What to use to replace melted armature tooth riser?

Not sure if this is going to make any sense. I'm currently in the process of rewinding a motor for an agate trim saw that decided to burn out. There looks to have been some sort of riser/spacer (not sure what to call it) on top and bottom ends of the armature, to keep the winding directly off of the armature teeth, which melted when the windings burned up.
What can I use as a replacement? I was thinking of something along the lines of a small nylon or ptfe tube? Or is there something more specific I should use?