# Sharpening Router Bits



## challagan (Feb 7, 2006)

Anybody here sharpen their own straight router bits? I have a couple little diamond hones that look like they would work good for that. Never done it before though. 

Corey


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## bobj3 (Jan 17, 2006)

Hi Corey

I don't recommend it , but that's just my 2 cents 

Router bits for the most part are made on CNC machines and they are true, that's to say if it's taged 1/2" that's what it is.
And if you chuck it up that's what you want it to cut, if you try and sharpen them, it will no longer be a true 1/2", a .010 is a bit deal when it comes to router bits.
They are cheap now days and when you burn one or dull it just replace it with a new one.
A sharp tool is a safe tool and a dull bit is just asking for it,and it can make fire wood in a heart beat.
Not to say anything about a matched set of bits.(rail & stile for just one of them)
Most bits now days are carb.tip type and would take more than a diamond hone to get the edge back on it,most are 800 grit. CNC and the good ones are more.

But again this is just my 2 cents 

Bj


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## challagan (Feb 7, 2006)

Good point Bob on the bit no longer being spot on to the dimension afterwards. Never thought about that. True straights are fairly cheap but some of these bits are very expensive and cost as much as a nice table saw blade and don't last anywhere near as long. but that is the nature of the beast. I have a drawer full of bits I don't use cause they aren't sharp anymore, but for some reason I can't bring myself to toss them 

Corey


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## bobj3 (Jan 17, 2006)

Hi Corey
I know I have a box full of them also, hahahahahahaha LOL
I have a thing for high test steel, I use them now and then in my lathe to make tools.
Most are 4140 steel and once I knock off the carb.part they make great cutters for my metal lathe or just anything I need to make.

http://www.routerforums.com/attachments/jigs-fixtures/2240-deep-spline-slot-jigs-s9a.jpg

But for the most part they are junk or to say scrap steel. 

Cost, that's the cache with routers , the router are cheap but the bits to put in them to work are not for the most part, and like they say you get what you pay for.
That's why the solid carb. bits are great, they will stay sharp and you can use them for so many router jobs. 
If you watch Bob & Rick they just about always use this type of bit. 
Drilling holes,guide work,temp. work,dados,making pattens,etc.

Bj


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## Mike (Nov 22, 2004)

Bit sharpening services are available through Woodcraft. You can also check your local saw sharpening services or tool & die shops, some offer bit sharpening. Here is the situation: a dull bit may have the face cleaned to provide a new sharp edge. This will not significantly alter the bits diameter. Remember we are talking a matter of perhaps .002". The trick is to be able to accurately remove an identical amount from both cutting surfaces, and that is not something you can do at home. While most bits can be sharpened a couple times quality bits such as Amana, CMT or Whiteside will withstand more sharpenings before losing tolerance. Any bit with a chip in the edge is done. When it comes to $10 bits you are better off replaceing than paying perhaps $8 to have them sharpened, but a $60 plunge/roundover bit from one of "the big three" is a sound investment.


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## awh (Mar 3, 2006)

Boy, Bob and I have been disagreeing on everything today! First raised panel bits and now sharpening!  But, hey, that's okay... after all we're all here to share experience and (hopefully) learn something new.

I'll tell you my dirty little secret.... I sharpen router bits all the time. I have 100's of both steel and carbide tipped bits, some that are over 30-years old, that have been sharpen numerous times with seemingly no ill affects.

There's an article I read a few years ago that gave estimates for how long you can expect bits to stay sharp, carbide outlasted steel but probably not by the factor you'd expect and carbide itself was only good for a few hundred linear feet... now, there are a lot of dependences on something like that such as wood density, feed rate, etc. but it's quite easy to route a couple of hundred linear feet a day... 4x around a 4'x'8 sheet and you're right at 100 lf.

The current brand of bits I've been buying are Bosch, primarily because they 'feel' sharper out of the package than some other brands I've tried recently and partly because they seem to stay sharper longer, another plus is that I can easily purchase them at my local Lowes.

As you probably already know, when you put a new bit in the router, you know it, it just feels like it cuts with no effort at all. However, once I feel the bit start to lag I don't hesitate for one second to give it a sharpening and return it to the just-out-of-the-box feel.

For the steel bits I do them on a fine grain sharpening stone (just like I do chisels) a few drops of oil, a few stokes on each flat side and sharp as ever.

The same for carbide bits, except that they get sharpened with a small, very-fine diamond file. Again, a few strokes on the flat surfaces and the bit is as sharp as new.

At the grits we're talking about here it's a process that's probably closer to polishing, but it does it job and produces a keen edge. I try to use the same pressure and same amount of strokes on all surfaces to keep the original balance, but again, we're removing so little material it's doubtful it'll make any difference one way or the other.

Does it change the original diameter? Well, sure... but, we're only talking a few thousandths of an inch with each sharpening, if even that, plus you'd have to remove a lot of material, a lot more than these fine grits can remove in a few strokes for it to really make a difference. And for bits like round overs, roman ogees, coves, etc. +/- 1/16" makes absolutely no difference at all.

There are some bits I don't sharpen, like spirals, and the only reason I don't is that I haven't found a file with a small enough cross section to fit the spiral profile.

Now, just because I sharpen router bits doesn't necessarily mean that you should... only you can judge for yourself if that's something you feel comfortable doing. I have been doing it for over 30-years and I have never encounter any problems, even with bits that have a critical diameter/dimension; I sharpen rail/stile, dovetails and straight cutters all the time and never experienced a problem with fit... maybe I'm just lucky or maybe my work is so sloppy I can't tell the difference! 

Just my 2-cents, you mileage may vary, not affiliated with any of the mention brands, etc., etc.


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## bobj3 (Jan 17, 2006)

Hi awh

"I have been disagreeing on everything today!" 
That's great I think and the way it should be, it's always best to get both sides 
There is no string with one end  

"I'll tell you my dirty little secret" = I do it SOMETIMES but I don't recommend it, you can turn a so so bit into junk real quick, now for blade cleaner I recommend it all the time and teflon spray that I get from sommerfeldtools.com 

Have a good one awh
Bj


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## challagan (Feb 7, 2006)

Thanks for all the info guys. I have to agree with Bob, it seems like if you sharpen a particular straight bit much, you are removing material and it will not be spot on very long. However, this shouldn't hamper uses where you are using a larger straight bit and using the fence to control size of the rabbet or a use like that. Daddo's though, I can see where that would be a problem over time. I sharpened a couple old ones tonight using a diamond file and sure feels sharper. I did finally throw away the old dinged up bits. Some of the large bits like my rail and stile cutter or expensive profile bits it seems like it would be worth sending those out for sharpening. Others like roundovers and such are fairly cheap and I have just been replacing. Anyway, thanks for the opinions and help!

Corey


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## Joe Lyddon (Sep 11, 2004)

Tony,

That sure sounds interesting... would it be possible for you to take a few pictures showing how you do it?

Thank you.


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## Joe Lyddon (Sep 11, 2004)

*Woodsmith #167 Oct-Nov 2006*
*"Router Bit Revival"*, page 8
Describes cleaning and *sharpening* procedures to bring them back for more use!!

... and it looks to be very simple!!

*Basic tools required:*
*1. *Tooth or Brass brush.
*2. *Resin, Gum, & Pitch remover.
*3. *Diamond Bench Stone
*4. *Diamond Needle files (2)
*5. *Diamond pocket stones (2)
*6. *Screwdriver, etc. for bearing removal (if any)


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