/16″ x 2 1/2″ High Speed Steel (HSS) tool blanks. (Note: the older, non-Sieg, Homier/Speedway lathes use 3/8″ x 2 1/2″ tools) I usually get mine from Enco. They are normally about $1 each but often go on sale for about $0.80.

Side relief (or clearance) is the angle ground into the side of the tool which allows only the side cutting edge of the tool to contact the workpiece. There are two rake angles, both on the top of the tool. Back Rake is the angle from the tip of the cutting tool toward the back of the tool.

This specialty bit is designed for the pocket hole jig. The reason for the shape is to drill a clearance hole (the large bit) and a pilot hole (the small bit) at the same time.

Becasue of their unique shape, they don’t really have any other function for woodworkers. They are also expensive so you wouldn’t use it for a different purpose either.

You usually want to set the tool on center to about .003-.005 above center but almost never below (the workpiece will try to roll over the top and chatter) cutoff, threading and most carbides should be on center while HSS for general turning can be a hair above to make up for the deflection of the workpiece and machine which will bring it back on center.

The four sides of the blank are ground to a smooth, shiny finish. The ends usually are a coarse finish with a preformed angle of about 15 degrees.

Tool grinding is part science and part art, but can be an enjoyable side activity to working with the lathe. My goal here is to teach beginners enough to get them started with a few basic tools. Here are some additional resources:

To stop breakout with a holesaw, drill in one way until you can see the centre drill bit, and then finish your hole from the other side. This will also help you cleaning out your holesaw bit. You can do this technique too with the spade bit when you can see the centre tip coming through the other side of the timber.

Buy good quality here. There are cheaper versions available that use different methods, with different thicknesses of holesaw cutters. They are crap.

As a final step, you may wish to smooth the cutting tip on a fine diamond hone or oilstone. I’ve found that the tip tends to get smoothed pretty quickly after a few cuts, so I usually skip this step, but it does make a difference if you need a fine finish.

Because of this, they serve a very specific purpose. You could use them to drill holes but their sizing is measured by the size of the plug so you might find it hard to get the size hole you want.

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Now we’ll grind the left side of the tool. The procedure is essentially the same except that we hold the tool with the side at about a 10 degree angle to the grinding wheel.

Forstner bits cut larger holes (up to 76mm or 3 inches that i’ve seen). The difference between them and a holesaw bit is twofold

But for fine woodwork, they aren’t suited I find. They turn the hole into wood shavings like the Forstner bit but their construction means they don’t have the support at the drilling face.

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For example, I have made some very small boring tools from 3/16″ tool blanks which are quite handy for boring out a small hole, say .373 in diameter, to press-fit a 3/8″ shaft. Additionally, a properly ground High Speed Steel (HSS) tool often will give a better surface finish than a carbide tool.

You can, of course, buy ready-made carbide-tipped cutting tools. If good quality, these work well and last a long time. The real advantage to grinding your own tools is not cost savings, but having the ability to make a tool for whatever purpose you may run across in your work.

The main thing with drill bits is the steel that they are made from. Better quality steel will last longer. But it’s hard to compare this from different manufacturers.

Wikipedia says that the angle is 118° however I don’t change the angle, I just clean them up when sharpening. I was taught in trade school, the less you do, the better.

Plug cutters are different to all the other bits we have covered in the fact that they are concerned with the ‘plug’ not the hole that is left in the timber.

Personally, in my workshop I use metal drill bits mostly because they come in large sets (metric and imperial) and are easier to sharpen.

I tend to use Forstner bits in the high school workshop becasue holesaw bits get hot and getting kids to take out the ‘hole’ in the holesaw bit takes time. It’s easier for them to clean up their mess.

One of the two common types of CNC inserts is available in the form of plastic, brass, and other metals such as aluminum, stainless steel.

But the truth is they didn’t always work properly. They often created a ‘star’ pattern, instead of a circle. The reason being is that the star countersinks tend to chatter and jump around when spinning at speed.

I haven’t had experience with tapered so I can’t speak to their effectiveness. But the straight ones do cut straight dowel.

Grinding causes the tool blank to get quite hot so you will need to dip the end of the tool into a water bath every 15 seconds or so during the grinding operation. When you see the tip of the tool start to discolor from the heat its a good time to make a cooling dip.

Handy if you ever need plugs, but I must admit I rarely use them. If you need plugs buy the one you want individually. You can also buy a set with most sizes in it.

Now we grind the top surface to form the rake. Be careful during this operation not to grind down the cutting edge or you will end up with a tool whose tip is below the center line of the lathe.

