Take the 2-minute tour ×
Home Improvement Stack Exchange is a question and answer site for contractors and serious DIYers. It's 100% free, no registration required.

Anybody used Dremel effectively to sharpen knives and things like chisels and scrapers? What kind of bits are good for that application?

Also, what do you call an electromotor that is clamped to a table (like a vise) and has a grinding/sharpening wheel? I was thinking of getting one of those if Dremel (with an adequate bit) won't do.

share|improve this question

3 Answers 3

up vote 2 down vote accepted

The motorized grinder you are refering to is a "bench grinder". They will come in a variety if sizes. Most homeowners use a 7 or 8 inch model. You can purchase accessories like a wire brush or a buffing pad. Most models will have shafts extending from both sides of the motor. This allows for having a fine and coarse stone installed at the same time. I prefer the bench grinder over a Dremel as the bench model has a "toolrest" built in which allows for more precise grinding. For sharpening expensive wood chisels and gouges I prefer a hand stone and a jig that sets the tool at the precise angle for sharpening.

share|improve this answer

First item in sharpening things. When you're sharpening chisels and knives, you don't remove that much metal that you require powered implements. Manual movement on broad, flat stones is sufficient.

Second item in sharpening things. Using a powered grinding implement will destroy any edged tool by heat buildup. A very light touch is needed, once you've exceeded the temper temperature, toss the tool.

A dual sided carborundum water stone will fill the bill for most people. The coarse side takes out the nicks (sign you're maltreating your edged tools) and the fine side puts the honed edge on the implement. Get some polishing compound and a piece of leather to make a strop if you want a really fine edge, it takes the burr off that forms during sharpening.

This is one of those situations where the beauty of having a tool spinning a grinding disk at 10,000 rpm will quickly cause the need for reacquiring everything you attempt to sharpen with it. Any heat buildup takes the temper out of the edge, ruining the tool. Typically, you don't have enough surface area to keep the edge straight either which destroys the straight edge needed on chisels and plane irons. They appreciate the broad, flat surface of any number of sharpening stones.

Same thing with axes, I've seen them destroyed with a common bench grinder, any time the metal turns blue, you've removed the hardness required to keep the edge, at which point, there's no point trying to sharpen it. Best to use a mill file for first sharpening and one of those Norton Carborundum handled file stones for the sharp edge. These tools work best for axes and soil implements.

Start with the manual methods, learn control and what a properly sharp edge for that tool looks like. Once you've graduated up to where you're sharpening lawn mower blades and other blades (such as brush hog blades) that get driven into media under mechanical power, then start considering using a bench grinder. You need to remove larger amounts of metal to restore the edge, you also need to learn now to take a reasonable amount of material off so you don't overheat the edge and ruin its temper.

share|improve this answer

Trying to "free hand" a Dremel to sharpen knives, blades and tools is not a very effective way and works lousy. I tried this once trying to put a better edge on a round point dirt shovel and even that was a lousy method. For the shovel I found that a large hand file worked so so much better.

share|improve this answer
    
I have a 10 inch double-cut bastard file I use for shovel sharpening. It speedily removes metal for quick sharpening and leaves a slightly serrate edge that cuts through tree roots quite nicely. If I want a smoother finish, a Silicon Carbide Norton Utility File (sharpening stone with a handle) works wonders for the finishing pass or, once you've got the initial sharpening done, touchup. –  Fiasco Labs Jan 6 '13 at 6:02

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.