How to fit parts to existing hardware for RC hobbyists

Q: Is LunarWerx 3D Print free to use?

The tools are free to use. You use them on their website, which is hosted on Cloudflare, and they run in a web browser. Signing in keeps your settings, recent test prints and print results with you on every computer.

A practical guide for RC hobbyists fitting printed parts to existing hardware, with steps for measuring, test fitting and tools that can help.

By TexHouse · 2026-10-23

TexHouse is published by the makers of LunarWerx 3D Print, Vector3D and MeshyDL, which are compared here alongside other tools.

Measure the existing mounting points and clearances first, then test fit a small sample before you print the full part. Check each step against your own hardware, since a model that looks right on screen can still bind once it is attached.

Option	What it does	Fee
LunarWerx 3D Print	Browser tools that work out ironing settings, check parts for injection moulding and design 3D-printable foam inserts ^[1]	Free to use ^[1]
Other tools for this job	Not described on this page; check the tool's own page before you choose	Not published

What you need before you start

Before you fit a new part to existing RC hardware, gather what you need. Keep the original part or chassis piece nearby, because it is the reference for every measurement you take.

A set of calipers is a useful first tool for this job. It measures bolt spacing, post diameters and wall thickness with enough detail to plan a fit.

Keep the screws, nuts and spacers that the original part uses, so you can check whether the new part leaves them room. A notebook or text file helps you record each measurement and the clearance you chose, because small differences add up across a build.

You also need a way to edit the part, such as a CAD program or an existing model you are allowed to change, and a printer you already know well. Expect to run more than one test print, since a fit often takes several attempts.

Step by step

Measure the existing hardware. Record the mounting hole spacing, the post or screw diameters, and the space around the part. Measure more than once and write down each reading.

Note the clearance the part needs. Decide how much gap each mating surface needs and write that next to your measurements. A printed part rarely matches the model exactly, so the gap is an estimate until you test it.

Model the new part to match the measurements. Place the mounting holes at the recorded spacing and add the gap to each surface that meets the existing hardware. Look at the model from more than one angle before you export it.

Check the file. Open the model and look for faces that point the wrong way or holes that do not close. Fix them before you slice the file.

Print a small test piece. Print only the mounting area or a thin slice of the part, so a failed fit costs little time and filament.

Test fit the sample. Offer the test piece to the existing hardware and check that the screws go in, the part sits flat and nothing binds. Adjust the model slightly and print again.

Print the full part. Once the sample fits, print the full part with the same settings, material and orientation you used for the test, because changes to any of these can shift the dimensions.

Fit the finished part and check it under load. Tighten the fasteners gradually, move the parts through their full range and look for cracks or rubbing before you run the model.

Tools that can do it

LunarWerx 3D Print is made by the team that publishes this site. It is a set of browser tools that work out ironing settings for your printer, check a part for injection moulding and design 3D-printable foam inserts. ^[1] It runs in a web browser ^[1] and you use it on its website, which is hosted on Cloudflare. ^[1] The tools are free to use. ^[1]

When you open an STL file with faces turned backwards, it turns them right side out and says how many it fixed. ^[1]

For it, the tool works out settings for your printer, material and finish and exports a ready 3MF file, a common project file format for 3D printing. ^[1]

For an uploaded Bambu or Orca project, it adds per-object ironing settings and keeps the rest of the file unchanged. ^[1]

It runs only in your browser. Signing in keeps your settings, recent test prints and print results with you on every computer. ^[1]

Before you choose any other tool for this job, check its own published fee, the file formats it reads and writes, and whether it works with your printer.

Common mistakes to avoid

Trusting a single measurement is a common mistake. A reading taken once can be off, so measure again and compare the results before you model anything.

Skipping the test piece is costly. A full part that does not fit is the most expensive way to find a clearance problem.

Changing the printer, material or orientation between the test and the final print can change the dimensions. Keep those the same so the fit you tested is the fit you get.

Slicing a model without checking its faces can produce odd results. Open the model, look for reversed faces and fix them first.

Tightening fasteners too hard can crack a printed part. Snug the screws, check the fit and add load only after the part sits correctly.

Frequently asked questions

How do you measure existing RC hardware for a printed part?

Use calipers to record the mounting hole spacing, post diameters and the open space around the part you are replacing. Measure each point more than once and write the readings down. Measure from the existing hardware itself rather than from memory or from a listing, because small errors in the reference carry through to the printed part.

What clearance should a printed RC part have?

The right clearance depends on your printer, your material and how the part moves, so no single figure works for every build. Print a small test piece and adjust the gap in small steps until the fit is snug without binding. Record the gap that works so you can reuse it on the next part you fit.

Can LunarWerx 3D Print fix faces on a downloaded STL file?

Yes, it can handle that step. When you open an STL file with faces turned backwards, it turns them right side out and says how many it fixed. ^[1] It runs in a web browser ^[1] and the tools are free to use. ^[1]

Is LunarWerx 3D Print free to use?

The tools are free to use. ^[1] You use them on their website, which is hosted on Cloudflare, and they run in a web browser. ^[1] Signing in keeps your settings, recent test prints and print results with you on every computer. ^[1]

How do you check a mounting pattern before printing a replacement part?

Print a sample that covers the mounting area, then lay it over the existing hardware and check that every hole lines up. Measure the spacing with calipers from the original part rather than from the model alone. If a hole is off, correct the model and print the sample again before you commit to the full part.

The tools are free to use. ^[1]

Try LunarWerx 3D Print

Sources

LunarWerx 3D Print's own description of itself (the product of this site's publisher)