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Router bit burn

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Forum topic by kpfoto posted 12-12-2012 08:03 AM 1231 views 0 times favorited 20 replies Add to Favorites Watch
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kpfoto

5 posts in 756 days


12-12-2012 08:03 AM

Topic tags/keywords: routers bit burn tip

Hey All-
I just started into woodworking and I’m doing some cutting boards. I’m cutting finger slots on the edges with a cove bit. I’m having trouble with burning, especially at the end of the cut. I don’t sit in one spot so I’m confused as to why I still get the burn. The wood is walnut and hard maple. I just bought a new bit. What’s the secret?? Is it bit rpm?? Thanks for your help. This is a great site!!


20 replies so far

View live4ever's profile

live4ever

983 posts in 1763 days


#1 posted 12-12-2012 08:12 AM

I had the same problem doing the exact same thing, so I’m interested to hear what others suggest. If I remember correctly, backing off the rpm a bit helped, but not completely. Enough that I was satisfied after a fair amount of sanding.

-- Optimists are usually disappointed. Pessimists are either right or pleasantly surprised. I tend to be a disappointed pessimist.

View David Craig's profile

David Craig

2135 posts in 1861 days


#2 posted 12-12-2012 08:54 AM

how much material are you taking off at a time? You might want to go with multiple, lighter passes until you get the desired depth of cut. Also, what manufacturer created the bit? Bit quality is a large factor as well.

-- There is little that is simple when it comes to making a simple box.

View Monte Pittman's profile

Monte Pittman

15512 posts in 1091 days


#3 posted 12-12-2012 09:53 AM

High speed steel bits dull faster than carbide. I think they cause burning more often as well.

Welcome to LJ’s

-- Mother Nature created it, I just assemble it.

View kizerpea's profile

kizerpea

746 posts in 1120 days


#4 posted 12-12-2012 12:49 PM

Thats it ..don,t try to take off too much at one time.

-- IF YOUR NOT MAKING DUST...YOU ARE COLLECTING IT! SOUTH CAROLINA.

View Tennessee's profile

Tennessee

1578 posts in 1267 days


#5 posted 12-12-2012 12:52 PM

Actual bit sharpness varies, especially on high-speed bits, which personally I try to not use anymore. Some carbide cheap bits will do this if the cutting angle is not designed properly. Taking lighter cuts is usually a good answer to the problem. You might also want to take a final light cut where you can run the router more quickly through the cut, unless you have variable speed, then just slow the motor down and go through at your regular rate.

-- Paul, Tennessee, http://www.tsunamiguitars.com

View kpfoto's profile

kpfoto

5 posts in 756 days


#6 posted 12-12-2012 12:59 PM

Thanks for the replies. I use multiple passes and don’t take off too much. The problem area is when doing the finger slots, are the end “pockets” when you start and stop the cut. I don’t linger. But that 1/2 second of delay gets a burn going. I look at others work and there’s no burn at all,.....frustrating.

View 404 - Not Found's profile

404 - Not Found

2544 posts in 1722 days


#7 posted 12-12-2012 01:09 PM

Walnut and maple tend to burn anyway. If you have variable speed on your router, turn the speed down and just take a whisker off the last cut.

View cutworm's profile

cutworm

1068 posts in 1546 days


#8 posted 12-12-2012 01:20 PM

I saw a video where a guy placed blue masking tape on the wood where the bearing rolls. He made the cut then removed the tape and made another pass removing the burn marks. Haven’t tried it but it worked on the video….

-- Steve - "Never Give Up"

View SnowyRiver's profile

SnowyRiver

51450 posts in 2233 days


#9 posted 12-12-2012 02:10 PM

I agree with taking very small cuts at a time. Sometimes with light wood like maple its hard to not get a burn at some point, but I think the key is to use a sharp bit, keep steady movement, dont stop the movement, and take small cuts. I sometimes run the router over a cut 4 to 6 times to complete the cut, especially on light wood.

-- Wayne - Plymouth MN

View lumberjoe's profile

lumberjoe

2847 posts in 1001 days


#10 posted 12-12-2012 02:35 PM

Are you routing into endgrain? End grain tends to burn more than flat/edge grain. One trick I like to use in end grain is to climb cut. When you make climb cuts, you actually cut with the direction the bit is spinning instead of against the rotation as you normally would. This is dangerous and can get out of hand quickly. If I am removing more material than can be done in a single pass, I will cut normally first, then use the climb cut for my final pass.

-- www.etsy.com/shop/KandJWoodCrafts

View Tyler's profile

Tyler

52 posts in 765 days


#11 posted 12-12-2012 02:48 PM

take your time and make sure your bits are sharp.

-- You can get alot further with a kind word and a hand gun, than just a kind word alone

View ChuckC's profile

ChuckC

724 posts in 1688 days


#12 posted 12-12-2012 02:52 PM

+1 on the climb cut. Take a very small amount off on the last pass.

View Cosmicsniper's profile

Cosmicsniper

2199 posts in 1911 days


#13 posted 12-12-2012 03:54 PM

Faster feed rates are better than slower. This prevent too much friction heat. If the last swipe with the router is a fast, wispy thin cut, you’ll be fine, even on the maple.

-- jay, www.allaboutastro.com

View NiteWalker's profile

NiteWalker

2710 posts in 1329 days


#14 posted 12-12-2012 04:01 PM

What Jay said.
I use a combination of a very shallow final pass (1/32” or so) and a quicker than typical feed rate. No burning.

-- He who dies with the most tools... dies with the emptiest wallet.

View lumberjoe's profile

lumberjoe

2847 posts in 1001 days


#15 posted 12-12-2012 04:08 PM

He’s making a stopped cut though, so a quick pass isn’t quite as easy.

-- www.etsy.com/shop/KandJWoodCrafts

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