My early 60's Ideor road bike has a steel Ambrosio stem. It has no minimum insertion line. I'm trying to get my handlebars up a little because the frame is just a tad too small. Any ideas how much of the stem I need to have inserted to be safe? Since it's steel, can I have more of the stem exposed than on an alloy stem? I'd like to keep the original stem and not change over to a Nitto Technomic. Thanks.

I'd try to keep the expander below the threaded portion of the steerer. Maybe someone can be more specific though. You might post this in the Mechanics forum.

I would keep a minimum if 1 1/2 to 2 inches inserted. If that is to low replace the stem with a new one and keep the original if you decide to sell the bike later. Roger