The Auto Glass Blade Guide: Cold Knife, Sheath, and SDS

Auto glass shops reorder blades more often than any other tool, and usually pick them out of habit. Choosing well takes three questions. What tool are you feeding, what is the job asking for, and how much sharpening are you willing to do. Cold knives take cold knife blades. Reciprocating cut-out tools take sheath blades. The Diablo and the Beast take SDS blades and nothing else. Oscillating tools take their own. This guide covers what GT Tools stocks in each family, how the options inside each family differ, and what a blade costs a shop beyond the price on the box.

Match the Blade to the Tool First

Blade families do not cross over, and most confusion around blade selection comes from assuming they do. There are four families in the GT Tools catalog, each built for a class of tool.

Cold knife blades fit hand-powered cold knives, where the technician supplies the force. GT Tools stocks the Quick Release Cold Knife at $86.10, the Ultrawiz Two Handed Cold Knife at $31.50, and the Windshield Removal Cold Knife at $25.20.

Sheath blades fit reciprocating auto glass cut-out tools. GT Tools states its sheath blades are designed for the GT.357, GT.38 Special, and GT.44 cut-out tools, as well as other industry-recognized reciprocating tools.

SDS blades are a closed system. GT Tools states they are used exclusively with the Diablo™ and Beast™ cut-out tools, and those tools take nothing else.

Oscillating blades fit oscillating tools such as the Fein Supercut, which use a star-shaped mount rather than a shank.

Settle the family before comparing anything else. The Cord, Wire and Knife Tools collection is organized around these tool types.

Cold Knife Blades: Three Options

GT Tools stocks three cold knife blade types. All three come in five-packs and in the same three lengths: 0.75 inch, 1 inch, and 1.5 inch. Steel and edge shape are what separate them, and each one solves a different problem.

Blade	Steel	Built for	Price
Standard Cold Knife Blades	Carbon steel	Taking abuse and holding an edge. GT Tools states continuous sharpening does not compromise the integrity of these blades.	$17.90 to $24.20
UltraWiz Serrated Cold Knife Blades	Carbon steel	Cutting with less resistance. A radius bottom reduces drag and the serrations reduce surface tension as the blade slices.	$30.50 to $34.70
UltraWiz Coated Cold Knife Blades	Hardened steel	Protecting paint. A scratch-resistant coating on the neck of the blade prevents scratching in tight tolerances.	$33.60 to $37.80

Prices are GT Tools list prices checked 1 September 2026 and vary by blade length, with the 1.5 inch at the top of each range. Confirm current pricing on each product page.

Choosing between them

Standard carbon steel is the working blade for most shops. It is the cheapest of the three, and GT Tools designed it around repeated sharpening rather than edge retention, stating that continuous sharpening does not compromise its integrity. If your technicians touch up blades between jobs as a matter of course, this is the blade that suits that habit, and paying more for a longer-lasting edge buys something the shop will not use.

Serrated blades are for urethane that fights back. The radius bottom and the serrations both attack cutting effort rather than blade life. Thick beads, cold weather, and long shifts are where they earn the extra $12.60 over the standard blade at the shortest length. Technicians whose shoulders and wrists take the load on a high-volume day tend to feel the difference before the accountant does.

Coated blades are for tight clearance near paint. This is the only cold knife blade in the range aimed at damage to the vehicle rather than cutting speed or blade life. The coating sits on the neck, the part of the blade that touches body panels when there is nowhere else for it to go. Weigh the roughly $16 difference per five-pack against one comeback for a scratched A-pillar.

Plenty of shops carry two: standard blades for routine glass, coated blades for the vehicles where clearance runs out. If a blade separates from its assembly, the Cold Knife, Bolt and Spacer Assembly is $5.30.

Blades for Powered Cut-Out Tools

Powered cut-out splits into two systems that share nothing. Knowing which one a shop runs settles the blade question before any comparison starts.

Sheath blades for reciprocating tools

Sheath blades come in three lengths, 3x10 inch, 3x12 inch and 3x14 inch, and three edge types.

Blade	Construction	What it adds	Price
Standard Auto Glass Sheath Blade	High carbon spring steel	The baseline, built for durability across three lengths.	$45.00 to $47.00
H1 Slick Sheath Blade	High carbon spring steel	Lubrication dimple points that keep the blade lubricated through the cut. GT Tools states the H1 construction offers longer blade life.	$45.00 to $47.00
H2 Serrated Sheath Blade	Spring steel	Lubrication dimples plus a side serrated edge for horizontal cutting, with longer blade life from the H2 construction.	$51.00 to $53.00

Prices checked 1 September 2026. The 3x14 sits at the top of each range. Confirm current pricing on each product page.

The H1 and the Standard blade cost exactly the same at every length, and both are high carbon spring steel. The H1 adds the lubrication dimple pattern and a longer stated blade life on top of that, so if your tool takes both there is no price reason to choose the Standard.

The H2 adds side serrations built for horizontal cutting, which is the bottom bead. Shops that find the bottom bead the slowest part of a removal are the ones paying the extra $6.00 for a reason.

Two shorter blades cover specific reach: the 1.5" x 10" Standard Sheath Blade at $45.00 and the 3" x 10" Round Standard Sheath Blade at $47.00.

