Inside Diameter Fixture Clamps





Secure a workpiece from the inside diameter, leaving the outside clear for machining. Machine these clamps to match the precise size and contours of your workpiece ID. Mount the clamp to your fixture with the included screws and place your workpiece over it. Turn the socket head cap screw to expand the clamp.
Top-actuated clamps tighten from the top of the clamp, so workpieces need a through hole.
Side-actuated clamps tighten from the side of the clamp, gripping parts without a through hole in the top.
For technical drawings and 3-D models, click on a part number.
Thread | Drive | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
For ID Range | Max. Clamp Expansion | Ht. | Flange OD | Max. Clamping Force, lbs. | Size | Lg. | Size | Style | Mounting Fasteners Included | Material | Screw Material | Each | |
Top Actuated | |||||||||||||
0.16"-0.29" | 0.005" | 27/64" | 25/32" | 250 | 2-56 | 1/2" | 5/64" | Hex | Yes | Steel | Steel | 0000000 | 000000 |
0.28"-0.49" | 0.01" | 55/64" | 1 11/64" | 950 | 8-32 | 1" | 9/64" | Hex | Yes | Steel | Steel | 0000000 | 00000 |
0.48"-0.56" | 0.013" | 63/64" | 1 15/64" | 1,900 | 1/4"-20 | 1 1/4" | 3/16" | Hex | Yes | Steel | Steel | 0000000 | 00000 |
0.53"-0.79" | 0.015" | 63/64" | 1 15/32" | 2,500 | 5/16"-18 | 1 1/4" | 1/4" | Hex | Yes | Steel | Steel | 0000000 | 00000 |
0.71"-1.06" | 0.015" | 1 1/8" | 1 31/32" | 4,500 | 3/8"-16 | 1 1/2" | 5/16" | Hex | Yes | Steel | Steel | 0000000 | 00000 |
0.9"-1.39" | 0.015" | 1 1/4" | 2 13/64" | 5,900 | 1/2"-13 | 1 1/2" | 3/8" | Hex | Yes | Steel | Steel | 0000000 | 00000 |
1.15"-1.65" | 0.015" | 1 9/16" | 2 47/64" | 10,000 | 5/8"-11 | 1 3/4" | 1/2" | Hex | Yes | Steel | Steel | 0000000 | 00000 |
1.15"-2.03" | 0.015" | 1 9/16" | 2 31/32" | 10,000 | 5/8"-11 | 1 3/4" | 1/2" | Hex | Yes | Steel | Steel | 0000000 | 000000 |
1.15"-3.06" | 0.015" | 1 51/64" | 4 15/64" | 10,000 | 5/8"-11 | 2" | 1/2" | Hex | Yes | Steel | Steel | 0000000 | 000000 |
1.15"-4.06" | 0.015" | 1 51/64" | 5 15/64" | 10,000 | 5/8"-11 | 2" | 1/2" | Hex | Yes | Steel | Steel | 0000000 | 000000 |
1.15"-6.89" | 0.02" | 1 51/64" | 5 15/64" | 10,000 | 5/8"-11 | 2" | 1/2" | Hex | Yes | Steel | Steel | 0000000 | 000000 |
1.15"-9.85" | 0.08" | 1 51/64" | 6" | 6,000 | 5/8"-11 | 2" | 1/2" | Hex | Yes | Aluminum | Steel | 0000000 | 000000 |
Side Actuated | |||||||||||||
0.71"-1.12" | 0.012" | 1 5/8" | 1 31/32" | 4,000 | 3/8"-16 | 1 1/2" | 1/4" | Hex | Yes | Steel | Steel | 0000000 | 000000 |
Inside Diameter Fixture Clamps for Castings and Rough Parts


These clamps wedge against the workpiece ID to grip cast, unfinished, or uneven parts, leaving the outside clear for machining. Do not use these clamps on smooth or finished ID’s because they will leave a mark. The clamp’s screw tightens from the top of the clamp, so workpieces require a through hole. Thread the clamp into a tapped hole in your fixture and place your workpiece over it. Reach through the hole to turn the screw, expanding the clamp.
For technical drawings and 3-D models, click on a part number.
Thread | Drive | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
For ID Range | Max. Clamp Expansion | Body Ht. | Overall Ht. | Max. Clamping Force, lbs. | Size | Pitch, mm | Lg., mm | Size, mm | Style | Mounting Fasteners Included | Material | Screw Material | Each | |
0.768"-0.945" | 0.178" | 23/64" | 29/64" | 450 | M4 | 0.7 | 12 | 3 mm | Hex | Yes | Steel | Steel | 0000000 | 000000 |
0.925"-1.142" | 0.217" | 33/64" | 43/64" | 1,120 | M6 | 1 | 18 | 5 mm | Hex | Yes | Steel | Steel | 0000000 | 00000 |
1.122"-1.417" | 0.295" | 43/64" | 7/8" | 2,000 | M8 | 1.25 | 25 | 6 mm | Hex | Yes | Steel | Steel | 0000000 | 00000 |
Expanding-End Lathe Mandrels

