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# Howards Cams Seal Cutter & Valve Guide Cutter Tools
- URL: https://www.mechanicaddicts.com/howards-cams-seal-cutter/
- Published: 2026-11-12T12:00:00.000Z
- Updated: 2026-11-12T12:00:00.000Z
- Description: Howards Cams Seal Cutter delivers precision valve guide machining for proper seal installation, improved engine performance, and reliable results.
- Author: Todd Bandel
- Tags: Tools

If you're rebuilding a set of cylinder heads and need to convert from old-style umbrella or O-ring valve seals to modern, positive-locking seals, you need the right cutting tool. 

Howards Cams seal cutter tools are purpose-built to machine valve guides quickly and accurately, delivering professional-grade results without a trip to the machine shop.

This guide covers every Howards Cams valve guide cutter currently available, explains what each one does, and walks you through the correct process for using them.

### Overview: What the Howards Cams Seal Cutter Cutting Tool Does

The Howard's Cams seal cutter machines cylinder head valve guides so that positive valve stem seals can be installed correctly. Positive seals , made from Viton, Teflon, or metal body designs , fit directly over the top of the valve guide and require a precisely machined outside diameter and a squared boss height to seat properly. Without that precision, seals wobble, rotate, or leak oil into the combustion chamber.

These valve guide cutting tools work by reducing the outer diameter of valve guides to match modern seal requirements while simultaneously squaring the top of the guide boss. The tool reduces the outer diameter of valve guides to match modern seal requirements. 

Each cutting tool assembly is designed to work with a specific valve guide diameter - .500", .531", and larger sizes — and can be driven by a standard hand drill or a dedicated seat and guide machine. The cutter is designed for use in home garages without requiring large machinery, making it accessible to anyone doing a head rebuild on their own bench.

Howards Cams offers multiple cutter sizes for different valve guide dimensions, and cutter sizes must correspond with specific valve guide and stem dimensions to produce a proper fit. 

All part numbers covered here , Howards Cams 92035, 92040, 92045, 92049, 92065, 92070, 92075, and 92080 , are American-made tools that fall under the valve guide cutting category. The valve guide cutter material is steel, and each features a carbide cutting tip for long service life.

![](https://storage.ghost.io/c/9f/11/9f11ecee-a2e2-4302-be07-77a062158668/content/images/2026/11/1.png)

Howards-Cams-Seal-Cutter

***Key benefits of these tools:***

- **Precision and repeatability.** Each cutter includes a pilot arbor that maintains concentric cutting, keeping every cut centered and square to the guide bore.
- **Positive seal compatibility.** The cutter allows for installation of positive-locking valve stem seals by machining the guide to the exact OD and boss height required.
- **Durability.** Steel bodies with carbide-tipped cutting edges hold up across dozens of heads without losing sharpness. The valve guide cutter tip material is carbide, ensuring clean cuts in bronze, cast iron, and aluminum guide materials.
- **Accessibility.** No large equipment needed; a low-speed hand drill and proper setup get the job done.

![](https://storage.ghost.io/c/9f/11/9f11ecee-a2e2-4302-be07-77a062158668/content/images/2026/11/4.png)

Howards-Cams-Seal-Cutter

## *Individual Howards Cams Seal Cutter / Valve Guide Cutter Part Numbers*

Below is a short, concrete description of each specific Howards Cams valve guide cutter. Each entry covers the tool's size, what it fits, whether the arbor is included, and how it's typically applied in the shop. The quantity for each listing is one tool per part number unless otherwise noted.

![](https://storage.ghost.io/c/9f/11/9f11ecee-a2e2-4302-be07-77a062158668/content/images/2026/11/92035.png) 

#### **Howards Cams Seal Cutters 92035*

***Valve Guide Cutting Tool, Steel, Carbide-Tipped, Cuts Guide .500 in. O.D., 11/32 in. Diameter Pilot, Kit**

[Summit Racing Equipment](https://summitracing.pxf.io/m4KzB7?ref=mechanicaddicts.com) 

### *Howards Cams 92035 – .500" Valve Guide Cutter*

This steel, carbide-tipped seal cutter is designed to machine guides with a valve guide diameter of .500 inches. It's the go-to choice for small-block and big-block Chevy performance heads that originally used umbrella or O-ring seals. The[ 92035](https://www.summitracing.com/parts/hrs-92035?ref=mechanicaddicts.com) comes with a matching 11/32" pilot arbor (arbor included) and is sold individually. Use it to cut the guide OD and boss height so .500" positive valve stem seals press on squarely without leakage. UPC: 840793121045.