SDS blades for the Diablo and the Beast

SDS stands for Smooth Drive System. GT Tools states the Diablo's engineered stroke dampens the impact while allowing the blade to maintain contact with the urethane bead, which makes control on the A-pillars, roof and bottom beads faster and less physical for the specialist.

All three blades use a high carbon spring steel shank with precision-milled edges. The number on the box is the overall length. The usable blade is shorter, and GT Tools publishes both figures.

Blade	Actual blade length	Price
Diablo SDS 3 x 12 Inch	8"	$46.00
Diablo SDS 3 x 14 Inch	10"	$47.00
Diablo SDS 3 x 16 Inch	13"	$49.00

Prices checked 1 September 2026. Confirm current pricing on each product page.

Only $3.00 separates the shortest blade from the longest, so length is a question about the vehicles you work on rather than the budget. GT Tools states the 3x16 was designed for maximum reach into long windshield and dash situations, and is ideal for cab-forward vehicles with wide dashes that require an extended reach to access the urethane. That describes a growing share of newer vehicles, which is worth weighing before ordering a case of the short one.

Oscillating and Utility Blades

Oscillating tools use a star-shaped mount, so nothing from the other three families fits them. The Fein Auto Glass L-Blade comes in a two-pack at $64.95 in each of three lengths, and suits shops running a Fein Supercut as their primary cut-out tool.

Utility blades are the other consumable that empties fast, used on trim, tape and cleanup rather than urethane. GT Tools stocks Long Utility Razor Blades in a 10 pack at $11.60, Long Serrated Utility Razor Blades in a 10 pack at $28.40, and standard Utility Razor Blades in a 100 pack at $21.00. Long blades and standard blades are different products, so match the blade to the knife rather than to the pack price. A PipeKnife Auto Glass Utility Knife at $28.40 gives them somewhere to live.

What Blades Really Cost a Shop

The price on a five-pack tells you very little. Three other things change what a blade costs over a year.

Sharpening is labor. A blade that needs attention twice a day costs more in technician time than the few dollars separating one five-pack from another. That arithmetic works out differently for a shop with a bench and a sharpening routine than for a mobile technician who would have to stop in a customer's driveway, which is why GT Tools stocks blades built around both approaches.

The wrong blade damages the vehicle. A coated blade neck exists because uncoated necks contact paint when clearance runs out. One comeback for a scratched pillar costs a shop more than a year of coated blades.

Most blades die between jobs, not during them. Edges chip in a toolbox, in a van, and against each other. The Auto Glass Protective Blade Sheath at $32.00 protects the edge in transit, and it is the cheapest way to extend blade life without changing blades at all.

Length changes the price. Every blade in this guide costs more in its longest size, sometimes noticeably. Check which length your work calls for before standardizing the shop on one size.

Frequently Asked Questions

Will a cold knife blade fit my powered cut-out tool?

No. Cold knife blades fit hand-powered cold knives only. Reciprocating cut-out tools such as the GT.357, GT.38 Special and GT.44 take sheath blades. The Diablo and the Beast take SDS blades exclusively. Oscillating tools take oscillating blades on a star-shaped mount. None of the four families cross over, so identify your tool before comparing blades on anything else.

Which cold knife blade should most shops buy?

The Standard carbon steel blade, at $17.90 to $24.20 for a five-pack depending on length, handles routine glass and is designed for repeated sharpening. Add coated blades for vehicles where clearance near paint is tight, and serrated blades if thick or cold urethane is slowing your technicians down. Many shops carry standard and coated together and skip the serrated until they need it.

Why would I pay more for a coated blade?

The UltraWiz coated blade carries a scratch-resistant coating on the neck, which is what prevents scratching on vehicle paint when you are cutting in tight tolerances. It is the only cold knife blade in the range that addresses damage to the vehicle rather than cutting speed or blade life. At roughly $16 more per five-pack than the standard blade, it pays for itself the first time it prevents a comeback.

Which SDS blade length should I stock?

The three SDS blades span $46.00 to $49.00, so length is a job question rather than a budget one. The 3x16, with 13 inches of usable blade, was designed for maximum reach into long windshield and dash situations and for cab-forward vehicles with wide dashes. If your work skews toward newer vehicles, the longest blade covers the widest range of jobs.

Do sheath blades work on tools that are not GT Tools?

GT Tools states its sheath blades are designed for the GT.357, GT.38 Special and GT.44, as well as other industry-recognized reciprocating tools. SDS blades are the exception, used exclusively with the Diablo and the Beast. Check the compatibility list on the specific product page before ordering for a tool from another manufacturer.

What is the difference between the H1 and H2 sheath blades?

Both carry the lubrication dimple pattern that keeps the blade lubricated through the cut, and both offer longer blade life than the standard construction. The H2 adds a side serrated edge built for horizontal cutting, which is where the bottom bead gets worked. The H1 costs between $45.00 and $47.00 and the H2 between $51.00 to $53.00, so the serrations are the only thing the extra $6.00 buys.

Why do blade prices differ within the same product?

Blades are priced by length. The 1.5 inch cold knife blade and the 3x14 sheath blade both cost more than their shorter siblings in the same pack. Check the length selector on the product page rather than assuming the headline price applies to every size.

Browse the full range of blades, knives and cut-out tools in the GT Tools Cord, Wire and Knife Tools collection, or reach the team at gtglass.com to confirm compatibility with the tools already on your bench.