Newbie Scratch Build - D575A Dozer

[Originalrob]

Hi everyone and happy new year to wherever you may be !

This is my first post and I must say I think its harder to start this than the actual build ! I have been a long time lurker and reader of builds ( Coopers D11 was the first one I looked at and envied :D ) as I had accidently stumbled across this hobby a year ago on youtube. special mention to Titandigs, DR8 and the guy with the Dresser ? excellent builds and I am in awe of such dedication and workmanship. As a bit of history my day to day work has nothing to do with machining or engineering and 6 months ago I brought my first mill and lathe ( smallish). My available space is tiny so I have to be very studious as to what tools and equipment I gather. I have to date I have turned countless £'s ( I am UK based) of brass and steel into worthless chips on my shed floor :). I find it very calming and therapeutic ( apart from the cost of the metal itself!)
I thought long and hard about doing a build thread and I figured eventually that I should try and help the next new guy as you longtimers have helped me so far. I figured it may help some others based on the other side of the pond like me and also I can ask critique from the more experienced builders here ( very selfish of me but I'm getting stuck on a few things!). so where to start ?
Well I grew up in the bush in Tasmania and was always around heavy equipment and I remember an old guy with an equally old D8 working on our farm which lead me to the desire to make a dozer of some sort. There are a lot of cat fans here and amazing builds to match so I decide to go another route. I have decided to make this :

https://i.postimg.cc/XGySkgPp/D575-3-D-Model.png (https://postimg.cc/XGySkgPp)

I think its mainly a mining dozer and it looks different so here goes !

This is what I have built to date :

https://i.postimg.cc/D4Fj4d3V/IMG-3410.jpg (https://postimg.cc/D4Fj4d3V)
https://i.postimg.cc/y3Pfmg7D/IMG-3411.jpg (https://postimg.cc/y3Pfmg7D)
https://i.postimg.cc/1nrNWD2r/IMG-3404.jpg (https://postimg.cc/1nrNWD2r)
https://i.postimg.cc/MXtQVbyW/IMG-3397.jpg (https://postimg.cc/MXtQVbyW)

plan is for an all steel build with some cosmetic top parts beingd 3d printed (may eventually make everything in steel)

ill post some more descriptions of work done to date and pics ( I am not sure how this posting works :confused:)

Cheers

Rob

[egronvold]

Yoy’re off to a good start :) Looking forward to see the progress.

[Lil Giants]

So what scale you building in?

[Originalrob]

Its been an ok start but I guess the pictures don't show all the drawings, searching, reading and trawling forums for the last 6 months to get to a point of something tangible on my dining room table even though its just a few bits of metal bolted together ! Actually when you finally decide on what to build and a scale that's only the beginning and a whole raft of decisions become apparent - motor size, realistic details or more functional, build materials, what you can actually build at home and what has to be outsourced, electronics ( I haven't even looked at this yet:jaw:) and hydraulics/actuators etc. Looking and reading others build threads have been the most help as they are slightly different in lots of ways and shows that you can achieve the same result by using different designs.
I have finally decided on a 1:14 scale although it was originally more a 1:16-18 size. I found that trying to build the tracks was a pain in the *** so brought some roller chain with attachments to shorten the process. This made me upscale to 1:14 to make things look the right size but somehow the roller chain didn't cut it for me in the looks department ( wanted more detail) and I switched back to home made links:
https://i.postimg.cc/PN7FKhMF/PHOTO-2020-01-01-19-07-24-5.jpg (https://postimg.cc/PN7FKhMF)
i decided to stick with the 1:14 scale as i had gone down that road to far already to turn back and plus the additional size made things easier to squeeze things inside and or make parts.
With the amount of time they take to produce, i am still worried that the tracks wont work properly somehow. I think i will just make one side complete with pads and run to make sure its all ok before continuing further. 3d printing is also a great help to make functional prototypes
https://i.postimg.cc/xq9mXFNx/IMG-3401.jpg (https://postimg.cc/xq9mXFNx)https://i.postimg.cc/pm38yWKz/IMG-3399.jpg (https://postimg.cc/pm38yWKz)
but without cnc, my manual milling abilities still has some variance that's not there on a 3d print ( still learning the milling operations as its my first mill)

Fusion 360 has been a revelation in the build and has helped me no end plan things out before spending time and money on possibly wasted parts. I purchased a 3d model and started scaling and drawings parts in fusion 360that I could use and make:

https://i.postimg.cc/Sntv1MC8/iso.png (https://postimg.cc/Sntv1MC8)

As my mill and lathe is on the smaller side, there is only some much time in the day to make parts so I decided to design parts in a sort of a layered manner to have someone laser cut the rough outlines for me to mill all the finishing touches and tolerances. I can then weld or bolt together the layers and grind/mill to shape.

For the mechanical moving parts and drive train i have been trying to utilise readily available parts like bushes, bearings and pins to minimise my machining time but still ended up making what seemed like a million 6 mm brass sleeves for my track pins https://i.postimg.cc/Z0sXg6JH/PHOTO-2020-01-01-19-07-23-6.jpg (https://postimg.cc/Z0sXg6JH)
i love having to learn new skills to make parts I cant buy !

I am currently working on finishing one side of tracks ( tedious so i am trying to do 3 sets of links a day ) and breaking this up by working on the drive train design and internal mounts for the motors etc.
i do need some advice of the sprocket RPM etc but will put some questions together tomorrow and post
cheers for now
Rob

[frizzen]

Heck of an introduction there.
Very cool machine, should be really unique once it's done. Are these used inside mines?

