How do 'you' sharpen your router bits ?

Hi guys,

Very new to woodworking, but am planning on making a workbench soon for outside. One tool I might be using to make the joints, is a router, though the router bits have been stored with other bits, used, and possibly knocked around, and because of that, I'm planning on sharpening them.. but, never sharpened before, was wondering if I could get some suggestions ?

I watched a couple of youtube vids, and they used a 600grit diamond honing plate, but could you use a non-diamond sharpening stone ?

What do you guys use ?

Read the section on sharpening router bits in "The Complete Guide to Sharpening" by the late Leonard Lee.
It was totally bass-ackward to what I expected to be doing! BUT, that's how it's done.
For all I'm using my router, I'd buy a new bit!

There was a thread on this some time ago. It also mentions an article in the Australian Woodsmith Magazine you may be able to back order?

https://www.woodworkforums.com/f20/sh...er-bits-196608

Yes you do have to use diamond to sharpen the bits. A normal sharpening stone whether oil or water stone will not touch the carbide.
As stated in the article that Lappa linked to you must only sharpen on the flat cutting edge not the profile edge. If they have been chipped at all on the cutting edge there is nothing you can do to fix that.
Are the router bits you have good quality ones or just a generic set that was picked up cheaply? If they are just the cheaper ones it probably isn't worth your effort and you would be better off buying new ones of reasonable quality as you need them, but that also depends on your funds available. You may be able to struggle through your first job the way they are to get an idea of what you need in the future.

It's probably less a case of "sharpening" than "honing" on the diamond stone. For me its almost a ritual to give a few strokes on a saliva whetted small credit card diamond stone after each & every use irrespective of the intensity/duration of actual use. Little & often seems to work for me. That way, the bits are stored sharp & ready for use.

Maybe it's an OCD thing, but I do similar to my chisels & planes too after just about each & every use.

For about $10 you can buy a thin 150mm diameter circular diamond plated grinding wheel as used by lapidarists and mount it in a conventional bench grinder.

I have mine mounted against the side of a CBN wheel.

Attachment 429207

Because they are relatively thin they need some sort of a backing disc otherwise they will flex.
Mine only uses a 70mm diameter x 10mm thick mild steel disc which I turned up on a metal work lathe.
I used this size because I picked it up as scrap from a metal merchant but a bit bigger would be better.

I set up this to sharpen tungsten TIG tips but I found use it more for touching up carbide bits for my MW lathe, and the odd router bit.
Like others have said, with router bits only the flat leading side of the cutting edge should be ground but I have very lightly touched up some flat trailing edges.
It takes some practice ( a good use for damaged older bits) to get a straight, flat grind even on just the leading side but once you have done a few its not that hard to do.

Depends on the cutters are they Carbide or HSS if HSS there is no need for Diamond

For quick touch-ups I generally go with a Coarse DMT plate, the Fine plate takes too long and the surface finish off Coarse is more than good enough.
If it's chipped, send it out to be done properly.

Thanks guys :)

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Originally Posted by [URL="https://www.woodworkforums.com/members/67431-robson-valley"

Robson Valley[/URL]]Read the section on sharpening router bits in "The Complete Guide to Sharpening" by the late Leonard Lee

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Thanks Rob, Ill have a read of it :)

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Originally Posted by Treecycle

Are the router bits you have good quality ones or just a generic set that was picked up cheaply?

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Good question, though I'm not too sure. They were purchased some time ago, with minimal use I believe, then stored. As they are, they still cut, but could be better as iirc, they burn as they cut, which is a sign of being blunt, isn't it ?

[QUOTE=BobL;2068539]For about $10 you can buy a thin 150mm diameter circular diamond plated grinding wheel as used by lapidarists and mount it in a conventional bench grinder.

I have mine mounted against the side of a CBN wheel.

Because they are relatively thin they need some sort of a backing disc otherwise they will flex.
Mine only uses a 70mm diameter x 10mm thick mild steel disc which I turned up on a metal work lathe.
I used this size because I picked it up as scrap from a metal merchant but a bit bigger would be better.

Oh nice, where did you buy the disc, if I may ask ? Looks like it may come in handy sharpening other tools too(?), like drill bits and chisels ??

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Originally Posted by China

Depends on the cutters are they Carbide or HSS if HSS there is no need for Diamond

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not too sure, I'll have to dig some out, see if they HSS on them. I don't believe they're in a box anymore, just stored loosely in the tool box.


