Electric Grinders

Which electric grinder is right for the job? This is more of an article on finding the right grinder for around the house, garage, and small shop. There are a variety of grinders available in a wide range of prices. Are the expensive electric grinders worth the price? When your income relies on your tools, the choice is obvious. Especially when those tools become a tax deduction. But what about around the house and for those weekend projects? We will look at a number of grinders, stones, cutoff wheels, wire wheels, and other attachments for electric grinders.

There are 2 basic sizes of electric grinders, larger 7 inch and smaller 4 ½ inch grinders. Grinders come in different speeds, have different attachment sizes, and offer different features. First we will look at the different sizes and some of the features.


Electric Grinder Sizes

Let’s start with the 4 ½ inch electric grinders. They are smaller, easier to handle, and have much higher RPM’s. That means they rotate at a much higher speed. There are advantages and disadvantages to higher speed. You have to match the stone or abrasive to the speed. Check stones, etc for speed ratings. The problem with a high speed grinder is, they can tear up a wire wheel in minutes. Not to mention, sending wires all over the place.

The 4 ½ high speed electric grinder come in speeds from about 7000 to 12,000 RPM. Slower speeds are normally found on cordless, battery operated models. There is a little trick to speed. There is an item called a Router Speed Control. You can buy one for under $20 and it will basically give you a 3 speed grinder. You can slow it down for wire wheels, and speed it up for rough stones. If they are rated for high speeds.

4 ½ electric grinders get into some restricted places. There are other choices for restricted areas we will discuss later. Prices vary, but consider how often you will be using to tool.

There is an advantage to economy electric grinders. You can purchase a few and set them up for different operations. Which saves time without having to change stones, wire wheels, etc, when moving from one task to another.

Harbor Freight offers a dependable 4 ½ inch electric grinder for well under $20. They last a long time, and with a good stone, have no trouble with just about anything you would grind. I’ve run a number of them through tests, and they are all still running.

Next up is the 7 inch grinders. Of course these are for larger jobs in open areas. They weigh more and are a bit more difficult to handle. Many 7 inch grinders come with a variable speed option. That can come in handy. The old tried and true Milwaukee 7 inch electric grinders and other brands seem to last forever. They are the choice of professionals as well as companies in many industries. The heavier they are, the more heavy duty they seem to be. Top brands also cost more, but will last the weekend user a life time. Again, check out on line ads and second hand stores for some real bargains. It seems this next generation has little or no interest in the tools dad or grandpa used. So lots of those old grinders wind up in second hand stores, or at the local junkyard. Small towns now have recycling centers where tools like these are taken out of the dumpsters and resold at very low prices. I’ve see it happen.


There are a number of other, smaller grinders, but to keep this article short, I will cover the majority of those in another article about pneumatic tools and grinders.

Dremel and other companies produce very small electric grinding tools. They are more along the hobby range. I don’t have a lot of experience with those, but if you want to add a comment about your favorite tools and grinders, be my guest.

One of the things I’ve noticed about those small electric grinders is they come with a cord, and are now offered as battery powered units. Look at the battery type to make sure it is the newer Lithium batteries, and not the older type that last maybe a year or so.

Grinder Speeds

Many 7 inch electric grinders come with variable speed controls ranging from very slow speeds to up over 8000 RPMs. 4 ½ inch grinders usually begin at about 10,000 RPMs and may go well over 12,000 RPMs. Does speed matter? In a sense it does. For one thing, you have to purchase and install a stone or other implement on the tool that exceeds the speed rating on the grinder. In other words, make sure your stone, wheel, or whatever you put on the grinder is rated for the maximum speed of the unit.

That brings us up to another issue, wire wheels. Wire wheels also have speed ratings. The faster a wire wheel rotates, the faster the wire breaks, is pulled off the wheel or cup, and wears down. Try and use wire wheels at slower speeds. Variable speed 7 inch grinders are best. If you use a wire wheel on a 4 ½ inch grinder, consider buying and using a speed control unit.



Amperage is a measure of the tool’s power, The higher the amperage, the more powerful the tool is. Amperage is also an indication of quality, and how long the tool will last. Higher amps can be a better buy, but do you need the maximum about of amps available? At times you need the power. A good stone will do the job, and you really don’t need to bear down on a grinder to get the job done. Let to stone or wheel do the work for you.


There are a variety of grinding stones and wheels to do a number of tasks. Rough stones are used to grind welds. Welded material is much stronger and harder than most normal metals. Stones come in different shapes and sizes. Thin wheels known as cut off wheels are used for cutting material as well as cutting through welds. Flat wheel are used for larger areas. Make sure the speed ratings on wheels and stones exceeds the maximum speed of the grinder you are using.

The main feature of stones and other attachments you need to pay attention to is the attachment point. 5/8-11 thread is the most popular for 7 inch grinders. Some grinders may come with a metric thread. Make sure the attachments you buy match the thread on your machine.

