Tales from a sporadic modeller.

Discussion in 'Talk' started by adrian, 4 March 2011.

  1. Dog Star

    Dog Star Western Thunderer

    Given that you and I share a professional background I shall take your comments as a good recommendation for a drafting package, one I shall try out when Peter tells me that we need to get some parts produced by etching.

    thank you, Graham
     
  2. adrian

    adrian Flying Squad

    Given that they are both free it's worth giving both a quick trial. I very quickly got going in QCAD, the shortcuts were very intuitive, snap endpoint was S,E , hatch contour was H,C etc. Entering data from a works drawing I'd click where the line was to start, then hit the space bar takes you to the command window to enter x,y co-ordinates for the next point, preface with an @ and the co-ordinates would be relative to the first point. I was drawing at 12" to the 1ft so I just typed in the dimensions straight from the drawing. I could then set up the print scale at 7/(12*25.4) to get my 7mm scale print.

    Anyway next instalment. Again this is something else that has been sat in my to do box for longer than I care to remember. Many moons ago I purchased a wheel profile tool from the Scale7 stores so that I could turn up wheels for another few planned projects and so to kick off that project I wanted to start on the wheels.

    The wheel profile tool is just supplied as a disc of steel with the correct profile cut in it. It is left to the user to work out how to mount it in the lathe. As I didn't have any square steel stock I found a length of 5/8" round bar. So a short length was clamped in the tool stock holder on the lathe and an end mill in the chuck. The cross-slide travel was limited to a couple of inches but was sufficient to turn the round bar into something square (albeit with rounded corners.) This was then drilled and tapped M5, a steel bush turned up to clamp the profile tool in place. The rest of the round bar was used to make a couple of mandrels for mounting the wheels.

    wheels_3.png

    Here I'm reprofiling a few diesel wheels from Roxy Mouldings. They were very nice to convert to Scale7, only needing 12 - 15 thou removing from the rear face to thin the flange down and then touching up with the profile tool.

    So I now have a set of 2'6" disc wheels to start my new project.

    wheels_2.png

    Getting this sorted has also helped with the 3F kit. As mentioned I'm looking at insulated horn blocks and split axles for this. So I thought I'd get a set of castings and turn them up myself rather than fiddling with Slters wheels. So I ordered a set of tender wheels from JPL to turn up. Whilst not in the same league as AGH I had heard they were an improvement on Walsall Wheels. Although having received a set I'm not so sure - there is certainly a lot of metal to remove!

    Scale7 dimensions max width over tyre 3.26mm, casting width 9.5mm.:eek:

    wheels_4.png

    Maybe the Slaters option wasn't so bad after all. I'll have to see what they are like once they have been turned up.

    I've also been experimenting with the design for the 3F tender chassis. I really like the continuous springy beam suspension system for it's simplicity and equalisation. So my current idea was insulated horn blocks with the spring beam fulcrum points being copper paxolin for insulation. I've used a little bit of milled angle to solder this in position but if I was to get it etched they would just be a set of fold up tabs. The plunger for the axle box goes through the insulated axle box but is not attached to the axle box. This is so that the wheels can be removed as required and the suspension is left in place. It's a bit tall at the moment for the tender chassis, I need to reduce the height by just over 1/8" to squeeze it all in but there is enough slack in the parts to do this. However as mentioned in another thread the Slaters design has changed for these horn blocks so I'll have to get a set ordered to see if it'll still work with the new design.

    wheels_1.png
     
  3. Dikitriki

    Dikitriki Flying Squad

    Hi Adrian

    Here are some pics of my JLTRT tender. This is one of the original ones (a la Eric Underhill) with a nickel-silver etched body as opposed to the resin block. The second one I have is with the resin block, and I much prefer the metal one.

