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Bloody Mary 1/8 Scale


Jo NZ

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On 16/09/2022 at 22:43, Malc2 said:

I don't want to derail your thread too much, but what sparked your interest in making a model of the Bloody Mary?

Its  great subject and I am really pleased you are doing it!

 

Malc.

A good question!  I wanted to fully scratchbuild something, and I didn't want to get overtaken by someone producing a kit before I'd finished it! (That's happened twice so far). I came across BM while researching the Birkin Bentley, and I was intrigued by it's small size and apparently simple build. As far as the size goes, I want to display it next to the 1/8 Pocher Alfa Monza - it's only about 2/3 of the length and half the height.

 

I went to visit my sister in West Sussex in 2019 and Beaulieu is just down the road - well 2 hours down the road - and I took about 240 pictures of Bloody Mary. Not enough, as usual!

 

Did I say simple build ? Even John Bolster didn't remember where all the parts came from, and very few of the components he used are documented anywhere. I was thinking that I'd bitten off far more than I could chew, but then discovered that there were drawings for the engines. Another modeller kindly supplied me with a part drawn 3d model and I could see a way forward. I'm still enjoying it and have learned heaps doing it.

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  • 3 weeks later...

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

 

mag1

 

mag3

 

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

 

Screenshot 2022-10-03 at 10-19-10 BTH Magneto Instruction Book.pdf

 

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

 

Screenshot 2022-10-01 141831

 

Screenshot 2022-10-01 141732

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 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

 

Screenshot 2022-10-11 150709

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

 

IMG_3789

 

 

..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

 

IMG_3795

 

 

IMG_3796

 

 

IMG_3797

 

 

Edited by Jo NZ
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Well done to the people from Beaulieu for being so helpful.

Your resultant "X-man" looks very good indeed.  Well done also with the chain drive.  That would have tested my patience to the limit.

Trevor

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Great update, I know its a bit late, but I found using a small blob of blu-tack on the end of a cocktail stick to pick up the individual chain plates (1/12 bike chain) much better than tweezers for making these chain sets. Suddenly the carpet monster was being deprived of parts!

 

Malc.

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58 minutes ago, klubman01 said:

Well done to the people from Beaulieu for being so helpful.

Your resultant "X-man" looks very good indeed.  Well done also with the chain drive.  That would have tested my patience to the limit.

Trevor

Thanks Trevor. The chain tested my patience too. I think I walked away 4 or 5 times....

32 minutes ago, Malc2 said:

Great update, I know its a bit late, but I found using a small blob of blu-tack on the end of a cocktail stick to pick up the individual chain plates (1/12 bike chain) much better than tweezers for making these chain sets. Suddenly the carpet monster was being deprived of parts!

 

Malc.

I'll try it with the next chain. Please don't mention 1/12 scale chain again, I'll have nightmares....

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  • 4 weeks later...

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

 

Screenshot 2022-11-04 155939

 

Screenshot 2022-11-04 155848

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

 

Screenshot 2022-11-04 160231

 

Screenshot 2022-11-04 160213

 

 

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!

 

IMG_0247

 

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.

 

Screenshot 2022-10-01 154820

 

Screenshot 2022-10-01 154900

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 if the spring support plate, and the spider spring is the same as on the front friction damper

 

IMG_0356

 

IMG_0435

 

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

 

Screenshot 2022-11-04 155545

 

 

Screenshot 2022-11-04 155627

 

 

IMG_3801

 

 

 

Jo

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Wow...  just wow...

 

With the rear tyres, are you revolving the complete tyre, and then using the circular array / pattern to cut the tread around the whole thing, or modelling just a small slice of the tyre & tread, and then repeating that around?  Wondering if that might get around the issue?

 

On 22/08/2022 at 02:25, Jo NZ said:

I printed the tyre in grey resin (I have some flexible black resin 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...

 

 

Have you tried extruding the letters out (perhaps with some draft angle on them), and then trimming them back with a revolved cut, using a cut profile offset slightly from the sidewall surface?  I haven't used Fusion, but am familar with it's sibling Inventor, and used to use Solidworks professionally, and that method would certainly work in those. 

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On 13/11/2022 at 11:15, Paul H said:

Wow...  just wow...

 

With the rear tyres, are you revolving the complete tyre, and then using the circular array / pattern to cut the tread around the whole thing, or modelling just a small slice of the tyre & tread, and then repeating that around?  Wondering if that might get around the issue?

