Poreba Apron/American Pacemaker Tailstock Rebuilds

PSMTR began by fully disassembling both assemblies down to bare castings.

For the Poreba apron:

• gears, shafts, clutches, pumps, and feed components were removed
• sludge, hardened oil, and debris were cleared
• internal cast surfaces were inspected for wear patterns
• lubrication passages were evaluated for blockages or damage
  

For the Pacemaker tailstock:

• the quill, screw assembly, handwheel, and internal mechanisms were removed
• the quill bore and quill OD were checked for scoring and taper wear
• sliding surfaces on the base and bottom ways were evaluated
• alignment measurements were taken to determine drift from centerline

These inspections established clear repair paths and the corrective machining required.

Both assemblies underwent aggressive cleaning to prepare them for precision work:

• stripping of old paint, dried oil, and heavy contamination
• flushing of internal oil channels
• removal of rust and corrosion
• restoring metal surfaces to bare, inspectable condition

With clean, stable surfaces, PSMTR could proceed with machining, scraping, and component refurbishment.

Poreba Apron

• mating surfaces were trued to restore proper registration
• worn shaft bores were machined or sleeved as needed
• gear faces and clutch surfaces were cleaned and corrected
• pump mounting areas were trued to restore reliable oil delivery

Precision machining ensured that rotating and sliding components operated smoothly with minimal clearance variation.

Pacemaker Tailstock

• the quill bore was lightly machined/honed to remove scoring and restore roundness
• the quill was polished and refitted for correct clearance
• base-to-way surfaces were checked and corrected to ensure proper alignment
• bottom ways were cleaned, corrected, and prepped for final scraping

This machining restored the foundational geometry needed for accurate alignment.

Scraping was performed to ensure proper accuracy and contact patterns.

On the tailstock:

• the bottom was scraped to re-establish correct contact with the bed
• the centerline was carefully re-aligned relative to the headstock
• uniform bearing points were established across the full length
• oil pockets were formed to maintain proper lubrication during heavy loading

On the apron:

• sliding and mating surfaces were scraped to improve contact and movement consistency
• critical fits were refined to ensure predictability under load

Scraping ensured smooth operation, accurate alignment, and long-term wear resistance.

The apron’s oiling system received a full restoration:

• pump was rebuilt and tested
• oil galleries were flushed and cleared
• metering points and lines were renewed
• new seals and bushings were installed

Rebuilt shafts, gears, and clutches were reinstalled, ensuring clean, reliable feed and threading operation.

• the screw assembly and handwheel mechanism were rebuilt
• lubrication points were restored or replaced
• all plugs, wipers, and seals were renewed
• internal surfaces were coated for corrosion resistance

This work eliminated drag, improved feel, and ensured predictable quill motion.

Once reassembled, both units underwent a complete functional evaluation.

• feed and rapid functions were tested
• clutch engagement was checked at multiple load levels
• oil-flow verification ensured consistent delivery
• mechanical noise and vibration were analyzed

• quill travel was checked for smoothness and uniform resistance
• alignment was verified with test bars and indicator readings
• base movement was tested across multiple bed positions

Final results confirmed restored accuracy, geometry, and operational consistency.