Burning wood with the router how to stop...

I am cutting some grooves in my cutting boards and it is sure hard, I mean really hard to keep from burning the wood a little.
The boards are purpleheart and maple.
I have slowed the router down as slow as I can (Bosch 1617) the bit is new and very sharp.
When I slow down to make a corner that is where I have the problem, if I keep moving at a good cutting rate I have no problems.
I am taking very small cuts at a time it try and keep this from happening.
The maple is the worst, I blink my eye and it will burn.

So what am I doing wrong or how can I keep this from happening.

http://i.pbase.com/o6/87/15787/1/834...G.P8061593.jpg

I'm going to go with feed speed seemings how the bit is sharp. I also have trouble with maple burning on intricate cuts. If there is something in your approach that is causing you to slow down too much at the corners, I would try a pattern to guide you. this should allow you to more confidently (and more quickly) turn the corners.

This may require a different bit (with a bearing) or a collar for your current bit. I prefer a pattern that encloses the area. That is I would rather route around the inside of a frame than the outside of a square pattern panel. Did that make sense?

Quote:

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Originally Posted by glenn bradley

I'm going to go with feed speed seemings how the bit is sharp. I also have trouble with maple burning on intricate cuts. If there is something in your approach that is causing you to slow down too much at the corners, I would try a pattern to guide you. this should allow you to more confidently (and more quickly) turn the corners.

This may require a different bit (with a bearing) or a collar for your current bit. I prefer a pattern that encloses the area. That is I would rather route around the inside of a frame than the outside of a square pattern panel. Did that make sense?

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That was what I was afried of, I am using and guide busing and cutting on the outside of a template. I guess I will have to go to making inside ones so I don't have to slow down so much to make the corner.

Thanks Glenn

You say it's a for a cutting board. Hmmmm.

I would try cutting a sample corner from the same maple, but put some penetrating oil finish on it first. I'm guessing that you will be able to do the corners now without burning.

When I scroll maple it will burn, unless I put Scotch Tape on the surface. That little bit of lubrication goes a long way towards stopping the burning.
This is why I think the oil will work.

When I want a nice finish with a router bit with a bearing, I sometimes put a layer masking tape on the bit, and then remove the tape for the final cut that is then very thin.

Hi Bill! I know how difficult this is, and have my own simple solution. Don't rout the final cut until you have just the tiniest of wood left to trim. Let it burn if that's what it wants to do. When you do the "finish" cut, make it a steady, rather rapid pass. This works for me. Gotta keep that bit moving!

Also, on the end grain I sometimes climb cut the final pass.

Sounds like you have some Christmas projects in the works already, eh?

Bert

Did some more practice tonight, things worked out a lot better.

First I put a 1 1/2 inch radius on the corners of my template and that helped a bunch. I didn't have to slow down some much when I come to the corners.

Second I put some strips of wood the same thickness as the template on the edges to help support the router so I would not have to worry about it tilting.

Made the last 2 cuts very very shallow.

I made the groove with NO burning, it looks real good, now if I can just do it on the good boards.

Thanks guys.

Bill,
You say the bit is sharp. With all that burning, it may not be sharp. Even when I use brand new out of the box, if I get burn marks, it doesnt take long for the router bit to lose its sharpness. I would suggest get bit cleaner and scrub off any and all burnt pitch. Then when you are ready to cut, the very moment you detect burning, easy the bit away and give it few seconds to rev and try again. Not only do you not want to show burn marks, you dont want to have them on the cutter.

As well as the other suggestions, I usually use an upcut spiral bit that is a little narrower than the planned bottom width, plan the depth so the core box or round bottom bit you are using for the final shape will trim the last remaining sides and bottom. Use a decent feed rate.

It also helps to hone the round/core box cutter before this final pass. I use the DMT honing sticks.

Take care, Mike

Would agree with Mr. Lucas, cutters with very little wear will burn stock in tight corners.
What to do? Use 2 routers and 2 identical cutters, collars, bearings etc.
Let router no.1 do 95% of the cut and let router no.2 take the last 5%.

So the deal is, you need a cutter with very little wear taking very light cuts to keep stock from burnng.
Routers and cutters have a lot of limitations, sometimes not so obvious. Routers/cutters burn wood, that's what they do; you just have to figure out what the work-around is to minimize it.
You're not doing anything wrong!
Routers