Yeah Frosty, the first project in gunsmithing school was filing a thread pitch gauge for a lathe. Gave two weeks for the project. Two tools: hacksaw and file. It was checked using a machinists square and holding it up to a light. If the instructor saw light between the pieces, keep working. Plus it had 4 60 degree angles to be filed in the same manner. This was for a $7 tool to buy one. I figured it it was a project to weed out people without the stick to-itiveness. The next 4 projects had the same scrutiny. possum