Black Prince Scratch Build

This section is for builds that are not strictly Tamiya or Heng Long. For instance, replacing the electronics from a WSN or Matorro, or even a scratch-build.
enginepeter
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Re: Black Prince Scratch Build

Post by enginepeter »

Thank you for your comments. Herman Bix - I wear blue overalls if machining a mucky Job such as spraying smelly cutting oil everywhere- else old clothes! No need to worry about grey men!

The next stage was to complete the inner hull. As the inner sides were thin alloy (1.5mm) strength would be needed front and back to hold and keep everything rigid.

The front armour and rear panel were made to scale thicknesses. The front proved more complex in view of both the size and shape with differing angles, so to save material and make the job easier it was made in two parts. Even so it took some time to first machine then drill the holes for all later fittings such as the mg mount and drivers port mounts. Especial care was taken with the holes that would be used for the two alignment pins to hold both parts in the correct position before drilling and threading holes for their securing bolts.

Large surfaces were left to fix the hull side plates to and then surplus material was roughed out wherever possible.

An extra thick panel was used at the rear beneath the scale back panel to provide strength and a good mounting point for the side walls, with some surplus material milled out.. To join these two pieces I experimented with Aluminium solder. The process appeared a bit rough and ready compared to using usual solder, but providing the pieces were strongly held in a jig to ensure continuous alignment it worked well enough.

Side and floor panels were then cut and the inner hull assembled. Diagonals were measured at the top before drilling all screw mounting holes to ensure everything was square. No problem at he bottom as the floor plate was square.
Attachments
Side walls and floor
Side walls and floor
Rear plates
Rear plates
Machined front
Machined front
enginepeter
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Re: Black Prince Scratch Build

Post by enginepeter »

Next the sponsons either side of the inner hull.

I acquired some alloy channel section that I cut and machined to size. Front and rear bulkheads were added, held in position by soldering and the 'box' closed with the addition of a roof. Holes were drilled in the floor of the sponson to mount the suspension, these mounting points using 3D printed top hats on the underside to locate/hold the swing arm springs.

The outer sides were rebated at the front so the horns could be mounted flush to the outer wall.

The next stage involve making the four horns and these were first sawn then shaped by filing to a 3D printed template. Thin brass was used to line the axle bearing slots, held in place using dummy bolts glued into the alloy.

The axle blocks were drilled and slotted to run in the grooves. To adjust the track tension the axles for the idler wheels were drilled and threaded 2mm and long socket headed screws were used to adjust the tension. To hold the axle blocks etc. in place, steel bar was used, bolted to the ends of the horns like to original tank. The socket head screws were a variation from the original but I wanted strong screws that could be easily adjusted.

Holes were drilled and threaded in the ends of the horns to hold the steel fittings, the steel studs (12ba size) being thread locked in place. Yet more dummy bolts were used to complete them. (By the end of the project I had spent a fortune on buying dummy bolts (0.8mm, 1.0mm and 1.5mm from Kupfner in Germany) as well as small BA bolts down to 16ba (1.35mm head) size.

Caps were fabricated from brass to fit the outside of the axle blocks and soldered in place.

The horns were then fitted to the sponsons.
Attachments
Completed bearing blocks
Completed bearing blocks
Fitting horns to sponson
Fitting horns to sponson
Tension adjustment on the horns
Tension adjustment on the horns
filing the horn to a template
filing the horn to a template
Completed sponson shell
Completed sponson shell
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BarryC
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Location: Savannah, GA. USA

Re: Black Prince Scratch Build

Post by BarryC »

Fantastic engineering and machining skills! :clap: :clap:

Barry
"Details make perfection, and perfection is not a detail."
Leonardo Da Vinci
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EAO
Warrant Officer 2nd Class
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Joined: Sun May 10, 2020 5:29 pm
Location: Central Missouri, U.S. of A.

Re: Black Prince Scratch Build

Post by EAO »

BarryC wrote:Fantastic engineering and machining skills! :clap: :clap:

Barry
Exactly what Barry said! Amazing skills! :thumbup:

Regards,
Eric.
"You can always tell a German, you just can't tell him much." Anonymous.

German cars, German girls, German beer, German firearms, German Shepherds, German motorcycles... Not necessarily in that order though!

UP THE IRONS!
enginepeter
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Re: Black Prince Scratch Build

Post by enginepeter »

Barry and Eric - Thank you for your comments. You might feel differently about my skill level if you could see the number of pieces in my scrap bin!

After fitting the horns to the sponsons, holes were drilled in the inner hull to mount them to it.

The Idler wheels were turned from alloy, miniature bearings being used for the axles. Tyres were 3D printed using a flexible filament.

Support pieces were added to the sponsons to hold the roof before track guides were also milled then bolted in place.

