This is American Pneumatic Tool part number 1280582678, previously 18723 spring, stocked at Crowder Supply as APT18723. It loads its mating part against the seat. When free length drops, the symptom is inconsistent operation the tool works, but not crisply.
The published breakdown lists it on the 307 & 317 Needle Scaler. It comes off the APT 307 Pneumatic Needle Scaler. Worth matching the reference number on the diagram against your own machine before you order the same part number can sit in more than one position.
Everything else on that machine is one page away, and the parts breakdown index indexes every breakdown we publish. Denver stock, with same-day shipment on in-stock orders in by 4 PM ET.
- Part number: 1280582678
- Previous part number: 18723
- Manufacturer: American Pneumatic Tool
- Crowder SKU: APT18723
- Listed on breakdowns for: 307 & 317 Needle Scaler

