Knew Concepts 5" Mk.IV Heavy Duty Fret Saw – Lever Tension

Get the reach of a deeper saw frame without sacrificing blade control with the Knew Concepts 5" Mk.IV Heavy Duty Fret Saw with Lever Tension. Designed for jewelers, metalsmiths, model makers, and precision craftspeople, this rigid, lightweight saw combines a 5-inch throat depth with high blade tension and fast cam-lever blade changes.

The heavy-duty Mk.IV frame is designed to apply 50–60 pounds of blade tension, helping reduce blade vibration for a more rigid, responsive feel while cutting. Its 5" throat provides additional reach compared with the compact 3" model, making it a strong choice for larger jewelry components, deeper interior cuts, decorative metalwork, and projects that require more clearance between the blade and frame.

The cam-lever tensioning system is particularly useful for piercing and other work that requires frequent blade changes. Release the lever to remove tension, reposition and clamp the blade, then return the lever to the cutting position. Your tension setting remains consistent instead of requiring a complete readjustment after every interior cut.

Features & Benefits

• 5" throat depth provides greater reach than the compact 3" Mk.IV
• Heavy-duty Mk.IV frame for increased rigidity
• Designed for 50–60 lb of blade tension
• High blade tension helps reduce unwanted blade vibration
• Cam-lever tensioning allows fast, repetitive blade changes
• Particularly convenient for intricate piercing and interior cuts
• Fixed blade position provides a straightforward, rigid sawing setup
• Aircraft-grade aluminum frame combines strength with low weight
• Weighs only 214.3 grams with blade
• Durable red powder-coated finish
• Uses standard 130 mm / 5-1/8" fret and jeweler's saw blades
• Supplied with a #7 Fix Blue premium fret saw blade
• Excellent for jewelry fabrication, metalsmithing, piercing, and precision cutting
• Made in the USA

Specifications

5" Throat for Greater Reach

The defining difference between this saw and the 3" 124.003C is the deeper 5-inch throat.

Throat depth determines how far the blade can reach into a workpiece before the edge of the material contacts the back of the saw frame.

That extra two inches can make a significant difference when working with:

• Larger pendants
• Cuffs and bracelets
• Decorative sheet metal
• Larger pierced patterns
• Sculptural jewelry components
• Model-making projects
• Deeper interior cuts
• Larger fabrication projects

For jewelers who regularly find a conventional 3" frame restrictive, the 5" version provides additional working room while retaining the same Mk.IV lever-tension system.

Heavy-Duty Mk.IV Frame

The Mk.IV is designed as Knew Concepts' heavy-duty frame, with greater rigidity and substantially higher blade tension than the lighter Mk.III design.

Knew Concepts specifies 50–60 pounds of blade tension, helping create a stable blade with less vibration.

That rigidity is particularly useful when following:

• Fine layout lines
• Tight curves
• Detailed pierced patterns
• Long straight cuts
• Complex interior shapes

The result is a saw that feels substantial and controlled without the weight of a traditional heavy steel frame.

Fast Cam-Lever Blade Tensioning

The cam-lever tensioning system is designed to make repetitive blade changes faster and more convenient, particularly during pierced and interior sawing.

Flip the lever forward to release blade tension, reposition or replace the blade, secure it in the clamps, and return the lever to the rear to restore tension.

Because the tension setting is maintained when the blade is released, you can return to your established blade tension without starting the adjustment process over each time.

Excellent for Piercing

The combination of a 5" throat and lever tensioning makes the 124.005C particularly useful for larger or more elaborate piercing projects.

The deeper frame provides additional reach into the workpiece, while the lever system simplifies the repeated blade changes required for interior cuts.

This makes it an excellent choice for:

• Pierced jewelry
• Decorative pendants
• Cuffs
• Larger earrings
• Ornamental sheet-metal designs
• Nameplates
• Decorative panels
• Sculptural components
• Intricate fabrication

50–60 lb Blade Tension

Blade tension has a major influence on how a jeweler's saw feels during use.

