Drilling holes straight

[john9159]

I am currently installing wall shelves using 40mm thick timber.
In recent times I have always had a problem drilling holes straight in thick wood, they always go at an angle.
Is there a jig somewhere whichenables holes to be drilled perfectly straight through timber so this is matched up on both sides?
Do not want a pedestal for the drill as no room available.
Thanks

[toptips]

Is this type of drill stand any use.

http://www.ebay.co.uk/itm/old-black-dec ... 4ab5b58c5a