After this operation we have a working tool with a very sharp tip. This tool is useful as-is for operations that need a sharp tip to turn down to an interior edge such as a shoulder.

They look a cone with a hole in it. And because of their shape and cutting action, there is no chattering. They create perfect circles every time.

A positive rake angle would increase this “hogging in” action, while a negative rake angle will push the tool away from the work, eliminating the tendency to “hog in”. “Hogging in” is an old term for the material grabbing the tool, pulling it into the material for a deeper cut than you are set up for. Backlash in your machine increases the possibility for such”hogging in”. Many projects are spoiled, as well as tools broken, etc, by this action.

No, rake angles and front relief are NOT the same. Front relief is the angle ground into the front of your tool which allows ONLY the front cutting edge to contact the workpiece. If the tool contacts the workpiece below the cutting edge, you will get a “rubbing” action, and the tool cannot bite into the workpiece.

One of the most important facts often overlooked by beginners is that the cutting face of the grindstone wheel quickly becomes dulled and clogged with metal particles. To maintain an aggressive cutting face it is essential to refurbish the wheel face frequently with a dressing tool.

There are two different styles of plug cutters. Straight and tapered. A tapered plug has a slight diameter changed and is designed to make it easier to put in the hole. Straight ones are straight.

I do keep some wood bits and use them mostly on the pedestal drill to help students who are drilling repetitive holes. The tip on the wood drill bit removes the need for the bradawl, effectively removing a step and making the process faster.

It may be either positive, neutral, or negative. If it slopes down from the tip of the tool toward the back of tool, it is positive rake, an upward slope would be negative rake, neutral is self explanatory.

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You can get holesaw bits with tungsten teeth. I advise you to stay away from them! If you hit a nail, they are broken. If the tungsten comes off, it is broken. The bi-metal holesaw bits are much better, and last a lot longer.

These drill and countersink in one bits have been around in a while. They are a bit fiddly and in my experience need to be re-adjusted semi-regularly (because the drill bits slide in).

I use a dressing tool with a single industrial diamond point for this purpose. I got it from Enco for around $15. I use this tool to refresh the grinder wheel after about every 10 minutes of grinding time. It makes a big difference.

A Bradawl isn’t a drill bit. In fact it looks like a screwdriver. The difference being Bradawls have a sharp point at the end instead of a flathead or philips head tip. They are used to make a point in your work, which helps centre the drill bit you are using.

As you can see in the images the hole can get clogged easily but it didn’t matter a great deal the hole was clogged or not. And they weren’t too expensive.

Great to have in the workshop for those occasions where they are better than metal bits, but not 100% necessary. I learned while writing this that you can get specialist larger than 13mm brad tips as well, but for larger than 13mm I like to use a Forstner bit.

Their best use is drilling the same hole again and again, for example screwing on the back of a cupboard or production runs. I didn’t like them personally, even expensive ones. The constant re-adjustment was a real pain.

On the negative side, you can get some smoke from them when in use due to the friction created by the hot spinning bit and the material so they do need to be semi-regularly sharpened.

Better off with a smaller range of bits than a cheaper set. Although a good set like this does make a good christmas/birthday present for someone that doesn’t know what to buy you.

You don’t need these (you can use holesaws to drill large holes), but they suit me perfectly in the workshop. They don’t need to be cleaned out after every hole and they are also the best option for boring holes.

If this happens, the tool will leave a little nub at the center of the workpiece when you make a facing cut. The usual remedy is to use a thin piece of shim stock or feeler gages under the tool to bring it back up to the center line. A much nicer solution is an adjustable-height tool holder.

It came in the mail (from eBay) and it works. I didn’t realise exactly how big it was. You can see in the picture in comparison with a AA battery.

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The essence of lathe tool grinding, as I think of it, is to undercut the tip of the tool to provide ‘relief’ so that the metal just below the cutting tip does not contact the work. This concentrates enough cutting force on the tip to cut into the metal of the workpiece.

You can get sets of wood bits in a hex shank quick change for your impact driver although I don’t recommend them. The accuracy (which is the biggest benefit of the wood drill bit profile) is gone because the slight looseness of hte quickchange chuck causes the bit to wobble when spinning.

Buy and use brand names here as they get used a lot. Here’s a good place to start for a full set and here’s what I keep in my office to replace broken bits.

I also don’t really worry about the coating. The drill bits I have (see images) coated in titanium nitride (yellow – see images). All the coatings are designed to extend tool life but I typically buy on price to be honest.

Although the shape is different, I find it useful to visualize the bow of a ship – the tip projects out beyond the lower part of the bow. The tip of the cutting tool must similarly project out beyond the surfaces below, and this is done by grinding them away.