A properly tensioned blade is more responsive and less prone to unwanted flex and vibration.

The Mk.IV is designed to pull 50–60 pounds of tension, and Knew Concepts specifically states that the resulting blade vibration is lower than with its Mk.III saws.

That can make it easier to maintain control when navigating a detailed pattern or following a precise layout line.

Aircraft-Grade Aluminum Construction

A deeper frame does not have to mean a heavy saw.

Knew Concepts constructs the 124.005C from powder-coated aircraft-grade aluminum, providing the rigidity required for high blade tension while keeping overall weight relatively low.

The 5" Mk.IV weighs just 214.3 grams with the blade installed.

For comparison, the 3" 124.003C weighs 179.1 g, so moving to the deeper 5" frame adds approximately 35 grams while providing two additional inches of throat depth.

Durable Powder-Coated Finish

The distinctive red frame has a durable powder-coated finish.

Knew Concepts describes this finish as highly resistant to scratching and damage, helping protect a tool designed for regular bench use.

Uses Standard Jeweler's & Fret Saw Blades

Knew Concepts specifies that the 124.005C uses 130 mm / 5-1/8" fret and jeweler's saw blades.

Premium Blade Included

The saw comes loaded with a #7 Fix Blue premium fret saw blade, according to Knew Concepts' current product specifications.

Fixed Blade Position

This particular model uses a fixed blade position.

That's important because Knew Concepts also offers the closely related 124.005CS, which adds swivel blade clamps.

The 124.005C is the appropriate choice for customers who want:

• The heavy-duty Mk.IV frame
• 5" throat depth
• 50–60 lb blade tension
• Fast lever tensioning
• Conventional fixed blade orientation

Customers who also want to rotate the blade independently of the frame should look at the 124.005CS instead.

3" vs. 5" Mk.IV

Knew Concepts confirms the respective weights of 179.1 g and 214.3 g.

Choose the 3" 124.003C when compact size and maneuverability are the priority.

Choose the 5" 124.005C when you want the same Mk.IV performance with additional reach for larger workpieces and deeper cuts.

Ideal For

The Knew Concepts 5" Mk.IV Heavy Duty Fret Saw is an excellent choice for:

• Jewelry making
• Jewelry fabrication
• Piercing
• Metalsmithing
• Silversmithing
• Goldsmithing
• Cuffs and bracelets
• Larger pendants
• Decorative sheet metal
• Model making
• Precision metal cutting
• Professional jewelry studios
• Jewelry schools
• Serious hobbyists

Frequently Asked Questions

What is the throat depth of the 124.005C?
This is the 5" Mk.IV Heavy Duty Fret Saw, providing greater reach than the 3" version.

How much blade tension is it designed to produce?
The Mk.IV is designed to pull approximately 50–60 pounds of blade tension.

Why choose the 5" model instead of the 3" model?
The 5" throat provides additional reach into larger workpieces. It's a good choice when your projects regularly exceed the capacity of a compact 3" frame.

Is this good for piercing?
Yes. The cam-lever tension system was specifically designed for rapid, repetitive blade changes such as those required during piercing.

Does the blade rotate on this model?
No. 124.005C is the fixed-blade version. If you want the 5" Mk.IV with swivel blade clamps, the corresponding model is 124.005CS.

How much does the saw weigh?
214.3 grams with the blade installed.

What type of blades does it use?
It accepts 130 mm / 5-1/8" fret and jeweler's saw blades.

Does a saw blade come with it?
Yes. A #7 Fix Blue premium fret saw blade as included.

What is the frame made from?
The frame is made from aircraft-grade aluminum with a powder-coated finish.

Where is the 124.005C made?
It is made in the USA.

Micro-Tools makes every attempt to provide accurate information for each item. Actual packaging and/or specifications may be slightly different from the information and picture provided.