# Router bit temperature



## Luka (Feb 12, 2011)

Hi all,

I have just started working with router and after doing only short flush trimmings I found that router bit, collet/chuck and whole drive end of the router is very hot. Between the runs I had to leave it for at least 15 minutes to cool down.
Ambient temperature of 35°C is not helping in shorting the cool down period.
I was trimming the door (34mm thick, 2meters long) with only one pass to the width of max. 3 mm. I am not sure about the terminology when it comes to flush trimming. In other words, router bit was cutting a cross section of 3mm wide by 34mm deep in length od 2m.
Router bit I am using is CMT (orange tools) carbide tip 1/2'' shank flush trim bit with diameter of 3/4''. My router is 2.1 kW Makita RP2301FC and the speed I used was around 20000rpm. Wood on the door side is mixture of pine and MDF.
When I tahe the bit out of the router 1 minute after routing it is still so hot that I cant hold it in my hand. Is that normal? Is my feed rate too high? It was actually heaps slower than what I have seen on internet video clips.

I know it should heat up, but, how much should I tolerate?
Should I suspect source of heat was faulty bearings as well?
I will probably check that by running the router unloaded today.

Thanks,

Luka


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## Glen L (Nov 24, 2010)

For starters 3mm is a lot of material to take off in one single pass and the fact you're running down a work peice 2 meters with the thickness of 34mm, that's a lot of demand even on a 3 1/4hp router like yours. I would suggest much lighter passes like 1mm would be a good starting point. listen to the motor on you're router.. if it's bogging down you know it's overworking. The router should be running at full speed for the bit you're using.

Cheers
Glen


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## Luka (Feb 12, 2011)

Thanks Glen,

By the sound of motor if feels like it is not strugling at all.
I tried with 1mm and don't see any difference in temperature. Am I just worried about something that is normal? I will try to measure the temperature today.

Cheers,

Luka


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## Glen L (Nov 24, 2010)

Luka said:


> Thanks Glen,
> 
> By the sound of motor if feels like it is not strugling at all.
> I tried with 1mm and don't see any difference in temperature. Am I just worried about something that is normal? I will try to measure the temperature today.
> ...


When you're placing the bit into the router you're not seating all the way are you?


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## bobj3 (Jan 17, 2006)

Hi

It almost sounds like you are running the stock by the bit the wrong way..(climb cut) that will heat the bit more than the norm..

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## Luka (Feb 12, 2011)

I am sure i am feeding the router bit in the correct direction. I have tried with no load and it is not heating up, which tells me bearings are properly installed and healthy. I have left about 1/4'' of the shank outside the collet. I have read about it and cooling beforehand.

I guess I am really trimming too much at the time.

Thanks guys.


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## peterrum (Jan 22, 2011)

I think you need to come over here and do some routing in my carport, its -2C right now. While you are at it you might as well bring some of your nice Australian hardwoods with you.:lol: Hope you solved your problem

Cheers


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## Mike Wingate (Apr 26, 2009)

I get this on both my Trend TR11 and DW625. Hot stuff.


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## Tempest (Jan 7, 2011)

Sounds like a heavy cut. Faster feed rate will actually keep the bit cooler as it has to take fewer cuts and there is more material to carry heat away. Surface finish can be compromised, though.

Heavy cuts will put more stress on the motor, however.


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