With regards to my last post - gorrilla glue expands big time (Great stuff though). If you get a cone shaped sanding bit for the dremmel/moto tool, it will take it off easily.
Also, while glueing/screwing in the stringers...be careful not to crank down on the srew as the screw heads meets with the wood. If you do, it will split the wood. (I used screws to temporarily hold stringers in place while glueing then pulled them out.) One way to avoid splitting wood is to just use a washer. Pre-drilling is not enough. You could also use a rounded head (not a countersinking head). Hope this helps someone else from splitting stringers as we all know how fun they are to cut.
Jeff, what wood did you use for your stringers? i used doug fir for mine and had no splitting. i pre drilled and countersunk thru the ply, and used stainless so i could leave them in permanently, filling the countersinks with thickened epoxy. i hope i dont have to remove them, cuz if i do i will really be "screwed" :roll:
There shouldn't be any issues with stringers splitting if the clearance hole for the threads is correctly sized. The pilot hole will allow the threads to pull the ply against the stringer or the stringer against another piece tightly without splitting the wood as long as the clearance hole is just large enough to allow the screw to pass without a lot of the tread grabbing on to the clearance hole. That will allow the countersunk head to pull the piece down tightly but pulling it any further isn't necessary.
If there there is no clutch on the electric drill/screw gun so that torque is controlled it is a bit more difficult to control or if the drill isn't variable speed. Most often splitting is the result of trying to overtighten the screw to pull pieces together where the clearance hole for the threads is too small and you keep on tightening the screw but the pieces don't get any tighter/closer together and then the wood splits.
Check out different types of drill/countersink combinations. They are numbered to correspond with the screw size and some brands have variable depth settings for the clearance hole and pilot depth. Worth it if you are doing a lot of this type of work. It also is well worth it to set the depth adjustments for each different length of screw.
Adjustable depth drill/counter sink bits will generally allow for good performance and allow for depth adjustment between the tread clearance and pilot bit depth.
I took the simple approach of screwing the doug fir stringers to the hull sides and bottoms (for the seats) since I was removing screws anyway. Since there is a bit of an angle on the screw head to countersink, you need to drill a countersink hole, but I didn't because I was intentionally removing screws...therefore I had splitting issues if I cranked too tight.