Here is a picture of a few of my frame blocks. Wood blocks are the foundation tool for any frame builder. They have the right amount of ability to both hold and move the frame without readjusting the vise pressure. Aluminum blocks don't work as well when constantly changing the frame's position. The block on the left is made out of hard maple (that works perfectly for frame blocks and better than most other woods). The one 2nd to the left is made by Paragon Machine Works. The one 2nd from the right was made by Bicycle Research. The one on the right is made out of oak. It works well but doesn't stand up to hard use like a maple one. Its edges chip and its open pores fill with flux.

I buy hard maple just down the road from me from at Johnson's Workbench. They sell online too. I buy it 5/4th thick (I think that is what woodworkers call it). This means it is 5 X 1/4" or 1 1/4" thick. I cut the stock so it is 3" square. I place them together with a piece of cardboard in-between. That makes it easy to know where to center the drill bit. It is important to drill the hole 90º to the grain of the wood or it might eventually break. I have a vertical milling machine and after using a large drill but to clean out the center, I finish the hole with an end mill of the chosen size. A hole saw will work (I've tried them) but they leave a rougher surface and leave a slightly large hole. A piece of leather can make the hinge. I use belts I get at Goodwill if I can't find any leather.

If I am trying to get out a dent, I start with the wood blocks before finishing with an aluminum block.