SCX24 3D Printing Parts Guide

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  Key takeaways
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  Why part size changes everything on an SCX24
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  How powder-bed metal printing builds an SCX24 part
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  Which SCX24 parts should be metal and which should stay plastic
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  Post-processing small metal parts without losing the fit
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  Material choice for small crawler parts
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  Step by step: from a broken SCX24 part to a printed metal replacement
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  FDM, resin, and metal printing compared for SCX24 parts

The SCX24 chassis is roughly 1/24 scale, so a link arm may be 40 mm long and a diff cover 15 mm across. At that size, the ratio of surface area to volume is high: heat escapes fast, thin sections cool before the next layer bonds, and warp appears on any long, flat part. A process that works on a 200 mm bracket often behaves differently on a 20 mm knuckle.

This is the first thing to understand in any SCX24 3D printing parts guide. You are not choosing between plastic and metal in the abstract. You are choosing a process window that has to fit inside a few cubic centimeters and still leave room for a bearing, a screw head, and a 2 mm wall.

Small parts also magnify tolerance error. If a printer holds ±0.1 mm on a 100 mm part, that same ±0.1 mm on a 10 mm bore is a 1% size error — enough to make a bearing loose or seized. Design clearances around the process, not around the nominal drawing.

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  Thin walls under 1 mmProne to warp and incomplete fusion in metal; keep 1.5 mm minimum where loads run.
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  Long, flat platesCurl at the corners; add ribs or split the part instead of fighting distortion.
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  Tiny boresPrint undersize and ream, or drill after printing for anything that holds a bearing.

Laser powder-bed fusion spreads a thin layer of metal powder, melts a cross-section with a laser, then drops the build plate and repeats. Layer thickness typically runs 20–60 μm, which is why surface finish comes out satin rather than polished. Down-facing surfaces that touch powder print rougher than up-facing ones, so orientation is a design decision, not a detail.

Shrink is the second mechanism. The melt pool solidifies and contracts, and the part is built attached to a plate. Internal stress builds until the part is cut free, then it relaxes and moves. Long thin SCX24 links are the worst case. Short, chunky parts such as diff covers move far less because the stress has somewhere to go.

Porosity is the third. A well-tuned build reaches high density, but internal voids still exist. For crawler parts that see shock loads — gear teeth, pivot bosses — hot isostatic pressing closes most of that porosity and evens out fatigue life. For cosmetic or lightly loaded parts, it is usually unnecessary cost.

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  OrientationBuild load-bearing faces vertical so layers do not sit in the tension direction.
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  Support removalBudget time for support scars on hidden faces, not on bearing seats.
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  Heat treatStress relief before cutting from the plate limits post-cut movement.

Metal helps where stiffness or wear resistance decides the outcome. Diff covers that grind on rock, skid plates, link ends that wallow out, and shock towers that crack at the screw holes are all good candidates. These parts fail by abrasion or by fatigue at a stress riser, and metal removes both failure modes.

Plastic helps where mass sits above the axles or high on the chassis. A heavier axle housing raises unsprung mass, and on a 1/24 crawler that changes how the truck settles on a ledge. Printed nylon or polycarbonate can be the better engineering call for battery trays, body panels, and upper link mounts.

A practical middle path exists. Print the part in resin or FDM first, fit it, check suspension travel, then commit the same geometry to metal once the shape stops changing. Iterating in plastic costs hours; iterating in powder-bed metal costs days and real money.

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  Choose metalDiff covers, skid plates, link ends, shock towers, worm gear housings.
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  Choose plasticBody panels, battery trays, upper mounts, anything high on the chassis.
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  Choose hybridMetal insert bonded into a printed housing to take the screw threads.

Printed metal comes off the machine near-net, not finished. Bearing bores, threaded holes, and flat mating faces usually get machined after printing. On a 15 mm part, that second operation is where the real tolerance comes from — we hold ±0.005 mm on a machined bore and ±0.0002 in in imperial terms, which is what a small bearing actually needs.

Surface finish depends on the function. A sliding surface wants Ra 0.8–1.6 μm or better; a cosmetic cover can stay as-printed at Ra 1.6–3.2 μm and get bead blasted. Fine finishes down to Ra 0.2–0.8 μm are available when a shaft or seal runs against the part.

Coating is the last step and it changes dimensions. Anodizing, electroless nickel, and black oxide all add or remove material in the micron range, so mask bearing seats and thread roots. If a bore is critical, machine it after coating, not before.

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  Ream after printingPrint bores 0.1–0.2 mm undersize, then ream to final diameter.
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  Mask seatsKeep anodize and plating off bearing fits and thread roots.
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  Deburr edgesSupport scars sit on hidden faces; break edges before assembly.

For most SCX24 metal parts, 316L stainless and 17-4PH are the two sensible starting points. 316L prints cleanly, resists corrosion from mud and water, and machines well after printing. 17-4PH can be aged to a much higher strength, which suits gear teeth and pivot pins that see repeated shock.

Aluminium is a different trade. AlSi10Mg prints light and takes anodize well, so it suits covers and brackets where mass matters more than wear resistance. It is softer than stainless, so it is a poor choice for a surface that slides against rock all day.

Titanium TC4 (Ti-6Al-4V) is available and gives the best strength-to-weight of the group, but it costs the most and is harder to finish. On a 1/24 crawler, that spend rarely pays back unless you are chasing a specific weight target.

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  316L stainlessDefault for links, covers, and wet-running parts.
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  17-4PHAged for gears, pins, and high-cycle shock loads.
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  AlSi10MgLightweight covers and brackets; anodizes cleanly.
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  TC4 titaniumUse when weight is the binding constraint, not cost.