I picked up this Airbrasive model H from a machine shop the other day for a decent price. The shop still had it in production and it seems to have been taken care of pretty well. Can anyone tell me how old it might be? Also looking for a manual if any of you S.S. White users know where I can locate one. Looks like the vibrator has been replaced and everything seems to work on it. I'm thinking the hand piece should be replaced with something else but not quite sure where I want to get that. I typically use dolomite (44u crystal mark) on the shale I collect from the Maquoketa formation of N.E. Iowa. Any advice or tips on this unit would be greatly appreciated! Thanks.