Maybe check if it lets you choose a little bigger format for the pics?

[Jared]

Dang, you're off to an impressive start for a first build. Those track links are beautiful!

Frizzen, if you click on the pictures it'll open a bigger one.

[Hemi1966]

Great start Rob:)
I had to check how big this thing really is, and it's huge:eek:

Also very well said about the amount of work you have to do before you start making any parts.

[Originalrob]

I worked out the larger pics hot link :)

https://i.postimg.cc/wjTt1kvT/IMG-3420.jpg (https://postimg.cc/1f2RTwwL)

Half way through the track links for one side today.

I have also been trying to work out the drive train

printed a motor mount as a prototype to hold the 2 motors at the right angle to the drive shafts. I put the motors on an angle pointing at the axle so I would have to add in another set of gears before it turned 90 degrees. I have a 1:1 mitre gear set to get it to the sprocket.

https://i.postimg.cc/7L5fVY0F/IMG-3422.jpg (https://postimg.cc/cKNx1WDh)

https://i.postimg.cc/Z5RRbK7W/IMG-3423.jpg (https://postimg.cc/JGfmKmW8)

I am actually surprised how strong this plastic is (ABS) and have changed my mind that I might as well leave it in and see how it goes. This also led me to try the speed of the motors and sprocket as a test. The motors are rated at 24v and run at 41 rpm. aAfter testing them on a 9 v battery ( 16 rpm) I have decide that I will have to somehow get a 2:1 ratio before it get to the sprocket. I am thinking 20 RPM would be an ideal speed - has anyone had any experience in this?

thanks

Rob

[Lil Giants]

What diameter is your drive sprocket?

[Originalrob]

What diameter is your drive sprocket?

The sprocket has a 105 mm pitch diameter. I did a crude test with the sprocket straight in the motor and it looked too fast. 🤷🏼‍♂️
Is there an easy way to make it 2 speed?

[Originalrob]

So a little progress has happened since last time...

One side of the track links are complete ( awaiting metal to machine pads). these take so long !

Had some stock delivered for the idler wheel and roller wheels. will start machining over the next few weeks to size

https://i.postimg.cc/SR4YZV40/IMG-3670.jpg (https://postimg.cc/jw8j2HCv)

Started the idler wheel …

https://i.postimg.cc/Y2Q11L7K/2-DC6923-B-C125-4-F21-9177-F34-C22-DECA53.jpg (https://postimg.cc/Z0KBmR0V)

Quick question on electrics if anyone can help ?…

so I am planning on using a 24v battery, running 24 volt motors which is easy as the sabretooth controller can take that voltage but what happens if I want to use a Premacon 12v hydro pump in the system - does anyone know what I need to reduce the volts for the pump?

should have some more pics of the track carrages over the next few weeks once the metal turns up :)

Cheers

Rob

[crueby]

Those track links are looking great! Where did you get the laser cutting done?

[Originalrob]

I found a relatively local engineering shop that supplies all sorts of metal and cutting services. I have found that although laser cutting is fairly accurate, it still leaves me with a lot of work to bring the items to an acceptable finish. Laser cutting also leave poor edges and seems like it also hardens it?
Its still a lot better that cutting 10 mm plate steel with a hacksaw so I wont complain !

The round stock and flats I get from another supplier. I just send the diameters I need and lengths. I can use my lathe and mill to do the rest.

One day if I get space to do so, I would like some sort of cnc but for now its all manual

[Rakthi]

Quick question on electrics if anyone can help ?…

so I am planning on using a 24v battery, running 24 volt motors which is easy as the sabretooth controller can take that voltage but what happens if I want to use a Premacon 12v hydro pump in the system - does anyone know what I need to reduce the volts for the pump?
Rob

Why not get the pump without motor from Premacon and source a suitable 24V motor? Probably easier than having to find room for a voltage converter.

Nice project you have going!

[Originalrob]

Why not get the pump without motor from Premacon and source a suitable 24V motor? Probably easier than having to find room for a voltage converter.

Nice project you have going!

Of course! That sounds like a great idea ! :)

[Lil Giants]

You could get another Sabertooth esc that will handle the 24v input voltage & set the the output voltage with a multimeter to the 12v pump.

The 2nd output on the 2nd Sabertooth could be good for a powerful winch on the back of your dozer.

2spd track motors - 2spd cordless drill motors... use a linear servo to change gears.

[sparkycuda]

I always perk up when I see a Komatsu machine being built. Yes, the D575A is a monster! Was designed for mining use, but one was used in Nevada by a housing contractor. It had a ripper to break up the caliche (some refer to it as petrified clay) near Las Vegas where no explosives were allowed. It was the only machine that could rip the stuff - ripper tooth would get so hot during use, it glowed, and had to be replaced almost daily. 1150 HP and about 300,000 pounds, 90 cu.yd. blade over 24' wide. Ripper shank almost 7 ft long.

Ken

[Originalrob]

You could get another Sabertooth esc that will handle the 24v input voltage & set the the output voltage with a multimeter to the 12v pump.

The 2nd output on the 2nd Sabertooth could be good for a powerful winch on the back of your dozer.

2spd track motors - 2spd cordless drill motors... use a linear servo to change gears.

That is even a better solution ! the sabretooth controllers a relatively small so will fit in easily ( I say that whilst touching timber! ) I would like to buy a complete pump + motor hydraulic setup so I don't have to go into the intricacies of pump / motor specific ratios.

[Originalrob]

That's for the great ideas !

