Royal CNC Expanding Mandrels

ID Workholding Advantages:

  • Allows for full access to the entire length of the workpiece so all external diameters can be turned in a single operation, guaranteeing perfect concentricity.
  • On sub-spindle machines, ID gripping on the second spindle eliminates the risk of surface damage that can be caused by second-op OD gripping of a previously-turned diameter.
  • For many parts, the engagement-length of an ID bore can be greater than what is available for OD gripping, resulting in superior rigidity and torque transmission.
  • ID systems tend to be more streamlined than OD systems, enabling better part access – especially important for use on machines with live tooling.

ID Gripping is Often Overlooked as a Workholding Option, Yet in Many Situations it is the Best Choice.

Perfect Combination – A Royal Quick-Grip™ CNC Collet Chuck on the main spindle and a Royal CNC Expanding Mandrel System on the sub.

Bolt & Go™

Royal’s exclusive Bolt & Go™ mounting feature ensures maximum accuracy and rigidity with no adjusting required. Other systems require the mandrel to be trammed in – a hassle that wastes valuable machining time.

Oversized Flange

Borrowing from the winning design of our CNC Collet Chucks, all bodies feature an oversized flange to protect the machine tool spindle bearings from coolant penetration.

Z-Axis Repeatability

Pullback action draws the workpiece securely against a ground locating plate for maximum “dual-contact” rigidity and consistent z-axis repeatability.

Easy Installation

Royal CNC Expanding Mandrel Systems include all mounting hardware, wrenches, and a custom-machined drawtube connector to ensure hassle-free installation.

Heavy-Duty Construction

Royal consistently builds products that outlast the competition, especially in the most demanding environments. Bodies, mandrels, and expanding rods are all hardened to Rc 61-63 for maximum durability.

Same-Day Shipping

Royal maintains a huge inventory of standard bodies, mandrels, and sleeves to help us achieve our goal of same-day shipping on all orders.

Custom Systems

If our standard line doesn’t meet your needs, give us a call to discuss your special requirements. Capabilities include:

  • Larger sizes – up to 25" diameter
  • Extended-length systems
  • Multi-step systems for locating on multiple bore diameters
  • Automation enhancements such as ejector rings, part confirmation, etc.

Ultra-Precision Accuracy

System runout guaranteed to be 0.0005" TIR or better.

Modular Design

Mandrel models A-E all have a common mounting interface with the body so the system can grow with your needs.

Wide Gripping Range

A broad 0.032" expansion range (0.020" for model A) enables many bore sizes to be covered with a single expanding sleeve.

Parallel-Grip

Royal’s double-angle design provides parallel sleeve expansion, ensuring full-length part contact and positive release when the part is unclamped.

Outstanding Tool Clearance

Royal CNC Expanding Mandrel Systems have been optimized for superior tool clearance over other workholding systems.

Completely Sealed

All expanding sleeve slots are sealed to prevent contaminants from accumulating on the mandrel surface – ensuring years of trouble-free service. An internal O-ring on the drawtube connector offers additional protection.

How to Order:

  1. Choose the appropriate body assembly based upon the lathe spindle it will be mounted to. Just like with Royal CNC Collet Chucks, each ID gripping system includes a custom-machined drawtube connector to ensure hassle-free installation.
  2. Choose the appropriate mandrel based upon the diameter you plan to grip. All mandrels and bodies share a common mounting interface for full interchangeability. Each mandrel includes the expanding rod and an expanding rod adapter.
  3. If required, choose part locator to provide a banking surface for the workpiece.
  4. Choose the appropriate expanding sleeve based upon the diameter you plan to grip.

Dimensions

Note - dimension shown without optional part locator
SPINDLE
MOUNT
A B C D E F G
A2-5 3.75 4.34 See
Below 
6.45 5.00
A2-6 4.00 4.59 7.45 6.25
140mm 3.90 4.49 7.45 6.25
A2-8 5.00 5.59 9.45 8.00

1. Choose the appropriate body assembly.

  • The body provides a precision interface for connecting the mandrel to the lathe spindle.
  • Assembly includes body, custom-machined drawtube connector, and mounting hardware.
  • Order mandrels, sleeves, and part locators separately.

