HI All, I learnt at a very early stage, never to tighten gauge glass fittings when steam is present. The manner of learning was that as I was getting steam up on my first engine at it's Boiler test, the gauge glass started leaking, As soon as I got a Spanner out the Boiler Inspector beat a very hasty retreat to what he reckoned was a safe distance. Having never seen him move so fast before I asked him why and he told me in no uncertain terms. Usually as things warm up they usually seal themselves up anyway. Regards Clif ----- Original Message ----- From: "Ron Head" <ron.head@xxxxxxxxxxxxx> To: <modeleng@xxxxxxxxxxxxx> Sent: Saturday, August 05, 2006 9:44 PM Subject: [modeleng] Water gauge security > Hi all > > A incident occurred at my club's track today, the outcome of which could > have been very nasty. A new locomotive that had just been hydraulically > tested was raising steam for the steam test. As full pressure was > approached, the gauge glass started to weep and the owner decided to nip > up > the nuts with a spanner. Nothing wrong in that, but what happened next > was > most alarming. > > The water gauge on this particular loco follows a fairly conventional > design, with top and bottom fittings screwed into threaded bushes in the > boiler. The problem with this design, is to get both fittings pointing in > the right direction so that the glass passes through without binding. The > builder had achieved this by experimenting with copper washers of various > thicknesses, until he was happy that the fittings were tightened up in the > correct orientation. > > Now we all know that what is tight in a cold boiler, isn't necessarily > tight > in a hot boiler. When the owner tried to tighten the bottom nut, he > succeeded in freeing off the bottom fitting so that it rotated and > shattered > the glass. The resulting spray of steam and hot water travelled backwards > out of the cab for a distance of about six feet, and the owner was lucky > to > get his hand and face out of the way without being severely scalded. > > It occurs to me that no matter whether the top or bottom nut is tightened, > the torque of the spanner will always try to unscrew the fitting. Has > anyone else on this list had a similar problem and if so, what did you do > to > overcome it? > > Regards > Ron Head > City of Oxford SME > MODEL ENGINEERING DISCUSSION LIST. > > To UNSUBSCRIBE from this list, send a blank email to, > modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject > line. > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.1.394 / Virus Database: 268.10.7/410 - Release Date: 05/08/2006 > MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.