Kenworth K100 Cabover Update - In Primer

I finally got around to working on my Kenworth K100 that has been sitting in a box waiting for my attention (next to the dozens of other models that are waiting patiently as well).  My goal is to finish at least 1 of every model that I have designed so I have some examples to share on my Shapeways store.  I also feel it is important that I take every design from beginning to end, so that prospective buyers can feel confident about buying a model.  I have a hard time buying a model on Shapeways based only on a 3d rendering.

My K100 was designed with some specific finishing details in mind that are left to the modeler to add.  If you have one of my K100's already, or plan to buy one, I will explain how I intended to finish this model.

First, the handrails could have been designed into the truck cab, but I felt it would look much nicer with a free standing detail made from wire.  I use .010 wire on my trucks for mirror brackets and other details like railings.  On the K100, there are 3 sets of brackets to hold the railing to the side of the cab, which I designed into my N scale version.  I also designed a #80 hole right above the top set of brackets.  Using a prototype photo, I bend a wire into a railing, that can be inserted into the #80 holes, and then glued to each bracket to hold it in place.  It's a bit tricky, but it can be done.  I use a #80 drill bit to clean out the holes after painting.

It seems like most cabovers in the 1980's had stripes or multiple color paint schemes.  If someone wanted to spend the time to create a set of stripe decals for these trucks, that would be great.  However, I plan to paint mine a solid color, or maybe two tone.

Cabover trucks generally have a large opening in the rear of the cab where the motor is located.  I did the best I could on my model as I don't have any motor detail, and didn't want to leave a hole in the back of the cab and not have anything inside to fill it.  I did leave two openings for exhaust and air cleaner details.  The K100 has an air filter that is located on the driver side, which you can see on my model.  The air filter is usually fed by a stack on the back of the cab to pull in cold air from above roof.  The stack should be located on the rear of the cab, on the driver's side.  If you plan to do a single stack exhaust, locate it on the passenger side of the cab.  I plan to do dual exhaust on mine, which will be made from brass or aluminum rod.  Each stack should have a 90 degree bend on the bottom which can then be glued to the inside of the cab.  Refer to the photo below to see how a typical dual exhaust and air intake are configured on these trucks.

 Here are a pair of K100's in primer paint.  I used grey on these so I could get some better photographs.  White is hard to photograph.  These have 2 generous coats of primer, which I recommend.  Thicker paint seems to give a smoother finish on 3d printed models.

If you want your own N scale Kenworth K100, check out my Shapeways Store: K100

Ready to Print - 53' Utility Reefer Trailer

I started working on my 53' reefer again tonight and just couldn't go to bed until I finished it.  Well here it is.  You will notice some unique design characteristics with this model, and I will try to explain the various components.

First, this model will be expensive to print, so I tried to reduce the overall volume of the body.  To eliminate warping, I added some reinforcements to the inside while trying to minimize material.

Second, based on experience, vertical surfaces with detail can yield varying results from Shapeways.  I chose to design the rear door component as a separate piece.  This should yield a cleaner print, while making the painting process easier.  This idea actually came from my Pete 379/389 grill, as the design is very similar.  The door panel has a rim that mates perfectly to the rear opening of the trailer body.

Third, the landing gear and fuel tank will print onto a flat surface that will fit into the underside of the trailer body, where I have included a ledge to aid in locating this detail.  There is no reason to guess the location when it can be precisely located within the design.

Fourth, I eliminated the need for a piece of wire for the axles.  The suspension component now has axles designed in, exactly like my trucks.

Lastly, I created a sprue to hold the 3 components pictured.  My hope is that these pieces will be printed flat, which will yield the best quality prints.

There you have it.  A few new design ideas implemented into this model.  Time will tell if these will become best practices for me.

Who Needs a 53' Utility Reefer Trailer?

I was cleaning up some old files the other day and ran across this 53' reefer that I had started and then moved on to something else without finishing it.  I worked on it a couple hours today and thought I would take a look at a rendering.  It still needs some work, but it is getting close to completion.  I have 2 very nice prints of my UPS 28' pup trailer, so I know a box type model like this prints well, but it does get expensive due to the volume of material used.  However, I have opted to keep the walls on the thicker side to avoid warping, rather than go cheap on the overall print cost.

I'll post some updates as this project progresses.  I plan to use BLMA refrigerator units on these since they are already available as a separate detail.  The landing gear and fuel tank will be printed on a separate piece that can be added after the body is painted.  The sliding tandem axles will also be separately printed.

3d Truck Improvements

I have learned a lot about 3d design and printing from the various models I have created, and am trying to incorporate enhancements to my new designs.  I also plan to go back and add these same improvements to my existing models as I have time.

First, I realize that mirrors are a fairly critical detail for my trucks, and while my very first finished models had no mirrors, I began adding my own custom mirrors to my recently finished trucks.  I simply use brass wire bent to the appropriate shape, inserted into a #80 hole that I drilled into the cab.  I am amazed at how 3d printers can print a very small hole into a model like my truck rims, and I came to the conclusion that I could simply design my trucks with the hole already printed, ready to accept a piece of wire.  This way, I can avoid damage to the model from my drill, or trying to hold the model while getting the hole started.  The biggest benefit is having precision location every time.  On a couple of my models such as the Pete 386, I designed a mirror assembly, and added these details to the wheel and tire sprue.  I also added the appropriately located hole in the cab to accept the mirror.

Second, I recently uploaded a file of dual wheels and put them into a square pattern rather than a long straight line.  I have had mixed results from Shapeways, as they like to print these long lines at various orientations, since they likely find extra spaces in the print tray for these long strings around other models.  The wheels that get printed flat with the rim facing up are usually a very clean print.  If they are printed on their side, they have texture.  Since I changed the pattern, I have had great feedback on print results.  So, now my wheel sprue pattern is rectangular, to promote flat print orientation by Shapeways.

Third, I beefed up my front axles, and added a shoulder that allows the front wheel to slide to the accurate location.  Up to this point, I have had to trim the axle and eyeball the spacing of the front wheels.  I now realize that I was making things much harder for myself in the assembly stage.

I know there are probably many other things that I will discover in future models, but wanted to share what I am beginning to incorporate into my designs now.  As always, I am open to feedback and suggestions on how I can make these better.