Bob,
Is this your cutting deck?

[Linked Image]

Manuals can be found here.
https://www.toro.com/en-GB/parts/partdetails/?id=40448

You should be able to determine the thread using this.
[Linked Image]

If you have a push bike, look at the LH pedal for an example of a Left hand thread.





Last edited by mark electric; 16/11/15 11:26 PM.

Happy is he who penetrates the mystery of things.