Mini Hägglund

[RoosterBooster]

here is what i would do;

i would not do the filler pieces of flat stock and i dont think the rubber sleeves will last long if they rub against the bolts ...

i would cut rings that weld onto the outside of the cross-tubings

replace the nuts with custom turned "spikes" (maybe ~1" stock ...with a nice smooth bullet nose) that are treated to screw over the bolts.
maybe run even larger (hardened) washers to avoid that the spikes fold over.
the pointy spikes should fairly well "self-center" into the driver spocket (just dont make them too tall or you may run into misalignement problems as you pointed out in the side drawing)
... the metal to metal contact may even work-hardens itself some ...

[WILLD420]

You could try building internal drive teeth that will be held on with the bolt.

I don't have a drawing program, but I'm thinking small square tubing in short lengths that will fit between your drive teeth. Then put a short piece of angle on top to give the tooth a pointed top. If you angle cut the tubing, you can make it ramp from the point down to the track. Then all you would need is to put your guide plates on the ends of the tubes. This would do 2 things. It would strengthen your drive tubes, and provide a positive stop so your drive teeth could not go out the end of the sprocket.

The small lengths of tubing, I would drill them all the way through and try to get your bolt to go through both sides to strengthen the bolt and spread the drive forces into a shear load rather than a bending load on your bolt.

[beyondhelp]

Probably a little late, but check this out:



Here in Florida, they used to build fully tracked swamp buggies. Most used conveyor belt material / bolts / angle or channel iron and car tires for the bogies. I hunted for some pics but non so far showed the tracks very well. I did find this and it seems like a good idea especially in a lower torque scenario.

Looks like it was a solid rubber forklift tire / wheel that was drilled and cut to make it a drive sprocket. Seems interesting.

[87manche]

Originally Posted by RoosterBooster

here is what i would do;

i would not do the filler pieces of flat stock and i dont think the rubber sleeves will last long if they rub against the bolts ...

i would cut rings that weld onto the outside of the cross-tubings

replace the nuts with custom turned "spikes" (maybe ~1" stock ...with a nice smooth bullet nose) that are treated to screw over the bolts.
maybe run even larger (hardened) washers to avoid that the spikes fold over.
the pointy spikes should fairly well "self-center" into the driver spocket (just dont make them too tall or you may run into misalignement problems as you pointed out in the side drawing)
... the metal to metal contact may even work-hardens itself some ...

leave the nuts you have now, stack some acorn style nuts on top.
enjoy ghetto fabulous spikes.

[Steinbruchsoldat]

Originally Posted by RoosterBooster

i would cut rings that weld onto the outside of the cross-tubings

replace the nuts with custom turned "spikes" (maybe ~1" stock ...with a nice smooth bullet nose) that are treated to screw over the bolts.
maybe run even larger (hardened) washers to avoid that the spikes fold over.
the pointy spikes should fairly well "self-center" into the driver spocket (just dont make them too tall or you may run into misalignement problems as you pointed out in the side drawing)
... the metal to metal contact may even work-hardens itself some ...

Hmm, sounds like a good idea, but there`s no way i`m going to machine 500pc of those spikes...

Originally Posted by WILLD420

You could try building internal drive teeth that will be held on with the bolt.

I don't have a drawing program, but I'm thinking small square tubing in short lengths that will fit between your drive teeth. Then put a short piece of angle on top to give the tooth a pointed top. If you angle cut the tubing, you can make it ramp from the point down to the track. Then all you would need is to put your guide plates on the ends of the tubes. This would do 2 things. It would strengthen your drive tubes, and provide a positive stop so your drive teeth could not go out the end of the sprocket.

The small lengths of tubing, I would drill them all the way through and try to get your bolt to go through both sides to strengthen the bolt and spread the drive forces into a shear load rather than a bending load on your bolt.

Originally Posted by beyondhelp

Probably a little late, but check this out:



Here in Florida, they used to build fully tracked swamp buggies. Most used conveyor belt material / bolts / angle or channel iron and car tires for the bogies. I hunted for some pics but non so far showed the tracks very well. I did find this and it seems like a good idea especially in a lower torque scenario.

