Hello everybody,
well, this drive wheel really seems to be a hard nut, 
if one has a look at the next pictures of my friend Joe, 
who has diligently continued to model. 
Source: arcforums.com (crackerjazz)
At least here it becomes clear how many sub-steps are obviously necessary to capture and model all these contours and ledges, 
until finally this single sprocket is finished, which looks great. 
But I think, that now not much is missing to make a suitable 3D printing set out of it. And that’s why I’ve thought about the most favorable arrangement/orientation for printing and think that the sprockets could be arranged flat in a set consisting of two rows of nine wheels, whereby I would have two spare wheels. 
Now I’m curious to see what will come out in the end and what such a Set of 18 in FUD will cost. 
4 Likes
Now that’s what you call a drive wheel… I wouldn’t want to do track bashing on that lol
1 Like
Definitely, cause these are monster wheels. 
Hello everybody,
My friend Joe just asked me if it would not be better to just print only one sprocket first, to see if will mesh well with the Track shoes, which would certainly make sense.
Therefore, I had already pointed out to him in advance that the following condition had to be guaranteed, namely, that W2 fits into W1.
Source: microartwork.com (Mischa Klement)
But that would have to be guaranteed, provided that the drawings are correct, whereof I go out, and provided that he has correctly implemented them in his model (1:160). 
Therefore, he should first upload only a single, flat-lying wheel, so I can let print it in FUD and FXD on a trial basis. After the aptitude test we can then decide about the final Set of 18.
Well, just wait and see!
3 Likes
Hello everyone,
my hardworking ARC friend Joe has already uploaded his Main Sprocket 3D model.
Source: shapeways.com (Crackerjazz)
I was a bit scared when I looked at the 3D view and saw that the sprocket is hollow, which was completely new to me, 
Source: shapeways.com (Crackerjazz)
especially since the sprockets of other crawler modelers in the German Raumcon forum are full and not hollow, which I had in mind.
Source: raumfahrer.net (Sascha1990)
Source: raumfahrer.net (slimgo)
Therefore, I was very skeptical at first and have immediately searched for suitable photos to clarify this. But in my archives I did not find anything at first, because on the normal crawler pictures you can not really see the drive wheels under the chains. 
But in this photo, I found the first signs of cavities, if one looks closely. 
Source: forum.nasaspaceflight.com (AnalogMan)
But in NSF there is a special Crawler Transporter thread about the modification of the CT-2 for mighty NASA launches of the future Space Launch System (SLS), in which I then have indeed found clear evidences.
Source: forum.nasaspaceflight.com (MechTech)
Here to see beautiful in the falling sunlight.
Source: forum.nasaspaceflight.com (sprtnsky)
And here’s a Hi-Res look into a drive wheel or through it out, which would also eliminate the last doubts.
Source: forum.nasaspaceflight.com (MechTech)
And so I ordered two sprockets at Shapeways, both in FUD and in FXD in order to be able to test their interaction with the Track shoes.
3 Likes
Hello folks,
now I also got the corresponding screenshot with the Support Material showing the expected arrangement.
Source: shapeways.com (Crackerjazz)
The big lot of support wax would also explain the relatively high price of the Sprocket, half as much wax would certainly have been enough too, I guess … 
Therefore I also asked my friend Joe, also to upload a 3D model with an upright print orientation of the sprocket. I think that this would require less support material, so the price might be slightly lower.
The side effect thereby is, that the top side should be smooth and the bottom rough, which in turn is important for cleaning.
After the first joy Shapeways came up with the next unwelcome surprise and has stated that they cannot print the Main Sprocket. 
Supposedly they have informed the designer about the problems with the part, but which is a smooth Fake News. 
So slowly I start to doubt this club, I can’t think of anything more … 
The strange thing is that the shape of the Sprocket is less complex than that of the Track shoes, and the wall thicknesses are all according to SW specs, as my friend Joe says.
3 Likes
Hi friends,
the SW show goes on …
After I was first informed on my astonished enquiry that my already well-known SW friend Mitchell Jetten from the Track shoe story would answer me, now came this joke message … Awesome!!!
This reinforces my impression of SW, that’s an case of the right hand not knowing what the left hand’s doing … 
1 Like
Hello everybody,
after my friend Joe had uploaded the upright-standing Sprocket, to see how the Support wax is distributed at this printing orientation, I have ordered both variants FUD and FXD.
Source: shapeways.com (Crackerjazz)
And this is the distribution of the Support Material which shows that the wheel is quite bizarre wrapped in wax,
Source: shapeways.com (Crackerjazz)
which is why I think that the flat printing orientation might even be more favourable.
Source: shapeways.com (Crackerjazz)
Since at least the top side does not come in contact with the wax, it would remain smooth, and the rougher underside of the wheels would hardly be visible between the truck chains from the outside anyway. 
And then I tried the same trick from the Track shoe story again and ordered the sprocket once again in a flat printing orientation come hell or high water, in the hope that this time it might just as well come through the control like the criticized Track Shoe Set in those days, whereby this flat lying sprocket now, strangely enough, is only still offered in FXD. 
Now I’m curious how the story ends this time, so keep your fingers crossed! 
2 Likes
Hello everyone,
I have at least achieved a partial success, because the upright standing Sprocket variant, which I ordered in FUD and FXD, went through and is meanwhile In Production. 
Source: shapeways.com
The again ordered flat lying variant, however, is still under review (Processing), but still not rejected at least.
No matter how, at least that would prove that the Sprocket is printable, so I have an argument in hand to demand the printing of the flat version as well.
So far there is also still no explanation why this variant could not be printed at the first attempt. So SW is somehow in a tight spot, let’s see how it goes out …
Hello everybody,
this is the reason for SW’s rejection what my friend Joe will check now.
Source: shapeways.com (Mitchell Jetten)
That’s strange, because that is the same model as for the upright standing sprocket, which is in production. Why can this be produced and the flat lying sprocket not?
That is a contradiction, which SW should explain, whereupon I am curious.
1 Like
Hello friends,
here is the answer of “my” SW-Service Team employee Mitchell Jetten:
It looks like these 2 orders are checked by 2 different people.
One of them didn’t mind the 0,21 mm thickness while the other engineer did catch it and rejected the model for this reason:
Source: shapeways.com (Mitchell Jetten)
So right now the order 2672981 is being produced! These are the two standing variants (FUD & FXD).
As all models are subject by manual checking, if a part does’t meet the minimum required the 0,3 mm thickness, there are chances it gets rejected 
Would you be able to ask the designer to increase the thickness to 0,3 mm to make sure these are not being rejected again?
There you look!!! This is the same nonsense as at the Track shoes dispute.
I just wanted to answer him that this change would mean quite an effort for the designer, and that it would be easier if SW internally would enforce that this flat variant is to be printed since it is based on the same 3D model as the current upright standing variant which is just in production.
Only well, that for the umpteenth time I’ve checked the processing status of the newly ordered (previously rejected) flat version, because lo and behold, suddenly this sprocket is now also In Production …
Source: shapeways.com
What does that tell us? One has to go only long enough on the SW-species’ nerves to the motto Steady drops hollow the stone, then it works already …
Now I can sit back and wait until both variants are there to inspect the wax residuals …
And then we can decide from which variant my friend Joe should upload a Set of 16.
Attention please! Today came the happy message from Shapeways that both ordered Sprocket variants are shipped.
Now I’m curious how they will look!