Class 27 From kit to completion.

Discussion in 'Workshop Benches' started by York Paul, Jan 8, 2019.

  1. Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    Actually, I was going to suggest to Paul that a new stretcher may be the answer.. but you beat me to it..:thumbs:
     
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  2. York Paul

    York Paul Staff Member Moderator

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    Will do Steve, funnily enough today I was thinking the most sensible way forward would be to modify the stretcher beam instead as the line of least resistance, now if you rejig those bits I'll take the old ones out and replace with new as requested. Messing with the bogie is going to bring a new set of issues regarding delrin clearances and potentially set up weak spots in the bogie which could very well fail, particularly when considering the torque of the motor and gear drives. I'll get on with the bogie build as originally designed... should keep me happy for a while.It may also be that Part 21 the buffer strengthener plate will need removing or at least reducing across the centre point in order not to foul bogie headstock swing on its axis at the new "correct" ride height... not sure yet but certainly an easy fix if necessary.
     
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  3. York Paul

    York Paul Staff Member Moderator

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    I think a modified stretcher is the way forward, had Steve not redrawn the side profiles (which are the real problem) I would have scratched a new frame from 2mm brass micro channel and refitted a pivot plate which allowed for some shimming in the form of a turntable. I believe Steve and I have both arrived at the same conclusion to solve this but from slightly different routes. :thumbup: So yes Andy the answer lies in a new stretcher beam which you have confirmed too.
     
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  4. Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    Would it help if I I asked for some photos (if possible at that angle?) re the buffer beam and supports?
     
  5. York Paul

    York Paul Staff Member Moderator

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    I'll post you some pictures of the underside of the buffer plate and also the offending profile of the stretcher if you wish Andy. I'll include them in my next build report.
     
  6. Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    I meant the real thing. I can ask Terry.
     
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  7. York Paul

    York Paul Staff Member Moderator

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    Great stuff Andy... and some close up photos of bogie side frame details pls :thumbs:
     
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  8. Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    Leave it with me... not sure how soon it may be.
     
  9. paul_l

    paul_l Staff Member Administrator

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    1st bag o bits ready for the 26 that Toto will be sending to you, the bag of bits for the 27 should be ready for tomorrow as well


    Paul
     
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  10. Toto

    Toto I'm best ignored Staff Member Founder Administrator

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    Great stuff, I'll pick them up on Saturday. :cheers:
     
  11. York Paul

    York Paul Staff Member Moderator

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    Great stuff Dundee...I'll get cracking on it when it arrives. :thumbs:
     
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  12. Toto

    Toto I'm best ignored Staff Member Founder Administrator

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    I'll get the parts into the 26 kit box and get them posted down on Sunday.

    Cheers

    Toto
     
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  13. York Paul

    York Paul Staff Member Moderator

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    The inner bogie frames are now complete less soldering a holding down nut in place and a floating anchor for the motor mount, so after considerable thought and backed up with a same decision by Steve it is deemed best to alter the stretcher beam on the mainframe, this means the bogie is built as designed and no issues concerning gear chain clearances will occur. So this is where we are currently.


    And the first outer frame and the top wrap are now formed together, the lower wraps go on next, note the two tiny vertical slots, this is where the lifting lugs go and these will be located next and soldered from the inside along with the rest of the wraps. A production line will be set up to fabricate these and the two outer frames then put together.

     
  14. York Paul

    York Paul Staff Member Moderator

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    Thanks Toto I shall look forward to receiving this one and making comparisons... do you want pictures posting up ?
     
  15. Toto

    Toto I'm best ignored Staff Member Founder Administrator

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    What did you use to form the bend on the outer wrap at the end ?
     
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  16. York Paul

    York Paul Staff Member Moderator

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    This is what I did, I aligned the centre points together on both the outer frame face and the top wrap and soldered them in place, next I fashioned the top wrap to follow the two downward curves of the frame face and soldered them once I was satisfied the wrap sat properly, this then left each end of the top wrap with the curves to be dealt with. I did this by forming a mirror curve on the frame face which followed the groove line on the top wrap curvature, once satisfied I soldered it. Now the lower wrap is simple because it just follows the route between the axle keeps, the same with the lower end wraps... I'll sort this out tomorrow as I don't intend putting in a full day at work so I'll have some free time before the evening. Now another issue crops up... just study Part 53 which is the axle keep wrap and let me know your thoughts? This piece contains wraps for both axle areas but look at the length on the top face which forms the middle bit over the top of the axle box ... I think it is too long for the width of the axle box space... I'll have to get directions from Steve again.
     
  17. SBt

    SBt Full Member

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    I've been thinking and perhaps I should include some 3d printed formers in the kit for bending the curves like the side frame return to headstock and axle box.
     
  18. Toto

    Toto I'm best ignored Staff Member Founder Administrator

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    I suppose it could only be a good thing in terms of assisting the builder. A little bonus.

    Toto
     
  19. York Paul

    York Paul Staff Member Moderator

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    That is a good idea because forming the radii is a bit of a task in itself involving some delicate tweaking to get the curvature correct on both the top and bottom wraps, I did this alright on the first curve but care has to be given not to stress the etch face through multiple "hit and miss" bending of the part, a measurement diagram would be good to include also. Also can you check out the length of Part 53 inner axle box wrap please? When you split the parts down to the inner U shape the top centre section between the axle keep sides appears to be too long by about 8 mm or so.
     
  20. SBt

    SBt Full Member

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    What It is, is that I added the rolled part of the U to the wrong side :facepalm: when I drew it out in spite of checking it twice.....Ammended.
     
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