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Part built Allchin 1.5 inch

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derek blake24/08/2019 14:33:40
521 forum posts
135 photos


derek blake24/08/2019 14:34:35
521 forum posts
135 photos

Its just the 4 top ones, every other hole seems to have hit the plate..

Edited By derek blake on 24/08/2019 14:34:53

derek blake24/08/2019 17:07:11
521 forum posts
135 photos

I’d actually say it’s probably my fault not the previous builder, looking in the holes I’m just hitting the edge of the inner

plate, if my holes were 2mm or 3mm further round boiler I’d of hit it, so maybe my cylinder saddle is too slim.

derek blake24/08/2019 22:34:11
521 forum posts
135 photos

Do you think it will be OK? It’s a real shame as everything was going well but I guess I’m worried so little thickness for the stud the grip will mean it strips. frown

Jeff Dayman25/08/2019 00:06:11
1754 forum posts
45 photos

One dodge that could be tried, to reduce risk of stud thread pull- out in the thinner sheet, is to fit a screw in from inside, rather than a stud from outside. This depends on whether there is room between shell and firetubes to get them in, held on a bit of wire dangled through the big hole. You would need to saw a screwdriver groove across the ends of the screws to wind them out through the shell with a jewellers screwdriver. Just food for thought.

derek blake25/08/2019 08:19:22
521 forum posts
135 photos

Hi Jeff

i did wonder about stud/bolt from the inside but there no room to get inside.

its actually a pain because all the drilling and tapping went well, especially as I had to use a hand drill.

the threads haven’t stripped yet, but I just wonder how tight they will go on final bolt down of cylinder and what I do if they do give way.

as the studs are in a line I did consider loctiting in the studs and adding nuts after, but not sure if this would strengthen or weaken the situation.

i guess silver soldering them in would be ideal but no chance I can attempt that sad

derek blake25/08/2019 08:45:40
521 forum posts
135 photos

Hi Jason

what would your expertise advise, just do the bolts up carefully as the thread hasn’t stripped yet or loctiting in some studs and use nuts?



derek blake25/08/2019 08:49:46
521 forum posts
135 photos

I also considered adding two extra fixings in the space next to the boiler filling hole so I can get more clamping force without having to use the 4 bolts so much dont know

Clive Brown 125/08/2019 08:59:22
336 forum posts
8 photos

That's a real downer. You might just get away with it but at the risk of investing a lot of further effort only to find that the cylinder / boiler joint can't be well sealed. Also, a boiler inspector, assuming that he knew, might not be very keen on the departure from the published arrangement.

If you put in studs prior to mounting the cylinder, I think that you would find difficulty getting the studs through the cylinder flange unless you elongated the holes in the flange rather a lot and I don't see much real benefit.

My feeling is to consider drilling out the holes, say 6-7mm, countersink, and silver solder in 4 bronze bushes to be drilled and tapped. Not a too difficult job for someone who has boiler making expertise, and perhaps oxy-propane kit for localised heat. The bushes could be filed to blend with the boiler outer surface.

The existing threads need protection whilst soldering

Perhaps the local club has someone who can help. Best of luck.



Edited By Clive Brown 1 on 25/08/2019 09:03:18

Bill Chugg25/08/2019 09:00:43
1200 forum posts
8 photos

Jeffs suggestion sound good and must be worth a try , Made longer than needed the screwdriver slot could then be cut off.

Would studs that were then soldered in place with say Comsol not work as silver solder is a problem ?


derek blake25/08/2019 09:22:13
521 forum posts
135 photos

Thank you for your suggestions guys, unfortunately both wouldn’t work for me.

its been a year with my boiler away and I struggled to get it to where it is now so going out for soldering is a no no.

and looking inside the fixings I can’t get bolts in from the inside as the strengthening plate is in the way, when I tapped the holes it tapped into the edge of the plate, so one side has just the boiler thickness to grip and the other the boiler thickness and the edge of the strengthening plate.

this means I have no flat surface for an internal fixing.

its a blinking pain, I’m tempted to throw in the towel without sounding too dramatic, as this boiler has been the pain of my life for a year now sad

Bill Chugg25/08/2019 09:42:54
1200 forum posts
8 photos


Take 5 and step back for a minute

You do not need a flat surface inside - a step is fine as the head will bottom on the plate and once in place a spot of comsol would be fine

Se if someone local can help at your model club.

Failing that - rather than scrap it or anything drastic send me a PM and I will help you


JasonB25/08/2019 09:54:42
17259 forum posts
1858 photos
1 articles

If when you make the Studs/bolts don't tighten the die down too much so you get as tight a fit in the thread as possible you may well be OK

Even if the head of a screw inserted from inside sat partly on the edge of the thickening plate that would not hurt so worth giving Jeff's idea a go even is it is a pain to get to you may want to try turning the tread off the then of the screw so you can poke the plain end through the hole before screwing it in (outwards)

Bill Chugg25/08/2019 09:54:51
1200 forum posts
8 photos


Is that an external plate on your boiler ? I ask as all the station road archive boilers do not seem to have one.

There must be someone locally who can be of help ?

Off the top of my head I would go for the screw in studs from the outside and a local oxy chap to add the silver solder for you,

You could try Helen at Western Steam for a second opinion.

Worth persuing - i am sure it can be sorted.


derek blake25/08/2019 09:59:59
521 forum posts
135 photos

Hi All.

The holes still have good thread and the thread down the side of the plate, so I’m unsure how I’d get inside to screw the screws from the inside?

At the moment the bolts do tighten up, so maybe I’m worrying too much yet?

derek blake25/08/2019 10:05:09
521 forum posts
135 photos


JasonB25/08/2019 10:12:46
17259 forum posts
1858 photos
1 articles

Derek, as Jeff said cut a fine slot on the end of the screw and poke a jewlers screwdriver down into the hole or if you remove thread from the end as I suggested the screwdricve does not need to go into the hole.

Bill it's an internal plate.

derek blake25/08/2019 10:15:26
521 forum posts
135 photos

Jason I’m sorry for being thick, but you mean get screw down inside steam hole? What type of screw would I use?

Bill Chugg25/08/2019 10:22:27
1200 forum posts
8 photos

Thanks Jason

I see that now - when I first looked at photo above the black lines looked like the edge of an external plate.

I am sure Jason that your idea will work and I can see how to do it.

Derek have ago with Jason's suggestion

If all else fails then pM me , send me the boiler and I will do it for you.

Jason correct me if I am wrong but would not Comsol be adequate on them once in place to secure  I am assuming pb for the stud but maybe they are steel ?


Derek what is boiler diameter and size of big hole as shown in your picture

I can then make a mock up and give it a go .


Edited By 34046 on 25/08/2019 10:24:46

derek blake25/08/2019 10:26:25
521 forum posts
135 photos

Hi bill

the steam hole is 12mm across.bolier barrel 3 and 3/4 inch.

its the Allchin, I’m just a bit confused how I get the screw inside and what screw to use.

i really do appreciate everyone’s time on this,

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