So had a little machine time the last few weekends:

https://i.postimg.cc/Ls8bJ6FY/IMG-3745.gif (https://postimages.org/)

track profiles turned up so experimented with forming the right bends etc

https://i.postimg.cc/8CpqLmMC/IMG-3747.jpg (https://postimg.cc/LJWCpfyd)

it needed a little trimming

https://i.postimg.cc/3Nv63S5t/IMG-3750.jpg (https://postimg.cc/bSqLTRvn)

End result

https://i.postimg.cc/mDr8gdMQ/IMG-3753.jpg (https://postimg.cc/XZTw2ksJ)

the gap between the pads was a little too big so had to readjust the jig

https://i.postimg.cc/pLnC9hp6/IMG_3757.jpg
(https://postimg.cc/68tngQVr)https://i.postimg.cc/mrYSwv33/IMG_3756.jpg (https://postimg.cc/nsL7VwPM)https://i.postimg.cc/hPxWnjKK/IMG-3752.jpg
(https://postimg.cc/XpVDcnZP)https://i.postimg.cc/d1DpxQWP/IMG-3759.jpg (https://postimg.cc/62JM7KJY)https://i.postimg.cc/13ckgjgT/IMG-3758.jpg (https://postimg.cc/Js06vK5c)https://i.postimg.cc/3r4zjR42/IMG-3761.jpg (https://postimg.cc/XXW24ngv)

these are the ones I will be going with
https://i.postimg.cc/tCfTS72y/IMG-3820.jpg (https://postimg.cc/4m6snfDF)

they need slightly milling at the front so there is a couple mm tolerance but generally they operate well. still need practice on tig as my welds are shocking: )

[Originalrob]

Also started on the track supports:

https://i.postimg.cc/fRZFhfHv/IMG-3818.jpg (https://postimg.cc/7fsX30rC)

[skeeter]

Excellent progress is being made, & it looks great, ESPECIALLY for a first build!

[Lil Giants]

Premacon sells a hydraulic pump & valve block that many ppl have bought before. https://shop.premacon.com/index.php?cPath=35 The pump/motor originates from this guy https://www.modellhydraulik.com/ though I'm not sure if the rotatory valves are exclusive from Premacon or not.

[sparkycuda]

Wow! Excellent work - details of tracks are really great, so I'm sure the rest of the machine will be exceptional.

Ken

[Originalrob]

Premacon sells a hydraulic pump & valve block that many ppl have bought before. https://shop.premacon.com/index.php?cPath=35 The pump/motor originates from this guy https://www.modellhydraulik.com/ though I'm not sure if the rotatory valves are exclusive from Premacon or not.

Yes these are the ones I’ll be looking at getting when the time arrives. I’m not sure if I need to go for the 5mm fittings or the standard small 3mm yet or to have one value each for the front lift cylinders. Lots of thinking and work to do before then ! Was working on the tracks this weekend but I think I made a boo boo as the pads are now too close and rub so will have to order some more metal and rebend.
Thanks for a the kind comments so far
Rob

[Jared]

Looks like your track pads are on the right track:D In post #19, I was looking at the angle of the bends and the grouser bar fit thinking that'll bind up as soon as they get some dirt/rocks/sand in them but I see you've made some adjustments and they look real good now.

[Originalrob]

Few pics of things that are happening:

Experimenting with the track rollers:

https://i.postimg.cc/6QRzwLpg/IMG_3851.jpg (https://postimg.cc/f3zYfdXf)

https://i.postimg.cc/D05BHvwz/IMG_3852.jpg (https://postimg.cc/K3kPgyLX)

https://i.postimg.cc/NGxJ54kw/IMG_3858.jpg (https://postimg.cc/G9HJfvfM)

https://i.postimg.cc/HssS5y68/IMG_3856.jpg (https://postimg.cc/qgSXHzVp)

These have come out really well and run nice and smooth. plus they add a lot of weight

Track guides bolted together temporarily before welding together and milling to shape:

https://i.postimg.cc/MKP9YpLP/IMG_3854.jpg (https://postimg.cc/dLCRswwr)

https://i.postimg.cc/tTjkgZ1T/IMG_3857.jpg (https://postimg.cc/B8mHYvB9)

[crueby]

Great looking track parts, very well done!

[Originalrob]

thanks Chris 👍🏻
It’s slowly getting into a functioning shape but I need to start focusing on finishing off everything and then start adding all the details that I want. I can see why some of these models take hundreds if not thousands of hours to complete. I guess when it finally moves a bit of dirt around it makes it all the more worth it !
Oh and the steel splinters 🤦🏼‍♂️
Rob

[Originalrob]

Hi All

Hope everyone is safe and well !

Its been a wee while since I last posted any updates but I have been busy honing my skills and completing parts that just take ages (undercarriage).

I have nearly completed one side and making fast progress on the other now that I know how it all works !

enjoy the update pics:

https://i.postimg.cc/xjMm6NC5/IMG_4153_-_Copy.jpg (https://postimg.cc/BtZt662P)
https://i.postimg.cc/YCR20MSQ/IMG_4156_-_Copy.jpg (https://postimg.cc/qNtHZfy7)
https://i.postimg.cc/gJYvRYyd/IMG_4159_-_Copy.jpg (https://postimg.cc/hJ5zRR33)
https://i.postimg.cc/jSpcW0kd/IMG_4160_-_Copy.jpg (https://postimg.cc/YvxYVVHJ)
https://i.postimg.cc/zXP0rRCh/IMG_4158_-_Copy.jpg (https://postimg.cc/N5m18FPG)
https://i.postimg.cc/dtt5tfVN/IMG_4163.jpg (https://postimg.cc/Sj36gD8c)
https://i.postimg.cc/tRzrbbpV/IMG_4165.jpg (https://postimg.cc/t7YddL1X)
https://i.postimg.cc/ncR0s1sF/IMG_4196_-_Copy.jpg (https://postimg.cc/VdtjpnBp)
https://i.postimg.cc/T3KQnWmr/IMG_4233.jpg (https://postimg.cc/FYQj4zTR)
https://i.postimg.cc/MTSDkPLD/IMG_4237.jpg (https://postimg.cc/R3gfKR46)
https://i.postimg.cc/13bBB5cb/IMG_4238.jpg (https://postimg.cc/NK7Rftnx)
https://i.postimg.cc/q7XKKkms/TDWY6584.jpg (https://postimg.cc/7Chb8yrh)

