Have you ever wondered why it is, the 9x20 cross slide table has T-slots? Or 
why certain other things are made the way they are? Well, this link will show 
you where the chinese found the blueprints for the 9x20. Looks familiar? 

http://www.lathes.co.uk/emco/page2.html

he Austrian built EMCO Compact8 was a precision hobby lathe, priced 
approximately 2.5 times the current Chinese 9x20. Back in the 1980's, the C8
retailed somewhere between the Myford ML10 and the ML7. Materials used and finish were vastly superior to the later Taiwanese 818 and Chinese 920 copies. 
It is hard to quantify such differences, but it is about like comparing a 
Russian built Lada with a Mercedes G-Wagon. Neither is perfect, but there is an 
order of magnitude difference in quality. Just one example of many: the Lada 
makers were known to use brass for bushings, when in communist Russia bronze 
was temporarily unavailable. The 920 makers use brass for bushings all the 
time, instead of sinterbronze.... the list could go on and on.  

Now, what about these T-slots in the cross slide? The EMCO Compact 8 was a 3in1 
machine. Lathe, drill, mill. Most EMCO lathes of 11" swing and below were 
actually designed as modular 3in1's. Cutomers were able to start with just the 
lathe, then later add a milling attachement, and many many other accessories to 
turn their lathe into a complete machining center. The T-slots were designed to 
mount a vise, a swivel base, a chuck holder. The accessory list was large and 
included items such as collet chuck, tool post grinder, QC toolholder, milling 
column, vertical slide etc. The Chinese 920 makers just copied every detail of 
the C8 lathe, but do not offer the many accessories once available.

If you are intersted to get some more information on the C8, and maybe compare 
some construction details with your 9x20, have a look here:
       
http://groups.yahoo.com/group/8x18Lathe/

You may find valuable information and some ideas that equally apply to your 818 
or 920 lathe.