Safely using large router bits?

[Daygloworange]

Roundovers are not that bad. Large flat "panel raising" bits are more dangerous.

Yes, you can use 1 1/2" rad. roundover cutters, but not in a hand held router, and not at high RPM.

The large mass of the bit is hard on bearings and motors. The mass offset so far from the center of the bit makes them more prone to vibration due to any slop in the bearings.

We use the big Porter Cable 3+ horsepower router mounted inverted in a router table, with the variable speed control, and run bits over 3/4 rad. at 10000 to 15000 rpm. We also use 1/2" shanks whenever we can, they are better balanced, give a better cut, and are safer if the cutter accidently gets hit and the shaft is less likely to get bent.

Although the RPM is lower, the "rim speed" of the outside diameter is covering more distance than a smaller diameter cutter, so observe your feed rate.

Also, when using slower RPM's, the bit can more easily "grab" a big bite, so exercise caution when feeding.

A little side note...the variable speed controls on the big routers always give out over time, and become useless...

Be safe!

Cheers

[Phil Olson]

The chamfer bit is a good idea. I've also run stuff through the table saw with the blade at 45 degrees to remove the bulk of the material before putting mileage on the router bits.

[Moondog55]

This is a bit OT, but when insetting drivers into a baffle and having a curved profile leading out from the driver face onto the baffles ( sort of wave guide configuration ) is there a better profile than a half circle??
I have used router bits in 3/4 inch with no trouble and using the advice posted here I can see no difficuty in going to 1 1/4; although I should check with manufacturer first on biggest bit they reccomend (Triton only go to 1inch themselves so that may be the limit )

[R-Carpenter]

Your Makita should work fine. It is sold in US as a 3.1/4 hp router. I personally find Makita tools a little fragile but it'll probably fly through a pair of speakers just fine.

1)Make sure the bit is nice and tight in the collect.

2)Make sure that the hight of the router is not only held by the lever but also by a screw (some have double locking nuts on the threaded shaft, some side screw)

3)Make sure you start the router at the SLOW speed and away from the piece.

4)If you using router table, stand on the side so if the kickback happens, you don't get a piece of speaker stuck between your ribs. We all love speakers but there's no reason you need it permanently embedded in your body. Come to think about it, you could use an axillary guide piece on the side so if kick back does happen it will fly backward (were you are not suppose to be).

5)Carbide does chip and fly in your face. It happens very rarely and you are a lot more likely to get a piece of wood in the eye. Either way, have a face shield handy, not just goggles.

Good luck and god bless.

[ShinOBIWAN]

Yet more good advice given so thanks once again chaps.

I think I'm pretty much set. Only thing left now is to jump in and give it a go, very carefully of course.

[critofur]

Originally posted by Moondog55
This is a bit OT, but when insetting drivers into a baffle and having a curved profile leading out from the driver face onto the baffles ( sort of wave guide configuration ) is there a better profile than a half circle??
I have used router bits in 3/4 inch with no trouble and using the advice posted here I can see no difficuty in going to 1 1/4; although I should check with manufacturer first on biggest bit they reccomend (Triton only go to 1inch themselves so that may be the limit )

Moondog, I would like to discuss that topic over here in my thread:

W5-704 + ND20 can work together well?

I know that's not the original topic of my thread, but, it's my thread so maybe it's ok? It's a very interesting idea, using roundovers to get time-alignment + possibly some benefit allowing lower crossover/less distortion on drivers 2" and smaller...