Teen fiction fantasy novel, trying to remember title.

Brother Silk, Spider of the Eastto Everyone

This has been killing me for about a week, so I thought I would throw it out there. I have been trying to put together what books I enjoyed as a youth, one title has me stumped.

It involved three teens, cannot remember how the story began. At some point they were on some kind of a day trip with a picnic lunch. They were either shrunk or translocated to another world. The utensils from the picnic kit were relatively very large for them at that point (a spoon was used as an oar, and to fend off large avian attacker. I think someone used either the knife or fork in an actual fight as a large weapon.) It was significant that the utensils were made of cold iron. Any clues wha

t the book was?

I figure with this crew we might actually get somewhere with this. Thanks in advance.

Written by my hand on the 6th of Cloudburst, in the year 1237.