Router burn marks...

[Mike77]

I tried various methods today to avoid burn marks routing a cove on the lid of an oak box.

I tried various speeds, too slow and it ripped oat loads, too quick....more burning. Found moving the work piece quicker across the cutter and managed to keep the marks to a minimum but still had dark area at each end.

The trouble is they are really tricky to remove by sanding at the ends of the cove.

Any suggestions on how to avoid / remove the dark bits?

Thanks in advance - sorry I keep asking questions, but I've had loads of good advice already, I'm sure there's plenty to come

 

[RussianRouter]

Usually its a cheap bit that gives burn marks.

How much was the bit or did you buy a set in a nice looking box? :wink:

If its an expensive bit? then do it in two passes.

 

[misterfish]

My own recent experience also leads me to think it's the quality of the router bit.

Yesterday I had to route a 6mm wide slot in a couple of pieces of oak. I was using a new cheap Axminster bit (Perform) and although it worked fine there was still a bit od scorching. I then had to route a 19mm semicircular trough and used the newly delivered Wealden core box bit. Now I am aware that everyone says how good Wealden stuff is, but I like to see for myself. So, did the first pass and thought that the depth had slipped and I'd not actually cut any wood, but no, it was just like a knife through butter - a perfect cut with no burning and so little effort. Although a bit more expensive I'll be getting my future cutters from Wealden.

Misterfish

 

[Steve Maskery]

Both quality of cutter and technique are important. I think that a stopped cove is possibly the most difficult cut to make with a router. The trick is to stop as quickly as possible, minimizing dwell. This is easier if your router has an electronic brake.

If you can, clamp stops to your work, so that you can take several small passes to exactly the same point. That way, if you come off too early (in an attempt to minimize dwell) you can do exactly the same cut again.

Cheers
Steve

 

[Mr T]

Hi

I would agree with Steve that using stops wll help. Routing to a line means you slow down as you approach the line. Using a stop means you can maintain a steady feed speed then withdraw the bit quickly when you hit the stop.

Chris

 

[RussianRouter]

a steady feed speed then withdraw the bit quickly when you hit the stop.

Chris

I assume you mean release the plunge as it hits the stop?worse thing you can do is backfeed or withdraw from the line. :wink:

 

[TEO]

Maybe Mr T just meant pulling the router off the edge before releasing the plunge and trigger, that's what I'd do, carefully of course.

I agree with Steve, stops are the way to do this.

Is the bit sharp? A little honing might help even if it's a cheap bit.

If you've already got the profile you need on the edge then sanding or scraping is probably the best option to remove the marks.
If you can go a bit deeper, take another bite with stops in place and a sharp bit.

Good luck,

T

 

[Mr T]

Hi

Yes, I mean unplunge immediately the you meet the stop.[/quote]

 

[Newbie_Neil]

Hi,

IIRC, it was Ron Fox who recommended that when you had a problem with burning that you left everything on the router exactly as it was and repeated the cut in the opposite direction. I stress, that it is CRITICAL that you do not adjust any settings.

I have done this in the past and it has worked well.

Cheers,
Neil

 

[Richard D]

I've had lots of problems with burning. Direction of cut, multiple passes, altering the speed - it never seems to make much of a difference. Oh, and I only use Wealden bits.