Member postings for martin ranson 2

HI PETE ... being a member of the G1 railway group seems to be rather useful ... have you been a member for a long time ? I presume their meeting place is not too far away from your house ? ... hopefully less than the 45 miles I would have to travel for a pressure test ? ... as regards the gas pressure test itself ... it appears that the required pressures just keep going up as the years go by ... I have happily tested this tank to 250 PSI, but not up to 400 PSI ... many years ago I built a small tank to see what would happen at very high pressures ... I think at about 900 PSI it was starting to become a football shape, but the soldering did not split.

If you use 400 PSI for the test pressure let me know how the tank performs, please.

I started experimenting more than 30 years ago ... I have seen various graphs of pressure versus temperature ... at first I wondered why the apparent pressure was so high and then realised that most manufacturers data available at that time included a safety factor of 1. 9 for the pressure ... a lot of the graphs stopped at 25 bar and a temperature of 65 degrees . I did my own tests and discovered that at 100 degrees C the typical pressure was 245 PSI. This depends on the ratio of gas mix. I try to keep my tank pressures at about 40 PSI, this means a temperature of about 22 degrees C. If a tank was actually used at 100 degrees C. I would love to see how the flow is regulated ... to go down from 245 PSI to about 10 PSI in one stage is remarkable ... would the gas flow hit maximum as soon as the valve was cracked open ? would the safety valve be lifting most of the time ?

Over all this time I have never met anyone who has actually tested a gas tank at various temperatures ... is there anyone in the G1 society who has ever done it ?

You ask about the ratio of gas mix ... over the years there have been various makers of gas bottles , Taymar, Epigas, Coleman, Go-gas, Go system, any others ? once upon a time they used to put the ratio on the bottle e.g. 80/20 or 70/30 or 60/40 ... but not any more ... it is just a "mix" on the bottles from Go System, but they do refer to EN521 if you want to plough through it. I cannot answer that one directly.

As regards the tank labelling I stamp my tanks BEFORE the silver soldering ( Falcor part 3, page 647 and 648). I do not know if the G1 people use a stamp or an engraving tool on the copper tank, but I definitely think it is safer if using a stamp to do it first, just in case the resulting "thump" puts the solder under any extra stress. Let me know please if they use a stamp, an engraver, a sticky label or possibly even a painted label ?

For the boiler cladding I used a small circular saw to cut pieces about 1/4 thick and 5/15 wide ... not totally critical ... all that happens is that there will be a few more, or less, planks going round the circumference. The sides are tapered inwards to keep everything touching as it goes round the boiler.

I assume you mean the thickness of the plywood roof for the cab ? this was 2, or possibly 3, layers of 1/32 thin ply ... it is much easier to bend several sheets of thin ply rather than 1 sheet of thick ply.

martin

HI PETE ... starting with the lubricator, yes it fits in the 1/4 hole in the floor ... for figure 52, yes it is offset to the right slightly just to clear everything ... I found that position suited all the bits needing to fit round it ... putting it to the left made an awkward bend in the pipe. if you have already made the exhaust pipe adaptor in fig 45 try it for size ... the hole can be moved quite bit sideways to get everything squeezed in

For figure 47 ... the rod should be clear of the fork inner side, apart from any slight misalignment or any small smears of silver solder ... yes use a small needle file to make a nice sliding fit ... JASON B has already answered this question beautifully above ... a lot of the materials we buy are not EXACTLY to size ... they are only nominal ... for example, the difference between 5/32 and 4 mm is only a few thou. but if you try to fit things the opposite way then one is slack and one needs a sledge-hammer to get a fit ... if ever you get something precision such as decent ball-bearings the size difference becomes very apparent.

Same again for the fit of the piston fork ... the sizes are nominal ... JASON B has hit the mark very nicely again ... cut the slots first and then make the circular part to go inside it just a whisker bigger so it can be filed down, probably with a small needle file.