Royal Body Assemblies

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Spindle Type*
PART
NUMBER
PRICE
140MM
$1,550
A2-5
$1,200
A2-6
$1,450
A2-8
$1,960

*Bodies with other spindle mounts available. Contact Royal for additional information.

2. Choose the appropriate mandrel.

  • Mandrel models are defined by their gripping range.
  • Expanding rod, expanding rod adapter, and mounting hardware included with each mandrel.
  • Order expanding sleeves separately.

Royal Mandrels

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Mandrel
Model
Gripping
Range
C
D
E
PART NUMBER
PRICE
A
0.479–0.640
1.57
0.57
0.87
47100
$1,262
B
0.620 –0.901
1.81
0.59
1.06
47101
$1,262
C
0.870 –1.151
2.05
0.61
1.26
47102
$1,262
D
1.120 –1.651
2.32
0.60
1.50
47103
$1,262
E
1.620 –3.276
2.52
0.58
1.69
47104
$1,262

3. Choose part locator.

  • Part locators are an optional accessory.
  • Locator bolts to the front of the mandrel and provides a square surface for the workpiece to locate against.
  • Wider locators available to accommodate short parts.

Royal Part Locators

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Fits
Mandrel
Model
Width
Outer
Diameter
Part
Number
PRICE
A
0.47
1.57
$246
B
0.47
1.57
$246
C
0.47
2.95
$284
D
0.47
2.95
$284
E
0.47
2.95
$284

4. Choose appropriate expanding sleeve.

  • Order expanding sleeves according to mandrel models A thru E.
  • All expanding sleeves are fully sealed against coolant and chip penetration.
  • Parallel grip ensures full-length part contact for optimum accuracy and grip force.
  • All sleeves collapse 0.005" below nominal ground size to ensure easy part loading and unloading.

Royal Expanding Sleeves - Model A

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Nominal Sleeve
Diameter
Gripping
Range
Part
Number
PRICE
31⁄64″
0.479 - 0.499
$344
1⁄2″
0.495 - 0.515
$344
33⁄64″
0.511 - 0.531
$344
17⁄32″
0.526 - 0.546
$344
35⁄64″
0.542 - 0.562
$344
9⁄16″
0.558 - 0.578
$344
39⁄64″
0.604 - 0.624
$344
19⁄32″
0.589 - 0.609
$344
41⁄64″
0.636 - 0.656
$344
5⁄8″
0.620 - 0.640
$344

Royal Expanding Sleeves - Model B

Filters Sort results
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Nominal Sleeve
Diameter
Gripping
Range
Part
Number
PRICE
5⁄8″
0.620 - 0.651
$380
21⁄32″
0.651 - 0.682
$380
11⁄16″
0.683 - 0.714
$380
23⁄32″
0.714 - 0.745
$380
3⁄4″
0.745 - 0.776
$380
25⁄32″
0.776 - 0.807
$380
13⁄16″
0.808 - 0.839
$380
27⁄32″
0.830 - 0.870
$380
7⁄8″
0.870 - 0.901
$380

Royal Expanding Sleeves - Model C

Filters Sort results
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Nominal Sleeve
Diameter
Gripping
Range
Part
Number
PRICE
7⁄8″
0.870 - 0.901
$380
29⁄32″
0.901 - 0.932
$380
15⁄16″
0.933 - 0.964
$380
31⁄32″
0.964 - 0.995
$380
1″
0.995 - 1.026
$380
1 1⁄32″
1.026 - 1.057
$380
1 1⁄16″
1.058 - 1.089
$380
1 3⁄32″
1.089 - 1.120
$380
1 1⁄8″
1.120 - 1.151
$380

