Slide 003: Reverse Mounting, Base Finishing, and Advanced Faceplate Techniques

Slide Visual

Slide Overview

This slide covers techniques for finishing the base of a bowl (removing the tenon), reverse-mounting methods, and introduces advanced faceplate operations including platters and hollow forms.

Instruction Notes

Reverse Mounting Methods

After a bowl is turned, the base still shows the tenon or recess used for chuck mounting. Professional-quality work requires removing this evidence. Several reverse-mounting methods exist:

Jam Chuck (Friction Chuck) The most common method. Turn a cylinder on a waste block that fits snugly inside the bowl opening. The bowl is pressed onto the jam chuck, and tailstock pressure holds it in place. The base is then accessible for turning.

• Turn the jam chuck cylinder to fit the bowl interior with a slight interference fit
• Apply a non-slip material (shelf liner, thin rubber) to the cylinder for grip
• Bring up the tailstock with a padded live center to hold the bowl securely
• Turn at reduced speed (400-600 RPM for a 10" bowl)
• Remove the tenon using a bowl gouge or scraper, then sand and finish the base

Vacuum Chuck A specialized chuck that uses a vacuum pump to hold the workpiece against a flat or concave rubber-sealed face. Provides uniform holding pressure and leaves no marks. Requires a vacuum pump (minimum 10" Hg) and a rotary vacuum adapter on the headstock.

Cole Jaws Large-diameter soft jaws that grip the bowl rim from the outside. The bowl is mounted rim-down with the base exposed upward. Rubber bumpers on the jaw contact points prevent marring. Available for most scroll chuck systems.

Base Finishing Technique

1. Remove the tenon using a bowl gouge in light cuts. Cut from the outside toward the center.
2. Shape the base to a slight concavity—this ensures the bowl sits flat on any surface without rocking.
3. Sand through grits (150-400) and apply the same finish as the rest of the bowl.
4. Sign the base with a woodburning pen or engraving tool if desired.

Advanced Faceplate Techniques

Platters and Plates - Turned similarly to bowls but with a wide, shallow profile - Require very flat rim surfaces—use a heavy scraper or very controlled gouge cuts - The wide face amplifies any surface imperfections - Often turned from single-piece kiln-dried stock (12/4 or 16/4)

Hollow Forms - Enclosed vessel shapes with a small opening - Require specialized hollowing tools (Stewart, Jamieson, or Lyle Jamieson style) - Wall thickness is gauged by feel, sound (tapping), or laser wall-thickness gauges - Advanced technique—not recommended for beginners

Natural Edge Bowls - The bark edge (or live edge) of the log is preserved as the bowl rim - Bark must be firmly attached (harvest in winter for best bark adhesion) - The irregular rim creates intermittent cuts—tool catches are more likely - Requires very sharp tools and conservative speed settings

Key Talking Points

• Every bowl's base should be finished—a visible tenon marks amateur work
• Jam chucks are simple to make and extremely effective
• Vacuum chucks provide the cleanest hold but require additional equipment
• Advanced techniques build on the same fundamentals—there is no shortcut to skipping basics

Learning Objectives (Concept Check)

• Can students describe at least two methods for reverse-mounting a bowl?
• Can students explain why a slightly concave base is desirable?
• Do students understand the added challenges of natural edge turning?

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Last Updated: 2026-03-19