Most basswood specifications treat slat width as a single number. It is a distribution, and the width of that distribution is what your customer experiences after a year.
What slat width actually controls in basswood
The visual decision. 50 mm is the volume seller; 63 mm reads as premium.
That makes it a design decision rather than a purchasing one, which is why changing it after the product is fixed costs more than changing the material.
For Basswood blinds and slats, the working range is 25 / 35 / 50 / 63 mm. Inside that band the choice is commercial; outside it, the product changes category and so does the price.
How to choose a slat width option
| Option | What it changes in basswood | When it is the right choice |
|---|---|---|
| 25 | The lowest-cost option in the family. Warping and bowing is where it usually ends up. | Cost-led programmes with a short service life |
| 50 | The volume middle: enough margin for process variation without paying for headroom the end product cannot use. | Most repeat programmes, and the safest default |
| 63 mm | The top of the family, where the process is controlled tightly enough to guarantee it. | A warranty, a tender, or a specification that cannot be renegotiated |
These are alternatives, not points on a scale. Slat width is chosen by the application rather than by price, and a supplier who quotes one option as if it were interchangeable with another is quoting a different product.
The middle is where most programmes should sit, and it is the hardest position to defend in a price meeting because it has no story attached to it.
The figure that decides the outcome is not slat width itself but the tolerance around it. A supplier who quotes 25 / 35 / 50 / 63 mm without a tolerance has not quoted a specification, and the first lot will define the tolerance for you.
How to measure slat width
The reference method here is Moisture content, run to oven-dry method / pin meter, with an acceptance of 8-12 %. The method is the easy part; sampling and conditioning are where reports diverge.
Take samples from the beginning, middle and end of the run. A single sample from the top of a roll tells you about the top of that roll, and slat width varies more across a run than most buyers expect.
Record the measured value rather than pass or fail. A marginal pass on slat width tells you the process is running at the edge, which is the information you need before the next lot rather than after it.
Slat width does not stand alone
Slat width moves with slat thickness (2.3-3.2 mm) and with moisture content (8-12 %). Tightening one usually costs money in another, and a supplier who accepts every tolerance without comment has either not understood the interaction or is planning to substitute.
This is why a specification written as a list of independent tolerances is weaker than one written as a construction. The list lets a supplier satisfy each line while missing the product.
The clause to write for slat width
The line below is the version we can quote against without inventing anything. Slat width appears with a tolerance and a test, not as a standalone number.
Basswood venetian blind, 50 mm slat, 2.8 mm thickness, moisture content 8-12 %, vertical grain no knots, 3-coat water-based lacquer, warp <= 1.5 mm/m, cordless with tension device to EN 13120, stain 3A
Write it once and reuse it. The buyers who avoid claims are not stricter than everyone else; they send the same well-written clause every time.
When slat width goes wrong
Warping and bowing. Slats curve within weeks of installation, worst near windows and in heated rooms.
The cause is usually moisture content outside 8-12 %, or slats packed before equalising.
The test that catches it: Moisture meter on 10 slats per carton plus a 48 h conditioning test at 23 C / 50 % RH.
What to specify instead: Buy on measured moisture content, require kiln-drying records, and insist on 7 days of equalising before packing.
Note that the fix is a specification change, not a negotiation. By the time the claim is made, the only remaining lever is who pays for it.
Four questions about slat width, before you order
- What tolerance do you hold on slat width, and what did your last three lots measure against it?
- Which method do you use for moisture content, and which laboratory signs the report?
- When slat width falls outside 25 / 35 / 50 / 63 mm, do you rework, downgrade, or ship and hope?
- Which of slat thickness or moisture content would you move first to hit a lower price?
The answers are more useful than a certificate, because they show whether the process is controlled or merely inspected. Full ranges for basswood are on the product page, and the measurement regime is described on the quality control page.
Questions buyers ask before ordering
What moisture content should I specify?
8-12 %. Below 8 % the slat takes up moisture and cups; above 12 % it shrinks and bows. Ask for the meter reading on the shipped carton, not the kiln record alone.
Is 2.5 mm thick enough for a 50 mm slat?
For widths under 1.8 m, yes. Above that we recommend 2.8 mm, and above 2.4 m we reinforce the cord holes.
From quotation to specification in seven lines
Leave the tolerance and the method out and every dispute is settled by whoever needs the goods more.
- Grain and defects: agree the test method with the number. Two labs, two methods, two answers, one argument.
- Coating (water-based lacquer, 2-3 coats): state where in the band this order sits. The middle of the band is not what a tolerance is for.
- Warp tolerance: the figure you will accept inside the <= 1.5 mm per 1 m band, the tolerance on it, and the method used to measure it.
- Colour range (8-12 standard stains + custom): name the number, not the word. If the answer only repeats the band, ask which point inside it is being offered for this order.
- Sample retention: one production sample per lot stays with the mill for twelve months. Claims are settled against it, not against memory.
- Test reports: name the standard as well as the test. A pass on a development sample is not a pass on a production lot.
- Deviation rule: anything outside the agreed bands is reported before shipment, not after arrival.
Questions worth asking before the price is agreed
The questions below are the ones that cannot be answered from a catalogue, which is exactly why they are worth asking.
| Question | Answer that should worry you | Answer that holds up |
|---|---|---|
| Who signs the test report, and against which standard? | “Our QC department signs it.” | A named standard, a named method and a signature that belongs to somebody who can be asked again next year. |
| How do you hold coating at water-based lacquer, 2-3 coats? | “That is standard for us, no problem.” | The last three lots’ readings, the instrument used and who signs the report. Colour mismatch between slats starts here. |
| What happens if colour range misses the 8-12 standard stains + custom requirement? | “It will not happen.” | A re-test clause, the tolerance on the re-test, and the point at which the lot is remade rather than discounted. |
Need slat width specified and tested against your end use?
Send a window schedule or a single set size and we will return a quotation with the loading plan, the safety standard that applies to your market and the lead time for the colour you need. Catalogue and current price list on request.
Related reading
- Grain and defects in Basswood blinds and slats
- Slat thickness in Basswood blinds and slats
- Species in Basswood blinds and slats
Catalogue and current price list · Neutral packing and private label · Consolidation, documents and lead times