Royal Expanding Sleeves - Model D

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Nominal Sleeve
Diameter
Gripping
Range
Part
Number
PRICE
1 1⁄8″
1.120 - 1.151
$409
1 5⁄32″
1.151 - 1.182
$409
1 3⁄16″
1.183 - 1.214
$409
1 7⁄32″
1.214 - 1.245
$409
1 1⁄4″
1.145 - 1.276
$409
1 9⁄32″
1.276 - 1.317
$409
1 5⁄16″
1.308 - 1.339
$409
1 11⁄32″
1.339 - 1.370
$409
1 3⁄8″
1.370 - 1.401
$409
1 13⁄32″
1.401 - 1.432
$409
1 7⁄16″
1.433 - 1.464
$409
1 15⁄32″
1.464 - 1.495
$409
1 1⁄2″
1.495 - 1.526
$409
1 17⁄32″
1.526 - 1.557
$409
1 9⁄16″
1.558 - 1.589
$409
1 19⁄32″
1.589 - 1.620
$409
1 5⁄8″
1.620 - 1.651
$409

Royal Expanding Sleeves - Model E

Filters Sort results
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Nominal Sleeve
Diameter
Gripping
Range
Part
Number
PRICE
1 5⁄8″
1.620 - 1.651
$497
1 21⁄32″
1.651 - 1.682
$497
1 11⁄16″
1.683 - 1.714
$497
1 23⁄32″
1.714 - 1.745
$497
1 3⁄4″
1.745 - 1.776
$497
1 25⁄32″
1.776 - 1.807
$497
1 13⁄16″
1.808 - 1.839
$497
1 27⁄32″
1.839 - 1.870
$497
1 7⁄8″
1.870 - 1.901
$497
1 29⁄32″
1.901 - 1.932
$497
1 15⁄16″
1.933 - 1.964
$497
1 31⁄32″
1.964 - 1.995
$497
2″
1.995 - 2.026
$497
2 1⁄32″
2.026 - 2.057
$497
2 1⁄16″
2.058 - 2.089
$497
2 3⁄32″
2.089 - 2.120
$497
2 1⁄8″
2.120 - 2.151
$497
2 5⁄32″
2.151 - 2.182
$497
2 3⁄16″
2.183 - 2.214
$497
2 7⁄32″
2.214 - 2.245
$497
2 1⁄4″
2.245 - 2.276
$497
2 9⁄32″
2.276 - 2.307
$497
2 5⁄16″
2.308 - 2.339
$497
2 11⁄32″
2.339 - 2.370
$497
2 3⁄8″
2.370 - 2.401
$497
2 13⁄32″
2.401 - 2.432
$497
2 7⁄16″
2.433 - 2.464
$497
2 15⁄32″
2.464 - 2.495
$497
2 1⁄2″
2.495 - 2.526
$497
2 17⁄32″
2.526 - 2.557
$564
2 9⁄16″
2.558 - 2.589
$564
2 19⁄32″
2.589 - 2.620
$564
2 5⁄8″
2.620 - 2.651
$564
2 21⁄32″
2.651 - 2.682
$564
2 11⁄16″
2.683 - 2.714
$564
2 23⁄32″
2.714 - 2.745
$564
2 3⁄4″
2.745 - 2.776
$564
2 25⁄32″
2.776 - 2.807
$564
2 13⁄16″
2.808 - 2.839
$564
2 27⁄32″
2.839 - 2.870
$564
2 7⁄8″
2.870 - 2.901
$564
2 29⁄32″
2.901 - 2.932
$564
2 15⁄16″
2.933 - 2.964
$564
2 31⁄32″
2.964 - 2.995
$564
3″
2.995 - 3.026
$564
3 1⁄32″
3.026 - 3.057
$564
3 1⁄16″
3.058 - 3.089
$564
3 3⁄32″
3.089 - 3.120
$564
3 1⁄8″
3.120 - 3.151
$564
3 5⁄32″
3.151 - 3.182
$564
3 3⁄16″
3.183 - 3.214
$564
3 7⁄32″
3.214 - 3.245
$564
3 1⁄4″
3.245 - 3.276
$564