After fitting the suspension supports and top hats for the springs, the final pieces were the outer skins where holes had to be drilled through this and the sponson for the side hatches. In view for their size these were cut by chain drilling and then filing.
Attachments
Chain drilling hatch hole
Chain drilling hatch hole
Starting to fit outer skin
Starting to fit outer skin
Tyres fitted to idler and track guides on top of sponson.
Tyres fitted to idler and track guides on top of sponson.
Machined Idler
Machined Idler
A few road wheels in place
A few road wheels in place
Suspension support fitted.  Note top hats for springs.
Suspension support fitted. Note top hats for springs.
Drilling holes to fit horn to inner hull
Drilling holes to fit horn to inner hull
enginepeter
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Re: Black Prince Scratch Build

Post by enginepeter »

The next stage involved the fitting of the motors. Before getting to this point the drive cogs had to be made. The panther ones that fitted the track were too big a diameter so two lumps of steel bar were machined for the inner parts and steel plate used for the outers, steel pins being used to keep alignment. Slots were then milled for the cogs before filing to shape.

Housings were made for the small bearing that would be fitted to both the walls of the hull to support the shafts.

A word or two on motors. I bought a 5:1 in the mistaken impression it would be better for a very heavy tank – also they would just fit inside the inner hull with very few mm to spare. I connected everything up for a trial run to check how the tracks ran true as well as to see how the gear boxes coped with the weight. Extra lumps of metal were added as temporary weights to get near the final weight. All was well on the solid floor but it struggled on carpet.

Back to the drawing board and the acquisition of a pair of 4:1 gear boxes. The only problem was these would not fit by a couple of mm. The problem was solved by moving the drive motor on one of them to a different position, by adding a small mounting plate.

This worked fine even on carpet. Later on, however, I reduced the power to the engines to 60% as this would give me a scale road speed and of course this resulted in problems again on the carpet. I have left it for now but at some stage I will probably try to build a pair of gearboxes to give me lower speed but keep the torque.
Attachments
Gearbox with moved motor
Gearbox with moved motor
Machined gear cogs
Machined gear cogs
Bearing Housing
Bearing Housing
Fitting 5:1 motor with panther cogs to check alignment
Fitting 5:1 motor with panther cogs to check alignment
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Will01Capri
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Location: South Scotland

Re: Black Prince Scratch Build

Post by Will01Capri »

Fantastic work, looks great
HL camo E' Tiger
HL L' Tiger
M26 Pershing WW2 project
Tam K'Tiger project
HL Walker Bulldog project?
HL Panzer IV Munitionsschlepper für Karl-Gerät
HL Sherman project?

1/24 Leopard 2 Custom mod

2 many trucks to list!
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43rdRecceReg
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Joined: Fri Jul 31, 2015 11:38 am
Location: North West Highlands, Scotland

Re: Black Prince Scratch Build

Post by 43rdRecceReg »

Following on with a mix of envy, admiration, and sheer astonishment, Peter. :clap:
Note to self: must find a decent mini-sized lathe one of these days. :problem: :)
"Get your facts first, and then you can distort them as much as you please"- Mark Twain.
enginepeter
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Joined: Mon Jul 30, 2018 6:26 pm

Re: Black Prince Scratch Build

Post by enginepeter »

Thank you Will01Capri and Roy. I think I use the drill and file more than anything else. The major problem is eyesight and the size of parts, particularly when they fly off the work bench!
enginepeter
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Joined: Mon Jul 30, 2018 6:26 pm

Re: Black Prince Scratch Build

Post by enginepeter »

To finish the sides, the side hatches were made with working hinges as well as drilling numerous holes for various sized bolts scaled to match the originals.

The top deck was cut from sheet alloy, held in place with a lug at the front and rare earth magnets used at the rear. A hole was cut for the turret ring and a further ring added for the turret rollers, that give clearance over the mudguards.

A rebated frame for the front hatches was made by soldering two cut/filed pieces of brass before work started on fabricating the hatches themselves. This involved some intricate work with the soldering iron and a fair bit of cussing! They were made up of numerous thin pieces of brass and head sinks were the order of the day to stop everything disintegrating.

The air intakes for the rear were also fabricated, using sides and back made of steel that had been silver soldered together. Various pieces of sheet brass added to create the top and grill. Brass lugs were then shaped and soldered to the ends.

To complete the top deck various handles, covers and dummy hinges were added as well as a working barrel lock. The mountings for the periscopes were machined with the rain caps and dummy prisms to be added after painting. Holes were later drilled to mount the traverse motor.
Attachments
Completer top deck
Completer top deck
Rear air intakes
Rear air intakes
Completed front hatches with holes also drilled for periscopes
Completed front hatches with holes also drilled for periscopes
Hole and support ring for turret
Hole and support ring for turret
Completed side panel and top plate
Completed side panel and top plate
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