 

Have you tried extruding the letters out (perhaps with some draft angle on them), and then trimming them back with a revolved cut, using a cut profile offset slightly from the sidewall surface?  I haven't used Fusion, but am familar with it's sibling Inventor, and used to use Solidworks professionally, and that method would certainly work in those. 

As you said, I'm using the circular array on the pattern. It worked on the front tyre, but the rear has a more complex tread pattern and I think it's just too many points for my processor.... I will try building a section of the tyre and tread - good idea.

 

I did look at that method for the lettering, but after many tries to get the tread pattern to work I put it to one side! As long as I have four reasonable tyres to use while I'm still building, I'm OK. I'll address the rest when I feel braver, and maybe with a video card upgrade....

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  • 1 month later...

Happy New Year everybody!

It's been a while, I keep finding new things to model, but I'm now scratching around for the last details. I'll soon have to start building....

 

Starting from the front, the bracket on the front axle that attaches the hydraulic damper. I'm planning to use M0.8 bolts to attach it. At first I thought that I could draw in in one piece and slip it over the end of the axle: then I realised that the ends are bigger then the rest. So it's split.

 

IMG_0251

 

 

Screenshot 2023-01-04 140212

 

Next the drivers side of the car

 

IMG_0457

 

There are three tanks in front of the driver, two rectangular tanks and a cylindrical one. The big one at the front is for the methanol fuel, I discovered this by following the pipework out of the top of the tanks, and it goes to... the carbs

 

Screenshot 2022-12-03 150209

 

 

The cap is curious, but I did manage to model the diamond knurl ok.

 

IMG_0299

 

Screenshot 2023-01-04 135939

Next is the cylinder. One of the three hoses from the top of the tank goes through this to the fuel pressure gauge, so I'm assuming that it's a pressure leveller or something. I had wondered about a fuel pump in the past - I've just had a thought that as the tank cap has a thread in the middle of it, the tank may well be pressurised (perhaps with a bicycle pump?).

Far some light relief, I turned the tank from ally, which I can suitably distress. Pictures to follow later...

 

The red tank is a bit of a mystery. I think that it's an oil tank, as the are pumps on the dash for "front" and "rear" and copper tube leading away from them. Bolster used to drain the engine oil before a run to save weight and produce more power, as he reckoned the engines would last the short run up the hill, and they were stripped and rebuilt between each meeting. Maybe these are used to prime the bearings before starting?

 

Screenshot 2022-12-03 150640

 

 

The cap looks familiar, I just can't remember where from...

 

IMG_0296

 

Screenshot 2023-01-04 140033

The steering drop link, conveniently, is very similar to the hydraulic damper arm, even the same length! It has a clamp bolt rather than being part of the pivot. The steering connection has a curious triple slot in the end, so was easier to draw than to machine.

 

IMG_0285

 

Screenshot 2023-01-04 140443 Screenshot 2023-01-04 140640

Finally, the steering wheel

 

IMG_0280

 

This is my third try to get it right. I think I might be there this time

 

 

Screenshot 2023-01-04 140330

 

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8 hours ago, Jo NZ said:

Bolster used to drain the engine oil before a run to save weight and produce more power, as he reckoned the engines would last the short run up the hill, and they were stripped and rebuilt between each meeting. 

That sounds bonkers, your reasoning re the oil tank seems sound though. This just gets better & better. :)

Steve.

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  • 3 weeks later...

Looks like a 1950's homemade garden rotavator!

Seriously good work though, it must be super satisfying as you get the proportions of each part right which in turn allows you to figure out the unknown and those parts then fall in to place making the end result look just like the pictures of the real thing.

 

Malc.

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That looks fantastic Jo. Not a comment on your modelling which is acres better than anything I could conjure up, but the actual Bloody Mary was quite the lash up looking at what you've produced here & I'm sure it is true to the original. 

Steve.

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2 hours ago, stevehnz said:

That looks fantastic Jo. Not a comment on your modelling which is acres better than anything I could conjure up, but the actual Bloody Mary was quite the lash up looking at what you've produced here & I'm sure it is true to the original. 

Steve.

Thanks Malc and Steve!

I decided for the moment to paint it in it's original colours - most of which have worn off... I'll see about weathering when I'm further on. There are some pictures (probably 80s) where BM looks a lot better presented than she is currently.

