How small do you need? APC makes a 4.4X2 Sport prop and a 4.1X4.1 Electric.
I'd NOT use any metal prop, especially home made, under ANY modeling circumstances.
I haven't looked it up but I think metal props are not allowed under AMA rules.
You can always cut down a commercial prop it they are to long. Be sure to rebalance them before using.

Hope this helps.
Mike P