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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: Piston rings
20/02/2015 10:23:56

Hi Andrew,

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.

John

Edited By John Baguley on 20/02/2015 10:24:59

Thread: "New" Old Stock Kasenit; Does it expire?
17/02/2015 18:20:10

I bought my Kasenit in 1973 and it still works ok smiley

John

Thread: Ern Marshall
16/02/2015 13:19:10

I would have said cylinder drain cocks but looking at the photos in the album it doesn't seem to have them fitted. On Pansy it's usual to have just one drain cock at the back of the valve chest cover. There does seem to be a blanking plug in the position I would have expected the drain cock to be so maybe it's been removed?

It also looks as though the loco has dummy sanding gear fitted so the lever could be a dummy lever for that?

John

Thread: 5" Gauge Duchess
16/02/2015 13:14:01

Yes, try MECH. There is at least one person on there that has built the Duchess. I've seen it and he's made a superb job of it.

I should also add that Michael's drawings are very good. He keeps in touch with all the builders of his designs and if anyone finds an error Michael corrects it immediately and sends out a new drawing straight away.

John

Edited By John Baguley on 16/02/2015 13:26:12

Thread: Josie
13/02/2015 00:28:32

Hi Ricky,

The original pilot beams were often made from lengths of boiler tube with the ends flattened and bolted/rivetted to a frame so the 'casting' does sort of represent the full size versions.

John

Edited By John Baguley on 13/02/2015 00:29:14

Thread: Silver Flo 40
11/02/2015 09:54:29

Fizzy - expand the tubes in as Jason suggests. That's the normal practice. My brothers 5" loco has a steel boiler with copper tubes silver soldered/brazed in and they are starting to leak on the front tubeplate. We think the soldered joints are cracking and it's something very difficult to repair.

John

Thread: Hep with steam chest
07/02/2015 16:02:55

Neil,

Reading the above implies to me that you have not allowed for any lap on the valve i.e. you have made the face on the valve the same width as the port so it just covers the port? That will work (very old designs had this) but it means the cut off will be 100% i.e. the port will be open for the full stroke of the piston. Probably ok for running on air but very wasteful if running on steam as the steam won't be used expansively.

John

07/02/2015 14:17:36

Hi Eric,

You are really designing it a**se about face as you would normally determine the port width and the lap of the valve and then determine the required valve travel. But:

Total valve travel = 2 x (port width +Lap of the valve) assuming the ports fully open.

(Lap of the valve is the amount the valve land is wider than the port)

So if your valve travel is 20mm then your port width + valve lap will be 10mm assuming the port will fully open.

Things are complicated by the fact that the ratio of the lap to the port width determines the maximum cut off of the steam to the cylinder.

If you make the port width 5mm and the lap of the valve 5mm then the maximum cut off is 75%

If you make the port width 7mm and the lap 3mm then the maximum cut off will be 91%

Will you be using a fixed valve gear e.g. a fixed eccentric or a variable cut off valve gear such as Stephensons link? If you are using a fixed eccentric then you probably want the cut off to be 50 - 60% to avoid wasting steam.

The distance between the ports doesn't affect the valve timing and is more a case of picking a suitable figure so that the valve will fit in the valve chest without hitting the ends. You will also need to fit the exhaust port inbetween the steam ports.

If you're not too familiar with valve gears then this might help to explain the terms used etc.:

http://www.modeng.johnbaguley.info/Valve%20Gears/Basics.htm

Fizzy - your dimensions are half what they should be. Using your figures the total valve travel would only be 10mm.

John

Edited By John Baguley on 07/02/2015 14:24:48

Thread: Pansy 060 steam engine
06/02/2015 10:56:55

Hi Stewart,

What you are describing as a 3 way valve is the actual injector itself that puts the water into the boiler. It will no doubt be a commercially bought one (although some of us do make our own - not easy!)

John

Thread: Cutting curves in 1mm thick copper sheet
06/02/2015 00:08:13

For copper that thin just use decent hand shears. Cut a square and then trim to shape.

John

Thread: 7.25" GWR Toad
03/02/2015 17:59:33

Keith Wilson describes a 7.25" Toad for use as a driving trolley in ME Vol. 186 Issues 4146, 4148 and Vol.187 Issues 4150, 4152, and 4154. I'm not sure how close to scale it is though but might be useful?