    P1010171a.jpg

    P1010173a.jpg

    P1010175a.jpg

    I replaced both the axleboxes/springs and brake hangers/shoes with Griffin components, but I would be wary of suggesting you get Griffin's brake hanger/shoes as his moulds are time expired. I get 2 packets at a show, pick the best 6 castings, and hand the other 6 back as unusable.

    I had no problems with the build, but I was treating it pretty much as a straight kit build. It takes more time trying to find out what the front of the tender looks like, and toolbox placement.

    Yours

    Richard
     
  4. adrian

    adrian Flying Squad

    Thanks for that, as you mention I have found out that there quite a few variations on toolboxes, coal rails etc.
     
  5. adrian

    adrian Flying Squad

    A quick update - I've spent the time drawing up the artwork for the inner chassis. The plan being to use Slaters insulated horn guides, CSB suspension and split axles, courtesy of the guides from Steph Dale. So with the artwork finished and emailed off to PPD I turned back to the wheels and axles.

    The wheels turned up very nicely, no cold spots or holes, the only problem was watching the lathe disappear under a huge pile of cast iron turnings.
    update_3.png

    update_5.png

    So now I just need to make up the axles, they have been turned up and drilled for the GRP rod. They are currently in the oven for the first bake - curing the epoxy resin.

    Then today the etchings came back from PPD. So my first attempt at etching and I now have a new set of side frames for the tender, hopefully more like JLTRT than the original supplied!
    update_6.png

    The inner chassis also turned up but there are a couple of issues that need resolving so I'll have to get back to PPD before there's anymore progress on that side.
     
  6. Len Cattley

    Len Cattley Western Thunderer

    They look great Adrian, bought myself a book on QCad hope I can do as good as you.

    Len
     
  7. adrian

    adrian Flying Squad

    Prompted by a couple of discussions on other threads I thought I'd show you my etchings.;)

    I'd drawn up an sprung inner chassis for the JLTRT 3F kit I had, in an effort to fill the sheet I repeated the chassis drawing with 3 sets on a sheets. If it works the plan being able to offer them on request to Scale7 people but thought that I should include the Finescale brethren as well. So the sheet had three chassis, two with Scale7 frame spacers and one with Finescale spacers. Unfortunately I didn't check with PPD exact printing details so they took the first one and repeated it 3 times without realising the differences in the frame spacers so the first attempt I ended up with 3 fine scale chassis's. The nice man at PPD was very apologetic and printed off a second etch with the necessary Scale7 spacers. So slightly delayed but this is what I ended up with.
    3f_1.png

    So now I could get cracking on the tender to see if my drawings were any good. Parts were separated and folded. I'd included small tabs to be folded up for the CSB fulcrum points, these have a short length of pcb soldered to them so that the spring wire will be electrically isolated from the chassis.
    3f_2.png

    Something went slightly wrong with the slots on the frames, slightly too wide for the tabs, but fortunately all in the right place. This is the chassis assembled just on twisting the tabs, not soldered at this stage.
    3f_3.png

    The wheel slots have been sized for Slaters insulated horn blocks, although I have included a small fold over tab at the bottom so that the keeper plate can be screwed in from the bottom rather than the side. Here they are just clipped in, no glue as yet. Just waiting for some small BA screws to screw and glue in place.
    3f_4.png

    So I then decided to start looking at the cosmetic side. My etched frame is at the top, that supplied in the kit is at the bottom. Note that the outer tabs at the top of the frame are in completely different locations on the two etches. 3f_6.png

    Guess which one fits in the tender footplate supplied in the kit?
    3f_5.png

    Yes that'd be mine.

    Now that's the end of the good news. The rest is depressing - I often see people refer to JLTRT as NQLTRT, I'm sorely tempted to say FALTRT ( you can work it out yourself.) It's got to the point where I'm sorely tempted to chuck all the bits back in the box and stick it back on the shelf. I'm quite happy scratch building stuff but I thought I'd save a bit of time getting a decent kit that I could just throw together without thinking too much about what I'm doing.