Looks like it was a solid rubber forklift tire / wheel that was drilled and cut to make it a drive sprocket. Seems interesting.

That`s exactly what i`m going to do if my tracks won`t work. But chances are low, see below...

Originally Posted by 87manche

leave the nuts you have now, stack some acorn style nuts on top.
enjoy ghetto fabulous spikes.

Sounds easy, but i don`t get the idea why it`s better with those nuts on?

Made a prototype of the track assembly today. Everything works perfectly, exactly like i thought:





The second track connection is just improvised, but it already works perfectly. I even got a video if you guys want to see it...

Of course i had to take a seat:





I still have to design a (easy to make) centering device for the drive sprocket, any ideas?

[RiverRatXJ]

Sure aint gonna be fast is it... You have more ambishin (<--positive thats spelled wrong) in your little German neck than I do in my whole body. Good luck man.

[VelociJuris]

Very creative and interesting project Keep it going!

[Steinbruchsoldat]

Thanks guys. I`m going to pick up the donor car next weekend:



1,2l 3cyl 75hp...

[Elwenil]

I think I'd be more tempted to torch the lower half of the sides off, mount drive sprockets to the hubs, build a suspension setup for some road wheels and run that as is.

That or copy what the Russian's are doing:

METELICA.flv - YouTube

[Elwenil]

Never searched for any of this stuff before but YouTube seems to be full of little projects like this.


Mini Tank Test Drive - YouTube

Extreme Hagglunds - Track Building - YouTube

tracked pocket bike - YouTube

tracked offroad vehicle - YouTube

Bandvagn 2.3 D - YouTube

[Steinbruchsoldat]

Yeah i know. Most of them use some kind of sprockets (if not friction driven) and guides that are similar to my idea...

[Elwenil]

I think more importantly, most of the larger and heavier vehicles seem to use some sort of crossbar on the track for the sprockets to grip. I fear that as soon as you get your vehicle on a hard pull, it's just going to start slipping the sprocket and bending the bolts.

[Steinbruchsoldat]

That`s something that needs to be tried. I think no one can say it works or not...
But i think i`ll add some bars to the outside to increase traction, they should help stabilize the bolts too.
And if it doesn`t work, i`ll just build some snowcat tracks...

[Steinbruchsoldat]

Worked on the shop a bit today:

Before:



During:















Finished:





It`s nice to have some daylight in the shop...

[Steinbruchsoldat]

Got the donor car today:





The battery was completely dead, so we put in another one. It turned over on the first try and ran fine...



We drove a few feet and started parting it out:







After two hours of work:

[Steinbruchsoldat]

Built some track-assembly dummies to get an idea of the size. We can place all the parts where they`re supposed to go, so we can see easily if there`s enough room or not:



The little one had to check things out:



This is about where i`ll sit:

[Steinbruchsoldat]

Placed some stuff today, this is going to be tight:





This is about half of the wiring loom. That`s insane... :wow1:

[jtr]

You look like Sheldon from the television show "Big Bang Theory".

[cgwfab]

this is awesome!!!

[carslut]

this could be awesome! keep up the work

[Steinbruchsoldat]

Removed the engine today. Was a pain in the ass...





Looks like it`ll fit, i`m really happy about that...

[jeeper90]

are you going to use the justy transmission? those things are know to be incredibly weak even with the stock power levels, manual or automatic. Some good info http://www.dustysjustys.com/home.htm

other than that its looking good and cant wait to see more progress.

[Steinbruchsoldat]

Here are a few more pictures from removing the engine:







Also was able to have a look at a real Hägglund yesterday:

[Steinbruchsoldat]

Originally Posted by jeeper90

are you going to use the justy transmission? those things are know to be incredibly weak even with the stock power levels, manual or automatic. Some good info http://www.dustysjustys.com/home.htm

other than that its looking good and cant wait to see more progress.

Yes i do. I don`t think there will be any problems. The Hägglund will weight less than the Justy, and the drive wheels are about half the diameter. So it`s like i`m driving in Lo...

[Steinbruchsoldat]

Got a lot of steel tubes almost for free:





About 20 shorter pieces are still in my van....

Also bought a saw, to handle all that stuff: