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I got a mitre saw second hand and I am not sure how long it was in service for. I don't want to just buy a 12 inch blade as they can be expensive. Ultimately, I will have to purchase one at some point. The blade in question looks like it has over-sized tips that suggest I could go at them with a file.

Are there any reasons I should not do this? Such as efficiency or more importantly safety concerns?

If I can do this, is there any technique for going around the blade?

The question How do I know it's time to replace my circular saw blade? will tell me if my blade is truly dull.

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    Whatever you do, a chisel is not the tool for the job. A sharpening stone or a file would be more suited.
    – Doresoom
    Mar 21, 2015 at 21:06
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    Oh god.... I wrote chisel..... I meant a file. I don't even know how I would use a chisel on this.
    – Matt
    Mar 21, 2015 at 21:24
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    As I commented on another question related to saw maintenance, many times people believe their saw blade is dull when in reality it is dirty. Clean it with some non-diluted simple green. Let it soak in the soap for a bit then use an old toothbrush to really get at those teeth. It helps!
    – Peter Grace
    Mar 25, 2015 at 13:14
  • I am sorry, sometimes biting the bullet and just buying a good saw blade is really the only appropriate answer. All of the solutions below other than getting a professional to do it will take so much time, and in Matthais' case, the necessary tools might cost as much as a new blade in the first place if you don't already have them. If you keep the blade oiled it will last you years and years, just buy a Diablo 80T for your 12" saw.
    – Benjamin R
    Jul 23, 2015 at 10:07
  • Professional sharpening of these blades is not-unreasonably priced -- about $35, iirc -- and most can be resharpened several times. Considering the carbide teeth -- and the fact that the) pros might be able to weld a new tooth in, something you definitely don't want to consider at home -- I think that's a good deal. Some tight honing between sharpenings might be worth considering, but given the complexity of modern tooth grinds I'm not sure I'd try it.
    – keshlam
    Aug 24, 2015 at 3:40

7 Answers 7

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A 12" miter saw blade of the ilk normally found on a miter saw or cut-off saw looks like this:

enter image description here

The teeth on the saw blade are carbide material that is very hard. You will not want to take a file to those teeth as they will very quickly kill your file.

This type of saw blade has gained huge popularity in recent years because the hardness of the carbide material helps the saw to keep an edge for a long time. Another attribute of this type of saw blade is the extremely smooth cut that can be achieved with them. This smooth cut is possible because of the precision grinding of the carbide tips at the time of manufacture.

I do not recommend hand sharpening this type of blade because of the distinct possibility that hand sharpening will result in tooth shapes that are not perfectly uniform all the way around the blade. Variation of tooth shape, length, edge angles, and width will have a direct effect on how smooth and nice of cut that can be produced by the blade.

So find a seasoned professional saw resharpener that has the necessary power grinder equipment that can result in an almost factory equivalent sharpening job on a carbide tipped saw blade. Most blades of this type can be resharpened at least once or twice provided there are no teeth that are chipped, broken or missing.

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Here is another method from the always-interesting Mathias Wandel. Jig summary Mathias's jig

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    That is an interesting jig. This answer would be much better if you included a small synopses with some pictures.
    – Matt
    Mar 25, 2015 at 12:58
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    It looks like a saw blade connected to a radio. A brief explanation would certainly help.
    – Caleb
    Aug 25, 2015 at 19:10
  • @Caleb, pretty sure the "radio" is actually a power supply unit. Here's the guy's writeup on the jig. In the writeup, Mathias said it performed satisfactorily for his crappy blades but he'll probably leave his nice blades to be professionally sharpened.
    – RagingRoosevelt
    Oct 16, 2017 at 15:44
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I will try the method from John Heisz with diamond file when my saw blade will be used.

Video link here enter image description here

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  • That looks practical for minor honing. On the other hand, comparing the time a full sharpening might take, the value of my time, and the cost for a professional job....
    – keshlam
    Jul 16, 2015 at 15:21
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I agree with Doresoom, attacking it with a chisel** will only ruin both tools. You could probably hand sharpen the blade with a collection of sharpening stones. However, if you're not proficient at sharpening something simple like a knife or chisel, I'd say your best bet* would be to check the modern local yellow pages for a knife/saw sharpener in your area and get a quote there. Then compare that to the price of a new blade.

*Learning to sharpen your own tools is easily doable, and is a very worthwhile skill to learn. I just don't think that learning on a circular saw blade would make for a very good first experience.

**As noted in the comments, the original question mentioned using a chisel to sharpen the blade. It has since been updated to file.

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    Oh god.... I wrote chisel..... I meant a file. I don't even know how I would use a chisel on this.
    – Matt
    Mar 21, 2015 at 21:25
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    We all have those 'why did I even type that' moments. It's ok.
    – BrownRedHawk
    Mar 21, 2015 at 21:34
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Steel tipped blades can be sharpened by a touch with a dremel tool on the top of the teeth.

The key is to grind down the top until the front edge is sharp again. It doesn't take much.

You can only to this so many times until the tips dip down too much and he gullets are too small to take away the sawdust. Then is the time for a new blade.

Low tooth-count saw-blades also have a backwards-facing tooth that is meant to avoid a too deep bite, you may need to grind down those as well.

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    I would be wary of hitting it with a Dremel simply because of the rate of material that can be removed with one. With practice and a jig or two, I'd think that it could be pretty effective, but I believe our OP doesn't want to go to the expense of ruining several blades while he learns his craft.
    – FreeMan
    Mar 23, 2015 at 13:30
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Honestly this isn't something I'd try to tackle myself. You're going to have a hard time making the teeth uniform unless you make some kind of specialized and complicated jig which probably won't be worth the effort unless you're a very heavy user and need to sharpen a blade every week or so. I'd say this is unlikely though since I work at a large joinery shop where we make hundreds of hardwood windows and doors and we probably only change/sharpen our crosscut, mitre saw and ripsaw blades every few months.

I know that there are sharpening services in my area which will sharpen circular saw blades for about $10 equivalent. To my eyes this cost is well worth it - they will have special equipment specifically for sharpening circular saw blades and will give the blade perfectly sharp and uniform edges.

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  • This is sound advice but I dont really see anything here that is different from the accepted answer.
    – Matt
    Apr 8, 2015 at 14:23
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Just like what everyone else is saying, do not go at it with a chisel. A chisel is not an efficient tool for the job. If you have access to a machining shop, they will do it for you at almost no cost at all. For the sake of the saw and chisel, do not do what you are suggesting unless you meant a file and mistakenly said chisel.

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    I did make that mistake and fixed it in March.....
    – Matt
    Jul 22, 2015 at 23:16

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