Rehd -

On the bead and cove thing, I have used 1/4" cutters on 3/16" material quite successfully. The advantage of using the larger diameter cutters on thinner stock is the ability to lay a strip at an angle to the previous one and get a tight joint. Think about this: take two pieces of 1/4" stock with 1/4" bead and cove edges, and hold them together the way they would be on a boat hull. If the strips are flat in the same plane, they fit tight. But as you change the angle between them, a gap develops between the edges. The extreme is when the strips are at right angles to each other - the gap is total. Of course, you don't have this situation on a boat. The point is, at any angle other than straight flat, there is a gap. With relatively soft cedar, this gap is eliminated by clamping the strips tightly together, crushing the inside edge of the cove slightly. The greater the angle, the more clamping force is required to crush out the gap. Given the number of joints and the different angles of all of them on a typical hull, it is highly likely that there will be places where a gap will exist. I believe these gaps are the sources of the bubbles under fiberglass that sometimes appear.

When using cutter diameters larger than the stock thickness, the fit is much better, especially at shallow angles between strips. The cove edge is already removed as you suggested, and the new strip can be clamped with a lot less crushing of the inside edge of the cove. One thing that must be done regardless of cutter diameter and stock thickness is to be sure that the joint is tight the entire length of the strip. Staples won't do it, at least not well, and I never use them. I found that additional clamping between forms is a minimum requirement for tight joints, and ultimately elimination of the gaps.

Phil Green of Wood Song Canoes recommends the larger cutters, like 1/4" for 3/16" stock, and 5/16" cutters for 1/4" stock. An article on Phil and his museum quality work is in the latest issue (February) of Wood magazine.

Hope I haven't confused anyone.

John