Spot Welder

Make: Miller

Model: LMSW-52

Serial Number: MJ328801N

Ace: Needed (Makerhub@georgefox.edu).

Location: Welding Shop

Safety First

• Wear gloves and welding helmet.
• Don't have bare skin exposed.
• Don't weld in wet gear or standing water.
• Welded material will be hot.

Description

Resistance spot welding is a process in which contacting metal surface points are joined by the heat obtained from resistance to electric current. The Miller LMSW-52 Air-Cooled Spot Welder is a lightweight unit that is portable, easy to operate and excellent for welding mild, galvanized or stainless sheet materials.

• LMSW-52 spot welder manual [1]

Here is an example of spot welding and some good basic information.

Documentation

Spot Welder User Manual

Terminology

• Electrode Tips – The copper ends of the tongs that make contact with the workpiece to deliver welding current.
• Arms / Handles – The insulated portions you hold; provide leverage to open/close the tongs.
• Jaws – The part of the tongs where the electrode tips are mounted; may pivot to adjust pressure.
• Adjustment Knob / Screw – Used to set electrode pressure for consistent welds.
• Cable / Conductor – Heavy cable connecting the tongs to the welder to carry welding current.
• Spring Mechanism – Internal spring that helps return the tongs to the open position when released.
• Insulation / Grip – Protective covering to prevent electric shock and allow safe handling.

Training

Operation

Here are some general setup rules of thumb:

• The maximum weld capacity is 2 sheets of 16 gauge material.

Demonstration

For the demonstration you will need to perform a spot weld using two pieces of scrap material.

General Procedure

1. Ensure the material being welded should be clear of any oil or dust
2. Turn on the spot welder
3. Place the material being welded between the clamps.
4. Clamp down on the two pieces of material for approximately 2 seconds. The time required to weld may vary slightly depending on the material and thickness.
5. Grab workpiece with a set of pliers, and open the clamp.

Certification

Complete the Welding Shop - Spot Welder Module at the link below to gain access to the Spot Welder. The Maker Hub Canvas course pertains to all facilities and equipment contained in the Maker Hub; simply complete the quizzes for the facilities/equipment you wish to use in the Maker Hub. Please email makerhub@georgefox.edu if you have any questions.

Maker Hub Canvas Course

Troubleshooting

• No weld or weak weld:
  • Check electrode tips for wear, dirt, or oxidation; clean or replace as needed.
  • Verify proper electrode pressure; adjust using the adjustment knob/screw.
  • Ensure cables are securely connected and not damaged.
• Sparks at handles / arcing:
  • Inspect insulation on handles and tongs; replace if cracked or damaged.
  • Confirm all connections are tight and corrosion-free.
• Tongs won’t open/close smoothly:
  • Check spring mechanism for damage or debris; clean and lubricate lightly if needed.
  • Ensure pivot points are not seized or misaligned.
• Overheating tongs:
  • Reduce duty cycle; allow tongs to cool between welds.
  • Check for proper current settings and electrode contact.
• Uneven welds:
  • Inspect electrode tips for uneven wear; dress or replace as needed.
  • Confirm correct alignment of jaws and consistent pressure.

Maintenance

General maintenance

The welding tips should be inspected and cleaned as needed.

Specific Maintenance Tasks

Maintenance Procedure	Frequency	Done By
N/A	N/A	N/A