Free Test Tube Holder Generator: Gridfinity-Compatible Rack for 3D Printing

Need a test tube rack that fits your exact drawer layout and tube sizes? The TekOnline Test Tube Holder Generator creates a Gridfinity-compatible test tube rack with the dimensions you specify — download as STL and print.

Open the Test Tube Holder Generator

Why a parametric test tube holder?

Off-the-shelf test tube racks come in fixed sizes and rarely fit a Gridfinity baseplate. A parametric holder lets you set the exact number of tubes, the hole diameter to match your glassware, and the base footprint so it slots into any Gridfinity drawer. The block height is adjustable, so you can make deep holders for tall tubes or shallow ones for PCR strips.

Test tube holder parameters

• Grid X & Grid Y: baseplate footprint from 1×1 to 20×20 units (each unit is 42 mm)
• Height U: block height in Gridfinity units (1U = 7 mm) — deeper blocks hold tubes more securely
• Tube Diameter: 8 mm to 50 mm — covers everything from microcentrifuge tubes to 50 mL Falcon tubes
• Tube Columns: 1 to 10 columns of holes across the block
• Tube Rows: 1 to 10 rows of holes front-to-back
• Magnet Holes: add magnet pockets for magnetic baseplate setups
• Screw Holes: add mounting holes for permanent installation

Quick-start presets

Three presets cover common lab and workshop setups:

• 3×3 Holder (16mm tubes, 2×2 base): standard test tube rack — fits most 15-16mm culture tubes
• 5×2 Holder (13mm tubes, 2×1 base): narrow rack for 13mm blood collection or sample tubes
• 3×2 Holder (25mm tubes, 3×2 base): wide rack for 50 mL Falcon/conical tubes

Gridfinity compatibility

The test tube holder uses the standard Gridfinity base profile with per-cell feet. It locks into any Gridfinity baseplate — no sliding, no tipping. The base also accepts magnet and screw holes if you want additional security on metal or wooden surfaces.

How to generate a custom test tube holder STL

1. Open the Test Tube Holder Generator
2. Set your Grid X and Y footprint to match your drawer or baseplate
3. Choose block height in Gridfinity height units
4. Set tube diameter, number of columns and rows
5. Click Generate Preview to inspect the 3D model
6. Download the STL and open in Bambu Studio, Orca Slicer or PrusaSlicer

Printing tips for test tube holders

• Use PETG for lab holders — it resists common lab chemicals better than PLA
• Print at 0.2 mm layer height with 15-20% infill — holes come out clean and the block is rigid enough
• For precise hole diameters, calibrate your slicer’s hole horizontal expansion setting
• Consider ironing the top surface for a smooth finish that is easier to clean
• Print multiple holders and stack them — the Gridfinity base prevents sliding

All Gridfinity generators on one page

The test tube holder is one of five generators available on the TekOnline Gridfinity Generator. You can also create:

• Bins — storage bins with dividers, label lip, scoop, basket sides, dovetail connectors
• Baseplates — thin, weighted, skeletonized and screw-together styles
• Flower Pots — tapered planters with drain hole and optional drainage feet
• Washers — flat washers and spacers for any mechanical project

Generate a custom test tube holder STL now — free, no account required