Large Scale Central

Snow Dozer Build

Modeling Rolling stock
#161

Craig,

I had the exact same experience though mine was much less expensive. . .free actually. I made a part in sketchup and exported it to a .stl file. When I sent it to my friend to print he said it came out tiny on his printer software. I double checked it on sketchup and it was correct on my end. So something in the process between a sketchup file and what the printers program reads in the .stl file gets skewed. I had to give him the actual measurements so he could scale it correctly on his end.

Not sure what to say other than Sketchup was not designed for 3D printing, it was adapted. So something in that adaption is flawed.

#162

Well in my case it was 100% my fault. I downloaded the stl file and checked the measurements, and yep they were off. Somehow in the read along process I messed up. Oops. Leason learned for next time. Thankfully it wasn’t all of the parts, but ironically it was mostly the parts that I really needed to be 3D printed! I’m updating the files right now and adding a few more things as I’m realizing that some of the parts I wanted to cast aren’t cast worthy. I’m a little ticked off now because I want to get the side drag wings finished by the end of April for this years RPM meet (I’m presenting my NP presentation), and Shapeways has a 2 to 3 week turn around time!

#163

Your presenting at the RPM meet. Hmm wasn’t going to go but maybe now I might have too. Good excuse to come over and run at Dave’s if he will have me back

#164

My presentation is the same one that I did at Wallace. So you won’t be missing much as you where there… Or at least I thought you where?

#165

Craig Townsend said:
My presentation is the same one that I did at Wallace. So you won’t be missing much as you where there… Or at least I thought you where?

It was a good presentation. I wouldn’t mind hearing it again

#166

Devon Sinsley said:

Your presenting at the RPM meet. Hmm wasn’t going to go but maybe now I might have too. Good excuse to come over and run at Dave’s if he will have me back

Dave won’t be running that weekend, unless we get special dispensation.

#167

Steve, a dozen people descending on his place isn’t enough to get dispensation?

#168

David Maynard said:

Steve, a dozen people descending on his place isn’t enough to get dispensation?

Not when a normal ops night has up to 16 trains running at once… I think the record was 20 when TOC hosted an open house during the national convention.

#169

What is that is said, two steps forward, one step back. That’s how I feel after tonight. For some reason, my primer is acting up, and I’m not getting a clean sanding after its dried. To add to my frustrations, I’m pulled off the front window area as it was causing way too many problems because of how I originally shaped and made the piece.

The good news is, that I’m ready to reorder my Shapeway parts after spending time during my student conferences working on tweaking the 3D model. I also was able to nest the parts better dropping the price from $38 down to $25! Not bad considering there wasn’t much else to do while I was waiting for parents to come by and talk. One last check of the measurements and I should be ready to order again.

I was hoping to have the exterior of the Dozer done by the time of the RPM but its not looking up at the moment. Technically, I still have a month left of time, but I’m sure it will fly by fast.

#170

Craig, a month is plenty of time. Plenty of time. Just ask Devon.

#171

Praise for Shapeways customer service. One of the original parts that I had ordered came with a warp. I contacted Shapeways and they reprinted the warped parts for free. So I tweaked the design a bit, and double checked the scaling and reordered. I also reordered some of the other parts that I had scaled wrong. Finally, today I figured out how to draw a cross section of the roof, so now I’ve got that on order. A 1’ scale section of the roof should be enough to cast copies from and glue together to get the correct length. Should be a bit cheaper than ordering the whole roof from Shapeways.

All of these parts are due to me around April 10th, so that gives me a little under 19 days to get the exterior of the Dozer done for the RPM meet. So, I have 8 days right now to get the body of the Snow Dozer ready for these parts.

Shapeway Work

#172

In the process of trying to get this model more presentable for the RPM, I’m finding myself tearing more off and redoing parts again. The last few photos showed the front window area framed out, but I decided to tear it out and start over. The good news is that the sides of the body are just about ready for adding the 3D printed details. I also got some slide glass in the mail to cut out real glass windows.

Time crunch to see how much I can finish before the 29th. Photos will probably have to wait until after the RPM…

#173

Craig, perfection is the enemy of good enough. I’ve seen your work, its quite good.

#174

It wasn’t perfection, but rather a rediscovery of previous errors that I kept trying to fix. It was easier to cut out the mistake and start over instead of trying harder and harder to fix.

#175

So I haven’t forgotten about this build, but I’ve taken 3 steps back, 1 step forward kind of progress. For the past couple of months I have been working on the drag wing for the Dozer. On the prototype this is a 21’ x 4’ slab of sheet metal framed by 5" H beams.

Version 1 was tried by building up styrene H beams. I quickly found out that the extruded H beams don’t have a full right angle connecting the sides of the H beam. Instead it has a ever so slight contour from the extrusion process. This means that when trying to tie two H beams together at a right angle, you end up having to file part of the extrusion away. This lead me to version 2.

Version 2. Make H beams from .030 x .172 strip stock. Than glue together, and over lap with sheet stock to replicate the slab. Version 2 turned out fairly well on the first one, but construction of the second resulted in the styrene warping into a tight curve that proved to messy to deal with. This lead to version 3…

Version 3 was going to be the “final” solution. 3D print the H beams as one solid piece, and than laminate with a sheet of styrene. A few minutes designing, and I sent it off to Shapeways for a print. The Shapeways print came out good, but because it was such a flat piece, it had a curve due to the manufacturing process. A quick dip into boiling water fixed said warp. I proceeded to laminate a piece of .015" sheet stock on the 3D print, and left for vacation, hoping to finish the final assembly. Nope! The styrene rewarped the H beams to an even tighter curve. Another dip in boiling water to fix the curve. Nope, still there.

Version 4. Place an order for 5/32 brass H beams and use my resistance soldering unit to build up the parts.

Version 5? Hopefullly the brass version will work and I won’t have to make version 5!

#176

So I have been plugging along with this model over the last few weeks. I have almost completed the details on one side of the dozer including the drag wing, drag wing support crane, drag wing piston, and all of the associated handrails, grab irons and ladders. I ended using a HO mu cable receptacle to represent a plug in that the prototype had on the side. The grab irons are all 1/32 brass rod bent to fit, and then secured. Years ago, someone sent me some brass etchings that replicate the NBW detail for the grab irons. Those are than glued next to the grab iron and a HO scale NBW is added to complete the detail.

I still have to make a couple of brass ladders for the main door, along with a stirrup for the back porch. Than it’s cutting out slide glass for the windows, and making covers as on the prototype. It’s hard trying to keep all of the sub assemblies from hitting the paint shop!

On my MRH thread about chipping fluid and hairspray., I’m experimenting with trying to replicate the rusting patterns on the prototype. I’m hoping to finish the backside details, and the engineer side details over the next couple of weeks before I go back to teaching in September.

Craig

#177

I still love this thread!

#178

Sean McGillicuddy said:

I still love this thread!

Glad at least one person is following along. :wink:

#179

#180

Craig Townsend said:

Sean McGillicuddy said:

I still love this thread!

Glad at least one person is following along. :wink:

Make it two following along (http://largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-wink.gif)