A stringer notcher cuts rectangular notches into the bottom of stringers so that forks can enter a stringer pallet from the sides, making it a partial four-way pallet. A chamfering machine bevels the edges or corners of boards and blocks so that pallets slide, stack and handle without catching, which Euro pallet specifications require on defined parts.
Why notching exists
A standard three-stringer pallet allows fork entry only from the two ends, because the stringers block the sides. Cutting notches in the outer stringers, and often the center stringer, opens windows so that forks can enter from the sides. The result is a partial four-way, or notched-stringer, pallet; see two-way vs four-way pallets for the entry classification.
Notching has a cost: removing wood from a stringer weakens it, particularly in bending and when pallets are supported across racking beams. The notch depth, length and position are therefore specified to protect strength, and designers verify them with software or testing; see pallet design software and pallet load capacity.
Notcher types
Many pallet notchers have been patented over decades; the patent literature describes machines for notching stringers, feeding mechanisms and combined systems. In practice, three families exist:
| Type | How it works | Where used |
|---|---|---|
| Manual or semi-manual notcher | Operator positions the stringer and cuts with a router head, saw or chisel | Small plants, repair |
| Single or double-head notcher | Cutter heads or saw blades remove the notch; stringer is fed and clamped; double-head versions cut both ends or both notches | Medium volume |
| In-line automatic notcher | Feeds, positions, notches and discharges stringers automatically, often integrated with the assembly line | High volume stringer pallet plants |
Cutting methods include multiple circular blades with a chipper between them, router or dado heads, and hydraulic punches. Modern machines let the operator adjust notch length and spacing for different pallet sizes.
Tool wear and dust are the main operating issues. Carbide-tipped cutters last longer, and extraction is needed at the cutter head. Stringers with embedded nails (when reclaimed) can damage the tooling.
Notch geometry and quality
Notch dimensions vary by pallet design and standard. The key quality points are:
- Depth. Enough clearance for forks and fork-lift pallet trucks, but not so deep that the stringer's remaining cross-section is too small.
- Corners. Radiused or beveled notch corners reduce stress concentrations that start splits.
- Position. Notches must be placed where forks and pallet-jack wheels pass, symmetrically across the length.
- Consistency. All stringers in a pallet must match so the pallet sits level.
- Clean cut. Torn or burnt edges weaken the section and can snag handling equipment.
Checks belong in routine inspection as described in quality control in pallet production.
Chamfering machines
A chamfer is a bevel cut across an edge or corner. On pallets, chamfers appear at:
- Lead edges of the bottom deck boards, so pallet jack wheels and fork tips ride up rather than catching.
- Block corners and stringer ends, so the pallet slides in and out of racks and trucks and so that wood fibers do not splinter.
- Top board edges, to reduce damage to packaging and cartons.
The EPAL Euro pallet specification calls for chamfered corner blocks and chamfered board edges at defined positions, as part of its design for reliable handling across systems; see the Euro pallet guide and block pallet production lines. Chamfering is often done on separate machines upstream of assembly, for blocks and boards, or as a finishing step on assembled pallets.
Chamfering machine styles:
- Board end chamfering. A saw or knife head cuts bevels on the ends of boards as they pass through on a chain.
- Block chamfering. Cutter heads or rotary knives bevel each block's corners, sometimes combined with block cutting.
- Assembled-pallet chamfering. Cutters trim edges of assembled pallets, such as bottom-deck lead boards, on a conveyor.
- Manual router or saw stations. For low volume or special pallets.
Integration with the line
Notching and chamfering must keep pace with assembly. Common approaches:
- In-line. Stringers move from the cut-off saw through the notcher straight into the nailing line. This saves handling but couples machines, so a stop at one halts the rest. See stringer pallet assembly machines.
- Batch. Notched stringers are made in advance and stocked, which decouples the machines and handles size changes better.
- Outsourced. Plants buy precut, notched and chamfered components, concentrating on assembly.
Dimensions must be consistent along the entire flow: if length errors accumulate from cut-off to notcher, notches shift relative to the stringer ends. See cut-off and trim saws.
Safety and maintenance
Rotating cutters and clamping mechanisms present hazards. Guard cutter heads and use interlocks on feed doors. Dust extraction is important, because chipping produces coarse chips and fine dust, which also increase fire and explosion risk. Sharpen or replace cutting edges on schedule, check clamps and stops for wear, and lubricate chains and slides. See safety in pallet plants and maintaining pallet machinery.
Frequently asked questions
What does a notched stringer do?
The notches create openings in the stringer so forks can enter from the sides, making the pallet partial four-way instead of two-way.
Does notching weaken a pallet?
Yes, notches reduce the stringer's cross-section, so depth and position are limited and the design is checked for load capacity, especially in racking.
Why are Euro pallets chamfered?
Chamfers help forks, pallet-jack wheels and the pallets themselves slide in and out without catching, and they reduce splintering and damage in handling.
Can notching be done after assembly?
Generally not; notches are cut in the stringers before nailing, although repair shops sometimes modify finished pallets with hand tools.
Sources
- US4132253A: Machine for notching pallet stringers — Google Patents
- US6095208A: Pallet notcher — Google Patents
- US10836068B2: Feeder mechanism for stringer notcher — Google Patents
- EPAL Euro Pallet (EPAL 1) technical data — European Pallet Association