I know that you said that you wanted to make your motor mount (abbreviated mmt) from plywood, but you also said that you don't have the tools, so consider this:
I have had a lot of success making motor mounts out of cardboard for low power rockets. The cardboard back of legal pads works well. If you want a stronger mmt, just make several duplicates and glue two or more together until you get the thickness and strength that you want. The beauty of this is that you can usually scrounge the materials for free, and all you need is a knife or a pair of scissors.
You can also accomplish some really fast building times with this method, because you can use cya (cyanoacrylate - super glue) adhesive. Cya bonds cardboard to paper body tubes like mad. As a matter of fact, you have to put the parts of the mmt together, then put the super glue on the joints (I use the thin/fast setting cya). If you try to put the glue on the tube and slide the adapters in place, the cya will almost always set before you can get things lined up.
Once you get the mmt assembled, then you go ahead and put it into the body tube, then once again apply the cya to the joints. You can assemble a mmt and have it in the rocket in a matter of minutes.
Aerotech even uses this method, coupled with fin locks and through-the-wall fin mounting, on their medium power birds.
Just thought I'd toss another option your way.
- Ken
