Guides
Notched stringers: dimensions, rules and strength
Reviewed
A notched stringer has two cutouts in its lower edge so forklift tines can enter the pallet's sides, giving partial four-way entry. A typical 48 in stringer is notched 9 in long and about 1-1/4 in deep, starting 6 in from each end, with rounded corners (the Uniform Standard calls for a 1/2 to 1-1/2 in radius and rejects square notches). Notching removes material where bending stress is high, so it lowers racked capacity.
On this page
Notching is the cheapest way to let a forklift pick up a stringer pallet from the side. It comes at a price in strength, and the details of the notch (depth, length, radius, position) decide how much.
What a notch does
A plain stringer pallet is two-way: forks enter only the ends, between the stringers. Cutting two notches into the bottom edge of each stringer lets tines pass under the top deck from the sides. The result is partial four-way entry: forklifts from all four sides, pallet jacks from the two ends only, because a jack's wheels cannot get past the stringers.
Standard notch dimensions
| Dimension | Typical value | Uniform Standard guidance |
|---|---|---|
| Length | 9 in | Recommended 9 in long |
| Depth | 1 to 1-1/2 in (1-1/4 in common) | Opening about 2 in to the top of the notch, including the bottom deck |
| Location | 6 in from each stringer end | Location tolerance plus or minus 3/8 in |
| Corner radius | 1/2 to 1-1/2 in (3/4 in common) | Radius 1/2 to 1-1/2 in; square notches not acceptable |
| Flat top | At least 7 in of flat top | |
| Depth and length tolerance | Plus or minus 1/8 in |
Worked example: the GMA-style 48 in stringer
- Stringer: 1-3/8 x 3-1/2 x 48 in
- Notches: 9 in long, 1-1/4 in deep, 3/4 in radius, starting 6 in from each end
- Along the stringer: 6 in solid, 9 in notch, 18 in solid, 9 in notch, 6 in solid (6 + 9 + 18 + 9 + 6 = 48)
- Wood left above each notch: 3-1/2 - 1-1/4 = 2-1/4 in
- Fork opening height at the notch: notch depth + bottom deck = 1-1/4 + 5/8 = 1-7/8 in, just under the recommended 2 in
Why the radius matters
Stringers crack at notch corners. A square inside corner concentrates stress and starts a split along the grain; a rounded corner spreads it. That is why the Uniform Standard rejects square notches and why the corner radius is always on the drawing. The standard also tightens defect limits near notches: no decay within 2 in of notch ends and limited wane above the notch.
How much strength does a notch cost?
When a stringer pallet is racked across its length, each stringer is a beam spanning the rack beams. A notch reduces the beam's depth, and bending strength goes with the square of depth.
For the GMA-style stringer, the section above the notch is 2-1/4 in deep instead of 3-1/2 in. (2.25 / 3.5) squared = 0.41, so that section has about 41% of the full section's bending strength. Because the notch sits off-center, where bending moment is lower than at midspan, the net loss is less than that, but it is still large.
palletdesign.ai's indicative beam check shows the effect. For a 48 x 40 GMA-style pallet racked across the length on a 44 in span, the 1-1/4 in notch roughly halves the stringers' bending capacity at the notch compared with unnotched stringers. The check is a conservative screen for catching clearly weak designs, not a rating, but the proportion shows why heavily racked loads often use unnotched stringers or block pallets.
palletdesign.ai also warns when less than 2 in of stringer remains above the notch.
Design rules for notched stringers
- Keep at least 2 in of wood above the notch. With a 3-1/2 in stringer, that caps the depth at 1-1/2 in.
- Keep bottom boards out of the notch zone. Cluster the bottom interior boards between the notches. See deck board spacing.
- Make notches long enough for the tines. 9 in is typical; shorter notches are tight for common fork widths.
- Leave room between notches. The two notches must not run into each other; on short stringers move them toward the ends or shorten them.
- Radius every corner.
- Put the best lumber in the stringers. They carry the rack load, and the notch makes them the critical member.
Notched vs unnotched vs block
| Option | Entry | Racked across length | Cost |
|---|---|---|---|
| Unnotched stringers | 2-way | Highest for the lumber used | Lowest |
| Notched stringers | Partial 4-way | Reduced | Same lumber, small machining cost |
| Block pallet | Full 4-way | Depends on design; confirm with the manufacturer | Higher |
If you need side forklift entry but the pallet is heavily racked, the options are a fourth stringer, a deeper stringer (for example 3-3/4 in so more wood remains above the notch), a denser species, or a block pallet. See racking pallets and stringer vs block pallets.
Other cuts in stringers
- Strap slots (banding notches) are shallow cuts on top of the stringer or under the top deck so strapping can pass under the load. See strap slot.
- Chamfers go on bottom deckboards, not stringers; they let pallet-jack wheels ride over the lead boards. See chamfer.
Questions
- How deep should a pallet stringer notch be?
- Commonly 1 to 1-1/2 in, with 1-1/4 in typical on a 3-1/2 in stringer. Keep at least 2 in of wood above the notch; the Uniform Standard recommends about 2 in of opening height including the bottom deck.
- How long is a pallet notch?
- Typically 9 in, starting about 6 in from each end of a 48 in stringer.
- Do notches weaken a pallet?
- Yes, mainly in racking across the length. A 1-1/4 in notch in a 3-1/2 in stringer leaves a section with about 41% of the full bending strength; a simple beam check roughly halves the racked capacity.
- Can a pallet jack enter through the notches?
- No. Notches allow forklift tines from the sides, but a pallet jack's wheels are blocked by the stringers, so jacks enter only from the ends.