Highland Railway Drummond 0-4-4T Passenger Tank

Discussion in 'Kits, Kit bashes & Scratch builds' started by paul_l, Jan 11, 2019.

  1. paul_l

    paul_l Staff Member Administrator

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    Thanks Andy

    If I manage to keep all the drive chain between the frames within the tanks, then I have the smokebox, both tank sides, coal bunker and between the frames at the rear. Plus the lower representation of the fire box and ashpan could be filled with either a decoder, speaker or more lead if needed.

    I created a model of the 100DP 15T steel pinion and 30T brass spur gear (two versions with and without bosses). Data on the Ultrascale site.

    upload_2021-2-21_11-44-17.png

    To get the correct ceter spacing, the gears were first aligned on center

    upload_2021-2-21_11-46-51.png

    Then another trip to the Ultrascale site to the Spurgear calculator

    upload_2021-2-21_11-49-7.png

    My gears are 100 DP 15T and 30T. Fill in the values then click on Calculate centre distance button and the result is displayed in both imperial and metric.

    The instructions state that this for a tight mesh (theoretical) and some backlash is required adding 0.1mm (0.004") should be fine, so my final Centre distance is 5.815 mm.

    The 15T pinion was selected and the value to be moved entered into the move dialog box.

    upload_2021-2-21_11-55-32.png

    As the Pinion and spur gear faces are different widths I then moved the pinion 0.3mm to centre the gears

    upload_2021-2-21_12-2-37.png

    These were then grouped together to form a single unit that I can move around.

    As the Worm gear has a boss, the gear is not on the centerline of the chassis, I will rotate the spurs gears to put the motor on centre to the whole gear box.

    I will show that a little later - it's dinner time

    Paul
     
  2. Keith M

    Keith M Staff Member Moderator

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    Getting a bit too technical for me I'm afraid.......my brain hurts!!!:hammer::giggle::giggle::giggle:
    Keith.
     
  3. paul_l

    paul_l Staff Member Administrator

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    Keith - Dinner time - a meal between breakfast and tea time, sometimes referred to as lunch hope that helps :avatar:

    Paul
     
  4. paul_l

    paul_l Staff Member Administrator

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    Ah nuts

    The single 30T/15T doesn't raise the motor clear of the worm shaft.

    Added a second 30T gear and it still fowls

    upload_2021-2-21_16-13-40.png

    upload_2021-2-21_16-14-9.png

    Time to pick some other gears

    An increase in height of at least 2.5 mm is required

    upload_2021-2-21_16-29-25.png

    However that would make the motor too high.

    On the Taff Vale Models Mashima 1833 Compatable motors the motor mounting holes run across the shorter 18mm side, my preference was to have the mounting screws horizontal to make removing the motor easier, looks that will need to change.

    upload_2021-2-21_16-38-14.png

    Back to the drawing board. I would prefer to stay with the 30T spurs (gear dia of 8.13mm) combined with the 15T pinion and 40:1 worm gives 80:1 final ratio. 39T spur has a gear diameter of 10.41mm which would give me approx 3mm of height (approx 1.5 times the difference in gear diameters), the final ration would be 39/15 x 40 = 104:1.

    A bit more playing required

    Paul
     
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  5. Andy_Sollis

    Andy_Sollis Full Member

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    May cost a little more, but if you can draw your own gears, why not get one printed in metal at Shapeways to your own speck?
     
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  6. Gary

    Gary Wants more time for modelling.... Staff Member Administrator

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    Last night I caught up with your thread. Amazing work you are doing Paul. I am surprised that you find time to eat and sleep and do all those chores Mrs L has for you !

    Keep up the great work. :tophat:

    Cheers, Gary.
     
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  7. paul_l

    paul_l Staff Member Administrator

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    Started to make up 3D models of several motors

    upload_2021-2-22_2-24-3.png

    All the motors I have (at the moment) are 1833 Mashima Fit standard motors from Taff Vale models, I notice that an extended shaft version is also available.

    The 1227, 1525 & 1532 motors look interesting being a bit smaller.

    I will make up the other gears and the 30:1 worm & wheel.

    I did wonder (not for this gearbox) whether it would be best doing the worm reduction first before the spur gear reduction as the spur gears would then be rotating at a lower rpm. I would need to see what gear shaft diameters are available to see if its possible.

    Note to self - should have stuck to Suduko puzzles :facepalm: :avatar:

    Paul
     
  8. Vinylelpea

    Vinylelpea Full Member

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    You have far too much time on your hands Paul :avatar:
     
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  9. paul_l

    paul_l Staff Member Administrator

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    Ah but I can justify it - it's at the request of the goverment for public health reasons, although I was begining to think I am developing mental health issues, SWMBO however pointed out that I've always been like this, it's just now she's happy for me to lock myself away and give her some peace and quiet :avatar:

    Paul
     
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  10. paul_l

    paul_l Staff Member Administrator

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    I knew looking at the motors would make a difference

    I've swapped out the 1833 for a 1525 (I will need to order one now) and replaced the 30T spur gear with boss (Type 2) with a 30T boss less (Type 1) spur gear

    upload_2021-2-22_9-8-46.png

    upload_2021-2-22_9-9-46.png

    upload_2021-2-22_9-10-27.png

    I think I can move the worm gears a little further forward, or the motor a little further back.

    To secure the motor, i'm looking at clamping the motor between two bearings the front being effectivley a cast of the front end

    upload_2021-2-22_9-33-0.png

    upload_2021-2-22_9-33-37.png

    The rear clamp being similar but removable to allow the motor to be extracted for maint etc.

