16mm IDRIS

[SteambuffParticipant @steambuff]

The Essex 16mm Group has running sessions in peoples gardens once or twice a month over the late spring to early autumn … some are based in Chelmsford. (Most of these are 32mm gauge … so may pay you to build to allow the gauge to be changed.

I'm sure they would welcome you as a guest if you want. (If you are interested I can PM you the organisers details)

The nearest ME club with a 32/45mm track is Colchester. (They are currently discussing if they are going to keep the track or not.)

Dave

[Diane CarneyModerator @dianecarney30678]

Posted by Alex Collins on 08/07/2015 17:23:21:

Wot no bits to make in the latest edition !

Patience, Alex!

Sometimes it's difficult trying to shoehorn everything into the issues so Idris just had wee summer holiday. Rest assured he will be back in 4514

Diane

[John RuddParticipant @johnrudd16576]

Diane,

That is good to know as reading the contents for 4513 shows no indication of Idris's return……

[Alex CollinsParticipant @alexcollins55045]

Sievert torch finally turned up yesterday.
More offcuts of master board pressed into service ( My Hearth ).

Ok I have now got dribbles of solder on both sides of the boiler, they can be dressed down and will be covered up.
So easy with the right kit and a bit of thought about keeping the heat in.

It's still cooling down at the moment, then into the pickle for a clean up.

[martin ranson 2Participant @martinranson2]

Alex … could I echo the words above about using standard 32 mm track … the gentleman called "steambuff" has mentioned a possible source of track at Colchester … is there any way you could "beg, borrow or steal " enough track to make a small circle ? preferably in your own workshop ? … having your own test track is infinitely easier than waiting for a fine day to use the Chelmsford track … any final tweaking is done at your own speed with no-one watching when it goes wrong … everything I have ever built has needed a bit of T. L. C. before I was happy with its operation …e.g. gland packings to re-do … valves that do not seal … spindles that are too tight … bearings that seize up as the engine gets hot … realizing that I can not see the gauge in the place where I fitted it … etc etc.

Not that I have done this !! but I have heard of people waiting until the house was empty during cold days in January … temperature in the shed was 2 degrees above freezing and it was pouring down … the kitchen floor looked to be a much better alternative … a quick bit of circular track down on the floor and away you go … just remember to clean up afterwards.

The boiler photo above looks like you finally have enough heat available.

martin.

[Alex CollinsParticipant @alexcollins55045]

Another Edition and no bits to make

I'll have to get on with my DRO's instead then.
**LINK**

[Alex CollinsParticipant @alexcollins55045]

Hi All.

New Edition turned up today. Lots to be getting on with. That'll be great.
I have to say I'm intrigued by the square gas tank. Another 2 or 3 mm on the frame length at the back and you could have used the same 2" tube used for the boiler. I could have also used the End Cap formers again. Maybe hindsight is a wonderful thing here…..
I have lots of copper tube. Can I use the tube for the stays ?

All the gas fittings look easy enough to make.

My Offcut pack can be used for the 2 brass plates.
I probably have suitable material in stock for all the rest as well.

Alex.

[martin ranson 2Participant @martinranson2]

Alex … I am not sure if you intend to mount the proposed tank vertically or horizontally … if it is vertical and mounted under the frames in the same relative space as the original then the tank volume would probably be a whisker smaller than the existing one … (approx. 40 cc versus 42 cc) … assuming you kept the SAME rear buffer beam assembly then I think the extra length needed for the frames would be at least 14 mm.

If you fit the tank across the frames it would produce a very large tank … approx. 94 cc maximum volume … this would be very much an advantage … however it probably need the top edge to be lifted by 21 mm … this may be quite a squeeze to get everything into place !!!!

As regards using copper tubes for the stays, no problem at all … I have done this for years … just make sure you use tubing with thick walls … not the thin stuff … for a vertical tank use 2 or 3 with a diameter of 7/32 inch … these can be then used to fix the tank in place with 2 long bolts.

If the tank is horizontal then use 1 long tube as a stay between the two end plates … use 1 very long bolt to attach the tank through the engine frames … something like 7 BA or 2. 5 mm.

If you have another idea in mind please let me know … I struggled for hours trying to think of another place to put the tank … I could have used the tender but I did not find a suitable type of flexible pipe … ( anyone any ideas for buying a small quantity ?? )

If you do solve it can you send me a photo please ??

martin.

[Alex CollinsParticipant @alexcollins55045]

Hi Martin.

I think I need more drawings before a decision is made on the gas tank.
The 2" tube can go in 3 ways.

If I go Vertical it fouls the edge of the wheels by around 2-3 mm. Not an option.

If I go Horizontal In line with the frame, I can mount it on the buffer beam frame at 1 end. Make a bracket for the other.
How long can I make it ? In theory a tad under 2" to clear the wheels.

If I go Horizontal across the frame (not something I had thought of) I think it'd fit rather well and mount with a pin through a central stay tube.
Whichever horizontal way, I'd have to try and mount the 3 Bushes in the top. That'll get quite tight I guess.

Going to make a start on the engine frames tonight.

[Alex CollinsParticipant @alexcollins55045]

Please disregard my earlier ramblings. It helps if I'm actually working with the correct end……

Folding up the box seems like a lot of work and a likely large bit of scrap copper.

IF I can make a tank from left over 2" boiler tube.
It'll be 1 1/2" long to fit between the cross beam and buffer beam.
The tank will sit in line with the frame rails.
I need to work out how the bushes will work at this stage.
I may well create a 3 way single bush as a strip along the length and silver solder it to the top rather than 3 separate bushes.
I can put a stay between the end caps in the middle without any issues.
I'll probably soft solder some angle to mount it.

In my book that makes the tank about 52 ml. (48mm X 35mm X 3.14)

[John RuddParticipant @johnrudd16576]

Alex,

Fabbing a tank from round tube would be a better proposition…..Just make sure the wall thickness is appropriate…

There are less soldered joints in the round version….just the two end plates …..Add a phosphor bronze stay for added security (1/8 dia will suffice)

But do remember, a mix of butane/propane will have a higher vapour pressure than steam, so the gas tank needs care in manufacture…

I pressure tested mine to 400 psi for the Idris version that is on the net…(Dave Watkins version)

Edited By John Rudd on 04/08/2015 19:11:59

[martin ranson 2Participant @martinranson2]

To John Rudd … it has been a long time since I have talked about pressures inside gas tanks … thank you for pointing it out … I try to take the utmost care with tank construction … if I look at a plastic tank inside a commercial gas lighter I am horrified … it seems to be from a different world considering the armour plated heavy-weights I produce … many decades ago I was totally unable to find out much information about actual tank pressures and types of available gas jets … with only one exception no-one would tell me anything.

I got so fed up with the secrecy I collected everything together and published it in MODEL BOATS … the June 2005 issue … pages 40 – 45 ( ten years ago ) "gas tanks and burners for small steam boats"

One of the things I discovered was that the actual pressure in a tank 2/3 full of gas was a lot less than the figures I was quoted by the "experts" … I did eventually discover that the figures I was given had been roughly doubled for a safety factor and then, for some reason, they were doubled again … someone else added their own safety factor.

I was expecting hundreds of pounds pressure … the only way I could arrive at approx. 100 P.S.I. was to heat the tank to 55 degrees C … the pressure at 22 degrees C was about 40 P.S.I.

All my experiments were with the tanks 2/3 full of gas … NEVER heat any vessel which is TOTALLY full of liquid.

If this is of use to anyone, all the details are in the MODEL BOATS article.

martin.

[David Clark 13Participant @davidclark13]

Perhaps Paul Freshney may agree to publishing it on here. No copies on Ebay at the moment.

[Alex CollinsParticipant @alexcollins55045]

Gas tank is well under way.

It's made form the 2​" Boiler tube, 1 1/2" Long.
The end caps have been made the same way as the Boiler caps on a steel former with a Vice and universal adjuster to help things along.

The Tank will fit in line with the frames at the back of the engine between the Buffer Beam and frame beam.
It will however be proud of the frames. Just hope this won't cause me to many issues.
I plan to use Copper Tube to make a central stay and use that to mount the tank with.

The Bushes will fit on the top and will be made separately.

If all goes well the tank should be complete over the weekend. I'll try and take some pictures as things progress.

