I'm not trying to steal Randy out of a sale or anything but do yourself a favor and buy a real coin door. You might think that because you won't be using quarters on your mame cab that they are useless, but they are not. First off you can rig the coin returns (with the aid of a well placed blade ms) to coin up for you. Secondly it transforms a "home made" cabinet into something looking much more official and lastly you now have a door that gives you quick access to the inside of your cabinet as well as giving you a better place to mount admin buttons than on your control panel.
Btw I am NOT suggesting you buy one new from happs. They are over-priced! You can get one off ebay, shipping included, for under 50 bucks. You might have to paint it, but that isn't much of a chore... just take it apart, spray some black on it and you are good to go.