By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Forum House Ad Zone

Fixing to loco backhead

All Topics | Latest Posts

Search for:  in Thread Title in  
RickyT31/08/2013 16:52:02
19 forum posts

I have been building a 5" gauge Manor to Martin Evans' design for more years than I would like to admit. I have a John Ellis boiler which is some years old and have reached the stage where I have begun work on the various backhead fittings. Some of these (most notably the firebox door assembly and the atomising valve for the sight feed lubricator) need to be fixed to the backhead. My question is how this is best done. I am not aware of any solid stays in convenient positions. I am reluctant to drill into the backhead itself for obvious reasons.

I know that some builders attach these items to a separate plate on the back of the firebox, but that still leaves me with the question as to how the plate itself is then fixed.

I'd be grateful for any advice people may have here.

Phil Ashman02/09/2013 12:42:42
33 forum posts

Ricky,

I'm also building a Manor, and have a John Ellis boiler. I fixed my firedoor assembly by tapping directly into the boiler, fixing it with stainless steel screws. I'm not sure if this is correct, or whether I should have used bronze screws as Michael suggests.

The backhead is certainly not as thick as 3/16", nearer to 1/8th I would say, but the fixing seems perfectly sound.

Phil

RickyT02/09/2013 21:37:14
19 forum posts

Many thanks for the suggestions.

I was working on the basis (although only a working assumption) it was 1/8" copper as it seems to have been used so liberally elsewhere.

If bronze is indeed the best material to go for, would the screws then need fixing with a solder (comsol?) or adhesive of some description?

julian atkins02/09/2013 23:44:11
avatar
1285 forum posts
353 photos

hi ricky,

firstly you need to check with your club boiler inspector what is acceptable. i think most boiler inspectors will be ok with a few bolts tapped into the backhead with bronze or non-magnetic stainless bolts. if your club boiler inspector is 'iffy' then use michael's excellent suggestion using the backhead cleading (which you will have to make as it isnt on the drawings). the bolts shouldnt need comsol and if the threads are ok (as they should be) no sealant either.

the atomising valve on the martin evans/fred cottam hydrostatic lubricator is in my view quite unnecessary. i have a simple stop valve on the oil delivery pipe actuated by the regulator quadrant as can be seen in one of my pics in my album. also the martin evans nozzle in the sight glass has far too big a hole in it. No.76 or No.78 will give much better results.

cheers,

julian

RickyT04/09/2013 22:29:48
19 forum posts

Sounds like bronze screws is the answer then, although I'll only have 1/8" thickness in which to cut the threads. I will run it past the boiler inspector first as he will ultimately call the shots when it really matters.

Many thanks all.

KWIL04/09/2013 22:53:32
3681 forum posts
70 photos

Is it possible that you could insert and silver solder into the backhead blind tapped PB bushes. These bushes would need a narrow flange to allow them to be fixed against the back face??

Phil Ashman05/09/2013 12:12:05
33 forum posts

That idea occurred to me as well, but I didn't try it because I didn't think I'd be able to get the backhead up to silver soldering temperature. I made up some fixings that consist of a thin hexagon flange, with a threaded piece either side. These screw into the backhead, then the door fitting is fixed to the protruding thread with nuts, the idea being that the door assembly could be removed without having to unscrew anything from the backhead.

The firehole ring protrudes slightly from the backhead about the thickness of the flanges, so the door closes fairly snugly over the firehole.

But in view of what's been said, I think I'll change the fittings to PB instead.

Phil

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Sign up to our Newsletter

Sign up to our newsletter and get a free digital issue.

You can unsubscribe at anytime. View our privacy policy at www.mortons.co.uk/privacy

Latest Forum Posts
Support Our Partners
cowells
Sarik
MERIDIENNE EXHIBITIONS LTD
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest

 

Donate

donate