This is an offroading mountain board, if you ever wanted to ride down a trail and over obstacles off road, here is your chance. The mountain board rolls over roots, rocks, pine cones... and works great off road as well as on with great speed, and if you enjoy this project I would really appreciate the vote.

Step 1: Materials

Four Harbor Freight wheels.
An old skateboard to use for parts. You just need need the trucks w/ the bolts and the deck.
1"x4"x44" inch board or however long you decide you want your mountain board.
2 axles 5/8 inch diameter (this fits on the wheels). The length of axles will vary depending on how long your trucks are, the axles have to be as long as the truck and the two wheels added. Each Harbor Freight wheel is two and a quarter inches, so 4.5" is needed for the wheels, and my trucks are 9 inches so I need the axles to be 13.5".
8 bolts, nuts, and washers from the old skateboard to hold the trucks on the new 1"x4"x44" inch board (instead of on the old skateboard)
Screws to secure the skateboard deck onto the 1"x4"x44" inch board. I used drywall screws.
4 brackets that connect the old skateboard axles to the new ones and twelve nuts and 8 washers to use as spacers and to secure the axles together.
4 pvc spacers to put inside the wheels.
4 cotter pins to hold wheels on.

Step 2: Redoing the Grip on Your Skateboard

peel off any remaining grip before painting
paint the board with a thick layer of black enamel paint, for the sand to mix into.
sprinkle sand over the wet paint..
push the sand down into paint so it stays and doesn't easily fall off.
let paint dry.
screw the redone deck onto the center of the 1"x4"x44" mountain board.
(see pictures)

Step 3: Attatch Skateboard to 44" Inch Board

Measure in from the sides equal distance to the holes on the skateboard and make a mark, now use the existing holes in the board and drive screws down to connect the boards together. Basically place the skate board in the middle of the 44" board and screw down.

Step 4: Mount the Trucks

Mount the trucks two inches from the end of the board on each side, but if your making a longer mountain board you might want to mount them even farther in from the sides to prevent breaking or warping of the board towards the center. Make sure the trucks are centered and put four bolts in (used to mount the trucks on your original skateboard) use ny-lock nuts so they can't unscrew, if you don't already have them.

Step 5: Add 2 Nuts to Axle for Spacers

Slide two nuts onto the truck axle for spacing.

Step 6: Put a Lock Washer on After Nut Spacers

I needed another small spacer, so I used a lock washer.

Step 7: Make and Attach a Braket Holding the Two Axles Together

Making the Bracket

drill a hole that the skateboard axle will fit in
drill a hole that the mountain board axle will fit in close enough to the other hole, because the mountain board axle clamps to the trucks, holding it in place.

Attaching the Bracket

push the bracket's small hole for the skateboard axle on and secure with another lock washer and nylock bolt

Step 8: Mountain Board Axle

2 axles 5/8" inches diameter, or sized to fit your wheels.

The length of axles will vary depending on how long your trucks are, the axles have to be as long as the truck and the two wheels added, each harbor freight wheel is two and a quarter inches, so 4.5" is needed for the wheels, and my trucks are 9 inches so I need the axles to be 13.5"....drill holes in the ends of both axles where the cotter pin will go in later.

Step 9: Put on Mountain Board Axle

slide your mountain board axle through the holes in the brackets you
made and slide the whole axle down so it's pressing against the trucks in a nice tight fit.

Step 10: Center the Mountain Board Axle

make sure the length of the axle is the same from the bracket to the end of the axle, both sides need to be the same before sliding down to tighten against trucks.

Step 11: Pvc Spacers

slide a pvc spacer about an inch long onto the mountain board axle so that it's flush up against the brackets, you'll need 4 to do all sides; ( this keeps the wheel from sliding in to far and rubbing ).