Dual or single leadscrews?

[PsychoPig7]

Hi All!
Just a newbie playing around with the idea of building a cnc router lathe as something to 'keep me off the streets' - or more to the point - keep me pre-occupied and too busy to work on SWMBO's "to-do" list (which keeps getting longer and longer each day).
I have looked at the Solsylva 25x37 dual leadscrew machine as well as the jdro and other designs.
Can anyone tell me whether there is any significant advantage using dual leadscrews, or is it actually better to run only one x-axis lead screw?
Be warned, however, if any replies are received they are likely to release the evil dragon of 'endless follw-up questions.
So, at risk of opening Pandpora's box, has anyone any ideas on this?
My thoughts are that dual leadscrews might lead (no pun intended) to extra load bearing and consequently more drag????
Cheers
Noel :hpydans:

[rodm]

Dual screws stop racking (twisting) of the gantry. Some designs use a wide underplate joining the gantry sides to stop racking.
Dual screws can be operated by belts and a single motor or two motors direct coupled.
Design is a personal choice and there are heaps of variations such as moving gantry, bridge and moving table.

[Squirrel]

PsychoPig7

My CNC that I just finished is the Solsylva dual leadscrew machine. Still playing around with it and have had no general problems with it (other than the one's I created myself). I built the dual screw because it was only a little additional cost for a better machine (my opinion).

Squirrel.