There are a wide variety of knife types and styles available for working with miniatures. Most have disposable blades, which can be kept sharp or resharpened for further use. Choose a hobby, modelling or craft knife based on the use you will put it too, and the materials you intend to use it on. Some are better for particular purposes or weights of material, others are general all round knives with many uses and will accept a wider range of blades. Scalpel blades and finer craft blades are 1/4 inch wide, heavier blades are 5/16 wide and require different handles. Click on the photos for a larger view.
Lightweight Hobby Handles and Blades For Use on Paper and Thin Plastics
The lightest weight hobby knife handles from companies such as Excel, X-Acto, Testor's and Fiskars. Usually listed as #1 sized handles, which will accept 1/4 inch wide lightweight blades and scalpel blades designed to cut paper, mylar, and thin plastics. Scalpel blades may protrude slightly. Most will accept standard hobby blades #10 through #16 (the numbers indicate particular shapes). For a view of standard X-Acto blades (used for a range of hobby knife handles) see X-Acto's knife matrix chart (in pdf/Acrobat reader format).
#1 sized holders are generally sized similar to a regular pencil with thin barrels that may be difficult to grip. Most will roll down a work table and should be capped for safety when not in use.
Lighweight Handles with Cushioned Grips
Many companies make lightweight handles with cushioned and ergonomic grips. These knives are designed to accept 1/4 inch base blades (scalpel blades and blades # 10 to #16) Some accept only proprietary blades, check that the blades you like to use are available for a particular knife before you buy.
The 'Gripster' knife in the photo is available from X-Acto, Excel and from a number of other companies as a proprietary knife with local advertising. It is slightly more comfortable to use than a regular #1 handle, but the plastic grip does harden over time. It does have a square nut on the handle which prevents it from rolling on a work table. Newer knives in more ergonomic shapes are becoming available from craft companies like Fiskars.
Lightweight Swivel Knives
Swivel knives use special fine blades held attached to hard plastic holders that will swivel in the throat of the specially designed knife as you twist the knurled section of the blade holder. They are designed for cutting curves in paper and film. There are plastic swivel knives, some of them with retractable blades, but these generally cannot take the pressure created by the swivelling knife blade. The plastic types tend to break easily.
Choose a type with replacement blades which are available locally if possible, Some knives will accept only proprietary knife blades. Do not confuse these art swivel knives with swivel knives used for leather work which have a much heavier blade.
Retractable Blade Knives
Knives with retractable blades are designed to cut lightweight papers and films. They have spring loaded blade holders which work similar to a retractable ball point pen. Although they are useful only for fine cuts in paper and films, they are useful for people who must keep knives handy, as they will clip onto a shirt pocket, or the blades can be retracted for storage in a tool drawer. Better quality retractable blade knives are made of metal. Choose a knife whose blades you can find locally, as many of these knives require their own brand of blades.
Medium Weight Craft Knives
Medium Weight Craft Knives are designed to take thicker disposable blades than the lighter knives. These handles may not accept the fine pointed #11 blade as the throat will not close completely to hold them firm. Medium handles are usually designated as a #2 sized handle and will accept blades #18 through to 28. (See a matrix showing standard X-Acto brand blades. Most of these blades are suitable for working with wood, resin, or plastic as well as illustration and mat boards.
The #2 handle is designed to be used similar to a pen, so it is not suitable for materials where much force is required.For those materials you are better with a heavier #5 handle, which allows you to push the blade with your palm. These will roll down work surfaces.
Heavy Duty Craft Knife Handles
Number 5 handles (Excel K5 handles) are designed to hold most of the heavier blades made for craft knives, including saw blades. They have a hole in the center of the collet or throat that allows them to accept saw blades as well as the wider based 5/16 inch hobby blades numbers 18 - 28. They will not hold the finer range of 1/4 inch shaft blades below #18. Number 5 handles are plastic or wood, Number 6 handles, which hold most of the same blades, are metal. The design of these handles allows them to be pushed with your palm, so they are good for cutting heavier illustration, mat and bookboard, as well as for cutting stripwood, sheet styrene and some plastics. Cap when not in use as these handles will roll.
Veritas Carver's Knife
This sturdy metal handled carving knife is oval shaped so that there is no danger of it rolling down a workbench or table. It will accept scalpel blades and 1/4 inch wide craft knife blades making it very useful for anyone who does miniature carvings in wood, nuts, or man made materials. The knife is easy to hold in several standard carving grips, with a reminder that very fine scalpel blades should never be used in a lateral direction or they can break. As it is intended as a carving knife, this handle is available from woodworking suppliers, or Lee Valley Tools (Veritas is the manufacturing arm of Lee Valley). The handle has a magnetic holder which will store up to six blades.
Scalpel Blades For Fine Details
Scalpel blades are finer than similar numbered craft blades making them useful for very fine cuts in wood, plastics or resin. The most commonly used scalpel blade shapes for miniatures are the #11 pointed blade for fine details, the #12 inner curved blade for working into hard to reach places, and the #15 blade, which resembles a miniature pocket knife with a curved blade.
Scalpel blades are extensively used in marquetry and are often sold via woodworking or hobby suppliers. These are the same blades as used for medical purposes, except that they are sold unsterilized. Like the other craft blades, scalpel blades can be kept sharp or have their cutting edges restored by honing with micro abrasives or strops.
Micro Abrasive Paper For Honing and Sharpening Craft Blades and Scalpels
A number of very fine silicone and carbide grit papers are available for polishing car bodies and sharpening tool blades. The two shown here are mylar backed papers from 3M in grits of 5 micron and 0.5 micron. (equivalent roughly to 2500x and 9000x) (these particular papers are available online from Lee Valley
These fine grit papers can be used to hone and polish craft and scalpel blades. They are attached to either a piece of 1/4 inch glass or very smooth ceramic tile using spray adhesive (most papers are available with adhesive backing) and used dry to hone blades. For curved blades they can be attached to acrylic rod to reach into the curves of small blades.
Make a Simple Honing Block To Keep Knife Blades Sharp
You can easily make a simple honing block from the finer grits of self adhesive micro abrasive sandpaper in the 'scary sharp' sharpening and blade honing systems. For hobby and craft blades and scalpels, you will need a 1 to 2 inch wide and 3 to 4 inch long strip of very fine grit paper (I use Lee Valley's 5 micron paper) attached to either a piece of tempered glass or a glass smooth ceramic tile. You can find very fine grit sandpapers in your automotive supplier, or through woodworking stores.
Honing is the process of resetting the edge on your knife blade as the tool becomes slightly dull with use. Most woodcarvers assume that for every twenty to thirty minutes of work you will need to spend five minutes honing your tool.
Using a Honing Block to Reset a Sharp Edge on Craft and Scalpel Blades
To hone a blade you find the angle of the bevel on the cutting edge of your tool, and run the blade under an even pressure at that angle across your honing tool (or strop), multiple times in one direction until the blade is 'scary sharp' again. If you are at the incorrect angle, you will be able to see 'ripples' along the blade when you hold it to a bright light.
To prevent extra work, make sure you hone your tools often, at least once a work session. If necessary you can sharpen a blade edge using progressively finer grit sandpapers, but if you hone your blades frequently while you work, they will stay sharp, or sharpen up quickly on the hone. A few minutes work with a hone you keep on your workbench will save you a lot of blades!