David Andrews Princess Royal - 6206 Princess Marie Louise

Discussion in 'Platform1mrc 2022 Loco Build Competition' started by Rob Pulham, Feb 3, 2022.

  1. Rob Pulham

    Rob Pulham Happily making models Staff Member Administrator Feature Contributor

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    I also have a Hex collet block, but with thin walled tube it has a tendency to be deflected unless you take very light cuts so it's probably not far off as accurate to use a file.
     
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  2. Rob Pulham

    Rob Pulham Happily making models Staff Member Administrator Feature Contributor

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    The first stage of fitting 3D printed brake blocks is the hangers. Sadly the nice cast brass hanger are far too thick for the replacement block so it was either make some new from nickel sheet or try to mill off the shoes from the etches supplied in the kit. with the make new ones as a back up plan I decided I had nothing to lose in trying to mill of the shoes and use the existing brake hanger etches.

    So far so good. I now need to trim off the remains of the shoes, solder the fronts and backs together and then probably file a little more off to make the shoes fit.

    David Andrew Princess - milled off brake shoes.jpg
     
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  3. Mossy

    Mossy A classic grump Yorkshire man Full Member

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    It sounds to me that printing those 3d brake blocks has resulted in an awful lot of extra work to fit them to the hangers. I hope the effort is worth it.
     
  4. Rob Pulham

    Rob Pulham Happily making models Staff Member Administrator Feature Contributor

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    Not as much work as trying to sort out shorts when the brake shoes touch the wheels... I am sure it will be worth it in the long run.
     
  5. Rob Pulham

    Rob Pulham Happily making models Staff Member Administrator Feature Contributor

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    This week has seen a bit more progress on the Princess Royal. The brake shoes are now fitted to both sets of hangers. Next job is to remove those already fitted to the tender and replace them and then fit the others to the loco

    IMG_0003.jpg
     
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  6. Mossy

    Mossy A classic grump Yorkshire man Full Member

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    I hope you haven't lost track of which go where. :headbanger:

    Mossy
     
  7. Rob Pulham

    Rob Pulham Happily making models Staff Member Administrator Feature Contributor

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    I haven't had much time on this since my last post as I was asked to produce a video for the next Gauge O Guild Virtual show in November which was made up from thirteen separate videos and and numerous 'retakes' I hope it was worth it.

    I should be back on the Princess mid next week.
     
  8. Rob Pulham

    Rob Pulham Happily making models Staff Member Administrator Feature Contributor

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    Although not strictly speaking part of the competition build, I started to fit the replacement brake shoes to the tender first.

    Having stripped it down and removed the brake castings I quickly discovered that I will need to re-drill/position the brake hangers for the shoes to fit snugly to the wheel treads.

    IMG_0001.JPG

    IMG_0002.JPG
     
  9. Mossy

    Mossy A classic grump Yorkshire man Full Member

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    Rob,

    I could have easily printed brake hangers if you had asked, it would have saved you having to grind them off.

    Mossy
     
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  10. Rob Pulham

    Rob Pulham Happily making models Staff Member Administrator Feature Contributor

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    It would, and I apprecite the offer but I am not sure how resilient they would be on a loco, especially as it isn't mine. I would hate for them to get broken off while painting (which is being done by Warren Haywood) after I had thought that my bit was done and dusted.
     
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  11. paul_l

    paul_l Staff Member Administrator

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    I think the next batch of resin I order I will try a bottle of the tough resin to see if the detail is still present and if the parts are more resiliant.
     
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  12. Rob Pulham

    Rob Pulham Happily making models Staff Member Administrator Feature Contributor

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    More progress has been made this week and the loco and tender brakes are now complete.

    Tender brakes.jpg

    The loco brakes were a bit more interesting in that I didn't have to re-drill the mounting holes. However the brake hanger etches have a square hole in one end and a round one in the other so using some 1mm square bar, some tube and some 0.9mm rod I made up some mounting brackets

    New-Out99999.jpg

    These fitted nicely except for the rear pair which wouldn't fit between the rear wheelsets without touching. Not to be deterred I rounded the end of a couple of pieces of 1mm square bar and fitted that instead. I also had to shorten the brake cross beams by approximately 1.5mm either side so that the brake hangers didn't splay out beyond the wheels.

    New-Out99999.jpg

    IMG_0001.JPG

    The red bits are electrical sleeve, there to retain the brake hangers until I am confident that I can solder them up.
     
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  13. Mossy

    Mossy A classic grump Yorkshire man Full Member

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    Paul

    Who sells the 'tough resin' and what do you know about it. It could be really useful for brake gear etc. Currently I am loathed to do prints that are less than 1mm thick because of the brittleness of standard resins. As an example one of the models I posted to Rob, well wrapped in bubble warp etc got broken in the post, a lesson learned, any further deliveries will be hand delivered either at an exhibition or by travelling up to Wensleydale, luckily it's my favourite dale so any trips will be combined with a walk or a cycle ride hence the interest.

    Mossy
     
  14. Rob Pulham

    Rob Pulham Happily making models Staff Member Administrator Feature Contributor

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    After fitting the brakes I decided to return to the loco body to move that forward.

    That started out as a one forward one back because I had to re-solder the boiler section as for some reason the soldered seam had failed. Still better that it failed now than when the loco is finished. That little job done I looked in the box and sighted the chimney casting so decided to tackle that.

    There was quite a bit of discussion about the David Andrews Chimney, or to be more accurate about all the chimneys in the kit's that are/have been available for a Princess Royal with the consensus being that none of them were accurate. Mike Hopkins was commissioned to draw up and have cast an accurate replacement (by David Hill at Gladiator I think). Noting that I was building a Princess Mike dropped me an email and asked if I would like a replacement for the kit provided casting and I took him up on it.