![](https://storage.ghost.io/c/9f/11/9f11ecee-a2e2-4302-be07-77a062158668/content/images/2026/11/92040.png) 

#### **Howards Cams Seal Cutters 92040*

***Valve Guide Cutting Tool, Steel, Carbide-Tipped, Cuts Guide .531 in. O.D., 11/32 in. Diameter Pilot, Kit**

[Summit Racing Equipment](https://summitracing.pxf.io/k4Kz30?ref=mechanicaddicts.com) 

### *Howards Cams 92040 – .531" Valve Guide Cutter*

A precision valve guide cutter for applications where the valve guide diameter can also be 0.531 inches. This is one of the most popular sizes in aftermarket and OEM iron and aluminum heads. The[ 92040](https://summitracing.pxf.io/k4Kz30?ref=mechanicaddicts.com) features a steel body with carbide cutting edges, comes with a matching 11/32" pilot arbor, and is used to uniform the top of the guide so .531" positive seals can be pressed on without wobble or leakage. Arbor is included with the valve guide cutter. UPC: 840793121052.

![](https://storage.ghost.io/c/9f/11/9f11ecee-a2e2-4302-be07-77a062158668/content/images/2026/11/92045.png) 

#### **Howards Cams Seal Cutters 92045*

***Valve Guide Cutting Tool, Steel, Carbide Tipped, Cuts Guide .531 in. O.D., 3/8 in. Diameter Pilot, Kit**

[Summit Racing Equipment](https://summitracing.pxf.io/VOkZej?ref=mechanicaddicts.com) 

### *Howards Cams 92045 – .531" Valve Guide Cutter (Alternate Style)*

Also sized for .531" guides, the[ 92045](https://summitracing.pxf.io/VOkZej?ref=mechanicaddicts.com) is a different configuration from the 92040\. It uses a 3/8" pilot arbor instead of 11/32", which provides a more rigid pilot for heads with larger guide bores or when deeper cuts are needed on unusual boss geometry. Made in the USA, arbor included, and ideal when working on cylinder heads that require a different guide height or seat-to-guide relationship. UPC: 840793121069.

![](https://storage.ghost.io/c/9f/11/9f11ecee-a2e2-4302-be07-77a062158668/content/images/2026/11/92049.png) 

#### **Howards Cams Valve Guide Cutters 92049*

***Tool, Valve Guide Cutter, Steel, Carbide Tip, 0.531 in. Diameter, Each**

[Spring Seat Cutting Tool, Steel, Carbide Tipped, Cuts Guide 1.440 in. O.D., Each](https://summitracing.pxf.io/E069XD?ref=mechanicaddicts.com) 

### *Howards Cams 92049 – .562" Valve Guide Cutter*

The[ 92049](https://www.summitracing.com/parts/hrs-92049?ref=mechanicaddicts.com) is a cutter sized for 0.562" OD guides, often found in aftermarket performance or racing heads. It allows builders to machine the guide tops for .562" positive seals, keeping seal-to-retainer clearance safe on high-lift camshafts. The cutter provides proper clearance for high-lift camshafts in these larger-guide applications. It includes an arbor and is typically used when upgrading to larger-diameter bronze or cast-iron guides. UPC: 840793121076.

![](https://storage.ghost.io/c/9f/11/9f11ecee-a2e2-4302-be07-77a062158668/content/images/2026/11/92065.png) 

#### **Howards Cams Valve Spring Seat Cutters 92065*

***Spring Seat Cutting Tool, Steel, Carbide-Tipped, Cuts Guide 1.440 in. O.D., Each**

[Summit Racing Equipment](https://summitracing.pxf.io/MKq5zn?ref=mechanicaddicts.com) 

### *Howards Cams 92065 – .500" Deep / Alternate .500" Cutter*

The[ 92065](https://www.summitracing.com/parts/hrs-92065?ref=mechanicaddicts.com) is a .500" valve guide seal cutter that features a different cutting depth or relief compared to the 92035\. It's useful when cutting for taller seals or when more guide boss material must be removed. This makes it a strong choice on high-performance Chevy and Ford heads where additional retainer-to-seal clearance is needed for aggressive cam profiles.

