Rasps are an essential tool for any woodworker. They are used to shape and smooth wood by removing material in a controlled way. Choosing the right rasp for your project can make the job much easier. There are several factors to consider when selecting rasps for woodworking: type of rasp, coarseness, shape/profile, and material. This article will provide a quick overview of the different types of rasps, what they are best used for, and recommendations for must-have rasps for any woodworking shop.
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Types of Rasps
There are two main categories of rasps: cabinet rasps and woodworking rasps.
Cabinet Rasps
Cabinet rasps, also called patternmaker’s rasps, are designed for delicate, detailed work like furniture making. They have very fine teeth and leave a smooth finish. Common types include:
– Round cabinet rasp – Used for curved surfaces like chair arms or table legs. The rounded shape allows you to efficiently rasp concave areas.
– Half-round cabinet rasp – Has a flat face for flat surfaces and a half-round face for curves. A versatile option.
– Flat cabinet rasp – Ideal for flat surfaces like drawers or panels. The flat face keeps edges square.
Woodworking Rasps
Woodworking rasps are more aggressive and designed for quickly removing material. Common types are:
– Gouge rasps – Have a curved blade that can hollow out concave areas. Good for chair seats, bowl shapes, etc.
– Dogleg rasps – The blade is offset to make it easier to rasp challenging areas. Helpful for detailed scrolling work.
– Riffler files – Small rasps good for delicate work like jewelry making or instrument repair.
– Surform rasps – Have perforated blades that peel away wood strips. Quickly shape and flatten boards.
Coarseness
The coarseness of the rasp teeth determines how much material is removed with each stroke. Coarser teeth take off more wood. Finer teeth yield a smoother finish.
Cabinet rasps typically range from fine to extra-fine, around 40-60 teeth per inch. Woodworking rasps are coarser, with 10-25 teeth per inch.
You’ll need an assortment of coarseness levels. Start with a coarse rasp to do the bulk of material removal, then switch to a finer rasp as you get close to your final shape for a smooth finish.
Shape and Profile
The shape and profile of the rasp blade will determine what kind of surfaces you can work on.
Common rasp shapes include:
– Round – All-purpose shape good for convex curves and detail work.
– Half-round – Has both a flat face and a curved face. Very versatile.
– Flat – Best for flat surfaces like tabletops or drawer fronts. Keeps edges square.
– Knife – Thin and flexible for delicate concave areas. Good for guitar necks.
– Curved blade gouges – Allow hollowing out bowls, chairs, etc. Many widths available.
Consider what profiles you need. For example, if working on a lot of furniture, a half-round cabinet rasp would be a smart choice. For sculpture or curved details, grab some round and knife rasps.
Rasp Materials
Rasps are commonly made from high carbon steel or nickel steel. These hold a good edge and stand up to heavy use:
– High carbon steel – Most common. Durable, holds an edge when heat treated. Need to oil to prevent rust. A cost-effective option.
– Nickel steel – Contains nickel for corrosion resistance. Stays sharper longer than regular steel. No need to oil. Pricier but lasts longer.
You can also find exotic woodworking rasps made from high-performance materials:
– Japanese saw steel – Very fine yet tough teeth. Stays sharp incredibly long. Most expensive option but worth it for professionals.
– Tool steel – Extremely rugged alloy used for industrial files. Withstands heavy pressure without losing its edge.
– Carbide – Made by bonding carbide powder to steel. Carbide is nearly as hard as diamond. Teeth stay sharp through extensive use. A premium choice.
Must-Have Rasps
Here are 5 rasps that every woodworking shop should have:
1. Half-round cabinet rasp
A fine-toothed half-round cabinet rasp is arguably the most useful shape to start with. The flat face excels at smoothing flat stock like boards or tabletops. The curved face handles rounded work like chair arms or table legs.
Look for 14″ length with fine teeth (50+ per inch). Can’t go wrong with the classic Nicholson #49 patternmaker’s rasp.
2. Surform round rasp
Surform rasps have perforated blades that peel away strips of wood. Great for quickly shaping and flattening boards. A coarse round surform is perfect for fast stock removal on curves.
Get a 10″ or 12″ size with at least 10 teeth per inch. The heavy-duty Stanley Surform is a workhorse.