There are also open or non threaded attachments that use a large flat nut tightened by using a spanner wrench supplied with the grinder. Some wheels are universal fit. Check out all the features. And if you shop on line, read the reviews. You can tell a professional review from a backyard review in seconds. Not all wheels are created equal. Especially wire wheels. Some wire wheels have very good steel that will last a long time. Other wire wheels use cheap steel that shreds the first time you use it. Check the wire diameter. More expensive wire wheels and cups use a thicker wire. You don’t want to buy a wire cup, get half way through the job to find out, the wires are all over the floor. The last thing you want to do is track those wires all over the carpeting in the house. You know when you are going to find them. When you are walking around barefoot. And keep on mind, those wires can and will lodge themselves on your pet’s paws.

Cutoff Wheels

Cutoff wheels have their uses. Mostly for cutting off small object, cutting through rusted bolts, and cutting off welds. Cutoff wheels come in different diameters and thicknesses. Once again check the speed ratings. Also check the write ups on cutoff wheels to make sure they are designed for the material you will be cutting through.


Variable Speed

I can’t find a 4 ½ inch variable speed electric grinder. There are pneumatic die grinders and other grinders available I will cover at a later time. 7 inch grinder are available with built in variable speed control that comes in handy. Many of those are combination grinders/polishers. I’ve had a lot of luck with the lower priced Harbor Freight model. I also tried the router speed control that seems to work as a three speed control switch. Harbor Freight offers an extended warranty, but do you really need that if you plan on using it 2-3 times a year?


I can’t cover all the safety warnings here, but read the manual that comes with the machine. Here are a few common sense ideas you should follow.

Clean and double check your work area to make sure you are not going to bump into or get tangled up in anything. Especially the cord. Know where your cord is an how you plan on moving the grinder before you begin. Also look at where the sparks will be flying.

Wear eye protection, That us a given. Check out the full face masks available. Check the ratings on all eye protection gear.

Wear leather gloves. The newer gloves made from nylon will melt when sparks fly in them. By the time you are done you will have a nylon glove full of holes.

Clean up the floor and work area. You don’t want to be dragging grinder dust through the house or have children or pets walking through it.

Always be safe, take your time, and be safety conscience.

As always, if anyone has a copyright conflict, contact me on the DCMA Notice on top and I will take that information down.

Electric Power Drills

In an effort to keep this as short as I can, I am writing only on electric power drills in this section. As I buy and put more electric power drills through a vigorous trial, I will update this list. Hopefully the search engine will pick up the updates so you can find them. Just in case, you may want to bookmark this post, or leave a comment and choose the option for an email update when other comments are added. Hopefully other people will leave a few reviews. I will add a comment to this post when I add updates. That way everyone can receive an update via email.

Economy power tools have their place. I prefer quality tools over off shoot brands any day. But there is a time and place for less expensive electric power tool models. Do the less expensive models perform and last as long as the name brand models? That all depends on how much you use the electric power drills, how much you depend on each electric power drill, and of course, how well the electric power drills are built. Here we will go over a few different types of electric power drills, and explain how well they perform, and when it is important to purchase quality, and when it may be to your advantage to choose a less expensive electric power drill.

Electric Power Drills

I hope you don’t mind if I group 120 volt drills with cordless drills. Both are electric power drills. Before we get into the actual cordless tools, let’s look at batteries first. Of course you want to get the largest battery size. It has more power and lasts longer. You don’t want your power drill dying in the middle of a job. When shopping for cordless power tools, check out prices on spare batteries. That can be a determining factor. Good batteries are not cheap, and you can expect to pay $50 or more for a good battery. Maybe a little less depending on the brand. There is a lot of competition out there, and prices seem to drop from time to time.

The best batteries I have seen on the market and tried are Lithium batteries. They take a rather quick charge, hold a charge for a long time, even in storage, and recharge to full capacity time after time. You don’t really have to completely discharge a Lithium battery before charging it. I’ve recharged half full batteries plenty of times and have not seen any ill effects. The older NiCd (nickel–cadmium) batteries tend to have a memory, do not last on the job as long, and will refuse to charge over time. There are plenty of good articles on the Internet about battery types you can look at. I just wanted to mention a few basics.

Make sure you always use the original battery charge that can with the electric power drills. Don’t do anything stupid like try to make your own charger. And recycle your batteries. Places like Best Buy, Battery stores, and city drop off sites take in spent batteries. Once again, search the Internet for a place near you.

What to Look for in Electric Power Drills

There are a number of factors to look at in electric power drills. One is power. Some have power ratings like torque. The higher the torque, the more power the drill has. Amperage is another rating on corded drills. Everyday drills may have 2 to 4 amps. More powerful drills will have 5 to maybe 10 amps. They can just about tear your wrist off if you hit something that stops the drill, or you are driving down a screw and the screw stops. Do you need a drill with a lot of power? It helps when you are driving in 100 or so deck screws or drywall screws. Higher amperage drills are designed with better cooling fans and vent systems. Hence they will run cooler and longer before over heating.

