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Oct 15, 2019, 06:14 PM
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Build Log

Tiger 1 Tank - 3D Printed..... a fairly big one - 1/10th Scale


I was making a "robot car".....
Then saw a tracked "robot car"......
Then fluked a link to a 3D Printed Tiger 1 tank..... which led to another link of a much bigger 3D Printed Tiger 1 tank.....
By then I was thinking a big Tank might be a lot more fun! With more room in it to add anything I want, plus that is was going to be a 'robot' autonomous vehicle - but now it is going to be a mix of RC and Arduino/autonomous.....

I could sort of see it would be a fairly big project, but it is growing bigger and bigger - in work/time/effort, not size.
So this could be a very long project to complete!!

This specific Tiger 1 Tank version is originally made by Adam Owen, who made it as a PC case(!)... a whole high power gaming PC inside the tank!
http://community.coolermaster.com/to...ion-build-log/
A driveable PC Tiger 1 Tank !
https://www.thingiverse.com/thing:507034

But during investigations and testing of some parts of it I found a LOT needs modifying and improving, so whilst it is based off that tank it will actually be quite different - in construction, the stuff inside (no PC etc)......

Mine will also have a major addition of great importance! SUSPENSION ! I am still designing aspects of that, working out whether it will use Springs or Torsion bars.
It will also have Ball Race bearings for all wheels etc.
The motor drive system will likely be Nema17 Stepper motors, not normal motors running through gearboxes. Though they will still have one gearing stage of the motor Pinion to a larger Drive Gear.

Adam's tank is more of a BASE to build upon - so lots of it will be of great use, though more will be changed (improved) than kept as he designed it!
I have begun the project but who knows how long it will take!!
Last edited by PeterVRC; Oct 19, 2019 at 08:14 PM.
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Oct 15, 2019, 06:31 PM
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Tracks


For some reason the first thing I began with were the TRACKS.
All the pieces to join to make the 'tracks'.

Firstly, the SHAPE is not 3D printed friendly at all ! There is no way it can be placed and printed 'well'.
Adam did it one particular way, so I tried that and it comes out really poorly!
The only way to make it print well was to change it into more pieces that need to be joined later. And even that was a long winded task to work out! It is just a finnicky complex shape/design!

I ended up removing the track 'guide plates' to make them separate items that are glued onto the main track piece. Whilst this looks good, it is unknown how well they will LAST under stress.duress of operation! Mind you the stock track piece, and the poor printing, don't make for a very good and strong piece anyway!
The guide plates fit into 'slots' and are epoxied into those.

Adam, and some other makers, print the tracks in his format, but also as sets of TWENTY pieces at once!
Firstly, that whole printing angle used makes for bad printing anyway.
Secondly, when you print a lot of separate objects it means each one gets ONE LAYER done, then it moves to the next one.. then the next... and so on...
Even with just TWO objects ever done, the cooling of the prior layer before the printing comes back to that object, means the BOND of the next layer is not great at all ! It is just structurally lousy!
Then do TWENTY and you really get poor results!
I tried it....... even though I knew it was destined to a poor outcome....

So now I am doing them ONE at a time!! Over and over and over.... needing about 100+ in total.... (200 ? I am not sure yet)
And mine are properly, solidly, printed items!
Last edited by PeterVRC; Oct 15, 2019 at 09:49 PM.
Oct 15, 2019, 06:44 PM
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Track pins


To join the Track segments, I tested 2.0mm bullet head nails. They are HEAVY, and you also cannot get the 65mm length required.
I found 2.0mm x 500mm Aluminium WELDING rod on eBay, which meant I could cut it to size and it is LIGHT..... and relatively cheap versus all other options too.
AUD$14 for 50 lengths..... 7 pins cut per 500mm length.....

So I have made and joined about 16 track segments so far......
Printing these track pieces will be a quite long term task! Let alone GLUING the two track guides pieces onto each segment, Sigh....
There was just no other way to make them properly......

https://www.ebay.com.au/itm/2mm-500m...72.m2749.l2649


....
Last edited by PeterVRC; Oct 15, 2019 at 09:48 PM.
Oct 15, 2019, 07:12 PM
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Quality


Who knows WHY some modelers (most!) make 3D Printed things with such low quality design!??
The most common one is where they use LOW polygon counts, which means lots of 'angles' instead of smooth curves/surfaces.
Polygons are free!! And a 3D Printer - the Slicer really - has no issue forming the GCode/object that will be printed from a high detail 3D model. So why NOT use better detail !?