Another example of a nominal size would be for a certain size of bolt ... what we buy as a commercial bolt may be the EXACT size it should be, but most times they are a bit smaller than nominal ... sometimes they are a bit too big, if they are too large then it usually happens at a most awkward time ... this needs the threads to be reduced slightly with a die closed down in diameter ... that is when you discover you do not have that die size !!

You may have already discovered this problem with all the 6, 7 and 8 BA SIZES needed for this loco ... most people spend lots of time using a plug tap right to the end of a drilled hole or frantically trying to find the right size of die to clean the threads.

martin

HI PETE ... just a P. S. to my earlier message today ... there is some more information concerning poker-type burners ... it is in MODEL ENGINEER magazine issue 4504, March 2015 on pages 425 up to 429.

might be a help ... martin

TO ROD ASHTON PLEASE ... nice to hear from you ... on the inside cover of MODEL ENGINEER magazine there is a phone number for back issues ... 01795 662976 ... there is also a website ... www.mags-uk.com ... I think it is also listed on this website as well.

The Falcor articles started in March 2018 with issue 4581 ... there are 8 parts so far, I think part 9 is the final one, not yet published ... the previous parts are all in the odd-numbered magazines up to issue 4595.

There have been a FEW !!! printing errors along the series ... some of these have been covered in this thread ... some you may be able to work out ... anything remaining, then presumably you would be putting a question on this thread.

hope this is of some use ... martin

HI PETE ... your first paragraph ... do you mean what the burner actually looks like, or do you mean how the flame behaves ? there is usually quite a lot of difference between the two ... in free air the flame will spread out a lot more than if it is in its fire tube ... the ones I have made have usually been tested inside their tube ... beware, it will get very hot, very quickly !

For the second paragraph ... all the information is in part 2 of the magazine ... photo 13, figure 19 and the text on page 499 ... I do not possess a milling machine so I used a small hacksaw blade as per page 499 ... the slots I made ended up as 0. 017 inch wide ... can you tell me how wide is the slitting saw you used ? is it 1/64 inch or 0. 5 mm or even 0. 43 mm ? ... you said the "bar would foul the mill" ... does this mean the saw started wobbling ? ... or does it mean the tube was awkward to clamp ?

let me know please ... martin

To DMB please ... there is a website for the exhibition ... www.thedoncastershow.com and an e-mail address ...enquiries@the doncastershow.com ... last time I looked for the dates there were no details, but it is a bit early yet ... the usual time seems to have been about the second weekend in May ( 11th. to 13th. May in 2018 )

As regards the walk from the main car park ... it is at one end of the buildings and the entrance is at the other, so it is about 300 or 400 yards along a flat footpath ... there is a smaller disabled car park near the entrance ... there is also a large car park directly over the road. ( a dual carriageway, usually busy )

hope this helps ... martin

HI PETE ... working pressure for the boiler is typically 40 P.S.I ... so its pressure test would be twice this ... i.e. 80 psi ... the gas tank will actually have a typical working pressure of a lot less than 100 psi ... it could even be down at 10 or 20 psi on a cold winters day ... there are many variables for how and where people place the tank in relation to the boiler and hot surfaces of the burner ... the tank temperature and pressure can go up and down like a yoyo !

A few years back I was the boiler tester for a local model boat club for many years ... available advice was limited, but the boilers were tested to 80psi and gas tanks were tested to 210 or 250 psi ... the test rig was made by me and calibrated with a large brand-new gauge ... I just used to get people to remove the boiler and gas tank from the model so the testing panel could test each item individually ... that was considered acceptable ... however, the world has changed and the newest rules for gas tanks now need a pressure test of 350 psi or 377 psi ... it seems to vary with who I have asked over the last few years ... the nearest club to my house, willing to do the pressure test, is 45 miles each way ...I have asked various members of that club how to achieve the testing on 2 or 3 occasions and it seems that they do not yet have a CALIBRATED AND CERTIFICATED gauge that reads up to 400 psi, nor do they possess a force pump that will handle 400 psi ... I have received a lot of blank looks from many people when I have asked them if they plan to get anything organised !!

