The TIP120's won't work with 5v relays, as they have too high of a saturation voltage.
The IRF510 is not logic level; it needs Vgs to be 10v to be turned on.
The TIP42 is a PNP transistor, which won't work either.

If you want something to work, you will need to use the suggested parts.

 

SgtWookie, this is one of your many reversing circuits but does not show transistors.
http://forum.allaboutcircuits.com/showthread.php?t=37345&highlight=motor+reverse
Post #2

 

Thanks Bill, but I'd found it by reply #14:

 

If the OP chooses Sgts' circuit he would be able to use the TIP120 with 12V relays.

The OP will then need two SPST 12V relays, still with higher contact rating though.

 

Thanks Bill, but I'd found it by reply #14:

That's what I get for just using the e-mail link that there has been a response. I'll try to remember to look for additional posts beyond the link target.

 

If the OP chooses Sgts' circuit he would be able to use the TIP120 with 12V relays.

The OP will then need two SPST 12V relays, still with higher contact rating though.

If they go with my schematic, they will require a pair of SPDT relays, not SPST relays.

Two DPDT relays could also be used.

If TIP120 transistors are going to be used, the relay coils must be rated for 12v instead of 5v, and powered by the 12v side.

The base resistor will need to be 2k2 Ohms to 10k Ohms.

 

http://forum.allaboutcircuits.com/attachment.php?attachmentid=28840&stc=1&d=1300968146y
If they go with my schematic, they will require a pair of SPDT relays, not SPST relays.

Yeah... of course. Little typo.

 

What if you just forget about those relays I have. What parts would I need, would it be easier to design a simpler transistor circuit that can act as an on/off switch and another to reverse the polarity?