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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: Blown X1 Mill speed control
08/02/2010 01:13:57
Hi Oliver,
 
last year I repaired a couple of driver boards for the Machine Mart mini lathe (C3 etc) for a friend at the club. He was on his third board and getting fed up with the cost of the replacement from MM. I replaced the output mosfets on both with a higher spec version from RS and so far so good. The originals were the standard IRFP460 but I replaced them with IRFP22N50A which have a higher rating. The probem with the original IRFP460 is that they can't stand the current drawn if the motor stalls under load. By the time the fuse blows, it's too late!
 
John
Thread: Brass nuts on boiler stays?
05/02/2010 17:24:32
Hi Tony,
 
At least the threaded stays won't fall out or move at the worst possible time

Brass will be fine for the nuts. It's been used since LBSC days for stay nuts. I still use them for the boilers I build with caulked stays (shock, horror )

John
05/02/2010 14:35:00
Hi Tony,
 
You don't really need the nuts at all if both ends of the stays are going to be silver soldered. You only need them if they are to be caulked with soft solder (Comsol etc.). Nowadays, most people just use plain copper rivets for stays with the heads inside the firebox if they are all silver soldered.
 
John

Edited By John Baguley on 05/02/2010 15:01:05

Thread: Martin Evans Columbia Castings
26/01/2010 20:49:00
Hi Jim,
 
Blackgates Engineering list them in their catalogue.
 
John
Thread: Matin Evans, Holmside
20/01/2010 11:21:44
It was serialised in 14 parts starting with Volume 143 issue 3558 and finishing in Volume 144 Issue 3590. Relevant issues are 3558, 3561, 3563, 3565, 3567, 3569, 3571, 3573, 3575, 3578, 3581, 3584, 3587, 3590.
 
John

Edited By John Baguley on 20/01/2010 11:27:28

Thread: Captive steam fittings (on loco's))
16/01/2010 01:10:26
Hi Nigel,
 
the easiest way to adapt the original fittings is firstly to make a new valve stem with the outer part that the handle fits to a smaller diameter than the threaded part. Then make a new gland nut with the hole to fit the reduced stem of the valve. The gland nut then stops the stem from being unscrewed completely.
 

Are you wanting to do this to comply with the latest boiler regs as in the blue book? As far as I am aware, the regs are not retrospective and do not apply to older boilers, only new ones. However, it is a good idea to alter the valves, if only for safety's sake.
 
John
Thread: lifford hall
15/01/2010 10:08:50
John,
 
The backhead clack is for the tender handpump feed. The boiler does have two topfeeds but they were meant to be fitted without bushes, hence the lack of them. The idea is to drill two 1/4" holes in the boiler barrel either side of the safety valve bush. The top feeds are fitted into these holes and secured to the barrel with bronze screws and run over with soft solder to seal. I doubt if this would be acceptable now but I don't think it would be too difficult to retrofit a couple of bushes as the only joint you are liable to disturb is the safety valve bush. Would be a doddle if you know someone with oxy-acetylene gear. That's assuming the stays haven't been soft soldered. Would still be possible with oxy-acetylene to keep the heat local and a bit of care.

Ivy Hall was never intended to be a replica of a real Hall but instead LBSC's idea of what a 'modernised' Hall might look like. Lickham Hall was the closer to scale design that he did for Reeves, much to the annoyance of the head of Model Engineer at the time!

John
15/01/2010 01:10:32
John,
 
Have replied on MECH re the top feeds.
 
John
Thread: Stephenson valve gear for Derby 2P
01/01/2010 10:56:47
Hi John,
 
I will probably be able to do it for you if nobody else volunteers. I have the original LLAS articles with the drawings etc. Designing valve gears is pretty straightforward nowadays with the help of the work of Don Ashton etc.
 
John
Thread: Yet another boiler making question
18/12/2009 21:49:54
Tony,
 
is it just a rivet you've used to hold the firebox wrapper to the tubeplate and end plate whilst soldering these joints? I presume you haven't installed the firebox into the boiler shell yet?
 
If so, I wouldn't worry about it at this point in time. Wait until you've got the whole boiler assembled and you come to do the stays which you obviously intend to silver solder. You are going to have to get the whole firebox and outer wrapper damned hot to do the stays anyway so try and put a dob of Easyflo on the offending rivet then (inside the firebox). There's a good chance it probably sealed anyway with the solder that has been drawn into the initial joint.
 
Incidentally, you'll probably need to get a Cyclone burner to do the stays inside the firebox. If you have already soldered on the firebox backplate it's very difficult to keep an ordinary burner alight in such a small space.
 
John

Edited By John Baguley on 18/12/2009 21:53:43

Thread: castings
13/12/2009 00:42:57
John,
 
Mabel is an inside cylinder LNWR 2-4-0 so they definitely won't be the same cylinders. The stock codes on the Reeves website are different.
 
