I recently bought a PC7518 router and was also surprised that it did not come with a 1/4" collet. (Turns out PC does not recommend using 1/4" shanks with the 7518 because of the high HP....so be careful.) No problem I thought as I have a PC690L-RVS in the shop (approx 8-10 yrs old). Well the collets were NOT interchangeable. The new 7518 1/2" collet would not fit on the 690, and neither the 1/4" or 1/2" from the old 690 would fit on the 7518. After reading the reviews here I took a chance that there was a thread change. I am happy to report that the new 1/4" collet fits perfect on the 7518 and I have routed several projects with my old 1/4" bits. Hope this review helps someone else out too.