    Now I have to confess, having used one of Mike's chimney castings on the Class 5A, that I am not wild about the way that Mike designs the flare/inner chimney. I understand that being 3D printed the chimney needs to be supported and that those supports have to be cleaned up so adding them at the bottom makes sense I much prefer to remove the usual screw thread/stub from the bottom of the chimney, drill it out and them use the smoke box wrapped in wet and dry to smooth out the flare to make it sit on the smoke box properly.

    IMG_0006.JPG
    Although I forgot to take a photo of the Princess chimney before I started I had a J63 chimney in stock (for when I get around to swapping the lopsided one off my J63). The Princess chimney was similar to the photo above in that it had the remains of the casting sprue attached to one edge of the hole and the remains f the supports around the bottom of the inner chimney and the flare.

    I started by cutting off the casting sprue and then had made a start on the laborious job of filing out the rest when I thought that I could pop it in the lathe and use a tiny 3mm boring bar to remove the remains of the sprue from inside the chimney. To stop the rim getting marked I wrapped it in a strip taken from an aluminium drinks can (I have a few cut down cans in the workshop for just such tasks). Suitably protected I put the chimney in a collet and centred it as best I could (it still had a slight wobble). Then working steadily taking 0.1mm cuts I bored out the remains of the sprue. I also shortened the inner chimney by approximately 2mm which took care of the stubs of the supports.
    IMG_0005.JPG

    IMG_0002.JPG

    That done I used a diamond coated mini drill attachment to grind of the remains of the stubs on the base of the flare.
    IMG_0001.JPG

    IMG_0003.JPG

    At this point the hole in the smokebox is only about 1mm in diameter and I was wonder about the best way to enlarge it as the inner chimney is just over 10mm in diameter. I decided to use the practice smokebox that I ad created to ensure that I could successfully roll the thick material of the smokebox.
    As luck would have it I have a 5mm centre drill which up to now has been too big for anything that I might have needed. It was perfect to drill a hole and then use the countersink part of the bit to slowly open out the hole in the smokebox until the chimney would fit.

    IMG_0004.JPG

    This confirmed that the chimney would sit flush on the smokebox so now I just need to open out the hole in the proper smokebox to suit.
     
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  15. paul_l

    paul_l Staff Member Administrator

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    Great progress - completion is getting close.

    Regarding the brake hangers, for the tender all 3D printed parts would be fine as the tender sides will protect them from fingers, the loco on the otherhand, I think the approach Rob has taken is probably the wisest as these parts could easily be touched when handling the loco.

    Although Anycubic's ABS Like resin may change that view

    [​IMG]

    Paul
     
  16. Rob Pulham

    Rob Pulham Happily making models Staff Member Administrator Feature Contributor

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    Since my last update the loco seems to have fought back a little. I am not sure whether it was that I had folded the sides of the cab floor too tightly but the sides needed trimming down to fit. That said it's a snug fit in the cab so it's probably unlikely.

    IMG_0001.JPG

    IMG_0002.JPG

    My next task which again needed a lot of work for very little to show for it was the upper frame sections that fit between the splashers. Each piece was between 1mm and 2mm two long so they had to be patiently cut and filed until they fitted in the space between the splashers and seated properly.

    IMG_0005.JPG

    Still a bit of cleaning up to do.

    Having sorted the cab floor I looked at the upright pillar that support the cab doors. These have a pair of slots in them to take a half etched tabs on hinges of the cab doors. Again I am not sure if it was me but once I had folded the small section that is bent at right angles the slot was completely closed. To be fair that wasn't an issues as I had already decided based on past experience to make the cab doors removable.
    This I did by soldering a couple of short lengths of micro bore tube in between where the holes should be (even though the holes were no longer visible, there was a half etched recess). Then I used a small broach as a spacer and folded the half teched tabs on the doors around to make a hinge and inserted a cut down dressmakers pin to hold the doors in position while leaving them free to move and removable by lifting out the pin.

    IMG_0001.JPG

    IMG_0002.JPG

    Next I fitted the rear cab roof arch and started to form the cab roof.

    IMG_0006.jpg

    The cab roof was a challenge in it's own right and required quite a bit of coaxing to get it to curve to the right shape being half teched nickel I was very conscious of it wanting to crease across the top where the two strips either side of the opening are.

    IMG_0003.JPG

    In the end to get it to stay in shape with a chance at being soldered to the top of the cab I used a piece of scrap etch as a former/stay. this fits just inside the rear arch frame. I dropped lucky in that where one of the sections of arch was removed from the etch left this strip which was at exactly the same curvature as the front/rear so perfect for the task once the cusp etc was cleaned up.

    IMG_0004.JPG
     
    Last edited: Nov 18, 2022
  17. Steve Fay

    Steve Fay Full Member

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    Shaping up to be one of the best Princess builds I’ve seen
     
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  18. York Paul

    York Paul Staff Member Moderator

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    I'm fairly confident in saying Rob that your Princess build is the most comprehensive kit build I've seen so far. Lovely craftsmanship as usual but this one exceeds everything. :tophat::tophat::tophat::tophat::thumbup:
     
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  19. Rob Pulham

    Rob Pulham Happily making models Staff Member Administrator Feature Contributor

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    Thanks Gents I am enjoying it despite it putting up a fight now and then.
     
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  20. Mossy

    Mossy A classic grump Yorkshire man Full Member

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    It seems to me Rob the main fight is between yourself and your incredibly high standards.
     
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