    Paul
     
  11. paul_l

    paul_l Staff Member Administrator

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    I think I'm there

    upload_2021-2-22_23-55-42.png

    Just need to round off some corners.

    The red coloured bearings have been made 0.2mm over size as the printer tends to print holes approx 0.2mm undersize.
    I have ordered up some metric reamers from amazon (3mm/4mm/5mm/6mm/8mm/10mm/12mm/14mm/16mm) so will be able to fine tune the holes.

    Order of Assembly - I think :whatever:

    Insert wheel axle bearings into the box.
    Thread in axle, through bearing worm and then the other bearing.
    Insert 2mm ID 5mm OD bearings
    Insert 2mm worm shaft from the front through firts bearing, 30T bushed spur gear, inner bearing, worm gear and rear bearing.
    Adjust worm wheel to be on center to the Worm gear and tighten grub screw.
    Insert intermidiate shaft through the bearing, 30T bossless spur gear and rear bearing (this may need a drop of loctite to secure
    Insert motor into housing with the 15T motor pinion inplace but not secured. Secure motor then align 15T pinion and secure.


    Just need to break it apart and try a print, and then wait for the slow boat from China.

    Paul
     
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  12. paul_l

    paul_l Staff Member Administrator

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    Test print on the way

    upload_2021-2-23_9-38-45.png

    Printing a pair of them

    upload_2021-2-23_9-39-32.png

    3h 20m to go

    Then 6 to 12 weeks for the bearings to arrive, and no definate date for the gears from Ultrascale - subject to Covid restrictions. Seemingly the 2mm dia stainless steel rod has been shipped. Just need to order the motor and a flywheel.

    I have quite enjoyed this bit of the build (think I'm being a bit optimistic as I haven't tried to get it running - yet), and think I will have a go at making up something similar for use with the 1833 motors - I have approx 10 in stock. I may also look at building a bogie / gearbox assembly for the class 21 & 29, class 24 & 25 and the 26 & 27 loco's.
    Looks like I may have to hurry as Boris looks like he's going to penalise modellers and end lockdown.

    Paul
     
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  13. paul_l

    paul_l Staff Member Administrator

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    First the bad news


    Supports failed on one of the prints, the other is perfect


    Ran the 5mm reamer through, which just skimed the surface and passed straight through the 3 bearing supports, same with the other 5mm holes


    Then tried in over the drawing


    And easily drops in between the frames and bushes.

    For this model I will add some filler strips to the sides to make the width up to 21.6mm which will allow me to the gearbox in place, or add some mounting lugs to allow for it to be removed ....mmmmmm

    upload_2021-2-23_21-54-41.png

    Next .........


    Paul
     
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  14. Andy_Sollis

    Andy_Sollis Full Member

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    Er... wow!! Great progress. Shame about the delays. I found some bearings for my turntable from a place in Wales I think? Well this is who I used.
    https://ebay.co.uk/usr/bearingwarehouseltd
     
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  15. paul_l

    paul_l Staff Member Administrator

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    Cheers Andy

    I've managed to get the 2 ID x 5 OD x 2.5mm bearings from them, but they don't do imperial, but found another source for them, so I should get them by next week.
    Also ordered the 1525 motor from Taffvale Models, and a supply of M2 x 4mm cap screws to secure the motor.
    I'm going to order up a selection of 100 DP gears from ultrascale to allow a bit more playing with gearbox design, as I will have quite a few bearings to play with - eventually :avatar:

    Suppose it's back to the chassis now.

    Firebox / ashpan, and bogie next

    Nae rest for the wicked

    Paul
     
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  16. paul_l

    paul_l Staff Member Administrator

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    NUTS

    Went on to Ultrascale site to order some extra gears and just before I clicked to accept I noticed a disclaimer, they are currently running at 5 months backorders.

    Next few hours spent wiping the tears from my eyes, clearing the air from the bad language and thumping the keyboard to try and located an alternative.

    1st issue everyone else seems to supply 96DP and not 100DP :facepalm: :headbanger:

    Harking back to Andy's comment about designing my own ........ Fusion 360 (my copy has now timed out :headbanger: :headbanger: ) and Solidworks both have addons for designing gears.

    and here is the result of a 30T 96DP (no they don't support 100DP either)

    upload_2021-2-24_16-39-34.png

    A 50 min wait to see if these will be any good.

    If they are ok - I am printing with a 0.05mm layer height, I could easily reduce that to a finer amount if required, it will require a redesign of the gearbox to suit the new gears. However I can print any size gears I want, and if the fancy takes me helical or even herring bone gears.

    Back to the drawing board

    Paul
     
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  17. Andy_Sollis

    Andy_Sollis Full Member

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    123d had gears in the right hand slide in. Mine no longer works, but... you can still load them from your HD. Along with light bulbs, lamp shades. Locks, bolts and some other pretty useless mobile phone cases!
     
  18. Andy_Sollis

    Andy_Sollis Full Member

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    Draw one tooth and you can then duplicate around the arch to add the other 99 equally spaced? Or is that what you did?
     
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  19. paul_l

    paul_l Staff Member Administrator

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    Nah far easier on either solid works or Fusion 360 have a gear feature in the tool box, so you define the properties of the gear.
    In this case selected ANSI Imerial \ Powertrain\Gears\Spur gear draged that on to the work plane then set 96 DP, 30T, 2mm bore, Gearface 3mm and click go.

    On taxi duty - back soon

    Paul
     
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  20. paul_l

    paul_l Staff Member Administrator

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    These are the 96DP 30T gears

    OD 8.3 mm, shaft nominal 2mm


    I'm having a play with metric Mod 0.4 gears, teeth are a little bit coarser but the maths works a bit better.

    Paul
     
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