By continuing to use this site, you agree to our use of cookies. Find out more

Member postings for John Baguley

Here is a list of all the postings John Baguley has made in our forums. Click on a thread name to jump to the thread.

Thread: accurate measurement of steam temperature
07/02/2017 13:03:44
Posted by SillyOldDuffer on 07/02/2017 12:36:29

I wonder if anyone has ever comprehensively fitted a model loco with thermocouples? Comparing steam temperature in the boiler, super-heater, cylinder inputs, and cylinder outputs might suggest improvements.


Yes, the late Jim Ewins did it on his O-6-2T loco and measured the temperatures at many points in the boiler, flues, etc. under various load conditions. His results were written up in ME for 18th March, 1st April, and 20th May 1966.

It is interesting to note that the maximum superheat temperature measured was 378°F (192°C) giving a final steam temperature of 620°F (327°C). The maximum superheater temperature recorded was 1570°F (854°C!)


Thread: denham junior mk2
19/01/2017 01:42:21

Hello Peter,

I didn't put these pics on my website but here are a couple of the reversing gears in the gearbox - right hand side of photo:

gearbox 1.jpg

gearbox 2.jpg

This is part of the gear assembly that does the reversing - bottom right of the photo

gearbox 3.jpg

I've got a CAD drawing of the gear assembly and bronze bush that I did for someone some time ago. Funny enough, they were missing the reverse gears as well. It's not the same lathe is it by any chance?


Edited By John Baguley on 19/01/2017 01:43:13

Edited By John Baguley on 19/01/2017 01:45:00

Edited By John Baguley on 19/01/2017 01:46:40

18/01/2017 23:35:33


Check your pm box.


Thread: Stirling Single
20/12/2016 17:51:51

Hello Tony,

the Greenly drawing gives the tread diameter of the driving wheels as 4.0625". The bogie wheels are 1.96875" diameter and the trailing wheels are 2.21875. The tender wheels are the same as the bogie wheels.


20/12/2016 15:55:27

Hello Tony,

Henry Greenly did a design for the GNR 8' Single in 2.5" gauge which would probably date back to the thirties. We do have a copy of the drawing for it (L78) but it is only a single sheet general arrangemant drawing, as were a lot of HG's drawings.

If the number is original, I doubt that it would be a commercial design but it is possible that the number was added later.

The loco is well worth restoring and fortunately it seems pretty well complete apart from the safety valve cover.. Judging by the condition of the grate it has done a fair bit of running in the past.

Note that it will probably be to the older 1/2" to the foot scale rather than the more modern 17/32" to the foot.


Edited By John Baguley on 20/12/2016 15:56:16

Thread: 1/4 " Thinwalled Stainless Steel Tubing
03/11/2016 13:22:49

I get mine from Southern Temperature Sensors:

They do much thinner wall tubing (316L) than the ME suppliers in both metric and imperial sizes. They also advertise on Ebay but usually only in short lengths.

Usual disclaimer.


Thread: Salvage Hauls
24/10/2016 20:55:29


I'm sure that the bearings on the ch pumps are water lubricated which is why they are not sealed from the liquid. I doubt if they will last long being run dry. As Jason suggests, they can be used for pond pumps but are not self priming. I've never found them to last very long in that application though.


Thread: Tools I would like to have
24/10/2016 20:43:45

Check out Adam Booth (abom79) on Youtube. He uses 'metallisation' all the time for building up worn shafts. The equipment he uses looks like an oxy acetylene torch which is fed with metal powder that melts in the flame and is sprayed onto the worn metal. Looks quite simple to do and very effective.


Thread: Water pump problem
22/10/2016 16:44:47

The inlet ball valve of the pump may be leaking under pressure and allowing some of the water to go back into the tanks instead of into the boiler. It's also possible that the pump is simply not big enough to maintain the water level.


Thread: Little LEC 2016 Video
15/08/2016 20:14:30

Nice turnout from the 2½" gauge lads as well smiley Thanks for the video Stew.


Thread: Bassett-Lowke 2 1/2 inch flying scotsman
20/07/2016 01:13:04

Hi Derek,

Have sent you a pm regarding drawings.

So far as I am aware, the BL Scotsman was designed by E W Twining and had nothing to do with Henry Greenly.

HG did produce some excellent coal fired 2½" gauge designs for Bonds of Euston road which are quite capable of pulling a person or two. It was just Bassett Lowke that seemed to not want to progress beyond simple spirit fired boilers.