[Originalrob]

https://i.postimg.cc/fbwbwkjc/CFAQ5583.jpg (https://postimg.cc/LJbSD9W5)
https://i.postimg.cc/QCVsFTH7/BPSL8515.jpg (https://postimg.cc/gL915ryc)
https://i.postimg.cc/FssGJxr8/CNBU1438.jpg (https://postimg.cc/DmH19LbP)
https://i.postimg.cc/PJFDDYKn/COVX4142.jpg (https://postimg.cc/4HVnkKrW)
https://i.postimg.cc/CM6qkr4Q/TPYN2251.jpg (https://postimg.cc/Z0pnhc28)
https://i.postimg.cc/3Nw27PFg/IMG_4475.jpg (https://postimg.cc/wyS1Q4Pv)
https://i.postimg.cc/pLK5NWMw/IMG_4485.jpg (https://postimg.cc/ZWK5phRH)
https://i.postimg.cc/6Q073M3z/IMG_4487.jpg (https://postimg.cc/qtNBDX2C)

[Originalrob]

Sorry about the photo bombing :eek: didn't realise I had done that many !

https://i.postimg.cc/MZd1pK4V/IMG_4204.jpg (https://postimg.cc/Wtqd9js1)

https://i.postimg.cc/L6WfjQms/IMG_4495.jpg (https://postimg.cc/7fgfkVGv)

https://i.postimg.cc/tCJWZGQf/IMG_4494.jpg (https://postimg.cc/7fvfdcLM)

working on the transmission and making good progress so fingers crossed I can get it moving under it own steam soon

Rob

[kerst]

Beautiful work!

Kerst

[egronvold]

This is pretty awesome (and I can appreciate the hours spent before each picture could be taken).

[Hemi1966]

Excellent work !

[avel]

The more photos the better! I also enjoy text. I love reading about how people make their own models and how they get around/solve problems along the way.

[Originalrob]

The more photos the better! I also enjoy text. I love reading about how people make their own models and how they get around/solve problems along the way.

Yes totally agree ! and if I remember correctly it was a reason I started my own thread - to share my learning experience :) so I will keep true to this and add in my limited experience in this terrific hobby :)

Today I was adding in some details to the drive sprockets and fixing details:

https://i.postimg.cc/qBX8VTKC/IMG_4496.jpg (https://postimg.cc/qgqtyWjk)

https://i.postimg.cc/Wb1qBJjQ/IMG_4497.jpg (https://postimg.cc/rz7pWsDJ)

https://i.postimg.cc/Hkj5y8hQ/IMG_4498.jpg (https://postimg.cc/gxFn9jdJ)

https://i.postimg.cc/rscx0hBm/IMG_4499.jpg (https://postimg.cc/0MWbhC2R)

https://i.postimg.cc/dt5r3j4s/IMG_4504.jpg (https://postimg.cc/VdbdHMxp)

https://i.postimg.cc/YSG1JLNp/IMG_4506.jpg (https://postimg.cc/yJKgRdr5)

https://i.postimg.cc/d3qZthCZ/IMG_4509.jpg (https://postimg.cc/R6DZgVXv)

The drive and transmission has been the most time sapping process to date. as I am not of a engineering background this has taken maybe far longer than it should have. Although there are a few very amazing scratch builds on this forum there wasn't enough details to help me make a knowledgeable decision in my build. So this is what I have gone with :

24v motors https://gimsonrobotics.co.uk/categories/dc-electric-motors/products/gr-ep-52-high-torque-planetary-gearmotor-12v-and-24v-versions

1:2 reduction bevel gears to make right angle transition

Linear and thrust bearing on the internal shaft + locking nut

Tapered roller bearing in the hub/sprocket to sort out both axial and radial loads?

I will post some pics of the setup this week to illustrate

more details to follow :)

[Originalrob]

Mind dump incoming !

from my limited experience these are the following things I have learned that have made the most difference:

Get a DRO ! - its all about making parts that are repeatable ! this makes it so much easier ( CNC is the next step maybe one day)

Get quality tools if you can - you have probably heard this so many times before and I can attest buying a £20 M2 tap is far better than one that costs £2 ( trust me the cheap one will break on the first few holes whereas the other will just carry on for hundreds)

Be methodical - making repeatable parts means cleaning between parts , resetting dials, taking your time. don't take short cuts.

Design before any fabrication - as I am going along I actually wish I would have drawn everything up in Fusion 360 before I started. you can waste so much time re-centring / setting up parts that could be done in one .

Vinegar cleans all the mill scale and heat (soldering) blackening off metal you could ever need ! ( Bio Carb soda stops the process). I wish I knew tis from the first day. clean stock metal is very helpful when making repeatable parts.

I am still figuring out the rest !

