Joe, I have a couple of different ones and haven't had any problem with
them. I don't think they're dangerous but there are couple of things to
They will amplify any problems your router might have with its
bearings. If there is runout in the bearings, you'll see it more with
Due to the added distance between the cutter and the lower bearing,
side loads on the bit will have added leverage which will accelerate
There are a few longer shank router bits available. Magnate makes some
of those. Problem is, a long shank isn't any better than these
extenders in regards to the above.
The benefit of the extenders is that it might prevent someone from
short-chucking their router bit. Now, that is dangerous!