Materials & Build Guide

Engineer your pendulum for stability and repeatability. Balanced mass + low torsion = clearer reads.

Overview

Foundations

Three parts matter most: a center-weighted bob, a low-twist link (chain/thread) with a micro-swivel, and a comfortable, repeatable grip. Keep the overall mass moderate and the geometry symmetrical.

Target mass10–35 g

Bob diameter12–20 mm

Link length15–25 cm

SwivelMicro-bearing

Bob Shapes & Materials

Shapes

Isis/Egyptian (stacked discs): stable center-mass; forgiving swing.
Conical/Ogive: quick directional reads; aerodynamic.
Teardrop: gentle momentum, smooth damping.
Witness-chamber: holds a small sample; heavier, so watch fatigue.

Materials

Brass: classic, machinable, stable weight.
Hardwood: light, warm feel; add weight with an insert if needed.
Crystal (quartz/amethyst/etc.): symbolic pairing; ensure true drilling.
Stainless/Cu alloys: durable; mind total mass.

Chain / Thread & Swivels

Chain vs Thread

Fine chain: consistent length, durable, pairs well with micro-swivel.
Braided thread (nylon/silk): very low torsion; cheap to replace; knot securely.

Swivels & Hardware

Micro fishing swivels or miniature bearing swivels reduce twist accumulation.
Use small split rings or crimps; keep everything on-axis.

Grip & Handling

Grip bead or small bar that you can hold lightly with index/thumb.
Choose one grip style (pinch or overhand) and stick with it for consistency.
Elbows supported on table edge to reduce ideomotor drift.

DIY Build Steps

Workshop

Prepare bob: mark center; drill straight through on a press; deburr and polish.
Assemble link: cut chain/thread to 18–22 cm; add micro-swivel midway or at the top.
Fit hardware: split ring → bob; swivel → chain; chain → grip bead.
Check geometry: hang test—bob should point true without slow twist.
Finish: fine polish; optional clear coat for brass.

Tuning & Balance

Balance Test

Hang for 60 s—no gradual rotation should appear.
If twisting: re-seat split rings, check hole centering, add swivel.

Damping & Feel

Too lively? Shorten link slightly or increase mass a touch.
Too sluggish? Reduce mass or lengthen link by 1–2 cm.

Quick BOM (Example build)

BobBrass teardrop, 18 mm (~18 g)

LinkFine stainless chain, 20 cm

SwivelMicro-bearing swivel, size 12–14

Grip8 mm knurled bead + split ring

Rings2× micro split rings

FinishMetal polish + microfiber

I can turn this into a printable A4 spec sheet or a costed BOM table if you’d like.

Care & Upkeep

Wipe after sessions; occasional polish for metals.
Check rings and swivel play monthly; replace frayed thread promptly.
Store in a small pouch to avoid kinks and dings.

FAQ

Best starting mass? ~15–25 g is a friendly middle ground.

Chain or thread? Both work—thread is ultra-low torsion; chain is durable and consistent.

Do I need a swivel? It helps a lot for longer sessions; worth adding.