I would suggest the followings:
1. Check if the crack is always at more or less the same area. It could possibily be due to weak weld line (knit line due to material wrapping around the core pin which forms the hole for the insert), or weak sections due to voids.
2. Check with your ultrasonic...
Most machineries in the US bought long time ago are imperial. Many companies are still using imperial system. It is now a trend to go metric in many industries such as automotive and consumer.
It depends on your use of the drawing. Of course, 3-D drawing looks more realistic and is much easier to understand and can minimize confusion.
2D drawing is good for dimensioning. 3D drawing give a good pictorial view and is also good for layman to read.
I think rickyt is probably right. 2 UP means 2 parts produced everytime when the mold is cycled.
This is a common terminology used in metal die/stamping: a "2-UP die" means 2 parts can be produced from the die in every stroke of the press. (Note these 2 parts can be identical or...
0.25lbf/sq.in sounds a low load, but point and line contact is bad for wear. Success depends on durability requirements.
It is generally true two dislike materials have lower friction and better sliding life. Teflon is excellent for low friction but is expensive very poor in abrasion...