3. Needle file set
A set of needle files (small fine-toothed rasps) are indispensable for detail work. I recommend getting starter sets with round, half-round, flat, square, and triangular needle files.
The 6-10 piece sets from Nicholson or Bahco are affordable and provide an assortment of profiles.
4. Riffler file set
Riffler files have a tapered, flexible shaft that allows shaping in tight spots. The variety of profiles handle intricate scrollwork, instrument repair, jewelry making, and more.
Good beginner sets have 15-20 riffler files in a range of shapes. Brands like Grobet or Walton are excellent quality.
5. Curved blade gouge
A curved blade gouge rasp is useful for hollowing operations like bowl or chair seat carving. Look for a 1/2″ or 5/8″ width with an aggressive 10-15 teeth per inch.
Pfeil Swiss-Made is a top gouge brand. The 1/2″ #7 sweep is versatile for smaller projects.
Complete Rasp Selection
Here’s a more complete selection of rasps to have on hand as you take on more complex woodworking projects:
| Type | Profile | Brand & Size Recommendation |
| Cabinet rasp | Half-round | Nicholson #49 14″ Extra Fine |
| Round | Auriou 10″ Extra Fine | |
| Flat | Walton 10″ Fine | |
| Surform | Round | Stanley 12″ Extra Coarse |
| Flat | Stanley 10″ Coarse | |
| Needle files | Assorted set | Nicholson 10 pc Fine/Smooth |
| Riffler files | Assorted set | Grobet 21 pc Swiss Pattern |
| Gouge rasp | Curved blade | Pfeil #7 1/2″ Sweep Medium |
| Dogleg rasp | Curved | Auriou 7″ Fine |
Using Rasps Effectively
Now that you have the right rasps, let’s go over some tips for using them effectively:
– Use the entire length of the rasp – Avoid just using the tip, put broad strokes across the whole blade for even wear.
– Maintain a consistent direction – Generally go with the grain, and go opposite on the return stroke to avoid splintering.
– Use lighter pressure – Let the rasp do the work, excess pressure damages the teeth.
– Clean often – Clogged teeth won’t cut properly. Brush away debris frequently.
– Lubricate when needed – For materials prone to clogging, lubricate with wax, oil, or soap.
– Control the angle – Keep the rasp perpendicular to the workpiece to prevent uneven wear.
– Finish with a finer rasp – Use a coarse rasp to remove bulk material, then switch to a finer rasp for an ultra-smooth finish.
Rasp Maintenance
With good care, quality rasps will last for years. Here are some tips for maintenance:
– Clean thoroughly after each use and inspect for damaged teeth.
– Rub a little machine oil on metal rasps to prevent rust if storing. Wipe down wooden handles.
– Store in a dry place protected from dust and moisture. Keep various profiles separate to avoid contact damage.
– Between projects, rub fine emery cloth or a diamond lap lightly across the face to exposures any flattened teeth tips.
– As teeth wear down over time, periodically reshape the edges with a sharpening stone to expose fresh teeth. A diamond file card also works well for this.
– When rasps become too worn to reshape, it’s time to replace them. Most quality rasps can be sharpened and reused 3-5 times before replacement.
Safety Tips
While very handy tools, rasps do require some safety precautions:
– Wear eye protection – debris, chips, and filings can fly as you work.
– Use work gloves – Rasps can cause blisters with prolonged use.
– Watch hand placement – Don’t run your non-rasping hand across the teeth.
– Avoid clothing snags – Baggy sleeves or loose clothing can catch on rasp teeth.
– Secure workpiece – Clamp down anything you’re rasping on for control and safety.
– Go slow on curves – It’s easier to slip on rounded surfaces. Work carefully.
– Clean up filings – Don’t leave messy piles, they can create a tripping hazard.
– Maintain rasps – Damaged or worn teeth can lead to slips. Keep in good shape.
Conclusion
Rasps are one of the most versatile tools for shaping and finishing wood. With the right selection of cabinet rasps, woodworking rasps, specialty files, and maintenance practices, these “toothed planes” can tackle any sanding, smoothing, or removal task. Start with a quality half-round, surform, needle files, and curved blade gouge. Expand your collection as needed for increased profiles and coarseness options. Use proper technique for efficiency and safety. Keep rasps clean and sharp. With this guide, you’ll be ready to rasp away on your next woodworking project!