CASTER MOUNTINGS (ADAPTORS)

1. TOP PLATES:  Rectangular or square plate with 4 holes either round or slotted.  The strongest method of mounting a caster.  Critical dimensions are the bolt hole centers.  While the outside measurements are important, there is generally some room for small difference in size.  Bolt hole centers must match identically in most situations.   Each caster series comes with a standard top plate.  Other sizes available are shown within the optional fitting section for the caster series.  These optional sizes are available to match existing top plates for replacement purposes.   If size and centers required are not available, some manufactures will custom build top plates.

2. GRIP RING STEMS:  A round stem with a spring steel grip ring that fits into a groove in the stem.  Also known as a friction ring, it compresses when put inside a round tube, and prevents the caster from falling out of the tube.  Critical dimension is the diameter which must fit snugly inside the tube.  While the length can be important and must be considered, generally the stem is going into a long piece of tubing.  Special sizes not shown may be available, call for details.

3. THREADED STEMS:  Round stems with threads which can be threaded into a hold, or held by a nut.  Critical dimension is the diameter along with the number of threads per inch (course or fine threads).  Caster stems are standard with course threads.   NOTE:  Grip and threaded stems as well as other round stems are not recommended in rigid casters, as the stem will turn and affect the alignment of the caster.  If necessary on rigid casters, precaution must be taken to prevent the caster from turning, such as cross drilling the stem and tubing.

4. SQUARE STEMS:  Generally used with angle iron legs.  Stem is cross drilled on all sides with 2 holes to allow stem to be attached.  Can also be used in square tubing with cross drilled holes.

5. SQUARE "O"  STEM:  Same as square stem but with grip ring to hold stem inside square tubing.

6. PIPE STEMS:  Threaded with a standard pipe thread to fit inside pipe legs.   Caution, pipe sizes are not listed as they measure.

7. PIPE CAP:   Same as pipe stem casters but to fit outside of pipe legs.

8. SOCKET:  Available in cast aluminum and nylon.  Designed to fit inside tubing - both round and square, with a grip ring stem to be fit inside the socket.  Used to fit inside tubing sizes with not directly accept a grip ring system.

9. KEY WAY SOCKETS:  Designed with a key in the socket that matches a key way in the stem.  Used with combination brake and swivel lock caster to prevent stem from turning inside of socket when brake is engaged.  Eliminates the need to cross drill stem and tubing.   Can also be used on rigid casters in available sizes.

10. EXPANDABLE STEMS:  Uses various sizes of rubber membranes that expand when tightened to adapt to multiple size tubes.  This can be a very useful way to install casters but is not recommended for long term as the expandable parts can wear and eventually loosen up causing the caster to fall out.