Router burn

I have a router mounted in a table and use it as a shaper. However, in hardwood I get a lot of burn. What is causing this too fast feeding? This happens with new bits as well as old unsharpened bits. Thank you
Evon
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Turn down the speed and feed slower.
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You got it backwards on the feed rate. Slowing the feedrate will increase the burning - same principal as with a table saw.
Bob
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"Evon" wrote in message

Actually, a faster bit speed, and faster feed rate, may completely alleviate the problem. You may have to experiment on scrap, but IME, feeding too slow will cause more burn than feeding too fast.
Making incremental cuts will also help with this problem.
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Feed rate, probably. I've found I tend to burn more with higher spin rates, tho', on hard woods. Of course, I'm perfectly willing to accept that my bits are getting... aged. I recently moved and in setting up the new shop here, I've vowed to spend more time on tool maintenance than in the past. Unfortuantely trying to run a whole woodworking shop out of an 8' x 9' storage room in the past meant that I spent 40% of all my time in setup and teardown, not in work and tool maintenance.
Things are definitely looking up now. tho'.
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You could think of burning as being caused by the bit passing too many times per second in one spot on the wood. Slowing the turning speed of the router will help. As illogical as it may feel, increase the feed rate.
Another thing that helps dramatically is to use light passes, cutting a little at a time, while keeping the feed rate moving along.
To convince yourself this is right, get a piece of scrap and set up to cut a light pass. Now run the work past at a very, very slow rate. In fact, stop and let it sit for a second. I bet you will find the most burning where you fed the slowest. It might even be completely black where you stopped feeding.
Now go back feed the piece at a much brisker rate - probably faster than you've been using. Beware of being too slow at the start or finish of the piece.
Bob
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I am a noob but.... I found that with making raised panels I had the same problem and fixed it by:
1. Slowing the bit down(the speed was too high for the size bit) 2. Making a set of fence extenders that easily plug in the fence to decrease the amount of wood being removed without moving the fence or the bit. 3. Moving the wood faster. Just fast enough to hear the motor begin to slow down a bit.
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By "fence extenders" do you mean some kind of spacers that you insert, make cuts, then remove for subsequent passes until you get back to the bare fence? Please give more detail about your particular setup. I'm learning every day.
Bob
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Exactly right. Set your bit height and your *final* cut depth on your fence, then "pad out" the fence with spacers made of scrap wood or several layers of some thin sheet material glued together, then make several passes reducing the padding each time. Might take longer, but you'll be sure to not stress your router and ultimately shaving smaller sections off is better for the bits.
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wrote:

If you think about it, burn is caused by heat. So, you can't go too fast to cause burn. Either you are too slow or bits are dull. If you can't go faster at current depth setting then you have to take shallower cuts and probably still increase feed rate.
Edge routing is a dance between speed(avoid burn) and depth of cut(avoid tearout)
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