Just under the wire
 

How would you say this in Spanish. My guess is that you would incorporate the verb raspar but I'm really not sure.

This idiom is also rendered 'down to the wire'. It means 'at the last moment'.

en el último momento
estar al límite
contra reloj

tener el agua al cuello
estar con el agua al cuello

Thank you, Rusty.

Some more colloquial expressions:

- Al cuarto para las doce.
-> Los diputados aprobaron la ley al cuarto para las doce. (Meaning they passed little before the deadline.)

- (Using the verb you suggested) Raspando.
-> Pasé el examen raspando.

- Apenitas.
-> Llegué apenitas a tiempo.

- Dejar algo para el último. (To do something at the very last moment.)
-> Siempre dejas todo al último y por eso siempre tienes tanto que hacer.

can you give an example in English?

I arrived at the exam down to the wire?

I arrived for the exam just under the wire. (I got there just in time. Another second and they would have locked the door.)

We were just about down to the wire with this project. (The deadline came just after we finished.)
The voting results will go right down to the wire. (Those results won't be known until the very end.)

Lo mas comun. The most common.
 

I got there just in time. Spa. Llegué ahí justo a tiempo.