Slide 001: Roughing and Basic Spindle Shapes¶
Slide Visual¶
Slide Overview¶
This slide covers the essential first operation in spindle turning—roughing square stock to round—and introduces the fundamental shapes (cylinders, tapers, and gentle curves) that form the basis of all spindle work.
Instruction Notes¶
Roughing Technique¶
The spindle roughing gouge (SRG) is the dedicated tool for converting square stock to a cylinder. Proper technique is critical for safety and efficiency.
Setup: Mount the blank between centers with the tool rest positioned at spindle centerline height and 1/4" from the nearest corner of the square stock. Set speed to the lowest appropriate RPM for the blank diameter.
The Cut: 1. Position the SRG on the tool rest with the flute facing approximately 10 o'clock (slightly open toward the direction of cut). 2. Advance the tool until the bevel contacts the spinning blank. You will hear intermittent contact as corners pass. 3. Raise the handle slightly to engage the cutting edge. Begin with shallow cuts—1/16" to 1/8" depth. 4. Move the tool along the rest in the direction of cut, maintaining bevel contact. 5. Work from one end to the other in overlapping passes. As corners disappear and the blank becomes round, you can take progressively deeper cuts. 6. Continue until the blank is cylindrical. Check with a straightedge if needed.
Common Errors: - Starting with too deep a cut on square stock—catches are likely when corners are present - Tool flute facing straight up—this exposes too much edge and invites a catch - Moving too quickly along the rest—produces a ribbed surface
Basic Spindle Shapes¶
Once the blank is cylindrical, all spindle turning consists of combinations of five fundamental shapes:
| Shape | Description | Primary Tool | Direction of Cut |
|---|---|---|---|
| Cylinder | Straight, parallel surface | SRG or skew | Along the length |
| Taper | Gradually changing diameter | Skew or gouge | Large to small diameter |
| Cove | Concave U-curve | Spindle gouge | Rim to bottom (downhill) |
| Bead | Convex rounded bump | Skew or gouge | Peak to valley (downhill) |
| Fillet | Flat transition band | Parting tool or skew | Perpendicular entry |
Every complex spindle design—table legs, stair balusters, tool handles, candlesticks—is a combination of these five shapes arranged in sequence.
Layout and Reference Diameters¶
Before shaping, mark reference points with a pencil while the lathe spins slowly. Use a parting tool with outside calipers to establish critical diameters at transition points. This prevents removing too much material and ensures the finished piece matches the design drawing.
Key Talking Points¶
- Roughing is the foundation—poor roughing technique makes all subsequent work harder
- Always cut "downhill" (large diameter to small diameter) for clean surfaces
- Master the five basic shapes and you can turn any spindle design
- Reference diameters save material and ensure dimensional accuracy
Learning Objectives (Concept Check)¶
- Can students demonstrate safe roughing technique from square to round?
- Can students identify the five fundamental spindle shapes?
- Do students understand the "downhill" cutting principle?
Last Updated: 2026-03-19