Dapol 08, S7 conversion.

Discussion in 'S7 Group' started by eastsidepilot, 30 December 2016.

  1. eastsidepilot

    eastsidepilot Western Thunderer

    This recent Dapol loco has proved popular with some of the S7 guys and I now have the fifth example on my bench for conversion.

    Start by removing the coupling rod crankpins, be careful with these as they are fitted with some sort of thread lock fluid and I have already had one shear, spares should be available from Dapol having spoken to them at Reading. ( I had to mill the remains out with a 1mm cutter !)

    Next remove the brake linkages, these are plastic mouldings and are held on with some form of waxy glue.


    Remove the clips from the base of the axle boxes and the five screws retaining the base plate.

    The wheel sets can now be lifted out .....


    ....and the wheels and cranks and spacers pulled with a wheel puller. Use a plate behind the wheel or you'll be in danger of pulling the tyre off the centre !

    With the wheels in a set of soft jaws on the lathe remove 0.018" (0.44 mm) from the back only as far as and including the balance weights, the back of the spokes are nicely profiled and there's no need the remove material from the boss.

    (The wheels appear to have steel tyres and Mayzak centres ?)

    This should leave a wheel with a prototypical width of 3.26mm, but please measure the wheels first and then work out how much to remove as I can't guarantee Dapols consistency.

    I use an AGH profile tool on the tyre, the wheel must be held by mandrels bearing on the tyre only with the revolving centre.

    Turn up some axle spacers 1.50mm ( 0.060") thickness x 6mm dia. bored 4mm dia.
    Edit: The axle spacers can be dispensed with and the axles shortened by removing 1.6mm from each end. But please do take your own measurements to double check.
    When the cranks are re-fitted leave off the brass spacer that is originally fitted, the cranks will act to limit any side play by bearing against the axle boxes.

    With the spacers between the wheel and bearings, use the S7 back to back gauge ( 31.25 mm). but before pressing the wheels fully home set the quatering by eye ( R/H lead) , this is quite easy using the spokes and balance weights as a guide.

    Re-fit the cranks using a thread locker such as Loctite etc. noting the postion relation to the balance weights.
    Below is L/H side wheels looking from the cab.

    Below R/H set.


    Re- fit axle sets making sure the current collectors ers not caught on the wrong side of the wheel.
    Refit plastic clips in the axle boxes.


    Re-fit base plate, brake linkages and finally the coupling rods and crank pins with a drop of thread locker.

    There is just enough room for this conversion between the frames, you will not do it with out turning the backs off the wheels.

    NEXT !! :D


    Attached Files:

    Last edited: 4 February 2017
    Caggers, Emma H, Pugsley and 15 others like this.
  2. Scale7JB

    Scale7JB Western Thunderer

    Another coming to you shortly Col..


    Stumpytrain and 3 LINK like this.
  3. richard carr

    richard carr Western Thunderer


    I have a green one as well now Col.

  4. Scale7JB

    Scale7JB Western Thunderer


    Is it possible to chemically blacken the brass spacers before it goes back together? It sticks out like a sore thumb..

  5. richard_t

    richard_t Western Thunderer

    I've got a blue one as well that I'd like converted. I also have a similar thought about the brass spacers.
  6. eastsidepilot

    eastsidepilot Western Thunderer

    Yep, when your ready guys :thumbs:....and yes the brass spacer does need blackening, I can do that when converting if required.

  7. eastsidepilot

    eastsidepilot Western Thunderer

    Just an extra note to my original post, when deciding how much to remove from the back of any wheel, that already has a flange on it, always leave 0.7mm min width of existing flange to give enough meat for the S7 profile tool to work on regardless of how wide it leaves the tyre ( so long as the tyre is not reduced to below prototypical dimensions, 3.26mm ) , take too much and your b******d.

    adrian and Ian@StEnochs like this.
  8. 3 LINK

    3 LINK Western Thunderer

    Morning Col,

    Over on the other side, there is a similar thread but mainly to do with removing those brass spacers completely. The chap has removed the wheel sets and then taken out the spacers and then cut the axles down to the thickness that the bushes were. Supposedly this still keeps the rods and cranks away from the raised spring and running gear detail.

    Just a thought,


    Isambarduk likes this.
  9. Osgood

    Osgood Western Thunderer

    I read that and wondered at the end of it what if any purpose those bushes served! Not had a chance to look yet but seems they are redundant - if anything a thin washer would create adequate clearance between crank and side frame detail.

    Isambarduk likes this.
  10. TheSnapper

    TheSnapper Western Thunderer

    Hi Martyn
    Can you supply a link please - I can never find anything on there nowadays....!
  11. Osgood

    Osgood Western Thunderer

    3 LINK likes this.
  12. Scale7JB

    Scale7JB Western Thunderer

    Isambarduk and 3 LINK like this.
  13. 3 LINK

    3 LINK Western Thunderer

    Hi Tim,

    Oops, looks like I've been beaten to it, Dapol 08 - Page 44 - Dapol


    Ps. A quick edit, also it is easier to fit a speedo drive arm with the rods that bit closer.
    Last edited: 31 December 2016
  14. Scale7JB

    Scale7JB Western Thunderer

  15. fenman

    fenman Active Member

    Only another 950 to go and you will have the full set.
  16. Simon

    Simon Flying Squad

    Really good to see a practical demonstration of improving this already very nice model, thank you very much for sharing it with us.

    If only such a good model of an 08 were available in 1/32 scaleā€¦.

    Isambarduk likes this.