You can see in the pics of this Tank by Adam how he used quite low polygon count and thus all the rounded pieces are made with 'angular steps'.
Some are passable.. but many/most are not! So I am redesigning any I am not happy with. It is not overly hard to do, but when there are a LOT of them to do it adds up !

The aim is to at least have a 'decent' looking Tiger 1 Tank result !!

....
Oct 15, 2019, 07:38 PM
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Wheel system


An "issue" in Adam's design is the Wheel system..... It is not correct to the way the full scale was made.
I am not even sure how his 'works'....

The Track segments have two 'guide blades' on them. These run INSIDE the gap in the Road Wheels. You can see in the museum pic below. The outer wheels are a 'pair' with that gap. Adam did not do that - his are a single outer wheel.
You can't see it in the museum pic, but in the black and white pic of welding wheels assemblies those wheel sets are a heap of the two types they actually have.
There are actually THREE wheels per assembly. Either with two wheels inboard and one further outboard on a common shaft linking all three. Or two wheels outboard and a single wheel inboard on a shaft again. And these two types are interleaved, staggered.
The Track segment OUTER Guide Plate goes BETWEEN the outer pair of wheels, in that reasonable gap they have between them.
The Track segment INNER Guide plate goes down the path that runs between the single Inner Wheel, and the next position Innermost Double Wheel.
You can see how the outer Double Wheel set have a large gap - for the Guide Plates. But the inner Double Wheel sets only have a very narrow gap - NOT to fit the Guide Plates.

So I have been editing and modifying Adam's wheel set to be true to full scale. The Tracks themselves are accurate and fine in their current design.
Adam did not set up the Guide Plate paths as per the full scale, and I am not sure how they 'run' - but the wheels will still keep them 'confined' so the Tracks won't run off anyway.

Part of this editing is also making the wheels/shafts 'properly' 3D Printable so they are the least pieces possible AND the required quality and optimal strength.
Plus the new bearings and suspension axle design.

NO SUPPORTS. Using Supports is pretty much the 'enemy' of good 3D Printing quality! Sometime you just have to use them... but that is the minority case, if parts are designed for truly optimal 3D Printing.

.....

So all in all, my current stage/progress is MAKING TRACKS..... and designing the improved, and true to scale, WHEELS...... with Ball Race Bearings added....


OH!!! I should mention.....
The third pic below does NOT have any of the OUTER SINGLE wheels fitted. They would overlap the visible wheels, starting from the 'blank' shaft you can see to the front end. The missing single wheels run right to the outer track edge. As in the 4th pic (B&W).
The 5th pic is the fully restored Tiger1 #131 that was in the B&W pic before it. It is still drivable today..... and lives in a British Museum,
Last edited by PeterVRC; Oct 15, 2019 at 08:02 PM.
Oct 15, 2019, 09:57 PM
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Wheel System


Some changes required on the stock Wheel set design.....
I have not decided on dimension changes, but as they are now you can't run the "Twin wheels with gap" format.
They are only a bit amiss to achieve that, but now I am also not 100% sure on the exact path the Guide Plates do take. To do it as looks to be right is not even physically possible. I need to do more investigating..... but finding good details on the full scale is tricky.

The Track design LOOKS to be correct. Thus where the Guide Plates run... Drive Wheel Sprocket positions.... Width....
I am not sure where 'errors' are.
At worst I can make it "somewhat right" so that externally it will still all look correct.

I won't add the Bearings design etc until I finalise WHERE the Wheels go, and what thickness etc. I suspect I will have to narrow them down a bit....

....
Oct 16, 2019, 12:19 AM
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Wheel System


Now I know why....
I think I should have read MORE about Tiger Tanks first.
It had started as a 'simple' idea of 'grab some Tiger Tank 3D model and make a bigger one'..... but once you start looking at some pictures....

Info:
https://blog.tiger-tank.com/tanks/tiger-wheels/
https://blog.tiger-tank.com/headline...-widths-track/

There were two versions used......
24 Wheels and 16 Wheels.... 16 Wheels having much stronger wheels and were actually better than the 24 wheel version. But a lot of 24 wheels versions were in service/action right to the end of the war anyway.
8 axles with 3 on each..... or 8 axles with just 2 on each....
Basically the outer single wheels were left off seeing they were not needed. Which is why some pictures show them with, or without outer wheel of course.
And also how some pictures show them with narrower 'transport' tracks - even some in museums - versus the wider tracks used for combat.

But I still have a bit of 'rejigging' to do to the wheels anyway..... I have just a bit clearer idea to what to aim for!
I will most likely do the 24 wheel version - it just looks better, meaner... and with their smooth dished faces!

