Clark Deep Hollowing System – Setup1
The Clark Deep Hollowing System (patented US 7,191,689 B2) is also a unique tool to accomplish a
physically demanding task in wood turning. It is a heavy-duty system fitted to any lathe with maximum
turning diameter above 13 inches. With this system, a turner can manipulate the hollowing
bar in a more natural manner. It offers the flexibility of easily and quickly changing the
angle of attack of the tool tip. It also provides the possibility of hollowing without locking the rotation of the
hollowing bar for those instances when hollowing with a ring or hooked tool. In this instance, the angle of attack of the tool tip can be gradually changed as the tool is moved in and out of the vessel.
The basic Clark Deep Hollowing System includes – 1 base, 2 uprights, 2 connectors, 1 cross bar, 1 swivel-pivot device and installed grease fitting, angle of attack adjustment feature, adjustable bearing, hollowing bar, custom ground shortened set screws, 2 1/4″ set screws, 2 socket head cap screws, 5/8-18 bolt with washer and attachment plate. New pricing is list $375.
The socket head cap screws are for use with the ½” HSS cutter which is mounted directly in to the hollowing bar
without a holder. The setscrews are usually put into the farthest apart 2 positions. The socked head cap screws are
meant to mount in the 2 end positions. The longer setscrews are for thinner holders when using the ½ and 5/8 adapters.
Additional accessories are ala carte. The laser system, guarded tool rest, and Fulcrum Support Tube are important accessories to consider.
Laser Thickness Guide
The laser thickness guidance system is available as an option. The laser device is unique because
the laser holder wraps around the 12 o’clock steady rest arm. Notice the photograph below showing rotation
of the scaffold of the laser and return of the laser holder to the midline around the arm at 12 o’clock.
Guarded Tool Rest
The Guarded Tool Rest helps manage the weight of the long hollowing bar. Since the hollowing bar is quite long it will become difficult to hold the weight of the bar when as it becomes tail heavy when pulled beyond half
way out of the swivel blocks. The guarded tool rest replaces the factory tool rest and fits into the banjo of the lathe. The horizontal bar is very hard for long life. Its round shape will not damage the hollowing bar which will smoothly move over the bar. Typical tool rests that are standard on lathes have a sharper edge which may cause some resistance or marr the hollowing bar. The Guarded Tool Rest is needed as a place to mount the Fulcrum Support Tube.
Fulcrum Support Tube
The fulcrum Support tube is a great accessory which supports the hollowing bar for very deep hollowing. Any hollowing system is difficult to use beyond 12-15 inches deep. Even large diameter bars are difficult because they are more cumbersome and because the turner loses mechanical advantage through the lever arm of the bar extended beyond the tool rest. The Fulcrum Support Tube supports the bar and also creates a pivot point to recover mechanical
advantage. It is to be slid onto the horizontal bar of guarded tool rest accessory.