It might be wise to check with your local M. E. group that they are equipped to do the test ? I tried to work out a timetable and concluded that it would take me 2 days in their workshop to do the full strip-down, inspection, pressure gauge check, safety valve check, gas tank test ( and drain ALL THE WATER ), reassemble everything and then finally perform a steam test on their track.

I am afraid I chickened out and abandoned the idea ... all my locos have tanks tested to 250 psi and they chug happily round my back garden,. but nowhere else !!

If your local society can sort out a simpler method for you then can you let me know please ? I would imagine they are a long way South of my "shed" ... we are way North of Watford !

As regards your question about figure 32 shown in part 5 ... figure 32 and 33 show the suspension bracket ... just above them is photo 28 ... this clearly shows the 2 small holes in the bracket ... in part 6 on page 158, there is fig 43 ... the 2 holes are shown at the base of the drawing for the square piece of metal ... the words "10 BA clear" have disappeared from the drawing !! alongside the figure is photo 36 ... this shows the 2 holes just under the copper pipe heading to the left.

The rear end of the smokebox support fits over the front end of the suspension bracket.

hope this is useful ... martin

HI PETE ... your first message above ... it is very difficult to give an exact length for a piece of pipe with 2 or 3 bends in it ... why not go to your local plumbers merchant and buy a SMALL reel of plumbers solder, 3 mm in diameter ... I think the type with lead and tin is the cheapest ... this can be bent round your fingers and fitted into place to make a template for the copper pipe ... or you could bend it to shape and then straighten it out, then measure it to get a straight-line length ... whenever I do this I usually add 1/4 inch length to whatever I work out ... this excess can be slowly cut down to make everything fit properly.

The BRONZE burner tube ... yes you can use brass ... but over the years, mine made of bronze have lasted longer ... as regards the bronze rod ... is it straight ? try annealing it first, let it cool slowly ... to drill the actual hole down the length ... go in from each end to the middle ... do not force a large bit straight down the rod ... go up in 4 or 5 stages starting at about 1/8 inch ... how old are your drill bits ? to get a clean cut in bronze needs new, decent quality bits ... look at the flutes of the bits ... on the forward edge of each "flute" is a lumpy bit ... usually called a "land" ... this is the part that cuts going down the length of the bit ... if your drill bits are ancient, like most of mine, they will be blunt and cook gently trying to cut bronze ... buy some more of the larger needed sizes ... use some cutting oil to keep things as cool as possible. BE GENTLE, DO NOT RUSH !

The thread for the jet carrier can be 0.488 in length as in figure 19.

The bush for the heat shunt is shown in photo 16, about 2/3 up from the base, it is not critical, just make the heat shunt (photo 14) to join the burner rear to the tank, drill the hole in the heat shunt to make it all fit, AFTER you have made the bend ... there are many ways people would make the bend, all of which would slightly alter the dimensions needed.

The fire tube, as shown in figure16 ... this clearly shows the tube as 22mm plumbing pipe with a wall thickness of 0. 035 ... this is equal to 0. 9mm ... this wall is thicker than 0.6 or 0.7 mm that B and Q also sell / have sold.

Have you actually silver soldered the fire tube into place ? I cannot tell from your message above whether you have already used a piece of tube with a wall thickness of 1.2 mm ... if you have, then you may have changed the characteristics of the burner assembly !!

If it is already in place, then the brass collar shown in figure 19 will no longer fit ... with any of this type of poker burner, the size of the burner tube within the fire tube gets more critical as the two items get closer together ... the larger the fire tube the better ... smaller makes things more critical ... if this is the case then you may have to experiment with air-hole sizes, position, jet position etc ... your tubing with a wall thickness of 1. 2 mm will have reduced the internal diameter of the fire tube by about 12 or 13 thou. on each side ... you may get away with it, I do not know in advance.

P.S. any of the plumbers merchants where I live, will sell me a single length of copper pipe ... take a hacksaw or a tubing cutter with you and cut it in half to fit the car ... find other model engineers locally and see if someone else needs half a length of pipe.

martin

Hi Pete ... well done for sorting out the fork sizes in figure 1 and 2 ... it seems that 2 arrows have moved !!

