I was excited to get my EZ-Lap diamond needle files from Lee Valley. Alas, the first attempt to clean up the teeth on a sawtooth Forstner style bit met with poor result. I assume this may be a bonding issue but, the diamonds rubbed off as opposed to cutting the bit as desired. I have had similar experiences with Trend diamond products and wanted to save folks from the bother (on either). My DMT products do fine but, they do not make a needle file like product except thier chainsaw round. I'll report back if I come up with anything.