What size steel for a spear point?

A spear point's bar width comes from its height at the ricasso. The preset is a 4 in blade, 1 in tall there, with a 5/32 in (0.156 in) spine and a 4 1/2 in full tang. With 1/8 in added for clean-up you need 1 1/8 in, and the next stock width is 1 1/4 in, so this one comes from 1 1/4 × 5/32 in flat bar, forged or ground. The sheepsfoot, Wharncliffe and clip point presets use the same bar. Make the ricasso taller than 1 1/8 in and the calculator steps you up to 1 1/2 in bar.

The matching KraftyDesign blank (the "Draw this blank" link) puts the point on the centerline. The spine and the edge curve in by the same amount over about the front third of the blade, and the handle is contoured. Those curves come off a blade that is otherwise full height, so they don't change the bar. Makers on KnifeDogs talk about keeping the two sides alike. In a thread on symmetrical daggers, one poster suggests drawing the blade on stiff card stock and folding it in half exactly on the centerline. Another lays the blade on paper during rough profiling, traces around it and flips it over to check that it matches both ways.

The calculator starts this one on 1084, and 1095 gives the same 1 1/4 × 5/32 in bar with no flags. AEB-L and CPM-154 come from that bar too, by stock removal. The calculator won't forge AEB-L, CPM-154, 14C28N, MagnaCut or A2. Pick any of them and it works out the bar as stock removal, even with Forged selected. 5160 also gives this bar, but the calculator notes that 5160 isn't commonly listed in 1 1/4 in width or in 5/32 in thickness. Check what your supplier carries before you order.

By stock removal you cut the whole 8 1/2 in profile out of the bar, so each blade takes 8 3/4 in with clean-up. That is about 8 oz of bar for a blade that finishes around 4 3/4 oz. A 12 in bar yields one blade, and the 18 and 24 in bars yield two each. A 36 in bar yields four and a 48 in bar five. The 18 and 36 in bars tie for the lowest cost per blade.

The preset is forged, and forging the bevels stretches the steel, so just under 7 in of the same bar makes one blade with clean-up. That is about 6 oz of bar, and the blade finishes around 4 1/4 oz. A 12 in bar gives one blade, 18 in two and 24 in three. A 36 in bar gives five at the lowest cost per blade, and 48 in gives six. To start thicker and forge down, set "Forged thickness" to "One size up", which moves you to 1 1/4 × 3/16 in in forged mode only. The won't-forge rule above applies here too.

A centered point takes care at the grinder too. In a Blade magazine article on dagger construction, Travis Fry suggests scribing a centerline on the edge and the flats, grinding the tip first at a steeper angle than the main bevels, and trying not to cross the centerline until the very end. The last inch, he says, has to keep its thickness so the point can pierce without bending or breaking. Some makers sharpen the top edge as well, as on a CPM-154 spear point offered on BladeForums. A second edge can matter in law, and the rules vary from place to place. Massachusetts' model jury instructions for its law on carrying dangerous weapons, for example, list a knife with a double-edged blade. Check your local law before you sharpen the top edge.

What a spear point is for

A spear point is a symmetrical blade. Wikipedia's article on blades puts the point on the centerline of the blade's long axis. Gary Zinn, writing on chuckhawks.com, says the front of the spine and the edge curve symmetrically to the point. Users on BladeForums describe everyday jobs for it. In a thread on spear point folders, one post says spear points are not as narrow as daggers and are geared toward utility cutting, not thrusting. In a thread on what the shape is good for, one poster uses the spear blade of a Swiss Army knife for food prep, cutting bait for fishing and cutting limes. Another thinks the centered tip suits drilling. A third likes the even blade width of a single-blade spear point pocketknife for spreading peanut butter on a bagel. Views on the tip differ. Back in the folder thread, one post says spear points are often criticized for weak tips, but that this need not be true of a well-designed blade. Two other posts there lean the other way: one writer was under the impression that spear points have very strong tips, and another always thought they were among the strongest.

On pocketknives the shape has its own names. Zinn says a fairly large blade of this shape is called a spear blade when it is the only blade, or the main blade on a multi-blade knife. A small one used as a second blade is a pen blade, which he calls essentially a small spear point. He adds that spear blades are fairly common on modern locking folders and are sometimes used on fixed blades. A.G. Russell's knife encyclopedia says the pen blade, a very small spear point, was originally meant for trimming quill pen points. The Yorkshire Historical Dictionary says the penknife was first a small knife for making and repairing quill pens, kept in a sheath, and it notes references from the 1400s. One of its examples, from 1590, reads "your pen knife, a right Sheffield knife". The penknife we know now, it says, has a jointed blade or blades that fit inside the handle, and several found in the mud banks of the Thames are thought to date from the late 1600s.

The claims in this paragraph are unconfirmed: each source states them without citing anything. A knife company in Ohio says on its blog that the spear point comes from the spear itself. It says the tip, once taken off the shaft, served for dressing game and general utility, and it calls the shape likely one of the earliest all-purpose knife designs. It cites nothing. One BladeForums poster goes further and calls the spear point the original blade shape, older even than metal blades. The same poster says double-edged knives, in stone and in early metal, were a way of carrying two knives in one. Wikipedia says a true spear point is double-edged with a central spine, like a dagger or a spearhead, that the shape is found on many thrusting knives such as the dagger, and that it is one of the stronger point designs in terms of penetration stress. It cites nothing for any of that. Buck Knives says spear points are made for survival and rescue situations where piercing is needed. Gear Patrol says the shape is common on daggers and throwing knives. Neither of them gives a source.

Stock for a spear point

In for-sale posts on BladeForums, one maker lists a forged 1084 spear point with a 4 in blade, the same steel and blade length as this preset. Another post lists one in 1095 from 5/32 in stock, 8 1/2 in overall with almost 4 in of edge. AEB-L spear points there run thinner, such as one with a 4 in edge from 3/32 in stock and another with a 3 3/8 in hollow-ground blade from 0.121 in stock.

Widths assume blade height + 1/8 in rounded up to stock; thickness is the finished spine rounded up. Change the inputs above for your own pattern.

Steels that suit it

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