Just wondering, if you would use only 1 sharpening stone, what would be the better grit to use? I found these online,

https://www.ebay.com.au/itm/3x-Diamo...53.m1438.l2649

https://www.ebay.com.au/itm/AU-Thin-...53.m1438.l2649


They should work, shouldn't they ?


Thanks again :)

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For about $10 you can buy a thin 150mm diameter circular diamond plated grinding wheel as used by lapidarists ....

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Oh nice, where did you buy the disc, if I may ask ?.

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https://www.thk.hk/online-cart.php?cid=36&sid=39

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Looks like it may come in handy sharpening other tools too(?), like drill bits and chisels ??.

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Even though some people use them this way it's not considered advisable to use diamond to grind steel.
They can be used to sharpen TC tipped drill bits

As far as grits go, it's not usually possible to get a super fine edge on TC anyway so a finer grit will just take longer to sharpen the TC

The THK plates BobL suggested are great. I've three.

You can mount them on the lathe, drill press or even a home made jig for a hand drill.

They don't need to spin fast. 600 rpm is heaps.

I use the 600 and 1200. There is a 120 but it's far too agro.

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Originally Posted by woodPixel

They don't need to spin fast. 600 rpm is heaps.
I use the 600 and 1200. There is a 120 but it's far too agro.

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Dry diamond grinding has an optimum grinding linear speed of 3000 to 4500 SFPM , see http://graffdiamond.com/files/common...tes-013522.pdf
A 6" wheel needs to be turning at 1900 to 2850 RPM to reach these speeds and that's of course only on teh outer edge of the wheel.
It's still possible to grind at lower speeds and you will get increased control, but just be aware that there may be a tendency to push harder at lower speed and this may dislodge diamond from the plate.

As far as grits go, we have about 8 different grits ranging from 100 to 1200. I mainly use the diamond plate to reshape TIG Tungsten tips so I have the 170 grit on my grinder as standard and also use this for router bits but if you want more control then I agree with WP that a finer grit would be more appropriate. On a nearby bench in the shed SWMBO has a horizontal lapping wheel with a water cooling setup buried under a pile of crap. As she hardly ever uses it I think I will commander it.

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Originally Posted by Treecycle

Yes you do have to use diamond to sharpen the bits. A normal sharpening stone whether oil or water stone will not touch the carbide.

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An old oilstone does make for a quick cleanup after removing the bulk of any sap/resin build up but before sharpening with an ez-cut diamond plate. You're right, it doesn't touch the carbide but it removes any last traces of the mostly removed build up with only a pass or three, increasing the life span of the ez-lap.

FWIW, I use an old 'wedge' oilstone that was origonally profiled for sharpening the inner flutes of gouges... pretty much so old and deformed that it's not really suitable for much else nowadays. (Except, perhaps, hand honing axe heads and similar 'non-critical' cutting edges.)

I'll also add that this is typically only a step I use for bits that require it. eg. I'm using someone else's bits or I've been routing particularly resinous materials.

In general I prefer to give each & every bit a light clean & hone immediately before & after using it rather than wait for any... 'need.'

Thanks guys :), the wheel looks good, though in the pic, your bench grinder has a side mounted tool rest for the diamond disc, where'd you get that from, and is it needed ?

Here's my grinder I have, currently fitted with a wire wheel + grinding disc (grit unknown)

https://imgur.com/F3SMeC0https://imgur.com/F3SMeC0https://i.imgur.com/F3SMeC0.jpg

It doesnt seem to have an adjustable speed control, and mentions 2,950/min, which I assume is the RPM... is that more than enough, or too much for these discs ?

On the other hand, I picked up these on ebay, arrived today,

https://www.ebay.com.au/itm/3x-Diamo...53.m2749.l2649

haven't used them yet though, so hopefully they do the job too :)

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Originally Posted by Widget1983

Thanks guys :), the wheel looks good, though in the pic, your bench grinder has a side mounted tool rest for the diamond disc, where'd you get that from, and is it needed ?

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I made it and it's not needed for router or drill bits.

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It doesnt seem to have an adjustable speed control, and mentions 2,950/min, which I assume is the RPM... is that more than enough, or too much for these discs ?

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2950 rpm is fine for those discs