If you enjoy playing golf and are trying to improve your putting game you probably find that there is so many things to focus on and its hard to work out which one needs fixing. A great way to start is with a line marking jig. It allows you to accurately mark the centre line on your golf ball. When you line up your golf ball's centre with your target its one less thing to worry about. Instead of buying a shop bought jig which can be hard to find and expensive to buy try this quick and easy instructable.
Step 1: make a 44mm hole in some 12mm ply
take a piece of 12mm ply and cut it into a rectangle 70mm by 90mm. Use a holesaw to cut a 44mm hole through it in a central location.
Step 2: countersink a pine block using a 32mm spade bit
take a pine block 70mm by 90mm by 35mm, using a spade bit drill a counter sink into the middle of the 70mm by 90mm side (about 15mm deep should be enough).
Step 3: line the two pieces up
take a golf ball and sit it in the countersink of the pine block. squirt some superglue around the outside of the exposed surface around the golf ball. be careful not to glue the ball to the block. now take the 12mm ply and place the hole over around the golf ball and line it up so there is an even space all the way around the ball (about 0.5mm).
Step 4: stick them together
once you have lined the two pieces up apply pressure to the pieces and hold them for a minute or so while the superglue sets. once the glue has dried the jig is ready to use.
Step 5: using the jig
to use the jig you simply place the golf ball in the hole and use your thumb to hold it still. using a marker pen in the other hand mark around the ball using the edge of the jig as a kind of ruler. when finished you should have an accurate centreline around your golf ball.