    It just seems that every component I pull out of the box is dimensionally inaccurate. After the palaver of the side frames next is the rear buffer beam.

    3f_7.png

    Yes the rear buffer beam is actually nearly 3mm wider than the footplate. According to the drawings the buffer beam should be 7' 5" wide, that supplied in the kit is 7' 11", a full 6" scale or 3.5mm model too wide. I then dug out the resin block for the tender body.

    3f_8.png

    Again something didn't look right, it wasn't tall enough and didn't line up with the cab side sheets. Sure enough looking underneath.
    3f_9.png

    A 2950 gallon tender. Unfortunately the 3F's (according to the Wild Swan book) were paired with 3250 gallon or 3500 gallon tenders. This 2950 gallon tender is a scale 4' 2" high, the 3250 tender is 4' 10" high so the tender is a full 8" scale too short. So I'm currently waiting for a response from JLTRT about getting the correct 3250 gallon tender supplied, and currently wondering what else is wrong. It's a good job there's no name on the etches, if I met him I'd have a few choice words to say! So now I'm left with the hassle of checking the dimensional accuracy of very single etching because I no longer trust them to have got it right.
     
  8. Simon

    Simon Flying Squad

    Your chassis re-design is a very neat looking piece of work, especially the way in which you have incorporated the Slaters horn guides.

    If I were JLTRT I would withdraw the kit for a re-work or burial.

    Great work, and very well documented too.

    Simon
     
  9. Jordan

    Jordan Mid-Western Thunderer

    Here, hang on a minute.... :confused:

    You mean to say you got these wheels...
    [​IMG]

    ... from those castings :eek: ...????
    [​IMG]

    :bowdown::bowdown::bowdown::bowdown::bowdown:

    Is there anything that can't be done at the Front of the Class....??!!?? :( ;)
     
  10. adrian

    adrian Flying Squad

    Eventually!! Although the lathe disappeared under a mountain of cast iron chippings. I should have kept them for loco or wagon ballast.
     
  11. Dog Star

    Dog Star Western Thunderer

    No, no, no... as ballast for a GWR brake van, now that would be prototypical (some GWR general arrangement drawings of break vans mention the use of iron turnings in the ballast boxes which were built into the underframe).
     
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  12. adrian

    adrian Flying Squad

    So a small update - things are progressing slowly.

    First to bring up to date the 3F tender - the tender chassis was finished to a running state. It works fine and is nicely sprung, however the PCB fulcrum points were a little fiddly so the next iteration I might look at using the etched horn guides from Steph and the Slaters insulated axle boxes otherwise it seems to work as I want it to.

    update3.png

    So the replacement etches for the tender and the chassis development have been written up for the Scale7 newsletter. Once that was done I then turned back to the 4MT build.

    The brake gear has been fitted, although I don't seem to have any photo's of that. I'd been putting it off as the brake hangers were too wide. Actually they are fine for fine scale standards but in Scale7 the reduced wheel width and closer tolerances means that the coupling rods are closer to the chassis in Scale7 than for fine scale. This mean that the rear of the coupling rods were scraping on the brake hangers. I eventually decided to cut the outer part of the hanger off, the saw cut removing enough metal so that when it was soldered back together it was slightly thinner so there is now a little bit of a gap!

    I then looked at fitting the oil boxes and lubricators at the front of the loco. Hence recent posts in trying to find a supplier of copper wire in different thicknesses.

    Starting with the oil boxes at the front.
    update1.png

    Then it was the lubricators - I started off thinking it would help to make them removable so they were drilled and tapped 12BA so that I could screw them to the footplate. However I soon realised that once in place with the drive linkage and pipework I was never going to be able to remove them. Another small modification was required as the castings as supplied only had holes for the pipes on one side, however the photos I have for this loco show pipework on both sides of the lubricator. Also the ones facing forward from the lubricator go straight down so a slot had to be cut in the footplate to fit all the pipework.
    update2.png

    Once this was done I could finally fit the front footplate and saddle to the main body of the loco. It was at this stage it finally started to look like a loco. Once soldered onto the bottom of the smokebox I could then fit the steam pipes.

