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    1. Kit: , by (Yearly Subscriber) Jo NZ is offline
      Builder Last Online: Nov 2022 Show Printable Version Email this Page
      Model Scale: 1/8 Rating:  Thanks: 1
      Started: 12-25-19 Build Revisions: Never  
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      Bloody Mary is a hillclimber, built in the UK by John and Richard Bolster in 1929, when they were both schoolboys. It has a wooden (ash) chassis and was originally powered by a single JAP V-twin of 750cc. Through the years, pre-war, it was refitted with bigger engines and ended up with two 1000cc JAP KTOR V-twins, mounted in tandem. It competed until 1959, when it was put on display at the Montagu Motor Museum - and it's still there. It appears these days at events like Goodwood - the picture below is a from recent visit.

      Bloody Mary in 1/8 scale scratch build-bm1-jpg


      Bloody Mary in 1/8 scale scratch build
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  1. Jo NZ's Avatar Yearly Subscriber
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    On to the front hubs, this is the LH hub and brake drum

    Bloody Mary in 1/8 scale scratch build-img_0261-jpg

    The hubs are slightly different because of the steering arm on the LH side. I drew the RH one, and then mirrored it to provide a basis for the LH side. I tried to convert this to a mesh before I saved it.... Yes I know... The mesh included all components of both hubs, even though half of the components were hidden on the drawing. I saved it and went to bed. Next morning it worked!

    I made the kingpin holes on the axle vertical as I wasn't sure of the camber angle. I've guessed at 2.5ー positive, so the hub is angled instead.

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-07-14-165214-jpg

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-07-14-165408-jpg

    The air scoops are drawn at 4mm (full size) - printing at 0.5mm thick, as a realistic 0.125mm thick part would be far too flimsy. I haven't added the flanges to them yet - for some reason the ducts aren't symmetrical and the 2.5ー angle doesn't help either when trying to mirror. It needs more thought.

    There is actually a gap between the brake actuator (below the kingpin) and the backplate. It will print separately like this and save yet another drawing. I can always save it as a separate mesh if I need to print more. The kingpin is 1/16" brass (actual size 1/2" for an Austin 7) and the rod for the brake actuator 1/64" brass. In my drills that's 1.6 and 1mm

    Bloody Mary in 1/8 scale scratch build-img_3754-jpg

    PS yes I know its dusty, my cleaning tank needs filtering....


    Bloody Mary in 1/8 scale scratch build
    QUOTE QUOTE #62

  2. Roger Zimmermann's Avatar Yearly Subscriber
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    Sorry Jo, the citation from Don is the right one, even if yours can be said too! Anyway, your own project is an interesting one; I wrote that before...
    QUOTE QUOTE #63

  3. Jo NZ's Avatar Yearly Subscriber
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    Some more bits - the front damper arm modified to clear the steering link

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-07-25-120238-jpg

    Steering link end fitting (tie rod end??)

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-07-25-120448-jpg

    Brake actuator arm (this fits to the brake cross shaft and has a rod linking it to the brake pedal)

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-07-25-120618-jpg

    And the bit at the end of the cross shaft that pulls the brake on

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-07-25-120815-jpg


    Coming soon, the front suspension assembled!


    Bloody Mary in 1/8 scale scratch build
    QUOTE QUOTE #64

  4. Jo NZ's Avatar Yearly Subscriber
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    Having nearly got the front suspension finished, and feeling good about it, I decided to tackle the front wheels. They are Austin 7 wheels, and I foolishly thought that information for them would be easy to find... it isn't! There were 3 sizes over the life of the A7 - 19, 17 and 16 inch. I know that mine are 19" because it says so on the tyre. That narrowed it down a bit. Then I discovered that there are two spoke patterns for 19" wheels. Luckily I have the easy to model one with equally spaced spokes. I eventually got the rim width dimension from the tyre data! The rest was "derived" from photos - oh, I did find out that the spokes are 8SWG - a shade over 4mm, so that helped.



    Here's the wheel

    Bloody Mary in 1/8 scale scratch build-fwheel1-jpg

    I drew up the rim and hub together, but without spokes as I will use pins and wire.