An expanding screw widens the end of the mandrel for a tight hold on the inside of a workpiece. These mandrels are machinable to fit the exact ID of your part. Mandrels are also known as arbors.
For technical drawings and 3-D models, click on a part number.
OD | Overall Lg. | Shank Dia. | End Expansion | Material | Each | |
1/4" | 3" | 1/4" | 0.002" | Steel | 0000000 | 000000 |
3/8" | 3" | 3/8" | 0.002" | Steel | 0000000 | 00000 |
1/2" | 3" | 1/2" | 0.002" | Steel | 0000000 | 00000 |
5/8" | 3" | 5/8" | 0.002" | Steel | 0000000 | 00000 |
3/4" | 4" | 3/4" | 0.002" | Steel | 0000000 | 00000 |
7/8" | 4" | 7/8" | 0.002" | Steel | 0000000 | 00000 |
1" | 4" | 1" | 0.002" | Steel | 0000000 | 00000 |
1 1/4" | 4" | 1" | 0.002" | Steel | 0000000 | 00000 |
1 1/2" | 4" | 1" | 0.002" | Steel | 0000000 | 00000 |
1 3/4" | 4" | 1" | 0.002" | Steel | 0000000 | 00000 |
Expanding-End Lathe Mandrel Sets

An expanding screw widens the end of the mandrel for a tight hold on the inside of a workpiece. These mandrels are machinable to fit the exact ID of your part. Mandrels are also known as arbors.
For technical drawings and 3-D models, click on a part number.
Number of Pieces | Includes | End Expansion | Material | Each | |
8 | Five Hex Keys One 1 1/4" OD × 1" Shank Dia × 4" Lg. Expanding-End Mandrel One 1" OD × 1" Shank Dia × 4" Lg. Expanding-End Mandrel One 1/2" OD × 1/2" Shank Dia × 3" Lg. Expanding-End Mandrel One 1/4" OD × 1/4" Shank Dia × 3" Lg. Expanding-End Mandrel One 3/4" OD × 3/4" Shank Dia × 4" Lg. Expanding-End Mandrel One 3/8" OD × 3/8" Shank Dia × 3" Lg. Expanding-End Mandrel One 5/8" OD × 5/8" Shank Dia × 3" Lg. Expanding-End Mandrel One 7/8" OD × 7/8" Shank Dia × 4" Lg. Expanding-End Mandrel Stand | 0.002" | Steel | 0000000 | 0000000 |
Wide-Diameter Range Lathe Mandrels

The sleeve on these mandrels expands to hold a range of IDs for better versatility than solid and expanding-end mandrels. They can hold the workpiece at any position along the sleeve. To use, insert the sleeve into the workpiece before inserting the small end of the tapered body into the sleeve and pushing until it's tight. Mandrels are also known as arbors.
For technical drawings and 3-D models, click on a part number.
OD | Overall Lg. | Sleeve Lg. | Sleeve Accuracy | Material | Each | |
1/2"-9/16" | 5" | 2 1/2" | 0.001" TIR | Steel | 0000000 | 000000 |
9/16"-21/32" | 6" | 2 3/4" | 0.001" TIR | Steel | 0000000 | 00000 |
21/32"-3/4" | 7" | 2 3/4" | 0.001" TIR | Steel | 0000000 | 00000 |
3/4"-7/8" | 7" | 3 1/4" | 0.001" TIR | Steel | 0000000 | 00000 |
7/8"-1" | 7" | 3 1/2" | 0.001" TIR | Steel | 0000000 | 00000 |
1"-1 1/4" | 9" | 4" | 0.001" TIR | Steel | 0000000 | 000000 |
1 1/4"-1 1/2" | 9" | 4" | 0.001" TIR | Steel | 0000000 | 000000 |
1 1/2"-2" | 11 1/2" | 5" | 0.001" TIR | Steel | 0000000 | 000000 |
2"-2 3/4" | 14" | 6" | 0.001" TIR | Steel | 0000000 | 000000 |
2 3/4"-3 3/4" | 17" | 7" | 0.001" TIR | Steel | 0000000 | 000000 |
Machine-Your-Own Inside-Grip 5C Collets

The head on these collets acts like a mandrel to support the inside of a hollow workpiece. An expanding screw widens the head to firmly grip the workpiece. It can be machined to fit the exact ID of your part. All have external threads.
Head Dia. | Head Thick. | Min. Machined Dia. | Body Dia. | Overall Lg. | External Thread Size | TIR (Total Indicated Runout) Accuracy | Material | Each | |
1/2" | 1" | 0.25" | 1 1/4" | 4 1/2" | 1.234"-20 | 0.0005" | Steel | 0000000 | 000000 |
1" | 1" | 0.437" | 1 1/4" | 4 1/2" | 1.234"-20 | 0.0005" | Steel | 0000000 | 00000 |
1" | 2" | 0.437" | 1 1/4" | 5 1/2" | 1.234"-20 | 0.0005" | Steel | 0000000 | 000000 |
1 1/2" | 1" | 0.75" | 1 1/4" | 4 1/2" | 1.234"-20 | 0.0005" | Steel | 0000000 | 00000 |
1 1/2" | 1 1/2" | 0.75" | 1 1/4" | 5" | 1.234"-20 | 0.0005" | Steel | 0000000 | 000000 |
2" | 1" | 0.75" | 1 1/4" | 4 1/2" | 1.234"-20 | 0.0005" | Steel | 0000000 | 000000 |
2" | 1 1/2" | 0.75" | 1 1/4" | 5" | 1.234"-20 | 0.0005" | Steel | 0000000 | 000000 |
2 1/2" | 2 1/2" | 0.75" | 1 1/4" | 6" | 1.234"-20 | 0.0005" | Steel | 0000000 | 000000 |