Rob

[ThunderTruck]

As someone who has never tried to build anything like what is found on these forums I find myself coming back everyday for updates and to admire the talent and ingenuity (and zero drama). Thank-you for sharing.

[Azonic]

Very nice work, looks beautiful!

[Originalrob]

Hi Everyone

its been ages since i have updated my progress on the dozer but its been a crazy year and progress has been patchy.

This is basically where i have got to since the summer:

https://i.postimg.cc/YqqjKZwz/11.jpg (https://postimg.cc/K4wmt9j1)

Almost ready for a test run in the dirt ! :) Cant wait to see it actually move by itself !
( blade and ripper still in progress)

The main time consuming work were making the second track and all the under carriage elements. Not really worth posting as its just a replica of what i had already made and extremely boring !

What can be seen in the image above at the moment weighs in at 40 kg (88lbs) and with the ripper and blade/hydro pump etc should be about 50 - 55 kg in total. I may try and see if i can rig up a makeshift blade to see how the traction works.

So going back to where i left off, i had some issues with making a right angle gearbox and initially when with this:

https://i.postimg.cc/hGbnhrjc/7-DF7-CC57-15-D2-4-A9-C-8570-CB9002700-B81.jpg (https://postimg.cc/R3FyDwKD)

The gear box, axle and drive train have taken a lot of working out and time as i could not really tell if i was on the right track ( not from an engineering background) and i was worried ( still am a little bit :) ) that the whole things might chew it self apart.

after several trials with f

[Originalrob]

opps !

After several trial configurations i have settled on this:

https://i.postimg.cc/yYtM73ZY/IMG-6222.jpg (https://postimg.cc/6yVj03cD)

i found the bevel gears wanted to push each other apart under load so i had to move the larger gear up against the chassis to get rid of any deflection.

I also had to fab a motor mount for the two 24v dc motors:

the ABS 3d printed one just was not strong enough for all the torque

https://i.postimg.cc/nL8HzwN5/IMG-6221.jpg (https://postimg.cc/qNLfDQJX)

Image shows the steel bar that connects the two undercarriages together:

https://i.postimg.cc/vBhM08DF/IMG-6223.jpg (https://postimg.cc/PpCBxjm2)

it has a thread and counter sunk bolt at each end to pull it all together and then a couple aesthetic covers to hide them.

https://i.postimg.cc/Xvc0vNfG/IMG-6233.jpg (https://postimg.cc/2q6tcDXr)

https://i.postimg.cc/B6BZRcYz/IMG_6209.jpg (https://postimg.cc/62TNvRNV)

https://i.postimg.cc/qRsg4dRj/BEFC79E9-B0C2-47B1-91CC-67F92D8BDE1C.jpg (https://postimg.cc/k657vzWb)

https://i.postimg.cc/6qBqQ14w/575D245C-6C7E-4FF8-9ACD-89B53A0EE8C3.jpg (https://postimg.cc/vgSbqhvS)

I am still amazed by how much time all these little things take to make !

[Originalrob]

For a bit of a break from all the hand cranking operations on the mill and lathe i also started on 3D printing the cab and top elements that had no structural importance and were just for show.

https://i.postimg.cc/Hx6C9kXN/B73F9C16-5AD0-4AE7-86BD-8669EB5E047A.jpg (https://postimg.cc/9RwSWVxP)

https://i.postimg.cc/MT6SBQMR/E7F8B9D1-771C-4825-B35D-B5D5408F11F8.jpg (https://postimg.cc/FfB851xs)

https://i.postimg.cc/vBFDJmQ4/48294859-2A15-4D65-BDB3-6D103E54ABBA.jpg (https://postimg.cc/R3dMf4Jm)

the railings are just 2mm steel rod and bend/silver soldered together. really happy how these worked out!

my original idea was to weld all the elements of the undercarriage together ( bolted together first) and then two pack fill and sand/undercoat:

https://i.postimg.cc/k5Q31MDM/1.jpg (https://postimg.cc/wtjG3phn)

https://i.postimg.cc/TY1xdXNQ/2.jpg (https://postimg.cc/F1M8pw4J)

https://i.postimg.cc/hvMjQbVm/D1E7FB4D-8B40-4898-85B8-D974F5A66787.jpg (https://postimg.cc/ZvBZ1N7Y)

Filled and primed :

https://i.postimg.cc/d0KYvZyc/IMG-6227.jpg (https://postimg.cc/xXg73C56)

https://i.postimg.cc/k5Q31MDM/1.jpg (https://postimg.cc/wtjG3phn)

Yellow colour is just a filler/primer for the ABS prints and is used an acid etched primer for the steelwork

https://i.postimg.cc/br6ywYjH/IMG_6215.jpg (https://postimg.cc/XBCS2bqp)

https://i.postimg.cc/X7JND5w2/IMG_6217.jpg (https://postimg.cc/kD0d2BY8)

https://i.postimg.cc/dVZsJKNr/IMG_6219.jpg (https://postimg.cc/qN0VGWTv)

https://i.postimg.cc/9Qqj9Yh7/6.jpg (https://postimg.cc/yDB549W1)

https://i.postimg.cc/N0qvk2sP/7.jpg (https://postimg.cc/4Y50Jdhz)

https://i.postimg.cc/NfncLPWt/8.jpg (https://postimg.cc/CzbtQJhr)

[Originalrob]

Which brings us back to electronics !

So i did have this running ( up off the tracks on a stand) using a 2x32a Sabertooth controller from my openTX transmitter ( Radiomaster 16 channel) and it ran as expected (very well). The only problem was when i was at full stick forward the RPM of the track was about 30RPM at the sprocket. Far to fast for what i wanted. With the sabertooth, you can just ease off the stick to slow down but that comes at the cost of torque as the controller just turns down the voltage, slowing the motors. A 24v motor running at 9 v just isnt as strong at one at full power.