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-08-14-132615-jpg

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-08-14-132702-jpg

    I have shamelessly plagiarised Nick's (Unobtanium) method of producing the Bentley wheels. My wheel was easier to draw as there is only one row of spokes at the rim, and only 36 spokes, not 88.



    Here's the rim and hub on the jig. You may recognise the style. ��

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-08-14-132510-jpg

    The back row of spokes are headed and go through the holes in the rim of the hub. I found some 0.4mm entomological pins (for butterflies etc.) which with a coat of paint will look about right.

    All set to go, the components look like this...

    Bloody Mary in 1/8 scale scratch build-img_3757-jpg

    The pins needed careful bending to fit through the hub rim without breaking it.

    Controlling them all was a nightmare until I taped them into threes

    Bloody Mary in 1/8 scale scratch build-img_3761-jpg

    And then without too much drama (once I'd got the pin length right) the back row of spokes...

    Bloody Mary in 1/8 scale scratch build-img_3765-jpg


    Bloody Mary in 1/8 scale scratch build
    QUOTE QUOTE #65

  5. Jo NZ's Avatar Yearly Subscriber
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    The wheel is fully spoked! The guides that I marked for the initial spokes in each row aren't right, which threw me to start with, But it's nearly OK - except for the valve position, which needs to be between two diverging spokes so that you can get your hand in...

    Bloody Mary in 1/8 scale scratch build-img_3769-jpg

    Here it is off the jig and fitted to the hub

    Bloody Mary in 1/8 scale scratch build-img_3771-jpg

    The front tyre is an Avon Speedmaster Mk II. All the main dimensions are available so it was a case of drawing a box to the profile size of the tyre and then copying the profile as best as I could. The tread pattern is very simple and was a good introduction to creating one. I used the "circular pattern" feature, but it gets a bit iffy with over 100 repeats. Saving, closing and re-starting Fusion 360 fixed it.

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-08-22-130518-jpg

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-08-22-130657-jpg

    I printed the tyre in grey resin Bloody Mary in 1/8 scale scratch build (flexible black resin Bloody Mary in 1/8 scale scratch build is on order) and slipped it over the rim before it was post-cured. There is about a 2mm interference (to allow the rim profile to show), so I was pretty pleased that it fitted! I still have to find a way of adding the various scripts to the tyre. As the surface is a bi-directional curve Fusion can't do it yet...

    Bloody Mary in 1/8 scale scratch build-img_3774-jpg


    Bloody Mary in 1/8 scale scratch build
    QUOTE QUOTE #66

  6. Jo NZ's Avatar Yearly Subscriber
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    The rear wheels are 19" Rudge Whitworth. With a 4'' tyre width, the recommended rim width is 2.5", and with no other information, that's what I've used. This wheel has two rows of spokes on the rim, in the centre and on the outside web, 36 spokes at the back and 24 at the front.

    Here are the basic parts

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-09-12-232724-jpg

    The jig is similar to the front wheel. I used 3 spokes on this one so it's easy to tell the difference from the front one. No spoke guidelines, I only get confused!

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-09-12-232636-jpg

    This was my reference

    Bloody Mary in 1/8 scale scratch build-rwheel1a-jpg



    I had to make a shortened spoke nipple for the outer row as there isn't so much rim to go through

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-09-12-164547-jpg

    I spent a while getting the square adjuster right on the end of the nipple, even though it's difficult to see in 1/8 scale....



    First row of spokes

    Bloody Mary in 1/8 scale scratch build-img_3775-jpg

    And a completed wheel

    Bloody Mary in 1/8 scale scratch build-img_3776-jpg

    This time I've got the tyre valve in the right place - where you can get a hand to it...

    I've got some F69 resin Bloody Mary in 1/8 scale scratch build to print the tyres - more on that later.



    Another curiosity on BM is the rear brake. The drum is attached to the rear drive sprocket and the brake actuator (from the outside handbrake) must come from another vehicle, but I've never seen one...

    This photo looks back to the rear axle. The drum is on the right, and on the left of the contraption is the operating arm. You can see the shoe return springs inside the drum.