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  • 3 weeks later...

And now for some paint, assembly, extra discoveries, re-drawing....

First a temporary assembly

 

IMG_3821

 

IMG_3817

 

I still have some more brackets to make for the rear engine (the originals were found to be wrong when I got the front mounts correct) and then I can fit them permanently.

 

The front suspension is painted and reassembled (M1 screws and nuts. I'm so glad that I didn't use anything smaller!) and the Armstrong dampers just need the link to the axle brackets.

 

IMG_3810

 

 

I made the dash hoop by laminating 0.5mm strips of wood (possibly Matai - we have a model shop here that specialises in boats, and he makes all the wood strip). The footwell cover and dashboard are 0.4mm ally. The fuel and oil tanks are placed temporarily. The steering rod (is it a rod or connector?) and steering column are brass rod and tube, soldered and then nickel plated. I bet you thought I'd forgotten how to work with metal!

 

IMG_3813

 

There's a strut supporting the nearside rear suspension. It attaches to the chassis with a bobbin

 

Screenshot 2023-02-20 160156

and a rod, like this.

Of course the other side is different and is made from flat bar....

 

IMG_3815

 

You can see where I've glued the two good bits of tyre together so that BM can sit on her wheels.

 

When I was looking at how the rear friction damper attached (not the one you can see on the pivot, there's another one), I realised that I was missing a bottom connection to the axle. More peering at photos later and I modified the axle holder....

 

Screenshot 2023-02-16 145505 Screenshot 2023-02-16 145832

 

 

It's the grey bit that you can see through the wheel

 

IMG_3820

 

Now to draw up the friction damper, which is (of course) not the same as the others....

 

I love the leg ripping chainsaw. It won't be nearly so visible when the bodywork is on.

 

IMG_3818

 

 

Buoyed by doing stuff with metal, I roughed out the rear deck from ally sheet and  my vice mounted bending brake. Now I have to find 59 rivets (actually slotted screws, but no-one seems to make slotted screws in M1 - they're all cross head). There's a wooden frame underneath but I forgot to photograph it. Next time.

 

IMG_3825

 

 

 

 

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  • 5 months later...

After an absence,  due to an MX-5 wedding present, I've got back to BM. Producing the Mazda logos for the wheels and steering wheel on the MX-5 gave me a lot more confidence in using canvas to replicate emblems and logos. I've returned to the front tyre and added the sidewall detail. Probably the most time consuming activity was finding a font with a flat top 3 and a 9 with a bottom curve for the size marker! The letters are produced in F360 with the text function, extruded onto the sidewall and then cut to height with a rounded profile.

I'm still not sure how to print the tyre - now I have lettering on the sidewall I can't support it there. I was looking at extending some of the tread blocks and extruding them to a curved support. Any ideas?

 

Screenshot 2023-08-14 130136

Screenshot 2023-08-14 130222

 

Screenshot 2023-08-14 130045

 

Edited by Jo NZ
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  • 2 weeks later...

Thanks Pete,, good to see that someones watching!

 

What comes after the front tyre? The rear tyre, of course! This one is a different size, tread pattern and manufacturer, so I couldn't borrow anything off the front.

 

This is it. It's a Dunlop B5 4.00 x 19. (in other words, 4 inches wide on a 19 inch rim)

 

IMG_0282

 

 

 

Fusion 360 doesn't like multiple circular patterns (as I found out trying to build the complete tyre) so I created a 15° segment, which fitted the tread pattern, and built all the details onto that. I've also hollowed it out, which saves resin and avoids uncured resin slowly working it's way to the surface.

Screenshot 2023-08-26 110626

 

 

I needed to adjust the tread pattern to make it continuous across the joins, but once done it worked well.

 

Screenshot 2023-08-26 110437

Note that I've added stiffeners to keep the shape

 

Screenshot 2023-08-26 154004 Screenshot 2023-08-26 153919

And rendered...

 

Screenshot 2023-08-26 111235

 

 

I printed both tyres in normal resin to start with. Chitubox has nearly got the supports right, but I will need to move the ones around the logos for a final print,

 

Screenshot 2023-08-23 132407

 

 

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2 hours ago, Pete in Lincs said:

3D printing and the design aspects are still close to Sci fi. Awesome looking stuff. I like that you thought of the internal supports too.

More like a Dark Art!  Way beyond me.

Trevor

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