[Alex CollinsParticipant @alexcollins55045]

Gas Tank is ready to clean up and get soldered together.

I think this is going to be a 1 hit soldering job.
Bushes first then the end caps and Stay.
The cutouts in the end caps for the bushes should help keep them in place…..

[Alex CollinsParticipant @alexcollins55045]

All soldered up as planned.
The joints all look good. I will know when it's out of the pickle……

[Alex CollinsParticipant @alexcollins55045]

Hi Martin.

Gas Tank looks good and fits perfic.

P873 fig 17 and 18.
You call for 2 X 32 DP 30​ tooth gears for the final drive.

The wheels are nominal .750 Radus (Centre to edge)

My gears are .740 dia and together the centres are .700
This places the axle within the wheels.

Ideas / Comments please.

Thanks

Alex

[Alex CollinsParticipant @alexcollins55045]

Hmmmm

The Packet says '32DP 30 T .250'

The reality is:
There are 30 Teeth.
The Bore is 1/8"
If they were 32 DP the gears would be about 1" dia.

These are /not/ 32 DP Gears. Great……

Back to the shops again…..

[martin ranson 2Participant @martinranson2]

Morning Alex … if the gears you bought have 30 teeth then I am not sure what size they are … 48 DP would be a bit small and 40 DP would be a bit larger then the ones you have. ( does anyone use 43 DP ?? )

If they are metric, then 0.5 mod would be a bit small and 0.6 mod would be a bit larger than yours … maybe there is another system for small gears ?? I know there is a system for much larger gears called CP ( circular pitch )

On page 874 of the same issue I did put that 40 DP would be ok … the important thing is the outside diameter, so everything will fit in the available space.

Can I ask whether your gas tank and fittings will fit under the burner assembly hung out of the rear of the boiler ?? Does your design alteration include altering the position of the gas tank relative to the burner ??

martin

[Alex CollinsParticipant @alexcollins55045]

Hi Martin.

I have ordered new 32DP Drive Gears.

The ones I have don't seem to be anything that I can make sense of….

As for the Gas Tank, It may well cause me issues further down the line. I can drop it fairly low down in the frames but the Bushes will be proud. I can trim a bit off the bushes if need be. I can also cant it either way.
If things get really bad I can cut the top off and add a plate or I have material to make another.

I'm very much learning here and enjoying doing so.
If nothing else my soldering skills have improved no end.

[martin ranson 2Participant @martinranson2]

Morning Alex … good for you … the only way to learn anything is to experiment … my scrapbox is always full of my mistakes … usually the bits come in handy for something … a quick skim on the lathe or a dab of silver solder and an old "whatsit" is useful to make a new "thingummy"

martin

[Alex CollinsParticipant @alexcollins55045]

Made the Valve Bodies tonight. Fairly easy turning / drilling / Tapping job.
Going to use Metric Threa​ds for them (M3)

Started to make the 1st Valve needle. Ground the parallel and point with the dremel. Very easy.
Finished with a flour file.
Ground off .15mm to make the rod 3mm.

What's the secret to threading stainless ? Got it started after a bit of effort. About 1/2 way in it stripped.

Decided that's enough for 1 evening…..

[Neil WyattModerator @neilwyatt]

Make it a bit undersize, just as you would drill a hole oversize to tap in stainless.Use lots of cutting fluid.

Neil

[Alex CollinsParticipant @alexcollins55045]

Valve needles made tonight.Came out rather well.
Discovered the trick was to turn the die over and use the Back.
Maybe my M3 die is getting past it's best.

I'll make some nice knurled handles for them tomorrow.

You say to Silver Solder the side arms into the valve bodies.
Any reason why I can't soft solder them ? ​

[martin ranson 2Participant @martinranson2]

Hi Alex … yes you could soft solder them, but there is not much area of solder in the middle of the joint … Silver solder is a lot stronger … you could always make up a soft-soldered spare and test it to destruction with a spanner … if it does not need much force to break loose then stick with silver solder … I have used this type of assembly for many shapes of valve over many decades … so far, none has ever broken … maybe I am guilty of over-engineering ?? ( again ) … let me know what you think after you have done an experiment.

martin

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