Adam's original version is the 16 wheel version and he just made the Twin Wheel parts as a single wider wheel - which runs down between the Guide Plates.
I have still not verified the definite Guide Plate PATH..... it may, or may not, go down the GAP in the twin outer wheels.... there are no perfectly clear pics or outlines to be found, so far. Though the Wheel 'faces' positions you can see in some pics suggest maybe the Guide Plates do NOT go between those Twin Wheels.....

I can see this is getting to be a bigger and bigger project!!
Also needing almost 50 Radial Bearings..... so those alone will cost about AUD$40-$50
I am planning to use all the SAME bearings everywhere! So that the bulk set of 50 will do !
Oct 16, 2019, 07:03 PM
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Wheel Set/System


So the Track Segments are printing away bit by bit.....
I did a test of FOUR at once and whilst there is visible degradation versus a single segment print, it is still OK. And doing four at a time speeds things up quite a lot ! It will need over 200 in total....
One issue is that the BLACK PLA prints much worse than any other color! Silver and Yellow print beautifully! Black just seems to hate heat... possibly whatever they use to color it. I had tried two different sourced Blacks but they seem much the same.
I almost changed to using SILVER instead - which is more of a silver GREY really. And that looks quite nice, but is just not 'right'....

Meanwhile, I totally redesigned the Wheel System - to be far more to scale. After digging up pics that could be 'measured' to some decent degree, I worked out their thickness and dish shape etc. Pics below....
I pretty much have to print them in BLACK, so that they have the rubber tire portion (black) and then paint the rest to suit the tank. You can't really paint the black tire portion instead as that will rub off on the tracks.

The Wheels and Shaft adaptors etc are not finalised, but my 3D designs are very quick and easy to edit/change - versus the originals are a nightmare to alter anything on them! I have to work out exactly what Radial Bearings I will use, and alter the Wheels/Shafts to suit that. This will also set the exact piece and assembly manner that I will end up making/using. Remembering how I mentioned ALL items need to be 'flat faced' to the Print Bed and built upwards off that, with no supports ever. Thus planning the whole piece/parts and how which part attaches/glues to the next etc takes a bit of thought/time.

I have "visualised" both a Torsion Bar and Spring form of Suspension system. They are quite similar in parts and effort etc. Also both with similar costs to implement. I sort of want to do Torsion Bar, but I see an issue of Spring Strength (Torsion Bar strength) it might cause difficulty with getting right. I am not sure that even some simple 'test set' can be made of use, as you need the WHOLE SET to really test how they operate in total!
This means you really want an easily ADJUSTABLE format/set..... eg can change springs.... and changing Torsion Bars is much harder.
But I am still pondering that part....

I can't really begin the Hull design and printing of that until the Suspension is confirmed! Or maybe I can do the Hull and have a 'Suspension Plate' that fits to the side(s) - bolted - and thus can be changed/altered again at anytime anyway. Hmmm, a good idea!

....
Oct 17, 2019, 05:43 PM
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Wheel Set/System


I designed/decided upon the new Wheel Set System.....
Firstly, it is the first Tiger 1 design of 24 wheels - because those look much cooler!
Secondly, it had to be all 3D Printable in High Quality..... and also have that be 'assemble-able' in a decent and strong manner.
Plus adding the Radial Bearings..... Suspension Arms (which the stock version does not have at all).... and Torsion Bar Suspension, as per the Full Scale system uses.

Any Wheels that can be seen have the correct shapes and details. Some hidden ones are just flat, or simpler.
For the "Dual" Wheel sets they are two narrow wheels with a Spacer in between. This is because to 3D print them WITH a gap/spacer will come out lousy at the gap, but also ONE face - the 'down printed' one, will be lousy also. Thus you need to do them as THREE pieces.
To form the entire assembly of all thee parts, a common 'Axle Housing' is used - which is needed to house the Radial Bearings anyway, so it is just a sensible manner of achieving the total requirements!
The Wheels are a press fit onto the Axle Housing and then Epoxied on. Even the Axle Housing have to be done as TWO pieces, so that the end Bearing 'holes' are 3D printed clean and perfectly at EACH end. Even this need to join the Axle Housings is easy as there needs to be a Bearing Spacer - brass tube etc - inside the Axle Housing anyway, LOL. So this brass tube holds the two Axle housing pieces firmly and aligned (perfectly).... and then the Wheels and Spacers all fit onto the Axle Housing firmly and accurately/perfectly.....
And the end result is ONE perfectly formed Wheel?Axle/Bearing etc assembly!!

