You can make your butcher block chopping board any size you like. We had our 2.4m hardwood timber pre-cut at Bunnings into 4 x 600mm lengths. Pick the best two pieces of timber for both ends of the cutting board.
Starting with an end piece, measure and mark for the three pieces of dowel on the 90mm side of your hardwood. Measure in 60mm from each end, mark the centre holes for two pieces of dowel and mark one point in the centre.
Use the 10mm drill bit to drill holes for the dowel. A handy tip to make sure you don't drill too deep is to measure half way down the dowel to get the depth. Wrap tape around the drill bit at the required depth. This way you'll know when to stop drilling. Drill three holes for the dowel in the timber.
Put some PVA glue into the dowel holes and insert the dowels. Use the hammer to gently tap the dowel in place. Apply glue to the side of your second piece of timber with dowel holes. Place it onto the dowelled piece of timber and tap the pieces together with the hammer making sure it's snug and the dowels are all the way in. Repeat the process for all the pieces of timber.
Now clamp the butcher block together with two clamps. This will keep the timber in position while the glue dries. Make sure you wipe off any extra glue and leave it to dry.
Remove the clamps and sand back all of the surfaces. Use the 40 grit sandpaper first, then switch to a finer grade sandpaper, e.g. 240 grit, to round off the corners to create a nice, smooth finish. Wipe away any dust when you're done.
Use a rag or paint brush to apply food grade stain or oil to all surfaces of the butcher block. Wait for it to dry and lightly sand it. Apply as many coats of stain or oil as is necessary.