As regards the length of the new piston rods ... if I understand you correctly, did your new piston rods bear some relationship to the Roundhouse rods?

An idea for the exact thickness washer if you were to do it by that method ... it would be quicker if it was made from a piece of 1/2 inch round brass bar ... after it has been parted off, cut or file from the edge to the middle so it is a "C" washer with a 1/8 slot to the middle ... remove all the burrs ... this would save some of the dismantling.

martin

HI PETE ... my early years seem to be similar to yours ... I was using a soldering iron at 10 and silver-solder at about 13 or 14 ... first of all the piston and its rod ... carefully remove the O-rings ... the end of the piston rod was clamped in the vise ... using a thick leather glove for one hand I gently heated the piston on the assumption it was tight as well as loctited ... the piston was then removed by hand ... later In the proceedings the piston and its rod were put back together with a tight fit and some Loctite ... plus the glove.

There is an old saying about giving 6 people the same problem and possibly getting back 6 different answers ... I have my own saying ... "if it doesn't work, turn it through 90 degrees or reverse the whole idea" ... this is pinned on my workshop wall !! ... given the problem of aligning the cylinders, most people would drill the holes in the frames and try to fit the cylinders to the holes ... my method is the opposite ... I fit the cylinders to the frames and then drill the holes to match.

So, it is not an impossible scenario, it is just a different method of solving it ... there are several ways of accomplishing the fitting ... first of all study the Roundhouse cylinders ... mine have a total available travel of 0. 768 or just over 3/4 inch ... the cranks on the 2 axles are 5/16 throw and hence produce a total travel of 5/8 inch ... this leaves a spare amount of total travel = 0. 143 ... or, there is just over 1/16 inch space at each end of the cylinder ( 0. 071 inch)

I made a washer to match this thickness of 0. 071 with a 1/8 hole in its middle ... this washer was fitted on the piston rod adjacent to the piston and then re-assembled into each cylinder in turn .. place each of the front axle cranks at the rear away from the cylinders, make sure they stay there ... fit the con-rod on one side and then the other in turn ...pull the cylinder forward by hand with the washer inside it ... the cylinder can then be slid into position just behind the buffer beam so it is just clear ... using a scriber, each front frame can be marked round the cylinder base ... do the same for the other front frame in turn, some people may prefer to use a dab of epoxy resin to hold the cylinder ... the cylinder is now in its EXACT position to give exact amounts of clearance at each cylinder end ... this kills 2 birds with the same proverbial stone.

If the holes in the cylinder base are now measured and marked onto the front frames, they can be drilled and the cylinders can be trial fitted ... they should be pointing fairly accurately at the middle of the front axle. I ended up using a short Allen key as well as a long one.

Look at issue 4587, page 762, down near the bottom, the text says "the cylinders can be aimed directly at the centre of the axle" this is the easiest method of achieving the alignment that I can think of.

In the time I have taken to type the above I could have made the scribed marks round the 2 cylinder bases ... it is easier to do it than write it.

This is why I said the height of the front frames was not critical ... the top edge was cut and filed AFTER the cylinders were screwed in place.

I did not want to put all the above into the article in case I was detailing a problem that may not have arisen.

P. S. remember to remove the washer from the second cylinder when you have finished.

Keep calm and carry on, martin

HI PETE ... before you tie my brain in knots ... please can you tell me which sections of your loco are completed ??

Are you a very fast builder ? or are you studying all the plans in advance of building anything ??

With any project over the years I have always found it better to complete a particular section, and solve all the problems associated with that part whilst looking at the completed parts I have made ... that way I get a much better idea of what goes where.

For example, the boiler, is it finished ? have you had it pressure tested ?... not the steam test ... just the pressure or hydraulic test ... do you have a local model engineering society that can do the test ? ... If there is one nearby it might be worth joining so you can ask some questions of other people so that you can get more than one opinion ... I have always found it much easier to actually show somebody how something fits or, conversely, for them to show me something.

As regards the front frames and the main frames, do they exist please ? The height of the left end of the frames is not a critical measurement, about 7/8 will do.

