There is a version of bottom rail in the quotation and a different one in the goods. The gap between them is a tolerance, and it is where the money is.
What bottom rail actually controls in finished blinds
Weight affects how the blind hangs and how it operates.
The number is easy to quote and hard to hold, and the difference between those two things is what you are actually buying.
For Finished venetian blinds, the working range is wood, PVC, or aluminium. Inside that band the choice is commercial; outside it, the product changes category and so does the price.
What wood, PVC, or aluminium does not tell you
| Position | Value | Effect on finished blinds | Where it shows up |
|---|---|---|---|
| Floor | wood, PVC, or aluminium | Lowest cost, least margin for process variation | Cord lock slipping within a season |
| Working middle | wood, PVC, or aluminium | Predictable performance at a normal price | Nothing to negotiate, nothing to explain |
| Ceiling | wood, PVC, or aluminium | Best performance, highest cost | Cost the end product may not recover |
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 bottom rail itself but the tolerance around it. A supplier who quotes wood, PVC, or aluminium without a tolerance has not quoted a specification, and the first lot will define the tolerance for you.
How to measure bottom rail
The reference method here is Colour match, run to D65 + dE, with an acceptance of dE <= 1.5. 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 bottom rail varies more across a run than most buyers expect.
Record the measured value rather than pass or fail. A marginal pass on bottom rail tells you the process is running at the edge, which is the information you need before the next lot rather than after it.
Bottom rail does not stand alone
Bottom rail moves with child safety (cordless / tension device / short cord) and with width tolerance (1-2 mm on the finished blind). 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.
If a quotation is significantly cheaper, the difference is usually in one of these neighbours rather than in the figure being discussed.
The clause to write for bottom rail
The line below is the version we can quote against without inventing anything. Bottom rail appears with a tolerance and a test, not as a standalone number.
50 mm basswood venetian blind, 25 mm steel headrail, branded cord lock, 5000-cycle tested, cordless with tension device to EN 13120, square within 2 mm, stain 3A, valance included
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 bottom rail goes wrong
Cord lock slipping. The blind creeps down and will not hold position.
The cause is usually cheap zinc die-cast lock or a cord that is out of specification for diameter.
The test that catches it: Cycle test 5000 up/down operations with a 5 kg load.
What to specify instead: Specify a branded lock, matched cord, and cycle-test the assembled blind rather than the component.
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 bottom rail, before you order
- What tolerance do you hold on bottom rail, and what did your last three lots measure against it?
- Which method do you use for colour match, and which laboratory signs the report?
- When bottom rail falls outside wood, PVC, or aluminium, do you rework, downgrade, or ship and hope?
- Which of child safety or width tolerance 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 finished blinds are on the product page, and the measurement regime is described on the quality control page.
Questions buyers ask before ordering
Which child-safety standard applies to my market?
EU/UK: EN 13120. US: 16 CFR 1120. Canada: CCPSA. Australia: the corded internal window coverings regulation. They are not interchangeable, and a generic certificate is not evidence.
Can you supply made-to-measure?
Yes, with a 1-2 mm width tolerance. For recess fitting, tell us the measuring method you use, because inside-recess and outside-recess need different deductions.
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 valance at coordinated or hidden? | “That is standard for us, no problem.” | The last three lots’ readings, the instrument used and who signs the report. Safety device failure starts here. |
| What happens if slat misses the 25 / 35 / 50 mm, wood or PVC 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. |
Failure modes worth a clause in the purchase order
Claims rarely come from a batch that was obviously wrong. They come from a headrail figure that sat inside the quoted band and outside what the product needed.
| Failure | What triggers it | Test to demand on the production lot |
|---|---|---|
| Ladder cord fraying | Sharp edges on the headrail or an undersized pulley. | Operation cycles — internal 5000 cycles; acceptance no slip, no fray |
| Blind not square | Cutting error or unequal cord length during assembly. | Child safety — EN 13120 / 16 CFR 1120; acceptance pass for destination market |
The other two, with acceptance numbers attached, are in the full failure analysis for finished blinds. A supplier who cannot name the mode he sees most often is describing a catalogue, not a process.
Need bottom rail 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
- Ladder tape / cord in Finished venetian blinds
- Finished Blinds vs Shutters
- Finished venetian blinds Specification
Catalogue and current price list · Neutral packing and private label · Consolidation, documents and lead times
