Bench ServiceReference
Cascadia Precision Instrument Co. · Bench Service Reference
Post-Flush Minimum
Relubrication Protocol
Mandatory follow-through after any naphtha flush of an assembled dial indicator or DTI. A flush delubricates the entire mechanism — this document defines the minimum work that converts a flushed instrument into a serviced one.
§01
Governing Principle
Oil count, not oil coverage
A dial indicator needs oil at 4–10 discrete points, each receiving a droplet smaller than a pinhead. Most of the mechanism is designed to run dry — the gumming you just flushed out was almost certainly caused by a previous owner oiling surfaces that should never see oil. Excess oil migrates, collects dust, and oxidizes into the next owner's gum.
If you can see the oil glistening from arm's length, it is too much.
Why this document exists: the naphtha dunk is the correct triage step for any gummed indicator of unknown history — but it strips lubrication from every pivot. An indicator that feels fantastic dry is wearing itself out. "Flushed" and "serviced" are different products; the difference is this protocol.
§02
Oil-Point Map
Fig. 1 — Plan view, plunger indicator, back plate removed. Amber = oil. Blue = dry by design.
P1–P4
Gear-train pivot bearings
Every pinion staff in a plate hole or jewel. Typically 2–3 arbors × 2 ends = 4–6 points. This is 80% of the job. Droplet goes into the pivot hole, not on the plate.
P5
Rack guide / anti-rotation slot
Where the rack rides its follower or the plunger's pin rides its slot. One tiny drop.
P6
Rack–pinion mesh
One micro-drop on the pinion only, worked in by stroking the plunger. Debated — when in doubt on a tenths indicator, run it dry.
D1
Plunger / spindle & bore — NEVER
Mitutoyo, Starrett, and Federal all specify dry. Oil here wicks grit into the bore — the #1 cause of sticky indicators.
D2
Hairspring — NEVER
Oil between coils sticks them together and destroys repeatability.
D3
Gear teeth (dial train) — NEVER
Instrument meshes at these loads run dry; oil on teeth only collects debris.
Never oil
Dry by design
Plunger / spindle and its bore
If a spindle is dry-sticky after cleaning, the fault is geometry — bent spindle or bruised bore — not lubrication.
Hairspring
If the flush left it clean, it is done.
Gear teeth (dial train)
Rack–pinion mesh is the one debated exception — see P6.
Crystal, dial, case interior
No oil, no exceptions.
Oil these
The actual work · 4–10 points total
Gear-train pivot bearings 4–6 pts
Smallest droplet you can place, delivered into the hole. Capillary action does the rest.
Rack guide / plunger slot 1 pt
Plunger indicators only.
Rack–pinion mesh 0–1 pt
Micro-drop on pinion, distributed by stroking. Optional; improves feel.
DTI lever fulcrum & segment contact 1–2 pts
Interapid / BesTest / Last Word style. The feel-critical points on a test indicator. Minimum quantity.
Jeweled bearings as found
Even less oil than plate holes — the droplet must stay in the jewel cup.
§03
Oil Selection
| Verdict | Product | Notes |
|---|---|---|
| ■ CORRECT | Moebius 9010 | Synthetic watch oil. The standard for instrument pivots — doesn't spread, doesn't gum for a decade+. ~$25 for 2 ml, which will outlast you. This is the one to order. |
| ■ ACCEPTABLE | Nye clock oil · Starrett instrument oil | Dedicated instrument oils. Fine substitutes if already on hand. |
| ■ NEVER | WD-40 | A solvent, not a lubricant. Gums fast. |
| ■ NEVER | 3-in-1 · sewing machine oil | Oxidizes into varnish — this is literally what the flush removed. |
| ■ NEVER | Grease (any) · spray lubricants (any) | Not inside the movement, in any form. |
§04
Tools Required
Fine oiler — watchmaker's needle type with flattened tip (~$5); improvise with sharpened brass wire or an acupuncture needle. Oil cup — or a foil dimple to dip from.
You cannot apply correct quantities from the bottle. The oiler-and-cup method exists because a pinhead droplet is below what any bottle tip can dispense.
§05
Workflow · Post-Flush
- Second rinse in clean naphtha, then dry completelyTwo-jar cascade: dirty first rinse, fresh final rinse. Warm-air dry until the dial cavity clears and no vapor smell remains. Oil will not stay put on a surface carrying solvent film.
- Open minimum accessBack plate off (3–4 screws) exposes rear pivots and rack; bezel/crystal off exposes front-plate pivots and hand arbor. Most indicators give every oiling point from these two openings with zero mechanism disassembly.
- Oil the pivotsTouch the loaded oiler tip to each pivot hole — capillary action pulls the drop in. Stroke the plunger slowly between points so oil distributes into each bearing.
- Rack, pinion, and guide pointsMicro-drop each per the map, then a dozen slow full strokes to distribute.
- Verify before closingSmooth full-range travel, no hesitation. No visible oil migration or sheen on the dial side after 15 minutes sitting.
- Close up and prove repeatabilityGauge-block step or repeated drops onto a flat: return-to-zero within one graduation. This is the "serviced" evidence for the listing — and it reveals any residual fault the flush didn't cure.
§06
Sign-Off Checklist
- Fully dried before oiling — no solvent smell, dial cavity clear
- All accessible pivot holes oiled (count them: typically 4–6)
- Rack guide oiled; rack–pinion mesh oiled or deliberately left dry
- Spindle, hairspring, gear teeth, dial, crystal confirmed dry
- No oil sheen visible at arm's length after 15 min rest
- Return-to-zero within one graduation over 10 strokes
- Bezel set to reference graduation — repeatability logged for the listing
Inventory rule: order the 9010 and oiler before flushing a batch. The dangerous window is a flushed-but-unoiled indicator getting used — that's when dry wear happens. Do not let flushed units sit in the queue unoiled.
§07
Revision History
| Rev | Date | Change |
|---|---|---|
| REV 1 | 2026-07-10 | Initial release. Oil-point map, oil selection table, six-step workflow, sign-off checklist. |