There is a difference between the printed text and my original copy ... on page 290 of issue 4593, 4 lines up from the bottom the first word is "go" it should be "to" ... this could have caused some confusion if it was assumed that a slide was fitted adjacent to the valve.

martin

HI PETE ... the top bronze block does not overhang the boiler end ... its position is not so critical as the lower block ... as shown the top block is flush with boiler end ... the lower block must clear the boiler end by a small amount ... otherwise when the actual gauge fitting shown in figure 18 is installed later in the build it may be difficult to fit a spanner without hitting the boiler end ... both the top block and the lower blocks are best fitted with high temperature silver flo 24 first.

The 2 temporary bolts can be removed once the S.F 24 has been used to "tack" the 2 blocks in place ... yes, the top block is a 9/16 cube ... mine was filed out of a piece of bronze bar about 0.75 dia.

martin

HI PETE ... I cannot see "S.s" on figure 13, however there is one appearance on figure 11, assuming that is the one you mean ? ... the letters "s.s" have moved in the printing process ... they were underneath, between the 2 copper pipes !

In figure 13 the 2 stubs of thread have shrunk in relation to the diameter of the body ... they are o.k. but look a bit small.

martin

HI PETE ...hopefully I can get through everything in order ... the lubricator handle length is not critical ... mine is about 2 inches, some people might prefer it to be low down or up at the top ... or it could have a cross handle, depends on personal preference.

The diameter of the blower valve ? do you mean figure 11 ? the steam valve is 1/4 hexagon or round, to match the 1/4 x 40 thread ... if you mean figure 13 which is the blower valve, the diameter is shown as 0.250 ... s.s = silver solder ... as regards the missing dimensions on fig 11 ... it is labelled as "fig 11" ... on my original drawing there are 3 short lines of typing which would be underneath the label "fig 11" ... these are :- drill 0. 062 for 1. 2 ... drill 0. 098 for 0. 655 ... tap 1/8 x 40 ... for the steam tee piece shown in photo 4 ... in my list of drawings the STEAM FEED TEE PIECE is shown as being in figure 53 ... hopefully this is in part 7 of the new magazine which I have not yet received ... if you say it is not there then it must be in part 8.

For the existing pipes in the cylinders ... the pipes were filed off flush and then carefully tapped 8 BA through the remains of the copper tube ... keep backing the taper tap out of the hole to make sure it does not stick and jam ... I used a brass 8 BA screw, cheesehead, length about 3/16 inch.

For the water gauge position again it is not totally critical ... look at photo 6 and 8 in issue 4583 back in March ... the bottom corner of the gauge mount is approx. in line with the lower part of the fire tube ... yes, the water fill bush is approx. in line with the water gauge mount, best seen in photo 8.

hope this is everything covered, martin

TO THE OILY RAG please ... hi Ian ... again thank you for the information ... I have been building "things" for more than 60 years but only building railways for about 5 years ... any information is useful ... I am slowly building up lots of information files.

martin

TO the OILY RAG please ... thank you for your suggestion above ... my problem over the last few years has been that the commercial wheels I have used were not that accurate ... some of them have been best described as random ... this is why I have measured into the corners of the flanges ( as best as possible ) your idea for the back-to back is a good one ... some of my measuring ends up as needing a different spacer on different axles to allow for the wheel flange widths ... does that mean I should buy better quality wheels ? Is 50 p each wheel not enough ? I was aiming to ensure the wheels would go over some home-made points of 30 inch radius without jamming or jumping out of the tracks.

TO PETE RUSSELL please ... just a thought concerning the gas fill valve ... you have probably already solved this one, but if not, the valve is only tiny and delicate ... so it does not need smashing down hard with a big screw driver ... I took one of the flat screwdriver blades from my 1/4 hex. socket set ... it is 5mm wide ... using one of the grinding discs from a miniature drill I cut a notch up the middle of the blade ... wide enough and deep enough to clear the top of the valve ... this can be used to tighten the valve into the recess so the o-ring is clamped but not crushed absolutely flat ... finger-tight is about all you may need.

martin

Hi Pete ... the metric tap is available from GLR KENNIONS LTD ... the tap is made by APEX ... my catalogue is dated January 2018, and the metric taps are on page 26 ... I have tried a tapping drill of 3.9 mm and also one of 4.0 mm ... both seem to work OK.

