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 ) 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 :



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

This is what I have built to date :






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 )

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) 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:

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

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:



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
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

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



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.





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]

Originally Posted by Lil Giants

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



Started the idler wheel …



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]

Originally Posted by Originalrob

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]

Originally Posted by Rakthi

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]

Originally Posted by 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.

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:



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



it needed a little trimming



End result



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





these are the ones I will be going with


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: