What Is a Bow Bar Chainsaw?

A bow saw is a hand tool. A thin steel blade is held under tension inside a tubular or wooden frame shaped like a bow, and you cut with arm power alone. There is no engine, no chain and no fuel. It is a different tool from the one this page is about, and the two get mixed up constantly because they share a word.

A bow bar chainsaw is a powered chainsaw. The powerhead drives a saw chain, and that chain runs around a guide bar bent into a closed loop. The wood goes into the opening in the middle of the loop, and the cut is made at the end of the bar rather than along its side.

Bow bar or bow guide

The same object carries two names. Bow guide is the term in manufacturers' manuals and was the original trade name when the attachment first went on sale. Bow bar is what collectors, forums and secondhand listings say. Both mean the curved bar, and this page uses them interchangeably.

Where the word bucksaw fits

Bucksaw is applied loosely to both the manual frame saw and to a chainsaw with a large curved bar. That loose use is part of why the terms get muddled in listings and forum threads. When you see the word, check whether the item has an engine before you assume anything.

The bar is a closed loop with an open center. The chain runs on the outer edge, the log sits in the opening, and the operator pushes the bar down over it. Because the cut is made by the end of the bow, the bar does not have to be buried in the wood the way a straight bar does.

The three shapes

• Large bucking bow. Tall and wide, the southern pulpwood pattern, used to cut felled logs into lengths.
• Small teardrop clearing or brush bow. Much shorter and narrower, used on Christmas tree farms and for brush and saplings.
• Enclosed bow. An early type from the 1940s and 1950s, closed except at the bottom, fitted to slow gear-drive saws to stop the bar pinching.

The parts that matter

At the cutting face sit the bumper spikes, also called the spur or the gig. These are pressed against the wood and are the bow bar's primary anti-kickback device. A top guard protects the hand. A bottom guard protects the thigh, and it was added later, after operators were injured there.

How a bow bar is measured

Bow bars are sized by length and height, not by length alone. A small brush bar might be listed as 20 inches long and 8 inches tall, a bucking bow as 19 inches long and 14 inches tall. A single bar length figure tells you almost nothing about a bow.

Cutting capacity is around 8 to 10 inches of diameter in one pass. A larger log takes a second cut from the other side.

Southern pine pulpwood was the main job. Crews cut felled trees into short lengths at ground level, all day, at volume, and the bow bar was built around that single task.

Why it suited the work

• The operator could cut standing up, using the weight of the saw, instead of bending over every log. Across a thousand cuts a day, that difference is real.
• The bar is narrow in the kerf, so it pinched far less than a straight bar and could be pushed straight through.
• Chips clear away from the sprocket instead of packing into it.
• Fewer cutters are in the wood at once, so the chain needed less sharpening.
• It was quick on small-diameter softwood.

Other historical uses

Small teardrop bars went to brush and sapling clearing and to Christmas tree farms. Some small holdings used bow bars for firewood. What the tool was never built for is felling standing trees or limbing, and both of those limits matter later on this page.

It was a genuinely efficient answer to a specific industrial problem. Saying so is what makes the safety record that follows worth reading rather than sounding like a lecture.

Claude Poulan developed the bow guide in 1944, while he was supervising labor cutting pulpwood in East Texas. The problem was chain pinch: a third man was needed with a pry pole to hold the log steady while the saw cut.

Poulan's fix was to hammer an old truck fender into a curved attachment he called a bow guide. It became the founding product of Beaird-Poulan of Shreveport, Louisiana, in 1946.

The idea spread quickly through the late 1940s. Precision produced a one-man gasoline bow saw in 1946, Mall a one-piece bow saw in 1947, and Homelite a condensed teardrop clearing bar in 1955. The shift from gear-drive to direct-drive saws in the 1950s made the bow bar more practical, because direct-drive saws were lighter and faster.

The kickback geometry is the root cause. On a straight bar, the kickback zone is the nose. On a bow bar, the whole outer curve is a kickback zone. The contact area is vastly larger, and the bar is being pushed into the wood at its end.

Low-kickback chain does not solve it

The major manufacturers state in their safety manuals that low-kickback chain does not significantly reduce the risk of kickback injury on a bow guide. That single fact removes the fix most people assume exists.

The chain brake is not dependable either

The National Wildfire Coordinating Group's saw training standard, S-212, gives the reason: a bow bar changes the saw's center of gravity, which can prevent the inertial chain brake from engaging during kickback. Manufacturers' manuals likewise tell operators not to rely on the chain brake to prevent injury from a bow saw kickback.

The spur only works while it touches the wood

The bumper spike is the real safety device, and it only works while it is in firm contact with the wood. The moment a cut finishes, which is exactly what happens when limbing, the spur loses contact and the saw can grab.

Documented deaths

The National Institute for Occupational Safety and Health published a case in which a 33-year-old feller was killed in 1992 by a 16-inch bow-bar saw that kicked back and struck his throat. He was limbing a felled pine, not bucking it. That detail is the whole lesson.

The lawsuits

In Thompson v. Tuggle, a Louisiana case from 1986, a pulpwood cutter was killed when his bow-blade saw kicked back into his neck. The court found the design defective because no chain brake was fitted, noting that chain brakes were standard on competing saws in the US and on the same maker's saws sold in Europe. In Turner v. White Consolidated Industries, a 1995 Fifth Circuit case, a bolt holding a bumper spike broke, the saw kicked back and cut the operator's arm, and a verdict for the injured operator was upheld.

Product liability drove every major manufacturer out of the bow bar, and the large bows are no longer produced at all.

No federal statute names bow bars. They are not illegal in the United States in the way a prohibited weapon is, and any page that says so is overstating the law.

What OSHA requires

OSHA's logging standard, 1910.266, requires a chain brake, compliance with the ANSI chainsaw safety standard, a continuous-pressure throttle, and forbids removing or disabling any kickback device. It does not mention bow bars by name. A saw fitted with one is very hard to reconcile with those requirements, so in any workplace covered by OSHA a bow bar saw is effectively non-compliant rather than formally banned.

What the US Forest Service did

The Forest Service has gone further than anyone. Its saw program does not approve bow bars on any saw, and in 2018 the Service directed that all bow bars be removed from service in any situation, on legal advice, to reduce liability.

What the manufacturers say

The manufacturers' safety manuals say not to mount a bow guide on any of their chainsaws, do not recommend bow saws, and state that a bow guide increases the risk of severe kickback.

Private use and insurance

Private, non-commercial use is not generally prohibited by statute, but the civil liability and insurance exposure is real. An insurer may take a dim view of a saw used outside its manufacturer's instructions. Some state forestry and agency policies and employer safety programs restrict bow bars as well.

Nothing new comes from the major manufacturers. They prohibit the fitting of bow guides, so there is no current production saw sold with one. The market is used and collector only. Complete bow bars with their guards and chain turn up through specialist used-chainsaw dealers, collector forums, collectors' registries and auction sites, usually as secondhand or new-old-stock items.

What to check on a used bow bar

• Pitch, either .325 inch or 3/8 inch.
• Gauge, either .050 or .058 inch.
• Bar slot, around 0.37 in (9.5 mm), sometimes filed wider to fit larger bar studs.
• Drive-link count. A bow bar's chain is sized by counting drive links for that specific bow, not by bar length, so a chain bought for a 20-inch bar will not fit.
• The guards and the spur. A bow bar missing its top guard, bottom guard or bumper spike is missing the parts that make it survivable.

Condition and completeness matter more than anything else on a used bow bar, because replacement guards and spurs are not made.

The bow bar won on one narrow job and lost on everything else. The safety geometry is what finished it.

The rules below are the ones trained crews followed, recorded here as historical practice rather than as advice to go and try it.

• Bucking only. Never fell with it. Never limb with it.
• Never cut above waist height.
• Keep the spur in firm contact with the wood at all times. Never pull the saw out of a cut at full throttle.
• Stand to the side of the cut line, both hands on the handles, thumbs wrapped round.
• Wear the full protective set: helmet with face screen, hearing protection, gloves, cut-resistant leg protection and cut-resistant boots.

Some trained crews ran bow bars fitted with long top and bottom guards and a stinger on the cutting face, and found them safer than a straight bar for thinning small trees, because the stinger took the kickback force against the tree. That is worth knowing, and it does not change the record for everyone else.

One practical drawback is worth a line. Cutting at ground level leaves a sharply angled stump that other operators disliked.

For a homeowner, the answer is not to use one.

Each job the bow bar did has a modern tool that does it better.

Bucking small logs at ground level

A standard guide bar with a small-radius nose and low-kickback chain, used with a sawhorse or bucking rack so the log sits off the ground and you are not bending. That solves the back-strain problem the bow bar was invented for, without the kickback geometry.

Brush, saplings and Christmas trees

A brush cutter or clearing saw is what replaced the clearing bow in that trade.

Limbing and reach

A pole saw handles anything above shoulder height, and a top-handle or small battery chainsaw handles limb work at close range. Overhead work is pole saw work, never a chainsaw held above the head.

General homeowner cutting

A standard low-kickback bar and chain, which is what every current saw is built around. Most chainsaw injuries come from technique errors rather than from a weak motor, so the bar is only half the answer.