Thread: PTFE piston rings
19/06/2016 02:22:36

I've used them on several 2½" gauge locos with excellent results. Also used PTFE on piston valve heads with equally good results. With these smaller bores though I haven't used backing O rings and just relied on the plain PTFE rings on their own. I fit two thin rings side by side with the gaps 180° apart to prevent leakage. It is essential to allow clearance for expansion when the rings get hot.

I haven't done it yet but I've thought of using graphite filled PTFE for the rings as this material is harder and springier than virgin PTFE and may not need the backing O rings in the larger sizes.


Thread: 2 1/2" Gauge Dyak
07/06/2016 01:03:54


the drawings show the safety valve bushes as threaded 3/8" x 26.


Thread: Brittania superheater
08/05/2016 19:25:22

Hi Bri,

I would think that the 4mm bore to feed the regulator is far too small for a 5" loco. I use larger than that for a 2½" gauge!

Is your problem with silver soldering the leak on the foundation ring simply due to a lack of heat? You're going to need a hell of a lot of heat to get it hot enough. Are you using a propane torch or do you have oxy acetylene or similar?


Edited By John Baguley on 08/05/2016 19:26:39

Thread: Boiler Paint nightmare
27/04/2016 11:01:36

HI fizzy,

Have you tried Halfords high temperature enamel? I used it on my Helen Long smokebox and it's still good after 8 years. They do matt, satin, and gloss versions.


Thread: denham junior mk2
25/02/2016 13:45:20

Hello Peter,

Yes, it's got 8 divisions. You might be able to get a suitable gear ready made or perhaps adapt a complete unit from a lathe with the same size leadscrew (4tpi) if there is one.

Will send you a pm with regard to the manual.


25/02/2016 12:12:28

Hello Peter,

This is the dial fitted to mine:

screw cutting dial 1.jpg

I don't think it's an original part though as it looks homemade. I've had a look at the manual and there is no mention of a screw cutting dial so possibly the lathes didn't have one when originally built. I would expect one fitted at the factory would have had a cast body.

It looks pretty easy to make one. Couple of bits of bar soldered or welded together, with a spindle, dial, and gear wheel.


Just had another look at the manual and there should be a leadscrew guard that bolts onto the end of the apron where mine has the dial. That was obviously taken off and lost when the dial was fitted.

Edited By John Baguley on 25/02/2016 12:14:42

Edited By John Baguley on 25/02/2016 12:23:41

Thread: Wet Belt
16/02/2016 16:04:39

My Triumph T160 with Norman Hyde 1000cc kit has a Norman Hyde toothed belt conversion to replace the old Triplex? primary chain. Hasn't been on the road for a few years now (must get it rebuilt!) but never gave any trouble when it was running. The belt's not rubber though. Can't remember what material it is offhand but some type of plastic (polyurethane?) I think.


Thread: Superheater elements
09/01/2016 01:26:16

The ones I've made so far have all had the return bends silver soldered with Silverflo 24. No problems with them yet, touch wood! I've now got some Silverflo 20 so will use that next time. I use fully radiant superheaters with the return bends right at the back of the firebox so they keep a bit cooler. Would be nice to be able to TIG weld them though.


Thread: Steam Engine Design
01/01/2016 13:13:00

Hello Martin,

As Julian says, I made a study of the Jim Ewins formulae and converted them to easy to use spreadsheets.


Also, as Julian says, the formulae are not the be all and end all and they don't 'fit' a lot of published designs, not that that itself means the formulae are wrong. It could well be the designs that are wrong. Jim really just came up with his formulae to try and establish design criteria based on some published designs, some of which worked well, and some not so well.

After much thought on the subject I think the critical areas to concentrate on are the engine factor Ee and the free gas area of the tubes versus the area of the grate. Personally, I now don't think the Keiller factor Kt is of any importance in 'our' sizes. It's pretty much accepted that only the first few inches of the tubes contribute much to the heating effect as the flow is laminar rather than turbulent in such small tubes so the length is pretty immaterial within reason. That also means the boiler factor Eb is not really valid and I think can be ignored.

So, my latest thoughts are that you should design the grate area to match the cylinders (steam consumption) and then try and get enough tubes in the boiler to match that grate area i.e. 12 - 15%. Also, fit a properly designed valve gear to make the best use of the steam produced. Most published designs have pretty poor valve gears. Oh, and use as much superheat as you can get to increase efficiency!


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

Latest Forum Posts
Support Our Partners
Allendale Electronics
Eccentric July 5 2018
Eccentric Engineering
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