Grady Smith cleans out stay bolt tell-tale holes with a 3/16 inch twist drill bit. By regulation, tell-tales on the outer ends of rigid stay bolts must be free of obstructions, so that steam and water may exit in case of cracking or total failure to alert the operators of stay bolt problems as they occur. Even a small locomotive style boiler has several hundred stay bolts, and they all need cleaning. To find out more on the restoration of Moore Keppel Climax visit www.msrlha.org