# Dull router bit



## RonH (Jan 25, 2009)

Novice here....I just used my new router on it's first task. I did a 1/4 X 1/4 dado in 3/4 birch plywood. I made 2 passes to make the cuts that were a total of 53 feet long. I was using almost maximum speed having it set between 5 and 6 (6 being maximum). I used a freud 1/4 x 1 double flute straight bit. By the time I finished, I could tell that the bit was not performing as well as when I first started. I didn't burn the wood but the end of the router bit was dark as though it had heated and I had to put alot more pressure on it to move it along at the end of the cuts as compared to when I first started.

now my question...

Should the router bit be used up(dull) after this much use ?

How does the rate of feed effect the router bit performance ?

Just how much pressure should i put on the bit or in generasl what feed rate should I use i try for ?

Is it possible to use a diamong stone to touch up this type bit ?

Thanks in advance, ron


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## Ralph Barker (Dec 15, 2008)

Sounds like you might have been using a high-speed steel bit, rather than carbide. Either way, I wouldn't attempt to sharpen the bit myself. Even minuscule variations in balance can make the bit dangerous at typical router speeds. 

Feed rate and router speed both affect the bit's performance. Too fast a feed rate at too high a rotational speed will create excessive heat. Plus, plywood and MDF are tougher to cut than plain wood, due to the adhesives included, so bits won't last as long.


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## bobj3 (Jan 17, 2006)

HI Ron

All Freud bits are carb.tip, it sounds like you cooked the bit, heat kills any cutting tool and once it's been hot the edge is gone and the temper is gone as well the norm...sounds like you will need to get one more  

I will say speed = friction and that = heat..that's a very long pass for a router bit , give the bit time to cool down..you may want to use a slot cutter it will do a better job than a 1/4" strait bit, it pull the chips out of the slot, just like a saw blade... 



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RonH said:


> Novice here....I just used my new router on it's first task. I did a 1/4 X 1/4 dado in 3/4 birch plywood. I made 2 passes to make the cuts that were a total of 53 feet long. I was using almost maximum speed having it set between 5 and 6 (6 being maximum). I used a freud 1/4 x 1 double flute straight bit. By the time I finished, I could tell that the bit was not performing as well as when I first started. I didn't burn the wood but the end of the router bit was dark as though it had heated and I had to put alot more pressure on it to move it along at the end of the cuts as compared to when I first started.
> 
> now my question...
> 
> ...


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## Ghidrah (Oct 21, 2008)

A couple things affect the sharpness of a bit when dealing with plywood.
GLUE, SAND and SILICA.

If the bottom of your dado was plowing through a saturated glue line and or smack into a grain or 2 of sand. If the black is hard and slick, you might be able to clean it off. Glue gets real hard when heated up so you might have to do a bit of scraping with a utility knife before using a solvent 

Be aware a sharp edge doesn't reflect light back, get a magnifying glass and bright light if cleaning brings the normal metal color back take a boo on the edge if the edge reflects light its dull.


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## Hamlin (Dec 25, 2005)

Hi,

This is why I don't like straight bits. They don't "clean out" very well. I'm with Bob, sounds like you've cooked the bit. In addition to trying a slot cutter, try using a spiral bit.


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