    Bloody Mary in 1/8 scale scratch build-img_0396-jpg

    The front of the arm is bolted to a piece of shaped steel and rests (!) on top of the gearbox (this is a top view)

    Bloody Mary in 1/8 scale scratch build-img_0397-jpg

    Here's the basic arm, I'm going to use brass for the bit that rests on the gearbox (ooh metal again at last!)

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-09-12-164703-jpg


    Bloody Mary in 1/8 scale scratch build
    QUOTE QUOTE #67

  7. Jo NZ's Avatar Yearly Subscriber
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    Here's all the wheels

    Bloody Mary in 1/8 scale scratch build-img_3782-jpg

    Bloody Mary in 1/8 scale scratch build-img_3783-jpg

    Bloody Mary in 1/8 scale scratch build-img_3785-jpg

    Bloody Mary in 1/8 scale scratch build-img_3787-jpg

    Bloody Mary in 1/8 scale scratch build-img_3788-jpg


    Bloody Mary in 1/8 scale scratch build
    QUOTE QUOTE #68

  8. MODEL A MODEL's Avatar Yearly Subscriber
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    Wow! Really very nice!

    And combining so many materials and techniques / technologies.
    -craftsmanship is a lifelong project of
    self-construction and self determination
    QUOTE QUOTE #69

  9. Jo NZ's Avatar Yearly Subscriber
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    The one component that I had no details for was the magneto. It's buried under the front of the engine and all I had on my photos were tempting glimpses. I scoured the net for details, the first problem being if you google "magneto" it leads you to X-men.... I did find pictures of some magnetos (mainly Lucas and Bosch) but nothing that resembled the scant details that I had. As a last resort, I contacted the Beaulieu Heritage Trust, and sent them the link to the flickr folder where the build photos are. They answered almost immediately with the offer to take some pictures for me! They also identified the mag as a BTH. Searching for BTH magneto turned up a lot more data, why I'd never found it before lies in the depths of google's search algorithm...



    Two of the photos from those wonderful chaps at Beaulieu

    Bloody Mary in 1/8 scale scratch build-img_20220922_095453-jpg

    Bloody Mary in 1/8 scale scratch build-mag3-jpg

    I found a maintenance manual for the BTH mag, it had a scale drawing in it that was almost completely illegible

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-10-03-10-19-10-bth-magneto-instruction-book-pdf-png

    If you turn your head sideways and squint you can just about read the overall length, which curiously is in mm. I scaled off the drawing, here's the result

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-10-01-141831-jpg

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-10-01-141732-jpg
    The drive chain that I'm using is the 1/9 scale MFH chain set. I thought that putting together the 1/6 scale Tamiya Bloody Mary in 1/8 scale scratch build chain was difficult, but this is even harder. The links are PE, 1.6 mm wide and 3.3mm long. You need sharp pointy tweezers.

    I drew up the drive sprocket to match the chain pitch, knowing that there were 10 teeth. I drew it in 1/8 scale - a mistake, as I couldn't use any of the standard parts in Fusion - castellated nuts and threaded rod. Here's the non castellated version
    Bloody Mary in 1/8 scale scratch build-screenshot-2022-10-11-150709-jpg

    I used the drawings of the J.A.P. timing case, with the chain cover on it, to get the dimension and angle for the magneto position. It all looks like this when assembled



    Bloody Mary in 1/8 scale scratch build-img_3789-jpg

    ...at least the rear engine does. I had to imagine the magneto bracket as this is one part that seems to be totally hidden. However, the front engine is canted forwards so that the rear cylinder is vertical. The front magneto is horizontal, so that means another bracket for the front engine...


    The chain still needs a bit of working to get it floppy. I'm hoping it will droop nicely.

