Most any fixed base router will work if you can put the Leigh bushing in it's base. I prefer using a router with a 1/2" collet so I can use bits that are stiffer and don't flex when making the cuts. I've had problems trying to use 1/4" shank bits for dovetailing. Two routers gives you the ability to set the bit depth accurately, and not have to remove the dovetail bit to change it for the straight bit. Once you get the bit depths just right it's best not to change it until the job is complete, but if you have a digital caliper or some other way of measuring and recording the bit depth, and can replace it and get it set exactly right again, there is no other reason not to use just one router. Having two routers just makes it more convenient.
When choosing your routers, look for good balance and as low a weight as possible. Your arms will thank me at the end of the day. I also made a stand that's the same height as the jig, with an over size hole in it bigger than the router bushing in use. This is a place to park your router while changing boards. The VRS helps balance the router on the jig, but you need a place off the jig for the router when changing boards, a place that is at the same height as the jig will minimize the lifting motion needed to remove and replace the router on the jig. I have tried several sizes and brands of routers for use on my Leigh D4R, and have settled on using two of my DeWalt 618 routers (I have 3) with their D handle bases attached. I found that the trigger and balance of this combination made it very easy to control the routers when dovetailing.
For joint accuracy, centering the bit in the bushing is great, but if you change the router depth adjustment, the bit can move off center in the bushing. I drew a large arrow on the top edge of each of my router bases using a black marker, and I always point this arrow toward the dovetail jig when cutting the pins or dovetails. If the bit isn't perfectly centered on the bushing, the error in the cut will always be offset in the same amount and in the same direction during the entire dovetail joint cut. The joint will go together perfectly, but may be shifted right or left by the router bushing to bit error. This will not affect your joint at all, but you may need to trim one edge of your board by a few thousandths to get it perfectly aligned with the mating board. I would much rather have this than an error in the middle of the joint, causing the joint not to go together correctly. If you use two identical routers, be sure to label them so you don't pick up the wrong one. DAMHIKT. I put tape on the top of each motor and draw a picture of the bit on it.
Central North Carolina
Last edited by CharleyL; 10-01-2019 at 10:09 AM.