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: Allan Brothers Lampless Oil Engine|
I give up! I'll go and do some gardening instead
Just had a go at drawing it out and it seems impossible. To me, there seem to be some vital dimensions missing. You really need the position of the cylinder bolting face from the datum point. You can work it out from the drawing for the base. I reckon it should be 60mm. That makes the length of the slope at the datum end to be 32.45mm.
Can't understand why it's been dimensioned like it has. Don't like to be critical but It's a dreadful drawing.
Edited By John Baguley on 22/07/2015 16:23:51
The cylinder centreline should be 62mm - 20 + 17 + 40/2. That is also the dimension given for the height of the crankshaft centre.
The co-ordinates do give X and Y - the decimal points should be commas! Yes, C1, C2, C3 are the centres for R1, R2, R3 and C4 is the crankshaft centre.
The 62mm length for the cylinder also seems wrong as it's much longer than the height of the cylinder centreline. Maybe the drawing has been distorted in printing?
|Thread: stephensons link problem|
Just a thought - have you got the eccentric rods connected to the expansion link the right way round. You may have got the forward and reverse rods crossed over on one side.
Out of interest, which loco is it?
|Thread: LBSC Style Ratchet Wheel Mechanical Lubricator|
Don't forget that the pressure the pump actually needs to produce is proportional to the area of the ram. A 1/8" diameter ram has a cross sectional area of only 0.0123 sq. inches so to produce 100psi the pressure on the ram only has to be 1.23psi so the pressure trying to lift the cylinder off the port face is very low. Think that's right anyway!
Most good lubricators will easily produce several hundred psi. The biggest problem is getting the ram to be a good enough fit in the cylinder bore. I like the Jim Ewins type where the ram goes through two O rings which seal perfectly.
The LBSC oscillating type usually have a packed gland on the cylinder to seal the ram.
Whilst the ram may seem to seal perfectly when the oil is cold, as soon as it gets hot they may leak like a sieve!
Edited By John Baguley on 21/07/2015 18:26:30
Edited By John Baguley on 21/07/2015 18:27:57
|Thread: Help please Black 5 Super Heater|
Yes, one side of the superheater comes out of the header on the front tubeplate and the return goes into the dry header that feeds the cylinders.
If you can, TIG weld the joint in the firebox, but if not, something like Silverflo20 or 24 will be ok. Silverflo55 is fine for the smokebox ends.
The B5 superheaters are what is known as coaxial type. They consist of a 1/2" diameter stainless outer tube with a 5/16" diameter copper tube running down the middle. The outer tube is blanked off at the firebox end and the copper tube doesn't quite reach the end. The steam from the wet header travels down the stainless outer tube and returns up the inner copper tube to the dry header.
Frankly, the coaxial type of superheaters are not very efficient and you would do better replacing them with the conventional type with two separate tubes jojned at the firebox end, the sort you are used to. Extend them over the fire right to the back of the firebox and you will get superheat worth having.
Here's a cross section of a coaxial type that I drew up in 3D for Neville Evans's Didcot that I've got all the castings for.
This is slightly different in that the end of the inner copper tube is supported by the blanking plug in the end of the outer stainless tube and the steam enters via a slot in the end. I won't be fitting one of these but the normal two element type instead.
Edited By John Baguley on 20/07/2015 18:20:29
|Thread: Black 5 only need to sort my boiler|
Have sent you a pm.
|Thread: Boiler pressures 3.1/2 gauge Pacifica|
Both are 80psi. LBSC mentions testing the boilers to 160psi in the final part on construction of the boilers. I think the majority of his boilers were 80psi WP.
|Thread: Workshop Flooring|
That sounds like Altro flooring. It has carborundum embedded in it to make it non slip. It's used behind pub bars etc.
I used it for my workshop floor. Managed to get a big enough offcut from Ebay for a very good price. Only problem is it's light blue but most of it's now covered by machines and rubber mats so it's not too bad
It's best glued down if possible to stop it creeping which is what I did.
Edited By John Baguley on 08/06/2015 19:03:47
|Thread: Etching Brass and Photoresist|
It sounds more like underexposure of the resist. Try exposing it for longer? Does the developer come ready mixed or do you dilute it yourself? Might not be strong enough. When I last used the photo resist method the developer I used was ordinary sodium hydroxide solution.
|Thread: Purley Grange|
Ok will pm you.
Just to wet your appetite, here's a photo of a very nice chassis being built by David Williams taken last Sunday at our 40th Anniversary Rally at Cheltenham.
The valve gear as drawn by LBSC is very poor and I would recommend using the updated design by Don Ashton which was described in Engineering in Miniature January 2008. I can let you have a copy if you don't have access to it. I also redesigned the valve gear independantly of Don as I didn't realise he had already done it! Both new designs give much improved valve events.
You will need to update the boiler design by fitting bushes for all the fittings. On the drawings the blower valve and water gauge screw directly into the backhead and the top feeds screw directly into the boiler barrel which is not allowed now.
I started drawing PG in 3D CAD and found a few errors so far. The hornstays are shown as 3/8" wide but should be 5/16" to match the horns. Also if the front bogie stretcher is fabricated using brass angle, the angle obscures the bottom cylinder mounting holes in the frames.
|Thread: very low temp solder|
Have a look at the Carrs range of solders as used for building etched brass kits. Some of those are low melting point and I've used them in the past for various jobs including soldering tanks and tenders. I got my stock from C&L Finescale.
|Thread: Mr G F Wills scale model motorcycle combination|
It sounds like the one described in an article in ME Volume 103 Issue 2586 (December 12th 1950). I've got that issue if you can't get hold of it.
Here's one I made for my 2½" gauge Helen Long:
If I remember correctly, the thread on that is 3/8" Whit. The seat is bearing grade PEEK which contains PTFE and Graphite. The spring was supposed to take up any backlash in the thread but proved to be unnecessary,
I made a couple of smaller ones for two Tich's that used 5/16" Whit threads.
As Fizzy says though, ball (gas) valves are very good if you have the room to fit one. Just make sure it is rated for the pressure and the temperature.
Edited By John Baguley on 27/03/2015 00:36:50
I use the largest diameter Whitworth thread that I can fit in. I find that 1/8 to 1/4 of a turn gives ample opening for normal running. It's surprising how little an opening of the regulator you actually need.
My favourite is the screw (needle valve) type, preferably with a PTFE type material for the seat. Seals 100% and a nice smooth and gradual opening. Made quite a few and never had any problems with them.
I personally hate any rotating disc type regulator as it's virtually impossible to get them to seal against a hydraulic test and not easy to get them to seal against ordinary steam pressure.
|Thread: Piston rings|
I started using PTFE rings years ago and never looked back but have only used them on gunmetal cylinders so far. One of the locos has very high superheat. I don't see any problem with using them in cast iron as you have.
Edited By John Baguley on 20/02/2015 10:24:59
|Thread: "New" Old Stock Kasenit; Does it expire?|
I bought my Kasenit in 1973 and it still works ok
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