Activity 001: Rotary Engraving — Monogram on Glass

Activity ID: U12M4-ACT-001 Duration: 40 minutes

Overview

Students use a rotary tool with diamond burrs to engrave a monogram or simple design onto a flat glass piece. This activity builds hand control, burr selection skills, and technique for producing clean, consistent line work on glass. Students practice transferring a design template, selecting appropriate burrs, controlling tool speed and pressure, and using lubrication throughout the engraving process.

Materials & Equipment Needed

• Flat glass pieces (soda-lime, 4" x 4" or larger, 3mm thickness) — one per student
• Rotary tool with variable speed control (Dremel-type or flexible shaft)
• Diamond burr set:
• Fine point (1-2mm) for detail lines
• Ball nose (3mm) for broader strokes
• Cylinder (2-3mm) for flat-bottomed channels
• Water drip system or small brush and water cup for lubrication
• Design templates (monogram letters, simple motifs — printed on paper)
• Fine-tip permanent marker (for transferring design to glass)
• Isopropyl alcohol and paper towels (for cleaning)
• Non-slip mat or damp towel (to secure glass during engraving)
• Safety glasses (mandatory)
• Dust mask (N95 minimum, as backup to wet technique)
• Ear protection (optional — rotary tools can be loud at working speed)
• Task lighting (angled to illuminate engraving area without glare)
• Practice scrap glass pieces (for burr testing)

Instructions & Procedure

Part 1: Design Transfer and Setup (10 minutes)

1. Students select or design a monogram (1-3 letters) or simple motif (geometric shape, simple icon)
2. Clean the glass piece with isopropyl alcohol — remove all fingerprints and dust
3. Place the paper template under the glass and trace the design onto the glass surface using a fine-tip permanent marker
4. Place the glass on a non-slip mat or damp towel to prevent movement during engraving
5. Position task lighting to illuminate the work area — angle to avoid glare on the glass surface
6. Set up water drip or prepare water cup and brush within reach

Part 2: Burr Testing on Scrap (10 minutes)

1. Students test each burr type on scrap glass:
2. Fine point: practice thin lines, notice how speed and pressure affect line quality
3. Ball nose: practice broader strokes and area texturing
4. Cylinder: practice flat-bottomed channels
5. Set rotary tool speed to 15,000-20,000 RPM — instructor demonstrates the effect of too-fast and too-slow speeds
6. Practice wet engraving technique:
7. Apply water to the glass surface with brush before starting
8. Reapply every 30-60 seconds during engraving
9. Observe: wet cuts produce less dust and cleaner lines
10. Practice pressure control: light pressure lets the diamond do the work — pressing hard chips the glass

Part 3: Engraving the Design (15 minutes)

1. Begin engraving the monogram on the project piece:
2. Start with outline using fine-point burr
3. Work slowly and deliberately — speed comes with practice
4. Maintain consistent pressure throughout each stroke
5. Keep the surface wet at all times
6. Pull the tool toward you for better control (do not push)
7. After outlining, add depth or texture using ball nose or cylinder burrs as desired
8. Periodically stop and wipe the glass clean to assess progress
9. Make corrections by engraving deeper in thin spots — you cannot remove engraving, only add to it

Part 4: Cleanup and Evaluation (5 minutes)

1. Clean the glass piece with isopropyl alcohol to remove marker lines and residue
2. Hold the piece up to light to evaluate the engraving:
3. Is the line work consistent in depth and width?
4. Are transitions between burr types smooth?
5. Is the design legible and well-positioned on the piece?
6. Clean all tools and work area — dispose of glass dust slurry properly

Discussion Points

• How did tool speed affect the quality of your lines?
• What was the difference in control between pushing and pulling the tool?
• Which burr type gave you the most control for fine detail?
• What would happen if you engraved without water lubrication?
• How would you approach engraving on a curved surface (like a glass or vase)?

Expected Outcomes

• Students produce a legible monogram or simple design engraved on flat glass
• Students demonstrate consistent line quality with appropriate burr selection
• Students maintain wet engraving technique throughout the activity
• Students can differentiate between the effects of different burr profiles

Assessment Rubric

Criteria	Excellent (4)	Proficient (3)	Developing (2)	Beginning (1)
Line quality	Consistent depth and width throughout design	Mostly consistent, minor variations	Noticeable inconsistency, some chipping	Irregular, chipped, or incomplete lines
Burr selection	Appropriate burr chosen for each element, smooth transitions	Mostly appropriate selection	Limited burr variety used	Single burr used for entire design
Technique	Consistent speed, pressure, and lubrication throughout	Minor lapses in technique	Frequent technique issues	Unable to maintain control
Design execution	Clean, legible, well-positioned design	Legible design with minor imperfections	Design recognizable but rough	Design unclear or poorly executed

Safety Considerations

• Safety glasses are mandatory throughout the activity — glass particles can be ejected during engraving
• Maintain wet technique at all times — dry engraving produces hazardous silica dust
• Wear dust mask as backup protection in case water application lapses
• Secure the glass piece on non-slip surface — a moving piece during engraving causes tool slips and injury
• Keep fingers clear of the burr contact point — rotary tools cause deep lacerations
• Do not exceed 25,000 RPM — higher speeds increase thermal cracking and fragmentation risk
• Unplug rotary tool when changing burrs
• Clean glass dust slurry with wet methods — do not allow it to dry and become airborne

---

Last Updated: 2026-03-19