Acme-Gridley RA-8 CNC
This model was not found in Acme-Gridley's current lineup when we checked on 2026-10-03 . It may be a superseded or older model; the specifications below are as we last recorded them.
Key Specifications
number of spindles
max bar diameter
spindle speed range
main spindle drive
cross slides
end working slides
How much does the Acme-Gridley RA-8 CNC cost?
Estimated price range
Our best estimate for a multi-spindle automatic in this class — not a quote from Acme-Gridley. Configuration moves it a long way.
Overview
The Acme-Gridley RA-8 CNC is an eight-spindle bar automatic for bar up to 1-5/8 in (41 mm), depending on configuration. It is not in the maker's current lineup. The listed figures cover both the cam-driven original and the servo-driven CNC retrofit that the name points to.
Eight spindles mean eight working positions around the spindle carrier. A part that needs drilling, reaming, forming, threading and cut-off can have each operation at its own station, with cross slides cutting from the side while end-working slides cut from the front. The cycle is then set by the slowest single station and not by the sum of the operations, which is the whole case for a multi-spindle machine on high-volume parts.
With a CNC retrofit, the listed figures give an AC servo main spindle drive and CNC servo-driven cross and end-working slides in place of cams. Stroke lengths and feeds then come from a program and not from a cam set. The control is Siemens, Fanuc or Allen-Bradley, retrofit-dependent, and spindle speed is given only as variable, dependent on gearing and retrofit specification. None of this can be assumed for a particular machine, so read its retrofit specification.
The machine weighs approximately 22,000 kg (48,500 lb), against approximately 18,000 kg (40,000 lb) for the RA-6. Bar feed is magazine or hydrodynamic and coolant is centralized flood.
Full Specifications
| Parameter | Value |
|---|---|
| Number of Spindles | 8 |
| Max Bar Diameter | 1-5/8 in (41 mm) depending on configuration |
| Spindle Speed Range | Variable, dependent on gearing and retrofit specification |
| Main Spindle Drive | Mechanical (cam-driven original) or AC servo (CNC retrofit) |
| Cross Slides | Cam-driven or CNC servo-driven (retrofit) |
| End Working Slides | Cam-driven or CNC servo-driven (retrofit) |
| Bar Feed | Magazine or hydrodynamic bar feed |
| CNC Control | Siemens, Fanuc, or Allen-Bradley (retrofit-dependent) |
| Coolant System | Flood coolant, centralized |
| Machine Weight | Approx. 22,000 kg (48,500 lb) |
Specifications compiled from manufacturer literature and industry references. Not independently verified against a published spec sheet — confirm with the manufacturer or an authorised dealer before making a purchasing decision.
Strengths & Limitations
Strengths
- Eight spindles give eight stations for cross-slide and end-working operations on one part
- A CNC retrofit replaces cams with an AC servo spindle drive and servo-driven cross and end-working slides
- Runs bar up to 1-5/8 in (41 mm), depending on configuration
- Magazine or hydrodynamic bar feed, with centralized flood coolant
Limitations
- Spindle speed is not given as a figure; it depends on gearing and retrofit specification
- The control differs by retrofit: Siemens, Fanuc or Allen-Bradley
- Approximately 22,000 kg (48,500 lb), heavier than the RA-6 at approximately 18,000 kg (40,000 lb)
Best For
Frequently Asked Questions
01
Eight. Each spindle carries its own bar, and the carrier indexes the bars through eight stations where cross slides and end-working slides do their cuts. One finished part comes off at each index once every station is loaded.
02
According to the listed figures, the mechanical, cam-driven main spindle drive becomes an AC servo drive, and the cross slides and end-working slides become CNC servo-driven. The control is Siemens, Fanuc or Allen-Bradley depending on the retrofit.
03
Maximum bar diameter is listed as 1-5/8 in (41 mm), depending on configuration. Bar is supplied by a magazine or hydrodynamic bar feed. No spindle speed figure is listed, so surface speed on a given bar size cannot be worked out from the table.
04
The RA-8 CNC is listed at approximately 22,000 kg (48,500 lb). The RA-6 is listed at approximately 18,000 kg (40,000 lb). Plan the foundation and the lifting equipment around the heavier figure if the eight-spindle machine is the one being moved.
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