Thought about gearing the motors down further ( way to much work and i really didn't want to go back to the drawing board on the transmission!) but i remembered another build thread that talked about PWM control of DC motors. Main benefit being that you just pulse the motors very fast for a percentage of time so that the motors slow but are still getting 24v ( but only for very rapid short bursts)
So after a few weeks i ditched the sabertooth in favour of the following PWM setup:

https://i.postimg.cc/4ytb91GB/electronic.jpg (https://postimg.cc/9wm73Zr7)

OpenTX radio talks to two channels on the receiver.
2 channels on the receiver are connected to inputs onto an Arduino microprocessor
Outputs from the Arduino are PWM signals for motor speed and another for motor direction which get connected to a PWM capable motor driver.

That's the easy part ! The hard part was writing the code for the Arduino.

After a couple weeks of Arduino code for dummies and watching every youtube tutorial possible i was able to write the code for differiantial/tank steering.

its a steep learning curve but well worth the effort. Its not just the benefits of PWM motor control but also being able to control lighting, sound or anything really you wanted. I will post the code below so that hopefully it may help someone else one day.


Setup:
Open TX TX16s transmitter (2 channels for drive motors)
10ch receiver
Arduino Uno (Elegoo starter kit)
Cytron MDD10A Dual Motor Driver (PWM input)
2x24v brushed DC motors with 1:72 planetary gearboxes
7s LiPo at 24 v

Code:

int dir1 = 7;
int dir2 = 4;
//the following are all ~PWM capable ports
int pwm1 = 6;
int rc_channel4 = A0;
int pwm2 = 5;
int rc_channel2 = A1;
void setup() {

TCCR0B = TCCR0B & B11111000 | B00000010; // for PWM frequency of 7812.50 Hz (Output pins 5,6)
pinMode(rc_channel4, INPUT);
pinMode(dir1, OUTPUT);
pinMode(pwm1, OUTPUT);
pinMode(rc_channel2, INPUT);
pinMode(dir2, OUTPUT);
pinMode(pwm2, OUTPUT);
Serial.begin(9600);
}


void loop() {

int pwmA = 0;
int rc4 = pulseIn(rc_channel4, HIGH, 35000);
int pwmB = 0;
int rc2 = pulseIn(rc_channel2, HIGH, 35000);

Serial.print(" raw channel4: ");
Serial.print(rc4);
Serial.print(" raw channel2: ");
Serial.print(rc2);
delay(100);

if (rc4<1450 && rc4>1400) {
Serial.println(" stick centered");
analogWrite(pwm1, 0);

}
if (rc2<1450 && rc2>1400) {
Serial.println(" stick centered");
analogWrite(pwm2, 0);
}
if(rc4 > 1450){ //right stick
pwmA = map(rc4, 1450, 1910, 0, 255); //map our speed to 0-255 range
digitalWrite(dir1, LOW);
analogWrite(pwm1, pwmA);
pwmA = constrain(pwmA,0,255);
Serial.print(" right stick speed: ");
Serial.println(pwmA);
}
if(rc2 > 1450){ //left stick
pwmB = map(rc2, 1450, 1910, 0, 255); //map our speed to 0-255 range
digitalWrite(dir2, HIGH);
analogWrite(pwm2, pwmB);
pwmB = constrain(pwmB,0,255);
Serial.print(" left stick speed: ");
Serial.println(pwmB);
}
if(rc4 < 1400){
pwmA = map(rc4, 1400, 920, 0, 255); //map our speed to 0-255 range

digitalWrite(dir1, HIGH);
analogWrite(pwm1, pwmA);
pwmA = constrain(pwmA,0,255);
Serial.print(" right stick speed: ");
Serial.println(pwmA);
}
if(rc2 < 1400){
pwmB = map(rc2, 1400, 920, 0, 255); //map our speed to 0-255 range

digitalWrite(dir2, LOW);
analogWrite(pwm2, pwmB);
pwmB = constrain(pwmB,0,255);
Serial.print(" left stick speed: ");
Serial.println(pwmB);
}


delay(10);
}


I raised the frequency of the PWM to remove the high pitch whine and increase driver efficiency but not necessary. I have this working on my desktop (image) and its working as i would want. once its installed i may have to tweak the steering inputs but generally its a good starting point.

Thats enough for one day !

feel free to ask questions if needed

Rob

[Zabco]

Great work, was really nice to get an update. I really like the idea of using the Arduino and thanks for sharing the code. What will the approximate size of your machine be when finished?

[Originalrob]

Hi Zabco

the total length will be about 850 mm and the blade is 460mm wide (think its a coal blade). depending on a test on how it pushes dirt I may have to opt for a smaller blade width. ill see how it goes as with most of this, its trial and lots of errors :)

I threw all the metal for the blade and ripper on scale with the chassis and its already at 55kg ! its hard enough moving it about already !

can recommend the Arduino enough but If you use the code you will have to tweak the input ranges for your specific RC transmitter/ deadbands. I am sure they all vary a little bit.

Rob

[egronvold]

Congrats on a nice build and thanks for sharing your experience as a first time coder:)

[frizzen]

Great looking machine!

