Make sure that you are not bottoming out the bits.
Hello,
>
> It's the first time I'm using 1/2" shank bits on my 5615 router. I
> built a router table and all 1/4" shank bits work fine and 1/2" shank
> 1" diameter planner bit works great, but when I use 2 1/2" long 1/2"
> shank 1/2" diameter bits (I've tried both, as someone suggested the
> first one could be un balanced, freud and amana) the router sounds
> real loud and I can see the motor sparking. Also I'm using these bits
> with a jointer fence jig and the cuts come out with ripples all along > it's length! >
> Someone suggested that it could be the 1/2" collet, but the planner
> bit works great on it!
>
> Any suggestions?
>