1948 Jaguar XK-120 (Pinewood Derby Shell)

Summary

Full 3D View

The 1948 Jaguar XK-120 is a legendary sports car that debuted at the London Motor Show, showcasing Jaguar's new XK engine. Known for its sleek design and impressive performance, it was the fastest production car of its time, reaching speeds of up to 120 mph. This iconic vehicle marked Jaguar's return to sports car manufacturing after World War II.

I'm happy with how this model turned out, but it's tricky to print. For some reason, either the fenders come out rough (on a P2S) or the flat underside comes out really rough (on an X1C). You may need to play with the profile a bit.

What is a "pinewood derby car shell"?

The pinewood derby is an event created by the Boy Scouts many years ago. Each scout is given a pinewood derby kit typically consisting of a block of wood with slots for axles, 4 wheels, and 4 nails to be used as axles. The scout (and his dad, usually) will then carve the block of wood into the shape of a car, paint it and apply stickers, install the wheels on the axles, and then race it at the "derby", which involves a sloped track with a timekeeping apparatus.

An official scout derby will usually require that the parts in the kit be used for cars entered in the derby. Other organizations (including workplaces) often hold derbies, too, and some of them require the use of the parts in the box, including the block of wood.

These "pinewood derby car shells" are intended to be used with an official derby wood block, cut down to size, along with the axles and wheels included in the kit. A printable model of the shaped wood block is provided. You can either use the printed model or use it to accurately cut an official wood block down to size.

Print Settings

Notes:

• Car body: Extensive supports are required. In Bambu Studio, I use Normal (auto) supports in Snug style. I prefer ABS for my car bodies because it sands smoother than PLA, even after using the smoothing technique described below. But PLA will work.
• Some parts are really small, and may be best printed using a 0.2mm extruder. I did all parts with a 0.4mm extruder.

Post-Printing

Just super glue all the parts together.

Smoothing

I just sanded the ABS body, but I could have gotten it a lot smoother using 3D printing resin and baby powder. You can find videos and guides online that describe the process, but here it is in a nutshell:

• Mix 1 part resin and 2-3 parts baby powder in an opaque container (so that it can be stored without hardening due to UV exposure).
• Using a paintbrush or cotton swab, spread a thin layer of the resin/baby powder mix over the body, wherever you want to smooth print lines and gaps.
• Use a UV flashlight (a cheap one--like the kind used to harden resin finger nail polish, which you can order from Amazon or buy in the pharmacy department of Walmart) to harden the resin.
• Sand the body smooth until there are no thick layers left.
• Repeat over any areas that are still rough.

Weights

You can add tungsten weights to the holes in the rear of the body to end up right at 5 oz. Playing with different infills and weights can get you close to the ideal front/rear balance.

Patreon/Commercial License

I just do this for fun BUT if you insist on throwing a couple of bucks my way or if you'd like to sell prints of any of my designs, see my Patreon page.