    The chimney, "dome" and smoke box are just tack soldered into position for the minute. These have to be right, any misalignment will stick out like a sore thumb so I like to tack them in position and leave them. I'll take a few photos and look at it over a few days before I'll be happy they are in the right place.
    update5.png

    update4.png

    update6.png

    Still plenty of detail to add - but it's starting to come together now!
     
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  13. iploffy

    iploffy OC Blue Brigade

    Now
    that is rivet counting, lol
     
  14. Simon

    Simon Flying Squad

    A handsome looking loco, we were pulled by one when we travelled on the Llangollen Railway last week and this build certainly looks the part to me.

    As an aside, I picked up a few s/h MRJs at Carog to read (as you do) and on all of the JLTRT adverts on the rear covers the 3F you are having "tender fun" with is clearly shown with the axle box mountings attached to thin air as you and Richard demonstrated.

    So you were all warned.........

    (On IPad so no smileys available)

    Simon
     
  15. adrian

    adrian Flying Squad

    I thought I'd resurrect (AED required) this long dormant thread as it had the start of the 3F tender so it seemed a fitting place. Having met with Richard and (Northern) Mick of Finney7 at the Leigh show I returned with a new resolve to clear out the erecting shop as I desperately need the space for their imminent releases. One of these items cluttering up the erecting shop being the JLTRT [sic] Midland 3F. As posted earlier the tender has a number of issues so I kept putting off tackling it, I was seriously tempted by the Ragstone tender as a replacement (maybe for another project?) but then it would put the loco to shame so I decided to dive in and build the JLTRT tender as best I could with what was supplied.

    So I made the effort of trying to do something each night, even if it was just 5 minutes cutting out a part, and this is the current state. Basically complete as far as I want it, it just needs a good clean up and into the paint shop.

    3250_tender - 8.jpg

    3250_tender - 9.jpg

    3250_tender - 10.jpg

    So more or less as supplied except a few tweaks. As posted earlier a new chassis and frames were etched, the axlebox castings supplied were completely the wrong style, the bolts for the keeper plates were aligned vertically so these are some Alan Gibson castings which match much better.

    The kit instructions show the steps on a separate hanger plate, whilst there were a couple like this I don't think it was that common. Most steps seemed to be mounted on the frames directly so the instructions got binned and I just worked out things my own way.

    Other changes from the kit - the lamp irons are castings but are far too thick and bulky so the rear brackets were made from scrap etch. Some tenders had a small extension plate covering the front vertical handrails - a little bit of 15thou nickel was cut out and soldered in.

    The etchings for the coal rails were ok for the rails but the vertical tabs weren't connected in places, they should have been half etched but were actually etched all the way through! So I bent up some brass angle mounting brackets and soldered it all up as a unit with the front coal plate and toolbox.

    3250_tender - 1.jpg

    This could then be glued in as a single unit - this is one item that is usually prone to handling problems but this has made the made them surprisingly resilient.

    The other major issue for me was the cast brass brake shoes and hangers. Having gone to all the trouble of making split axles and taking care of insulation sticking bit lumps of brass as close as possible to the wheels didn't strike me as a good idea. As far as I was concerned there were two options either insulate the brake hangers from the frame or replace the brakes with insulating versions. In the past I have always made brake shoes from paxolin sheet for this reason. However this time I decided to use it to practice with Onshape and laser cutting.

    I was pleasantly surprised how quick and easy it was. A quick photo using my phone (found a magnifier mode in accessibility settings) was uploaded into OnShape. I then drew a circle and set it as the wheel diameter so that I had something to scale the image to the correct dimensions. I then sketched around the brake shoe.

