De France bonjour et bravo pour la simplicité qui fonctionne ... Bonne idée . Merci

Interesting.I sent an idler wheel for an (then) unknown brand turntable to Russell Industries in NY for rebuilding.They are nice people.A KZfaq man kindly put me onto them.

If the rubber originally was at the centerline of the support plate (on both sides of the plate edge), you also could have glued rubber on both sides, then it would be centered with the steel plate plane. Adjust or file for thickness accordingly. I think you can machine rubber better cold or 'frozen'. Dry ice comes to mind... Mr K L

very clever Mr Norton ..ill put this one into practice.

This is a great solution that can be improved on. Any links for the mat? You should do a second pass at the wheel to true it further, only this time fix the drill on the table using whatever means will hold it steady (not on the dining table!). If the table has a glass surface on it (or granite, marble what have you) it will be almost perfectly flat. Then you can use an L-shape (or a triangle ruler etc.) and fix the file on it. This way you can perform the cutting in much more controlled way. Alternatively, take to your local machinist. If they charge you more than 5-10 quid, haggle. It's a 5 min job for them.