John
Thread: Flux for HMP soft solder?
11/11/2009 20:07:42
The 'traditional' flux is Bakers Fluid but you have to keep slopping it on all the time as it quickly evaporates. Carrs Black Label works quite well but with the same evaporation problem. The difficulty is finding a suitable brush to apply it with that will stand the temperature without going all black and horrible! Maybe something like an eye dropper would be a better way of applying it?
 
John
Thread: LBSC Petrolea
05/11/2009 18:16:13
It's mentioned indirectly on page 326 of Volume 92, No. 2291 under hydraulically testing the boiler and should be 80psi. Unfortunately I can't scan the page myself as I've just replaced the old PC that went bang at the weekend and my scanner won't work with the new one!
 
John
Thread: Clarke CL300 Speed control
05/11/2009 00:12:22
Hi Pat,
 
Earlier this year I repaired 2 of the Clarke speed controller boards for a member of our club (he was on his third!!). I fitted higher spec Mosfets - IRFN22N50A - from RS and so far one of the repaired boards he fitted has been working ok. The problem is that the output Mosfets originally fitted are only just up to the job, the slightest surge and they're gone! Repairing the two boards cost less than the cost of a replacement board from Clarke.
 
John

Edited By John Baguley on 05/11/2009 00:14:24

Thread: Balancing the steam pressure on the slide valve
29/10/2009 10:10:19
Hi Nick,
 
I think it will have an effect on reducing wear although how significant that will be remains to be seen! I'm doing it more as an experiment (as a lot of my 'mods' are) to see what the effect will actually be. I want this loco to be as maintenance free and long lived as possible as it's going to be used for passenger hauling at the club on a regular basis.
 
I've more or less finalised the design and am going for a balance piston on top of the valve. This will be hollow and allow the exhaust to escape through the top of the steam chest rather than the rather tortuous route via the normal exhaust port. The diameter of the balance piston is such that the force holding the valve onto the port face will only be 90% of what it would normally be, but still leaving enough force on the valve to hold it on the port face.
 
The valve can still lift if necessary to allow any condensate to clear as the balance piston slides in a bore in the valve.
 
Much of this loco will be 'experimental' . The boiler has been redesigned to the late Jim Ewins formulae with a much bigger firebox and more fire tubes. I am now looking at designing a Lempor exhaust system for it as one will fit nicely using the original chimney height so it won't look out of place. All good fun!
 
John
Thread: show track
24/10/2009 10:54:46
Try The Miniature Railway Supply Co. Ltd:
 
http://www.miniaturerailwaysupply.com/specialist/specialist.htm
 
John
Thread: bits and pieces
13/10/2009 14:43:55
Hi Chris,
 
there is a website at:
 
http://www.users.waitrose.com/~n25ga/
 
They also attend most of the major exhibitions and will be at the Midlands one this weekend. They're a pretty friendly bunch and are always happy to speak to people at the shows.
 
John
13/10/2009 00:46:34
The Eagle castings are available from the 2½" Gauge Association. The castings officer is Christopher Kruikshank who can be contacted at:
chc@jacom.co.uk
 
The castings are normally sold at cost to members but are available to non members at a slightly higher price.
 
John

Edited By John Baguley on 13/10/2009 00:47:41

Thread: Building LBSC 31/2" Mabel
24/09/2009 22:12:57
Hi Stewart,
 
I'm not building Mabel myself but have had a look at your build notes on the other forum and the problems you are having.
 
It looks to me as though the problem could well stem from incorrect valve timing i.e. the setting of the eccentrics. The valve dimensions given by LBSC are fine, indeed the port and valve dimensions are pretty standard for a 3½" loco. The face of the valve that moves over the port is 3/32" wider than the port. This is the 'lap' of the valve and it's this lap that allows the steam to be used expansively and hence economically. The total valve travel in full gear should be twice the lap plus twice the width of the port which gives 7/16" (which I believe you have).
 
It sounds like the valve may be opening at the wrong point in the stroke due to incorrect setting of the eccentrics and you've corrected this by  shortening the valve by a considerable amount in order to get it to run.
 
Setting the eccentrics on these types of valve gear (Allan, Stephenson, etc.) can be very confusing and frustrating until you have done a few! It's very easy to get the forward and reverse eccentrics crossed over or the eccentrics leading the crank rather than following (or vice versa ! )
 
John
Thread: Boiler Test Codes
14/09/2009 00:41:39
The subject of fittings does seem to be a grey area. Appendix B of the code says:
 
"In addition to the normal inspection for leaks, adequate joints, correct thickness of materials and the absence of any appreciable distortion/bulging to any surfaces, inspectors may wish to consider the following points: "
 
Note it says may wish to,  not shall or should !
 
The criteria in appendix B for fiitings seems to be the same for new and previously tested boilers i.e.
 
'All screw operated valves should be checked to ensure that they cannot be screwed out whilst under pressure'
 
My interpretation of that is that a boiler with valve spindles that can be unscrewed should be failed whether it is new or old but the opening paragraph to appendix B suggests that the inspector can choose to ignore this?
 
Definitely something that needs to be clarified!
 
John
 
 

Edited By John Baguley on 14/09/2009 00:42:40

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