    Screen Shot 2017-05-27 at 21.55.17.png

    This was copied a couple of times and tweaked for the different shapes on separate layers, effectively like several etched overlays I was building up the shape from several layers.

    Screen Shot 2017-05-27 at 21.53.28.png
    I could then easily generate a drawing from this 3D image - export it to a DXF file. Import it into the laser cutter software and cut out the various layers

    3250_tender - 2.jpg

    I made the frame around the outside to align the various layers. So no more than evenings work I had made a test sample for comparison with the brass casting supplied.

    3250_tender - 3.jpg

    I was more than happy with the result so altered the drawing to make 3 brake shoes in one set.

    3250_tender - 4.jpg

    These were then fixed to the hangers and soldered into a unit to clip into the tender frame so that they could be removed to enable the wheels to be removed.

    3250_tender - 5.jpg
    The drawings are available in the public area of OnShape if anyone want to view or use my efforts
    Onshape

    3250_tender - 6.jpg

    That's nearly it for modifications - the draw plate buffers to the loco were not supplied but turned from a bit of brass bar.

    The plastic tender body has been a real pain I really didn't like it, the curved tops are too fragile, at the rear you can just see I've had problems with it breaking, it's been glued and filled with putty so I just hope it gets hidden under a coat of paint. On the inside along the length of the tender I glued some brass angle and drilled half a dozen holes for tapping 8BA. So the resin body is bolted to the external frame - these are the main components.
    3250_tender - 7.jpg

    Now to tackle the loco!!
     
  16. simond

    simond Western Thunderer

    Adrian

    I've just read this thread from top to toe. Lots of good stuff, some of which I will surely copy or use as inspiration on my Garratt (see RMWeb).

    One question if I may - which plastic (and from whom) did you use for the laser cut brake laminations?

    Best
    Simon
     
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  17. adrian

    adrian Flying Squad

    Thanks for the feedback - the plastic is the "TroLase Thins" from TroTec
    TroLase Thins - extremely flexible engraving material

    It is quite flexible, it's fine for non-structural items but for strength it would need laminating to some degree. It is quite expensive £33+VAT for a sheet, but that is just under A0 size so it'll last me a long time if all I end up doing is insulating brake shoes!! If you'd like a small sample to try just let me know.
     
  18. simond

    simond Western Thunderer

    Adrian

    Thanks for the info & the kind offer. T'isnt cheap, is it?

    I'm currently doing too many things, one of which is converting my laser from "Newlydraw" (which is appalling) to Smoothieboard & Visicut, which I hope will be rather better, and I also hope will resolve the "wandering datum" issue which has plagued my attempts to etch & then cut.

    I'll put a rain check on your offer for now & maybe get back to you when things are under control, if I may.

    Thanks again
    Simon
     
  19. adrian

    adrian Flying Squad

    There's nothing like having a new kit sitting on the shelf to focus one's mind on the current projects on the workbench ( not sure whether I've mentioned it already but I have a Finney7 V2 in the cupboard :cool:.

    I have above my workbench what originally started as a S7 test track but is effectively now the erecting shop for any 7mm projects I have on the go. To get started on the next project I am going to have to clear out some of the current projects. So to follow up on the tender and the fabrication of the coupling rods I'm pressing on with the JLTRT 3F build to make room in the erecting shop.

    As supplied the kit has a one piece etching for the loco chassis which folds up into a U channel. This forms a rigid chassis and is for finescale which doesn't suit me. So the sides were cutoff and the cutouts were made for some Slaters etched hornblocks I had in stock. These were soldered in place used the steel coupling rods I had made to to fix the location.

    3f - 1.jpg

    The small cutouts weren't wasted as they were trimmed down and drilled to make some fulcrum points for the "continuous springy beam" suspension which could slip over the axle boxes.