Cordless drills usually have a torque rating. Voltage and battery size is also important. You want at least a 16 volt rating on a cordless drill if you are going to use it on projects a few times a year. 20 volts are at the top of the list at this point in time. Batteries come in different sizes, specified by amp/hours. (Ah) They normally range from 1.5-5.0 Ah. The amp/hours are related to how long the battery will last, and how long it will take to charge. For normal jobs around the house, 1.5 to 2,5 Ah should be adequate. No matter which battery size you buy, a back up battery is a good idea.

Hammer Drill Power Ratings

Here is a good article on hammer drill power ratings .  Click the picture on the left. 

Ball bearing construction is important. Cheaper drills use bronze bushings that are supposed to support the chuck. Bronze bushings are okay if all you are going to do is use the drill 2 or 3 times a year, not over heat it, and only use the drill to drill holes and fasten screws. But if you use drills with bronze bushings with a wire brush, you will wear out the bushings and they end of the drill, the chuck will wobble. That is another thing to check in a new drill. Lock the chuck down and see if the chuck wiggles in your hand. If it has any wiggle in a new drill, look at something with more quality.


Key-less Chucks

I appreciate key-less chucks on drills. They are quick and you don’t need that little key. As far as I know, you really can’t over tighten a key-less chuck. But I’m sure someone has accomplished that task. Chucks generally come in 2 sizes, 3/8 and ½ inch. That describes the capacity of the chuck and the maximum diameter drill or tool bit you can insert in the drill. Some drill sets come the drills turned down or machined on the end so you can fit drills larger that 3/8 in a 3/8 chuck.

Used Drills

Now here is an idea. Look at second hand stores, rummage sales, and Craigslist for low cost, used drills. If you think the old drills were built better, you are right. The old Skil drills had ball bearing construction and lasted forever. The old Milwaukee drills are still going. At least some of them. Most used drills will have a keyed chuck, but here is the idea. If you want to use a drill for sanding? I don’t know why, but some people do. I guess it is alright to use a drill to sand a rusty part. But not so good for wood, body work, or painted surfaces. Sanding will place a lot of wear on the drill bearing. So why not use a good used $5 drill with a real bearing to support the chuck? A good used drill can also be used for wire brushing. And here is the best idea. Older keyed drills can be used to set one up with one drill size, another with a different drill size, and maybe one with a wire brush. Look for quality if you are buying new or used.


As usual, Milwaukee, Dewalt, are the top name brands that get all the attention. I see both Milwaukee and Dewalt competing for the expanding, near top quality market. I have seen a set of Milwaukee electric power drill plus driver kit with 2 batteries and a charger for about $200. Is that really a top quality Milwaukee drill set? Ecclesiastically it is. Of course it does not come with a nice plastic case. The batteries may be on the small side. But it appears you are getting the same quality that goes into every Milwaukee electric power drill. Dewalt is competing for the same market and offers drill/driver combo kits for about $175. Again, look at the battery size, and a kit with 2 batteries. Other not so name brands are also entering the arena, and some websites have some rather interesting tests and comparisons. I can’t stress this fact enough. Look at what is actually included in the kit if you decide to buy one. Some great prices include the tool only. Which means there is no battery or charger. Some off brands include accessories such as drill bits, screw driver bits, and maybe a few other things.

Another Important Consideration

Another important factor to consider is, once you purchase one cordless tool you are pretty committed to that brand. As far as I know batteries are not inter-changeable between name brands. Check the other tools they offer like cordless saws,grinders, flashlights, and other tools you may want to add to your collection. And always work safe. 

Drill Bits

I just want to mention a little about drill bits. I’ve run across this amazing product referred to as a step drill I saw people using them and was surprised how quickly they cut through sheet metal. I saw one at Harbor Freight and decided to try one. When I try a product, I take it to its limit. I tried light gauge sheet metal, 16 ga and lighter. That is about 1/16 inch think. The step drill worked fine. I went up to 1/8 and the 3/16 thick steel. I was amazed at how well it worked. I went back and purchased the set. After hundreds of holes that Harbor Freight step drill is still going strong.


My steel drill set is probably as old as many people reading this article. The drill bits are made of high speed steel. I bought a set in a metal case from Sears long ago and they are still working fine. There are a lot of companies selling drill bits and the lowest price is not always the best. Drill bits are made from a precise combination of metals. Leave one ingredient out and the drill bits are too brittle. Cheap drill bits will normally break on the first use. I had a few bit sets that were included in the old cordless drill sets I bought. The drill bits are gone and so are the cheap cordless drills. They were the old NiCd batteries.

When it comes to wood drill bits, I prefer the spade bits with the ears on the side. The ears or spurs will show you just how straight you are holding the drill, and will provide a much cleaner cut with less break out in the other side. I bought a cheap set without the side spurs that works okay and a set from Skil with the side spurs that still works great. Auger drill bits for wood also work fine. Again, you get what you pay for, and cheap bits will break on auger bits. Spade bits may not break, but will not hold an edge as long as a good set of spade bits.


Brand names like Milwaukee, Skil, Dewalt, and others mentioned here have copy rights. Of course, if anyone has any complaints or issues, they can contact me through the DCMA web page.


I am surprised I found some prices on Amazon that are better than at Harbor Freight. I’ll see how many of these I can add as I find them.