Starry Chan
Thank you for your tips.

The tie-bars are parallel. The blade is straight at 90 degree with a back to front difference of 0.002. Test cut measured with a caliper confirms the cut is straight.

I think the problem is the table is lower at the front. There are two set screws right on the top of the front trunnion possibly for making adjustment to the high of the table. I can see that if I loosen up the front trunnion screws, these two set screws can jack up the table in a very control manner.

I will try this out this morning.

Starry