    3f - 2.jpg

    I then cutout some new frame spacers from some nickel silver sheet and soldered up the chassis using my high tech chassis alignment jig. A small sheet of plate glass ensures that it isn't twisted. 3 lengths of silver steel ensure that the everything is parallel and the square is to ensure that the axles are square to the chassis.
    3f - 3.jpg

    You may spot some inside motion. This is the JLTRT inside motion - it's going to fill the empty space between the frames but is very similar to that posted recently by Heather. The casting for the axle to drive the conn rods are just eccentrics so it will waggle the motion around a bit but not a prototypical cylinder stoke by a long stretch, but I'm building it with what's supplied so some movement is better than none at all. It did need a little spacing to fit in the wider frames. So all soldered up I now have a rolling chassis.

    3f - 6.jpg

    I then started on the footplate. I know I said I'm just going to build it pretty much as supplied however this doesn't stop me making a few tweaks where possible to improve the look.

    One very small tweak was on the side rails to the footplate. The one at the bottom is the side rail as supplied, note the sharp S curve as the rail widens for the front of the loco. A very quick look at a photo showed this looks completely wrong, the upper rail has been filed to a more sweeping reverse curve. A very small tweak but to me looks far better than that supplied.

    3f - 4.jpg

    The footplate was then tac-soldered together to check spacing and alignment. The rear drag beam in the kit was too narrow so I had to make a new one from scratch. Also the half etch detail in the front buffer beam didn't really match the prototype so a new pattern of rivets were punched on the front buffer beam.

    3f - 7.jpg

    So this is where I'm up to now. Time to start added some of the above footplate detail. I've given up on the instructions, the drawing are virtually useless some secondhand faxed drawings - I've seen more detail in a pixelated crime watch photo. So I'm just cutting out bits from the etches and trying to decide what they were intended for which makes it entertaining!

    3f - 5.jpg
     
  20. adrian

    adrian Flying Squad

    The momentum continues so a small update to the 3F build.

    The next stage was sorting out the splashers and dummy frames. The etched splashers supplied don't have any half etched rivet detail but it is noticeable on the photos I have, so a little work later produced the following.

    3f - 1.jpg

    The splasher tops were over length so I then made up the splashers as units, bending the splasher tops around a suitable sized piece of tube. They could then be cut back and filed to sit flat.

    3f - 2.jpg

    On the footplate there are half etched slots which are presumably supposed to help locate the splashers unfortunately the slots are too wide apart so that when I put the splasher on there is a small gap between the splasher front and the footplate. The bizarre thing is that in addition to these etched splashers the kit also includes a set of whitemetal castings for the splashers, but these are even narrower than the etched version!!:confused:

    Either way I wasn't happy with the situation - I know I was intending to build as supplied but this needed sorting.

    3f - 3.jpg

    So various options were considered, from filling it with solder to making a completely new footplate. In the end I opted for getting a small length of brass angle and using it to fill the half-etched slot flush with the footplate. Dressing it a good 6" file got it flush with the footplate.

    3f - 4.jpg

    The splasher now fits a lot better with now gap to the footplate, this is just rested in place - no solder. Also to note is the small tweak to the dummy frames. There are too many half etched rivets in the dummy frames, only 6 are needed to punch through in front of the splasher, there is another one further to the front but this wrong and would end up in-front of the smokebox so should not be punched through. There is also the lifting hole which needs to be drilled.

    3f - 5.jpg

    So this is where I'm up to, the front 4 splashers tack soldered in position - the cab is next.

    3f - 6.jpg
     
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  21. Kev T

    Kev T Active Member

    Very nice Adrian. I keep hearing references to JLTRT as meaning Just Like the Rong Thing, this is just another of theirs that's not quite right. Pity really as I know several of our members have built JLTRT diesels which have gone together beautifully, look the part and have had first class support from them.

    What do you use to punch rivets? I've recently had a go with a Reynalds rivet punch which was just superb but unfortunately no longer available.

    Kev