Round over bit burns?

[dvddvd]

ive been cutting some various size holes in some timber at 50mm, 40mm, 30mm, and 20mm.
I want to put a small 3mm round over on each of the cut circles.
I used my palm router with a small 3mm roundover bit but no matter how fast I try to do them it still burns the wood. Ive slowed down the router and still the same, any ideas?

 

[MARK.B.]

Is the cutter sharp

 

[dvddvd]

it's brand new, never been used. One of the Bosch sets of profile cutters

 

[ChaiLatte]

Does or would it make any difference if you go clockwise or anti-clockwise around the hole?

 

[dvddvd]

I went clockwise which I think the correct way?

 

[dvddvd]

Not sure if Elm burns or marks easier than other timbers?

 

[Sideways]

Don't be reluctant to try going the "wrong way" around the hole.
Metal machinists call this "climb cutting" and it usually gives a better finish pass than the way we normally move a router, and for a good reason.
You just have to be able to hold the tool back rather than push it around.
A roundover isn't a big cut, it is worth a try.

 

[Sachakins]

Try the same on some other types of timber to see if they burn.
If they don't, it's just the type of timber you're using, if they do, check the cutter edges, incase it's been a faulty grind, even new can be poor grind, rare, but can happen.

 

[Phil Pascoe]

Has the cutter a bearing or is it pin guided?

 

[Deckerwoodworking]

Has the cutter a bearing or is it pin guided?

Suggest you use a cutter with guide bearing . I bit more expensive unfortunately.

 

[dvddvd]

Hi yes it has a guide bearing. I tried to sand them off with my dremel with a fine sandpaper fitting and that burnt the wood too.

Will try some rougher sandpaper bits on my dremel and hopefully it will sand them off quickly instead of only generating heat the fine grit ones did. If not it will be a hand sand job

 

[Phil Pascoe]

Get yourself better cutters - the default supplier is
https://www.wealdentool.com/index.html

 

[Myfordman]

Slow the router right down. If it is not variable speed wire in a old light dimmer to make a speed reducer but this is only for small trim routers not multihorsepower giants!!

 

[recipio]

A little WD40 in the bearing will help. Trim routers can do anywhere between 25 - 35,000 rpm so a slower speed will probably help also. I have found that cherry and maple burn easily - what wood are you using. ?

 

[toolsntat]

Clarification please.

Cutter guide causing burn marks?
Maintenance required of bearing.

Cutter itself causing burn marks?
Too blunt or feed rate too slow.

Cheers, Andy

 

[Hornbeam]

Have you tried taking a smaller cut, You should be easily able to do a 3mm round in 1 pass but have you tried taking off say 2.5mm and then doing a fine finishing cut
Ian

 

[Phil Pascoe]

A 3mm rounding over cutter takes off at the thickest point about 1.25mm - any decent cutter should do many tens of metres of it without blunting or burning no matter what the timber. The cutter is crepe.