    More pictures

    Bloody Mary in 1/8 scale scratch build-img_3794-jpg

    Bloody Mary in 1/8 scale scratch build-img_3796-jpg

    Bloody Mary in 1/8 scale scratch build-img_3797-jpg


    Bloody Mary in 1/8 scale scratch build
    QUOTE QUOTE #70

  10. Roger Zimmermann's Avatar Yearly Subscriber
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    You had luck with people so cooperative at Beaulieu. Not every museum is doing the same!
    QUOTE QUOTE #71

  11. Nortley's Avatar VIP/Sponsor
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    The Tamiya Bloody Mary in 1/8 scale scratch build supplement kit for their 1/12 Honda RC166 is very good and assembles well with the included tool.Bloody Mary in 1/8 scale scratch build-1002280018-jpg The timing chain on my '57 Ariel was bicycle size, so the 1/12 scale might look right as a mag drive.
    Last edited by Nortley; 10-12-22 at 03:31 PM.
    Scorpio - Builds models the way the prototype should have been built.
    QUOTE QUOTE #72

  12. MODEL A MODEL's Avatar Yearly Subscriber
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    To juggle so many considerations, you must keep some sort of journal?

    Excellent work!

    -craftsmanship is a lifelong project of
    self-construction and self determination
    QUOTE QUOTE #73

  13. Jo NZ's Avatar Yearly Subscriber
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    Thanks Don. I'm not quite sure what you mean by a journal. This thread is a journal of sorts, otherwise I have a collection of scribbled sketches and other information.
    By far the most important photo is one that my wife took while I was busy with the detail photos, and it's from directly above (there is a mezzanine balcony). I printed it on A3 and measure and scale it to discover the position of everything. Otherwise I spend a lot of time googling....
    Here's the overhead

    Bloody Mary in 1/8 scale scratch build-img_0457a-jpg


    Bloody Mary in 1/8 scale scratch build
    QUOTE QUOTE #74

  14. MODEL A MODEL's Avatar Yearly Subscriber
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    Photos like that are what I call "Rosetta Stones".

    With a good proportional divider, and a known dimension or two, you can determine the relationship and dimensions of so much! (I know, I know, I'm very old school. -that image could just as easily be used in various softwares to super-impose a ghost image while drafting.) (But I enjoy the old way, and it works for me.)
    -craftsmanship is a lifelong project of
    self-construction and self determination
    QUOTE QUOTE #75

  15. Jo NZ's Avatar Yearly Subscriber
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    With the photos of the magnetos came the solution to another mystery - how is the front of the front engine supported? The engine can be moved in order to tighten the chain drive between the two motors. I could only see half the story in my pictures - now I know.

    There is a frame that rests on the chassis rails so that it can move

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-11-04-155939-jpg

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-11-04-155848-jpg

    Also on this drawing is a (fictitious) magneto mount, in the style of other mounts of the period and placed to put the mag in the right orientation and distance from the motor. I can't see JVB mucking about with different chain lengths or position, both of which would probably affect the timing... Anyway it's almost completely invisible, which is why I don't have any pictures!



    Tidying up some other bits I hadn't modelled, the rocker gear

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-11-04-160213-jpg

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-11-04-160231-jpg

    I started to draw the other rocker, and then realised that I can mirror this when it's printed. Springs will be from my old scrapped printer collection. I decided not to vary the position of the rocker arm, they can all be at TDC!

    Bloody Mary in 1/8 scale scratch build-img_0247-jpg

    Here's a rocker, and in the background, the steering box. No idea what it's from, even John Bolster didn't know. It's far too small to make work (at least, it is for me) so it will be for show only.

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-10-01-154820-jpg

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-10-01-154900-jpg

    I might remove the bracket and make it in brass for better strength



    The rear suspension looked a bit odd, once again like nothing I had ever seen before. When I got down to it it was actually quite easy. I knew the size of the spring support plate, and the spider spring is the same as on the front friction damper

    Bloody Mary in 1/8 scale scratch build-img_0434-jpg

    Bloody Mary in 1/8 scale scratch build-img_0356-jpg

    Needless to say, the other side has a different support strut back to the frame, but I'll make those parts in brass.

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-11-04-155545-jpg

    Bloody Mary in 1/8 scale scratch build-screenshot-2022-11-04-155627-jpg

    Bloody Mary in 1/8 scale scratch build-img_3801-jpg

    Jo


    Bloody Mary in 1/8 scale scratch build
    QUOTE QUOTE #76

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