The Caffrey Platen attachment for Belt Grinders

The Caffrey Platen is an excellent attachment for use on belt grinders such as the KMG or the KMG-TX or other belt sanders which use 2x72 inch abrasive belts. Ed Caffrey, ABS Mastersmith, introduces the Caffrey Platen, now available at Beaumont Metal Works. Ed Caffrey designed and Beaumont produced the original Caffrey Platen, and today have teamed up to offer an updated version. In this video, Ed Caffrey explains its features and demonstrates the how the Caffrey Platen is helpful in custom knifemaking and used in related metal forming operations on belt grinders and belt sanders.

1:14 The steel platen plate is reversible and can be flipped along its vertical axis to enable use on either of its two operating faces. Beaumont is also offering a replacement platen plate with a safety shelf built-in to enable the customer to apply pyro-ceramic glass on its surface to create a low friction high-wear glass platen surface.

2:56 Align the platen plate between the wheels to improve control of the grinding surface. This platen has button head screws used to adjust the position of the platen plate holder in its slots. The button head screws require a 3/16” hex key or allen wrench.

3:56 See that 3/8” flat grade 8 washers are situated between the platen plate holder and the central body of the Caffrey Platen. These are used as spacers to improve the alignment of the platen plate with the wheels and the edge of the 2x72 abrasive belt. If the button cap screws are removed, remember to install the flat washers as spacers to properly center the platen plate during operation.

4:25 Set up the Caffrey Platen for controlled flat grinding by extending the operating surface of the platen plate approximately 1/16” past the outer edge of both the top and bottom contact wheels. A long straight edge can be used to properly tighten the platen plate holder in this position. Making the platen plate “proud” or slightly prominent past the tangent line of both contact wheels ensures the abrasive belt is fully supported by and in constant contact of the steel platen plate. When the platen plate is protruding just slightly, work can be flat ground against the platen plate without any unwanted contact on either the top or bottom idler wheels of the Caffrey Platen.

7:06 The tooling arm has a ¾” hole which holds the steel pin of the Caffrey Platen and enables 360 degree positioning and clamping. The black locking lever is loosened to allow rotation and then tightened to lock the platen into the desired position.

7:42 Why does the Caffrey Platen have a 1-1/2” diameter top contact wheel and a 3” diameter bottom contact wheel? A choke-up point or index finger groove can be readily imparted into a knife blank using the 1-1/2 inch top contact wheel with zero change to the existing flat-grind setup on the Caffrey Platen. Knife handles which are held most naturally by the human hand tend to be narrower in the front toward the blade and wider in the back towards the butt. The 3” contact wheel on the bottom of the Caffrey Platen provides an excellent working surface for creating the curved inner back of the knife handle. This contact wheel radius is immediately accessible for finishing and rounding even when the Caffrey Platen is setup for vertical flat grinding.

10:02 The platen can be rotated and repositioned with the 1-1/2 inch contact wheel in front for direct access to curved grinding.

10:22 The grinder accessory can be rotated to provide an easily and quickly accessible slack belt area between the wheels. This video shows how easy it is to start slack belt grinding with this setup.

10:46 With another rotation of the unit and re-clamping of the locking lever, the larger polyurethane contact wheel can be prominently positioned for radius grinding using the 3 inch diameter wheel.
11:12 People have asked if the platen’s contact wheels can be replaced with different diameter wheels. Yes the wheels can be changed. However, the threaded spindle locations on the Caffrey Platen have been positioned so that the tangents of the 3” and the 1-1/2” contact wheels are aligned with the platen plate. Changing the wheels will change this alignment, which may affect how the platen plate can be used with the wheels. Since the platen plate holder can be removed, different contact wheel diameters can be installed to allow immediate access to either contact wheel with quick rotation of the platen.

11:41 On the KMG-TX belt grinder / belt sander, Ed suggests that tracking control can be optimized when the ratcheting system tension arm is horizontal. This video shows how Ed marks his equipment to make such positioning easy and repeatable, so that abrasive belt tracking on the KMG-TX is very precise and finely controlled.

13:18 Beaumont has the Caffrey Platen available for sale on their website www.BeaumontMetalWorks.com There is also a page on www.CaffreyKnives.net about the Caffrey Platen.