I've got to say, coding your own dual esc is really impressive! i would have totally wimped out and just run 2 seperate esc and setup a channel mix through the radio

[9W Monighan]

Very Nice work Rob.
That coding definitely sounds complicated to me.
You may have to build planetary reductions in your final drives to slow her down thus having full power to the motors. That would take a lot of the stress off of your bevel gearing that you said you're already having trouble with.
I'm not up to date on all of the RC electronics but; Don't the brushless motor speed controllers act like an AC Inverter?
I have some of my machinery and mills in my shop equipped with 208VAC 3phase inverters to control the motor RPM. It seems I get full torque using them at low speeds.

I get a chance, I have a picture I'll post taken 29yrs ago of the first D575A built with my son and I standing next to it.

[Zabco]

Hi Zabco

can recommend the Arduino enough but If you use the code you will have to tweak the input ranges for your specific RC transmitter/ deadbands. I am sure they all vary a little bit.

Rob

Yes, I love the arduinos, been playing around with them off and on for several years now. Just never tried to do anything like what your have done. Am currently working with a couple of NANO 33 BLE boards on a small project that if it works out, I will post to the forum. Keep up the great work.

[Originalrob]

Hi !
Really appreciate the kind comments :)
Ideally I would to have liked to rotate each motor 90 degrees so that the motor shaft connected straight onto the sprocket but the space inside didn’t really allow it, well not for the motor/gearbox I chose. That would get rid of the need for a right angle transfer. When I first started at this I couldn’t really find any information on how much torque is required to make a 100lb model move itself and then somehow still have enough power to push a blade full of dirt so I just opted to get the highest torque motors that I could fit inside the frame. There are a few D10 builds on the forum that have used wiper motors out of cars etc but none really mention the motor specs In terms of rated torque. The ones I have chosen do have planetary gears already and are rated at 10nm continuous and can do shorter periods of up to 25 mm. Is it enough ? I don’t really know ! But I will post some results when it’s all put together so that the next person may benefit from all this.
I’m not really knowledgeable about inverters etc to comment but from a crude physical test ( hands holding sprocket) between the sabertooth @20% stick and then the PWM setup at 20%, I couldn’t slow the PWM at all , whilst the sabertooth I could make the motors slow/labour. Again I’m not expert at all and it’s just trial and error.
Please post the picture, I would be really interested in seeing it !!

Rob

[Originalrob]

Hi everyone !

First test video..... actually the first test at my mates allotment went ok until the set screws holding the gears to the axle gave up the ghost after 10 mins. So beefed them with bigger grub screws and seems to work fine.

https://youtu.be/BH8w4-jRwyY

[frizzen]

Might want to put a small touch of 'removable thread locking compound' (blue loctite) on the tip of your grub screws so they don't die so fast in use.

[Originalrob]

Hi Frizzen

that's a good shout ! I might have to go back an do all the screws to be on the safe side.

So I have started working on the blade and push arms(?).

I had an arm 3d printed ages ago although the wrong scale. So some steel stock and marked up so I don't f*** up :)

https://i.postimg.cc/x8fPX0pZ/IMG_6244.jpg (https://postimg.cc/1ndFTZQ0)

I have ordered some swivel and rod end bearings to attached so I have left the arms long for now until I can measure

https://i.postimg.cc/qvhxhDQp/IMG_6245.jpg (https://postimg.cc/TKxDB9Zs)

https://i.postimg.cc/Njmrv3p2/IMG_6250.jpg (https://postimg.cc/BjZvxVWJ)

https://i.postimg.cc/tJBNPLL4/IMG_6251.jpg (https://postimg.cc/LgZPF09c)

https://i.postimg.cc/yYrTNCmf/IMG_6252.jpg (https://postimg.cc/56LzPGkv)

A bit of filler and paint and should looks good ( I hope !)

[D8R]

Rob, very impressning build. Also interesting to see your mix of lasercut, 3d printed parts. Had no idea that ardino could be used for steering programing, that may come valid IF i change to electric drive on my build. Will follow this build.
Dan

[Lil Giants]

Your hard work over the last yr is taking shape nicely Rob, the dozer looks like an awesome beast! :cool:

[Originalrob]

Hi Everyone,

Little bit of progress since last time :

Making a blade and hydraulic ram pivots:

https://i.postimg.cc/kgm6bbzY/B1-A5-D9-DA-F33-D-4-FDB-9929-CAAF6-C53-ED39.jpg (https://postimg.cc/YhdCchpQ)

https://i.postimg.cc/KcCgmVN2/F0-EA96-CA-7775-412-E-8-D2-E-054-C61982929.jpg (https://postimg.cc/DmdzgxHj)

https://i.postimg.cc/3xXr5fLn/09054-B2-E-9660-4-C78-8-C30-389-B946-B1311.jpg (https://postimg.cc/DSz3163X)

https://i.postimg.cc/7hJDBKG1/16-A3-A23-C-B3-F5-4-CA8-920-C-97-DD98-C210-DE.jpg (https://postimg.cc/1VSLXcK4)

https://i.postimg.cc/W4pd9P2M/9-C926-E82-8-DDB-4934-BB62-170-BD2-FFF78-E.jpg (https://postimg.cc/mPqZDJ1D)

I also had a nice delivery from Premacon so I thought it would be best to put together a pump set that I could test outside the machine for leaks etc then simply bolt in position and connect the rams

https://i.postimg.cc/kG2M0nZb/C06-A0775-91-DE-4-BFF-B2-AD-B004-F66808-C3.jpg (https://postimg.cc/bSjjbjqy)

https://i.postimg.cc/xd9f0GhY/DF6-AE326-E595-4-AD3-8390-3-A1-BD8784-F86.jpg (https://postimg.cc/DSYk6G7Y)

https://youtu.be/hY6JiJXL7Pw

The weight of the blade is quite a lot and I am concerned that the rams wont lift it !

