The solution to these problems is to use tuning vises to keep your board under control, but at about $80 a set I just couldn't spend the cash, and why buy when you can make?
Step 1: Materials
You will also need 2 clamps of some kind to hold these vises to a table. I use my Irwin quick grip clamps, but c-clamps will also work great, and you can get em for a few bucks at a hardware store or watch Home Depot around Christmas for specials.
1 - 4x4 16" long
1 - 2x4 24" long
1 - 5/8" diameter "all-thread"(a.k.a. "threaded rod") 8"-10" long
2 - wing nuts and washers to fit on the all-thread
1 - small scrap of hardwood approximately 1/2" thick x 1" wide x 5" long
wood glue (optional)
Here is where I say that I'm not taking any responsibility for your safety at any time, especially while building this project. It is your responsibility to learn how to use your tools correctly and safely. I am not even going to tell you exactly how I cut my wood or even what tool I used to cut it. Use what you are comfortable with and have.
Some kind of wood saw( table saw, mitre saw, hand saw, whatever you got)
Various drill bits
Pliers (preferably vise grips)
Step 2: Cut the main pieces
Step 3: Cutting the 4x4
Step 4: Main assembly
Step 5: Inserting the all-thread
Step 6: Final assembly
Step 7: Tune it up
Here is a good ible on waxing and tuning
Have fun riding!