I will be having a Simplex boiler coming into my workshop over the next few days. The regulator leaked under hydraulic test .The owner tried to remove the front flange under the regulator handle, but the studs sheared off. 1. If (!!) I manage to drill out the studs and there is enough metal left on the boiler backhead flange, could I use BA or metric screws to replace the studs. ? ie would the threads be to coarse? 2. If I have to make up new studs and nuts, do I have to use bronze or can I use stainless steel (of as suitable grade)? 3. Is there an improved design for the Simplex regulator? Thanks
Post by Shawki Shlemon on Oct 14, 2015 10:21:13 GMT
What is the material of the original studs ? I think bronze or SS will be OK , I personally prefer SS , If the threads are not damaged I would use the same size and thread type but if they are then I would go one size up and use any thread you like . ONE advice whatever you plan to do check with the boiler inspector before you do it and face no problems after .
Your advice is greatly appreciated. 1. The original studs were a bronze like material. 2. I think the flange has been bodged before, so there may be a lack of material if I cannot rescue the original thread/holes. 3. I am a Boiler Inspector (but a very new one!) I will naturally consult with my learned peers at the club if I manage remove the fitting . 4. With the backhead flange hopefully revealed for inspection ,we will be able to see if the boiler can be rescued. 5. The boiler has a test history through the club records, so we can have some confidence there are no hidden horrors. 6. I no longer have the facilities to build boilers ,so if it proves to be non rescuable I will have a problem.
Depending on the type of regulator fitted to your simplex you may be able to fill in the old stud holes, rotate the flange and drill a new set of holes? In my opinion the studs are to far apart in any case. The problem I had was that the gasket surfaces were to good and the gasket couldn't deform enough to grip properly. The original builder of the engine was a locomotive fitter and everything was metal to metal with no gasket!
Would it be possible to drill right through the flange and backhead,into the boiler, thread it and then put a stainless or bronze bolt in from the inside, loctited to seal, of course. Maybe soft solder. I imagine that the bolt must be de-threaded for enough of its length to allow it to poke out from the flange so you could get a grip with pliers etc and screw into place. The opening in the flange for the regulator should be big enoough to manipulate a bolt into place. Don't drop a bolt into the boiler - inspectors may frown at that!
I actually had a bit of time to make some more progress today. I tried WD 40, heat and an "Easy Out" on the front boiler fitting but nothing moved. In the end I had no recourse but to drill out bush that holds the regulator tube. The regulator tube is now free and I am "trying" with the minimum of force to drive off the front regulator flange. If I am successful and the whole assembly comes out, I will then need to remake the front tube of the regulator and the flange. I will also need to remake some of the sheared studs on the front plate. Whilst I was working on the boiler I noticed that the blowdown that had been previously removed, was sheared off in the boiler. Another messy job to do! This makes me very reluctant to remove any of the existing fittings as I am not sure what condition they are in internally. The actual loco itself, looks in fair condition and it would be a shame to write it off. (I no longer have access to brazing facilities so I cannot build a new boiler.)