The hole you are talking about which is shown as 0.250 dia ... my original drawing shows it correctly as 0.125 dia !!

hope this is useful ... martin

To Jason B please ... oh dear! oh dear ! my original drawing were sent to Diane and a second set were sent to Martin Evans a bit later on ... I still have my original drawings which were photo-copied and sent in to the magazine ... over the series I have corrected a few of my errors, but the majority have been caused in the drawing office. As an example ... in issue 4591, page 158 figure 42 shows the smoke box assembly ... at the front end is a ring to hang the door on ... my drawing shows a dotted line from top to bottom ... the drawing office has changed this to be a double solid line ... this has caused some confusion and has been described as a channel section ... rather difficult to machine I would imagine ! ... the editor has that drawing as a paper copy and also as a CD if it is necessary to check.

I know I am old-fashioned with my methods but I do not have access to any computerised equipment to produce 100% accurate drawings ... if we get to the stage where this is the only method the magazine staff can accept then I should go and hide in a cave along with a few other rejects ... this would leave the magazine free to only receive contributions from people who are totally 100% infallible and possess the latest methods of production ... that would be wonderful, but I am not sure if that would leave very many subscribers to the magazine ... I know I am not perfect because God says so ... but I wonder how many people live in that perfect world?

I wonder why we are having this discussion at this exact moment ? in issue 4592 on page 250 is the "postbag" column with a heading letter from someone in Tasmania ... he is also complaining about drawing quality ... it is a very long letter ! ... I sent an e-mail to the editor on Friday 3rd. of August as a reply to his letter ... this will be published, I hope, in a few weeks or a few months in a future "postbag" ... it would be very relevant to this discussion ... maybe if this string of correspondence is of enough interest it could be published here ? .. if I am not worthy then I shall head for the knitting needles and sell the lathe.

martin

To Peter Russell please ... Hi Pete ... yes, you are correct ... 0.108 dia ... the magazine drawing is slightly different from mine ... someone in the drawing office has moved the arrows to the right and added a horizontal line to make it appear as if the 0.125 only applies to the hole at 7.480 from the left.

hope this helps ... martin

To Peter ... if you look at figure 42 there is a bored out flange formed at the rear inside of the smokebox ... this flange is 0.005 deep ...it is on the drawing ... its depth is 0.315, also shown on the drawing.

Figure 26, the frames ... no, the radius is not a precision size, usually I make it with the rear of a half-round file rather than leave it a square corner.

In figure 43 the brass sheet, you mention is used as a spacer to match up with the suspension bracket ... it is shown earlier as part of figure 32 and 33 ... I think I put the width in as 0.75 back on 22 June as a reply to your earlier question from the 19th. of June

The position of the square upright is to match the centre of the smokebox length ... I usually fasten mine temporarily with a dab of epoxy resin ... then spot mark the holes to match from the front support ... easiest way I can think of is to scribe round the square block and pick 2 hole positions to intersect the brass block 0.187 thick ...if I put an exact dimension for this it would be very easy for the whole assembly, and hence the chimney, to be off-centre ... the 3 holes you mention, one is a drain hole, this is on my original drawing but has not appeared in the magazine unfortunately ... a drawing office gremlin I am afraid.

the 2 notches you mention may be useful later in the build to clear some of the screws ... keep the idea in mind ... everything is easily removable, so if you need them then file to suit.

To latch the smoke box door the simplest way I can think of is to find a strip of mild steel about 1.5 x 0.031 and 0.25 wide ... bend one end up about 0.25 from one end ... the strip can be screwed to the inside of the door and bent to make it wedge on one side of the front ring ... if you use 2 x 10 BA bolts through the front plate these can be filed flat on the outside.

martin