Next, on one of the pieces, I marked a centre line (right->).
You are trying to set the centre of the bit with the centre line on your board. This is hard to do, so just get as close as you can.
I’m setting the fence so that the bottom cutter is level with it.
You must make sure you turn your router speed to a low speed, CMT recommend 18,000 rpm for this bit.
Here’s the first result. Its hard to see but ‘A’ is slightly higher than ‘B’. To get it right I have to higher the bit ever so slightly (This is where the fine height adjustment comes in handy on the router).
If ‘A’ was lower then ‘B’ you would lower the bit. It works out you higher or lower the bit about half the distance of the error.
You can buy the CMT Reverse Glue Joint Bit from Axminster Power Tools!
1/2″ Shank 855501
Axminster:- Tel: 0800 371822 Website: www.axminster.co.uk