A 5mm Hex Button Head bolt is the Axle. It runs through the Suspension Arm, with a Nut to lock it to that Arm..... then the Nut butts onto the Inner Radial Bearing Inner Race..... runs all the way out through the Outer Radial bearing.... and Lock Nut comes in to the Outer Radial Bearing Inner Race.....
Thus the Wheel Assembly is running on two Radial Bearings - one Inboard and one Outboard.

I found a "common mass used", thus cheap, Radial bearing on eBay. 5mm(ID) x 11mm(OD) x 4mm(W) = PERFECT for this system!
AUD$16 for 50 of them.... and they can be used in other areas also.
This is a 'low speed' with 'lowish loads' system, so you don't need costly High Performance Japanese bearings! Almost anything will do fine! (Even just brass Bushes really!!)
I can print a set of 'fake' Bearings to use in the meantime, to assemble a set of Wheels etc. for real-world testing right away.

I did a test print of a Dished Outer Wheel.... it came out great! In Silver PLA at least..... the real ones need to be Black PLA..... or MAYBE Grey PLA and PAINT the tirewalls. I will see how Black PLA ones print out.....

Some test Axle Housings were perfect 'press fits' (Interference Fits) into the Wheel on the first test. Handy - the Anyubic Chiron 3D Printer is accurately calibrated (by me!). Though I rarely TRUST tight parameters and always print a small version for a test to be sure anyway!!

The Suspension Arms (seen in pics here) are not 100% finished, but the design won't change much from what they look like now. They are NOT to scale, as they need to be STRONG in PLA/Plastic. Versus smaller if in metal. They are out of sight so it is fine to be 'wrong' shape/size etc..

A bigger "Not yet worked out exactly" task is the TORSION BARS, plus how to FIT them to the Tank Hull and the Suspension Arm. But I have ideas and am doodling the details now and then as I go along.....

I am VERY HAPPY with the new Wheel set and design! It will look great and Scale..... and OPERATE very well also.
Even the Plastic (PLA) "Rubber" of the Wheels is fine, as that will add NOISE to the Tracks operation/travel. At a small cost in wear.

Oh... a small "Cover" is added to the Dished Wheels as their HUB, to have the scale Bolts on them, plus to hide away the Hex Lock Nut that is down inside the Axle Housing. This is why that Lock Nut is recessed deeper into the Axle Housing....
The Hex Lock Nut has enough clearance to the Inner Axle Housing Walls for a "Tube Spanner" to fit in there to do them up(!!).

...
Last edited by PeterVRC; Oct 17, 2019 at 05:50 PM.
Oct 18, 2019, 12:45 AM
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Wheels AND Tires


DOH....
While I was making/editing some stuff it suddenly clicked..... I am making multiple Axle etc pieces, so why not the Wheels and TIRES also!!
Thus the Tire can be printed in Black... and the Wheel in its color......
This also allows the tire 'edge slopes' to be made for the one side that matters to view. Whereas when the Tire is a part of the Wheel that can be something you have to fore-go on the 'flat printer bed side' of it.

So that is a nice bonus!! Black Tires!
Plus, if I really wanted to, they could be printer in TPU to have RUBBER Tires. Though at this time I am fine with the hard plastic Tires, and the "Tank Tracks Noise" they will help it make anyway.

Now that all the Wheel stuff is decided, I need to modify the HULL so that it can be printed out for FITTING items onto it.
But the Hull needs that Torque Rod Suspension stuff worked out, so that the mounts etc for those can be designed into it.

....
Oct 19, 2019, 08:42 PM
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Wheels and parts test printed


I finalised all the Wheel, Hub, Suspension etc details, so it was time to 3D Print some parts to check out the 'theory' and see if it was going to be all workable as required.
So now I have the two piece Wheels of Rim (Grey) and Tire (Black). The Tires could also be 3D Printed in TPU if I really want them to be soft.
The Tires are an Interference Fit on the Rim - a very tight one! So for a start I will leave them just as that and see how they fare in use. Otherwise they can be Epoxied on later.

The Wheels, Axle Housings, Shafts etc, will be Epoxied together and I also made 3D Printed jigs the you use to ALIGN all the items to be straight and accurate etc. For EG, the Wheels onto the Axle Housing parts. Whilst the two piece Axle Housings are first assembled with their inner brass tube as their alignment device.
So I have 'built in' systems of HOW to assemble multi-piece items easily and accurately also!
This goes for ALL the Tank's items/pieces. ANYTHING that needs to be joined and aligned accurately, is designed with a method to achieve that!