[Originalrob]

So put everything together to see how it works.

The weight of the blade in the raised position seems to move the balance and pivot point towards the front idlers and there is a bit of slack in the tracks when reversing etc. i may need to install some stiffer springs to tension the tracks more and/or install the ripper to add weight to the back which should also balance it out. Happy the rams are up to doing the job though :)

Will try and get some videos of it pushing dirt soon

https://youtu.be/F8dfyTtsrY0

[Lil Giants]

Well done Robert! :cool:

Have you weighed it yet?

[sparkycuda]

Being an avid Komatsu guy, this build is great! Detail, proportion, function are just like the real Super Dozer. Congratulations on a successful first hydraulic test.
Ken

[egronvold]

Looking forward to see the power of this beast on the dirtpiles!

[Originalrob]

Well done Robert! :cool:

Have you weighed it yet?

Hey !

So had a bit of free time this afternoon and weighed it up as I need to think about the balance issue that’s causing it’s to sit on it’s front idlers. I don’t know what happened but I have miscalculated the weight somewhere. Without the blade and arms it’s 51kgs. The blade and arms is 21kgs so that’s why it’s causing an issue.I weighed the ripper metal I have ready to assemble and it’s about 7kgs plus it hangs far about the back it will help balance some of the blade weight. I might have to add some steel ballast to get it right. So in total maybe 80kgs in the end. A bit heavier than I anticipated but the motors still move it about easily
I can see my glass bathroom scales getting cracked tho :)

[Originalrob]

Being an avid Komatsu guy, this build is great! Detail, proportion, function are just like the real Super Dozer. Congratulations on a successful first hydraulic test.
Ken

Thanks Ken/Egronwold

It’s been a such a long process with limited time to work on it but I can’t wait to get it to a point where I can push some dirt around! I have promised myself this summer it will happen :) 👍🏼

[sparkycuda]

Don't think you miscalculated on the weight/balance concern. The real dozer has a massive counterweight when not equipped with a ripper. The 1:1 machine is very nose-heavy without either. So, maybe just about right!

Ken

[Lil Giants]

80kg WOW :eek:

Some general measurements of blade? LxH ...the dozer itself LxWxH? I'm not familiar with the background objects in your pictures to get an idea of its size.

[sparkycuda]

Just some comparative weights from the real machine.

D575A-3SD Super Dozer. Operating weight 336,000 lbs. Counterweight was 11,900 lbs. Had a 90 cubic yard blade.

D575A-3SR Super Ripper. Operating weight 289,000. Single Shank ripper could rip 6'9" deep.

They were rather large!!

Ken

[skeeter]

It's great to see this beast come to life! I LOVE scratch builds!

[Originalrob]

Don't think you miscalculated on the weight/balance concern. The real dozer has a massive counterweight when not equipped with a ripper. The 1:1 machine is very nose-heavy without either. So, maybe just about right!

Ken

HI Ken

i think your right, i added some crude weight to the back and its rolling a lot better on the tracks now. Plus i added some stiffer rate springs to the tensioner and that seems to help as well. I have started the ripper now so should have it attached in a couple of weeks.

in the mean time i added some details to the blade:

must be like strengthening bars on the side of the blade

https://i.postimg.cc/xjR4vRJW/1.png (https://postimg.cc/0rznx7Cf)

My own version:

https://i.postimg.cc/XJKDDK2B/2.jpg (https://postimg.cc/zbBjyhYq)

https://i.postimg.cc/NFgPhyVJ/3.jpg (https://postimg.cc/WFH7g4sg)

https://i.postimg.cc/FzDChrX9/4.jpg (https://postimg.cc/XBBk80vh)

I will take some pics to give a sense of size later today maybe with a can of coke or something but blade is about 500 mm wide ( 21 inch) x 250 high (10inch)

Rob

[sparkycuda]

Yes, ribs for strengthening but also anti-abrasion. These machines were used to push in all kinds of material. WV and KY machines worked slot-dozing in a lot of sandstone, so experienced extreme wear on the ends - I've seen those ribs completely worn away. Often users would add more abrasion resistant steel on the blade ends before ever putting them to work.
While the weight is extreme compared to other RC dozers, it was huge in real life - largest production dozer in the world. Big dozers are just heavy!

You are doing a great job!

Ken

[Originalrob]

Hi all,

Had a bit of time over the weekend so put together the steel for the ripper and installed to test out the weight balance.

https://i.postimg.cc/hPVDNKK4/1.jpg (https://postimg.cc/WhbckLDx)

https://i.postimg.cc/zfGqLWK3/2.jpg (https://postimg.cc/xXhwhXsS)

I dont have the rams yet just just mocked up with some bars and rod ends. Took it for a spin and the balance is much better.

Rob

[sparkycuda]

Keeps looking better all the time!

Ken

[Wibb]

Impressive machine!

[skeeter]

That machine looks fabulous with that ripper on it!

[dozerbuilder]

Do we have an update on this fabulous build?. How did it go in the dirt?
Cheers

[Orange RC Works]

This is one amazing build...

[Originalrob]

Hi everyone!
Wow I can’t believe it’s been so long. Life gets in the way too much now but I’m determined to get this done !

Just finalising the rams for the tilt on the blade and should be ready. Below is a video of the ripper hydraulic test which worked out great. More to follow. Thanks for the interest in the build.

Rob

https://youtu.be/-w3CDwHl3Ww

[dozerbuilder]

Do we have an update on this fabulous build?. How did it go in the dirt? Is it completed??
Cheers