Description
Needles per pair for trammel round rod (hardened steel) are the replacement tip set for a trammel bar — the layout tool used to scribe large-radius arcs and circles where a standard compass cannot reach. A trammel consists of a long round rod (the bar) with two sliding carriers; the operator clamps each carrier at the radius distance, replaces the carriers’ contact points with this needle pair, and scribes the arc by rotating one needle around the other over the workpiece surface.
The needles are made of hardened steel — necessary because the scribing action drags a needle under operator pressure over surfaces that are typically harder than soft steel. Soft steel needles would become dull within a single layout pass. The hardened tip provides a clean, visible, durable scribe mark that withstands subsequent shop handling. Supplied as a matched pair.
The needles fit standard trammel rod carriers via a threaded shank common to most trammel bar systems. Replacement is a routine consumable — needles become dull over time on hardened materials and need to be replaced to maintain scribe quality.
Common applications: large-radius arc layout on sheet stock during fabrication, sheet circle scribing for pattern templates, jig and fixture circular reference layout, and pattern shop arc work where a compass cannot span the radius.
Features
- Needles per pair for trammel round rod
- Hardened steel — durable scribe on hard surfaces
- Matched pair — same geometry on pivot and scribe ends
- Replacement consumable for trammel carriers
- Standard threaded shank fit
Specifications
| Type | Trammel needles (per pair) |
|---|---|
| Material | Hardened steel |
| Item number | 64-671234 |
Compatible accessories
Standard trammel round rod and trammel carriers (sold separately). Suitable for all standard trammel bar systems.
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