The Torsion Bar Suspension will have a Radial Bearing at the Hull exit point where the Wheel Suspension Arm then fits on. The Torsion Bar - which is really a ROD = Piano/Music wire length..... As per earlier posted pics of another Tank model has them. I better start calling them Torsion Rods !!
To fit the external Suspension Arm, that rod has an "L" Bend that feeds into the Arm and is clamped inside that Arm.
The the Rod runs across the Hull inside and into a metal RAIL on that opposing side.... which is Tapped and Threaded for twin clamping screws that hold the Torsion Rod in a fixed position then. To alter the Suspension 'strength' you can preload the Torsion Rod via rotating it in the clamps.
Both sides, left and right, of course have the same Rail running the length of the Hull - to take all 16 Torsion Rods (8 per side).

There is still some testing to be done to decide on the WIRE SIZE required. 16 Road Wheels, required to carry "X" Kg - unknown - of Tank. I can only do a very rough test of some diameters to calculate/predict a fairly ROUGH range of what it will need!
The Radial Bearings are 5mm Inner Diameter, which is WAY larger than it will need in Wire size! But that is GOOD because I will be making 3D Printed 'spacers' to make whatever Wire Diameter is used fit the Bearing anyway. I would think that maybe 2mm diameter Piano wire would be the approximate need.
The Torsion Rod End clamps can be made larger than required also, thus allowing changing the whole set to a different Diameter Piano Wire if need be.
So there is X amount of Preload adjustment ability, followed by Wire Diameter changes ability.

The design also allows for a SINGLE centerline metal rail, instead of one per outer side, and this means the Torsion Rod is SHORTER and thus a 'stronger' Spring tension per wire size used. Once I do some tests I will decide on the final, one or two Rail system. I guess a Single Rail means less metal, cost and weight really..... even less Torsion Rod length in total. But anyway, TESTS are needed to decide on that....

I have also redesigned quite a few of the stock LOW detail 3D Model items, to be higher polygon/quality - which I will do for ALL items that are visible and thus matter more to the overall final quality of the model. Anything meant to be ROUND now is round..... etc....
It really will be a MASSIVELY modified Tiger 1 Tank than the base model it is all built up from !!

....
Last edited by PeterVRC; Oct 19, 2019 at 08:53 PM.
Oct 19, 2019, 09:13 PM
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Motor Systems


The Tiger Tank's Motor Systems are 'Thought of" but not finalised so far.....
They can actually be done 'last' with no issue - to some degree - but I have it largely planned out.

1) Drive motors will be Nema Stepper Motors (!!)....
Well, that is the plan for now.
They are HEAVY, but give great control - very fine resolutions and effectively 'super smooth' control. When you see all the ready to buy model Tanks they are somewhat 'jerky' and struggle to start/stop smoothly, This is partly the use of a normal motor and gear box, though they could have made better designs of those system too!
The Tank has a TON of internal room, so the drive system will be all made MODULAR and thus easy enough to totally change it to a gearbox system, or whatever else....

2) Turret drive
This will be a 'large' servo modified for Continuous Rotation. Of course a pinion on that to drive a large Ring Gear, and thus will have very fine and SMOOTH operation also.

3) Gun Barrel drive
This will also be Servo driven, but not a direct pushrod idea. It will also be highly geared to allow very fine, smooth, operation.
I actually have to test that idea to see if it might also need a Continuous Rotation Servo running through gearing instead.
It is much more suited to a normal Servo form of operation so there are End Points (for up and down of course) easily controlled.

-----
The Motor System will be controlled via an Arduino setup so that the Tank can be controlled via an RC System AND ALSO via the microcontroller, which then allows a lot of extra options Such as GPS guidance.... intelligent obstacle avoidance etc etc etc.....
And of course even a MIX of both systems operating in conjunction.

Smoke Generator...
Model RC Tanks generally have a smoke generator, and these are quite cheapo to buy so I can fit one of those - or two of those (one per exhaust system) as required.... for some nice extra realism!!

Sound Effects...
I have a 'spare' TSB Mini Sound System lying around, so that can be set up with a bunch of sound effects - including the Engine and Track Noise sounds... machine gun... turret rotation.... etc....
Or you can even buy a pre-made model RC Tank sound system quite cheaply too.

Gun barrel 'firing'.
I only just realised a 'shortfall' in the stock design... the Gun Barrel is fixed. I need to alter it so it can MOVE in and out, when 'fired'.
Luckily the Tank is quite large and there is plenty of room to form/fit this sort of functionality reasonably easily.
Another TASK in the long list...


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