![](https://storage.ghost.io/c/9f/11/9f11ecee-a2e2-4302-be07-77a062158668/content/images/2026/11/92070.png) 

#### Howards Cams Valve Spring Seat Cutters 92070

***Spring Seat Cutting Tool, Steel, Carbide-Tipped, Cuts Guide 1.550 in. O.D., Each**

[Summit Racing Equipment](https://summitracing.pxf.io/k4KzEV?ref=mechanicaddicts.com) 

### *Howards Cams 92070 – .531" Deep / Extended Reach Cutter*

The[ 92070](https://www.summitracing.com/parts/hrs-92070?ref=mechanicaddicts.com) is a 0.531" guide cutter built for applications needing deeper or taller machining of the guide boss. Think high spring lift setups or larger-diameter retainers. The extended cutting profile helps avoid coil bind and seal contact on aggressive cam profiles, making it a practical upgrade over the standard .531" cutter in racing and high-performance street builds.

![](https://storage.ghost.io/c/9f/11/9f11ecee-a2e2-4302-be07-77a062158668/content/images/2026/11/92075.png) 

#### **Howards Cams Valve Spring Seat Cutters 92075*

***Spring Seat Cutting Tool, Steel, Carbide-Tipped, Cuts Guide 1.680 in. O.D., Each**

[Summit Racing Equipment](https://summitracing.pxf.io/oNKzDW?ref=mechanicaddicts.com) 

### *Howards Cams 92075 – .562" Deep / Alternate .562" Cutter*

The[ 92075](https://www.summitracing.com/parts/hrs-92075?ref=mechanicaddicts.com) shares the .562" diameter of the 92049 but is configured for deeper cuts or slightly different seal shoulder dimensions. It is well suited for big-lift solid roller cam builds where the top of the guide must be shortened and trued while still supporting a positive seal. If your build pushes beyond typical lift ranges, this is the cutter to reach for.

![](https://storage.ghost.io/c/9f/11/9f11ecee-a2e2-4302-be07-77a062158668/content/images/2026/11/92080.png) 

#### **Howards Cams Valve Spring Seat Cutters 92080*

***Spring Seat Cutting Tool, Steel, Carbide-Tipped, Cuts Guide 1.740 in. O.D., Each**

[Summit Racing Equipment](https://summitracing.pxf.io/3kKjWn?ref=mechanicaddicts.com) 

### *Howards Cams 92080 – .625" Valve Guide Cutter*

The largest in the lineup, the[ 92080](https://www.summitracing.com/parts/hrs-92080?ref=mechanicaddicts.com) is a 0.625" valve guide cutter aimed at serious racing and aftermarket heads using 5/8" OD guides. It machines the guide boss to accept .625" positive seals and creates uniform seal seating surfaces in both aluminum and iron heads. Common applications include drag racing, circle track, and marine engine builds where oversized guides are standard.

---

***Quick Reference Table***

| **Part Number** | **Guide OD** | **Arbor / Pilot** | **Arbor Included?** | **Notes**                        |
| --------------- | ------------ | ----------------- | ------------------- | -------------------------------- |
| 92035           | .500"        | 11/32"            | Yes                 | Standard .500" cutter            |
| 92040           | .531"        | 11/32"            | Yes                 | Most popular .531" cutter        |
| 92045           | .531"        | 3/8"              | Yes                 | Alternate pilot for larger bores |
| 92049           | .562"        | Included          | Yes                 | For aftermarket/racing heads     |
| 92065           | .500"        | \-                | Check listing       | Deep/alternate .500" cut         |
| 92070           | .531"        | \-                | Check listing       | Extended reach .531"             |
| 92075           | .562"        | \-                | Check listing       | Deep .562" for roller cams       |
| 92080           | .625"        | \-                | Check listing       | Largest guide OD available       |

## *How to Use a Howards Cams Valve Guide / Seal Cutter Cutting Tool Correctly*

While each cutter is sized for a specific valve guide diameter, the basic process of valve guide cutting is the same across all part numbers. Here's how to do it right.

