Hi,
Is this via a router ?
Or by two standalone machines and one Ethernet cable (no other network) ?
If via a router do you have the Show Share option enabled in the Finder's Preferences > Side Bar ?
In System Preferences > Sharing > File Sharing is the access allowed ?
If Bonjour Shares are not showing up in the Finder's Side Bar check this out
http://support.apple.com/kb/HT3789
You may also want to enable SMB in the advanced Button of File Sharing in the Sharing in System Preferences.
You may also want to check System Preferences > Network and see if they have IP addresses in the same range (the first three should be the same)
9:13 pm Sunday; March 9, 2014
iMac 2.5Ghz i5 2011 (Mavericks 10.9)
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb (Snow Leopard 10.6.8)
Mac OS X (10.6.8),
Couple of iPhones and an iPad