Acme-Gridley RB-8
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 It may be a superseded or older model; the specifications below are as we last recorded them.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
drive type
cross slide stroke
longitudinal stroke
How much does the Acme-Gridley RB-8 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 RB-8 is an eight-spindle, cam-operated bar automatic with a listed maximum bar diameter of 52 mm (2.05 in), or 60 mm on another model variant, and a 2.625 in spindle hole. It is not in the maker's current lineup, so this page is written from the listed figures for buyers of existing machines.
Everything on this machine is mechanical. The drive is cam-operated, the control is the cam set itself, and both the cross-slide and the longitudinal strokes are listed as variable and cam-set, with no stroke figure given. Spindle speed comes in multiple fixed ranges. In practice a job is defined by its cams and its speed range: quick to run once set, slow to change over, and dependent on having or making the right cams.
Back working is listed, through end-working spindles, so the cut-off side of a part can be machined without a second operation. Bar feed is automatic. Which bar size a given machine takes, 52 mm (2.05 in) or 60 mm, depends on the model variant, so check the collets and feed tubes against the stock you plan to run.
The machine is listed at 33,800 lb, with overall dimensions of 4 ft 8 in × 13 ft 2 in × 8 ft, and it needs a 460 VAC 3-phase 60 Hz supply. Nothing in the listed figures mentions a CNC version.
Full Specifications
| Parameter | Value |
|---|---|
| Number of Spindles | 8 |
| Max Bar Diameter | 52 mm (2.05 in) or 60 mm depending on model variant |
| Spindle Speed | Multiple fixed speed ranges (cam-selectable) |
| Drive Type | Mechanical cam-operated |
| Cross Slide Stroke | Variable (cam-set) |
| Longitudinal Stroke | Variable (cam-set) |
| Cycle Time | 1-4 seconds for simple parts |
| Throughput | Up to 7,200 parts/hour (simple geometry) |
| Back Working | Yes (end-working spindles) |
| Bar Feed | Automatic |
| Machine Weight | 33,800 Lbs. |
| CNC Control | Mechanical cam |
| Electrical | 460 VAC 3-phase 60 Hz |
| Spindle Hole Dia | 2.625" |
| Spindles | 8 spdl |
| Dimensions | 4'8" x 13'2" x 8' |
Specifications sourced from machinetools.com — verified 2026-03-28
Strengths & Limitations
Strengths
- Eight spindles with back working through end-working spindles
- Bar capacity of 52 mm (2.05 in), or 60 mm depending on model variant
- Automatic bar feed for continuous running from bar stock
- Spindle hole diameter of 2.625 in
Limitations
- Purely cam-operated: every new part needs its own cams and stroke settings
- No stroke or spindle speed figures are listed; strokes are cam-set and speeds come in fixed ranges
- Weighs 33,800 lb and needs room for a machine listed at 4 ft 8 in × 13 ft 2 in × 8 ft
- Requires a 460 VAC 3-phase 60 Hz electrical supply
Best For
Frequently Asked Questions
01
The listed maximum bar diameter is 52 mm (2.05 in), or 60 mm depending on the model variant. The spindle hole diameter is listed as 2.625 in. Confirm which variant a machine is, and which collets come with it, before buying bar.
02
Cam-operated. The drive type is listed as mechanical cam-operated and the control as mechanical cam. Cross-slide and longitudinal strokes are set by the cams, and spindle speed is chosen from multiple fixed ranges. No CNC version appears in the listed figures.
03
Yes. Back working is listed, using end-working spindles. That lets the cut-off side of the part be drilled or finished within the same cycle, so a simple part can leave the machine complete.
04
Machine weight is listed as 33,800 lb and overall dimensions as 4 ft 8 in × 13 ft 2 in × 8 ft. The electrical supply is 460 VAC 3-phase 60 Hz. The table does not say which dimension is which, so measure the machine before planning its position.
Videos
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