Thread: Correct Router Bit

Spiral upcut will do a good job on the side furtherest from the table, but may be inclined to chip out at the side moving on the table. If possible, use an insert to close the gap and the table surface as much as possible to maximise support and minimise lower surface chipout (a 1mm clearance gap means that the bit shouldn't chip back more than 1mm).
I suggest a chamfer bit or a small round over bit with bearing to clear any chipout and break the edges at the same time, but if you can get the edges quite clean and free of chipout, then you may achieve a good broken edge by sanding.

What I do when using a template is drill a hole through a piece of 3mm MDF the same size as the router bit and then clamp the MDF to the table at each end. The bit is raised up through the MDF this creates a zero clearance table so that there is no room for chipout at the bottom as Malb has suggested. The MDF should be wide enough to support your piece you are routing, and long enough so that it can be clamped to the ends of the table.

Thanks for the replies Malb and Treecylce.
After reading Malb's reply I did wonder about a sacrificial piece between the pine and table to eliminate chipping.
The zero clearance table sounds a good solution, save time removing chipout.

Thanks