John

Thread: Josie
01/02/2015 13:28:08

One of the chaps in the 2½" gauge Association made a 2½" gauge Josie by doubling up the dimensions. It makes a nice loco.

2.5 inch josie.jpg

John

Thread: Safety valves
29/01/2015 14:51:52

Are you using a decent accurate pressure gauge or the miniature one that you intend to fit to the boiler for use when running? The miniature ones can be very innaccurate and you should never set the safety valves using one of those.

As Fizzy asks, are the safeties starting to lift at 100psi and then rising to 120? You are allowed a 10% increase in the accumulation part of the steam test which means a maximum pressure of 110psi. If the pressure is increasing by 20% then the safeties are not adequate.

John

Thread: Cutting timing pulleys
28/01/2015 15:12:23

The second part is in issue 4456.

John

Thread: Josie
24/01/2015 17:00:34

Hi Ricky,

Josie was described in ME Vol 69 issues 1685 to 1696.

John

Thread: TV Volume control
24/01/2015 15:09:20

My brother used to have the same problem with the old lady next door who was very deaf and always had the telly on full blast (they got on well apart from that!). She eventually had an induction loop system fitted and problem solved.

John

Thread: 3D printing seems to have gone quiet. Where are we all at?
20/01/2015 11:20:27

That looks a nice printer smiley

John

19/01/2015 12:36:27

That was the reason I went for the D5S MIni. All the frame is steel and it's pretty solid. The Z axis uses a proper 16mm ballscrew.

The type using threaded rods etc. must shake like a jelly when they are printing and there is no way you are going to get accurately aligned layers which is critical for good surface finishes. I'm not convinced about the printers that use thin plastic and plywood for the frames either, although the Ultimakers seem pretty good, maybe the best of the 'hobby' type printers actually but not the cheapest by a long way.

As mentioned before, my Mini was let down by poor quality rods and bearings but it didn't cost much to sort that. out. Originally, the end of the nozzle could rock from side to side by something like 0.5mm.

Whilst I agree that you need to spend a lot of time with the settings to get the best results, if the mechanics of the machine are not accurate enough, the results will still be substandard.

If I had the time I would have built one from scratch but I've just got too many other things on at the moment. For me it was quicker to buy a reasonable printer ready built and modify it if necessary.

John

Edited By John Baguley on 19/01/2015 12:38:02

Edited By John Baguley on 19/01/2015 12:39:04

18/01/2015 10:37:33

I think it's only when you start to use the printer for serious work that you find the real problems with them. A lot of people seem to use them as just a 'toy' and seem happy with the finish etc. that they produce. I'm sure all of them can be improved though with a bit of work and maybe different software.

Reading on the forums, it seems the slicing software to have is Simplify3D. Unfortunately, it's not free but people changing over to it have reported vast improvements in print quality over the stock software that usually comes with the printers.

Unfortunately, the Wanhao D5S range use a unique format for the print files that they use (i files) so can't read standard Gcode files that most of the slicers produce. However, there is a slicer (Ideamaker) that has a translate function built in to it that will translate Gcode files to the Wanhao i format so you can use other slicers instead of the Wanhaomaker that is supplied. I've been able to try a couple of other slicers (Ideamaker and Cura) with success to see if my problem is slicer based.

I'm still chasing the problem with poor finish on wheel spokes but without a lot of success at the moment. I'm still not sure yet whether it's the printer or the software. There's not much left I can do to the printer! The finish on exterior surfaces is very very good. It's almost like glass and at 0.1mm layer height you can hardly see or feel the layers so the printer is obviously capable of good results. The prints are very strong as well so layer adhesion is good. I'm on my 3rd roll of filament without a failed print so far. Just this d**n problem with the spokes angry

Nigel - I decided against buying one off Ebay as well for the reasons you state - the possibility of poor or non existent support.

John

Edited By John Baguley on 18/01/2015 10:41:10

Thread: princess of wales
17/01/2015 20:08:37

Some of the singles did run with a smaller 6 wheel tender later in life.

I think Martin refered readers to the Nigel Gresley tender for the general construction of the tender chassis. He only gives very brief details for the POW 6 wheel tender i.e. the frame plates and a general arrangement drawing. No details of buffer beams, frame stretchers etc.

John

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