Definately use the "light tap" with the brass rod and stainless ball. Something to note though, and that is that you need to hit it very squarely onto the seat. To do this use a rod that is a neat sliding fit into the body of the safety, as then the body will act as the guide to keep the rod central. Oh, one other thing, put a sall centre in the brass rod and drill a shallow hole 0.7071 times the diameter of the ball in the end. This will ensure that you don't bruise the ball, as the contact angle is 45°. Lapping the seat is not a recomended proceedure, as it rarely gives you an even land width all the way around the seat which is the major cause of leakage later on, and, it doesn't preharden the seat for you. ----- Original Message ----- From: "Allen Messer" <al_messer@xxxxxxxxx> To: <modeleng@xxxxxxxxxxxxx> Sent: Monday, September 27, 2004 10:57 PM Subject: [modeleng] Re: Balls - what sort do you have and how do you seat them comfortably? > Ye had me worried for 'alf a mo' there, Laddie! > > I have always used the traditional method--a SS ball a > short piece of Brass rod and a tap with a hammer, but > you may want to inspect the seat with a strong > magnifying glass to make sure there is not a little > burr or defect in the seat first. If there is, your > idea of polishing/burnishing may be the best bet. > > Al Messer > --- Peter Sheppard <peter.sheppard@xxxxxxxxxx> wrote: > > > No it's not a porn site! > > > > > > I have recently been running the Hunslet on air > > (albeit briefly as even > > with a 50 litre tank it gets through the air at a > > phenomenal rate!) > > > > One thing I have noticed is that one of the safety > > valves starts to weep at > > around 30 psi, the other has a far sharper opening > > at 90psi (the loco is 90 > > psi working pressure). > > > > I have inspected the safety valve and it is a > > "standard" bronze ball on a > > flat seat arrangement (with a spring to give the > > pressure on the seat.) It > > is not a Ross Pop type, but a simple "standard" > > safety valve. > > > > Obviously I would like it to seat better, so I have > > a number of questions > > for the esteemed membership of the list! > > > > 1. What is better - bronze or stainless balls > > 2. Should I reseat by the traditional method of > > stainless steel ball, a rod > > and a sharp tap; or > > 3. Should I lap a ball into the seat (I silver > > solder a ball to the end of > > a piece of rod and "burnish the seat) - I don't > > usually use any form of > > paste, just pressure. > > > > The seat is about 50mm down in the depths of the > > safety valve, the only > > access is from the top (you can't separate the seat > > from the chamber). > > > > Any thoughts, any personal preferences? > > > > Cheers > > > > Peter > > > > 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. > > > > > > > __________________________________ > Do you Yahoo!? > New and Improved Yahoo! Mail - Send 10MB messages! > http://promotions.yahoo.com/new_mail > 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. > > > 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.