### *Preparation*

- **Disassemble the head fully.** Remove valves, springs, retainers, keepers, and old seals so the guide bosses are completely exposed.
- **Clean and inspect.** Strip carbon buildup and old seal material from every guide. Engine builders must measure valve guides and seal dimensions accurately before cutting. Use a micrometer or caliper to confirm the existing guide OD and boss height above the head surface.
- **Choose the correct cutter.** Match the target seal's required guide diameter to the appropriate Howards Cams cutter (.500", .531", .562", or .625") and verify that the pilot arbor fits snugly inside the guide bore.

### *Setup*

1. Insert the pilot arbor into the valve guide. Push it deep enough to center the cutter but not so far that it interferes with the seat below.
2. Slip the cutting head over the arbor and rest it on the guide boss.
3. Apply a light coat of cutting oil to the arbor and cutting edges. Proper lubrication is necessary to prevent chatter during cutting and helps with chip evacuation and surface finish.

![](https://storage.ghost.io/c/9f/11/9f11ecee-a2e2-4302-be07-77a062158668/content/images/2026/11/2.png)

Howards-Cams-Seal-Cutter

### *Cutting Tool Technique*

Cutting occurs with a carbide-tipped cutting head attached to a drill. The cutter should be used at low or medium speeds to ensure precision; high RPMs generate excessive heat and can dull even carbide edges prematurely.

- Apply light, steady downward pressure. You're typically removing only a small amount of material.
- Keep the tool square to the guide boss. Misalignment during cutting can result in an uneven cut or damage to the valve guide, which means starting over with a new guide.
- Periodically withdraw the cutter to clear chips and re-lubricate if needed.
- Stop when the desired guide OD and boss height are reached. The positive seal's shoulder should sit flat and even against the top of the guide.

### *Checking Your Work*

- **Measure the finished guide.** Use an external micrometer to confirm the OD matches the cutter spec (e.g., .500" or .531" within .001"–.002" tolerance).
- **Measure guide height.** Verify that the boss height relative to the head surface and retainer clearance is correct for the seal you're installing.
- **Test-fit the seal.** Push the positive seal onto the guide by hand and rotate gently. There should be no wobble, binding, or visible gaps. If the seal rocks or doesn't seat evenly, the guide surface may not be square.

### *Safety and Best Practices*

- Wear eye protection at all times; carbide shards and metal chips can fly during cutting.
- Clamp the cylinder head securely in a vise or fixture. Any movement will compromise cut accuracy.
- Use breathing protection if working with bronze or aluminum dust.
- Thorough cleaning after cutting is critical to prevent engine damage. Flush every guide bore and the surrounding head area to remove all chips before reassembly. Metal debris left inside a guide will destroy a new valve seal within minutes of startup.

![](https://storage.ghost.io/c/9f/11/9f11ecee-a2e2-4302-be07-77a062158668/content/images/2026/11/3.png)

Howards-Cams-Seal-Cutter

When properly used, Howards Cams seal cutters improve valve seal control, reduce oil consumption, and deliver results that rival a dedicated machine shop , all from your own workbench. These are shop-grade tools built for repeated use, and the steel and carbide construction means they'll pay for themselves many times over across multiple engine builds.

### *Key Takeaways*

- Howards Cams valve guide cutting tools let you machine guides for positive seal conversion without large shop equipment.
- Eight part numbers cover valve guide diameters from .500" to .625", with standard and deep-cut options for different camshaft lift and retainer clearance requirements.
- The correct arbor pilot, proper lubrication, and low drill speeds are the three pillars of a clean, accurate cut.
- Always measure before cutting, test-fit seals after cutting, and clean every chip before final assembly.

If you're planning a head rebuild and need to upgrade to positive-locking valve stem seals, start by measuring your valve guide OD, then match it to the right Howards Cams cutter from the list above. These tools are available through Summit Racing and other major performance parts retailers; grab the one that fits your build and keep your valvetrain sealed right.

Thank you for reading!

Your friend,

Todd

*#HowardsCams #SealCutter #EngineBuilding #ValveGuideTools #EnginePerformance #AutomotiveTools #CylinderHeadRepair #PrecisionMachining #EngineRestoration #PerformanceEngines*

🔧 🛠️ ⚙️ 🔩 🚗 🏎️ 🏁 💪 🔥 ✅

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