This guide covers a Kanpur RFQ for a cold-drawn seamless rotogravure cylinder blank. Copy the exact standard, material, delivery condition, OD, wall, length, bore, finish, runout and inspection requirements from the approved drawing. We do not engrave or plate.
RP Sales does not engrave; the enquiry concerns the upstream blank. A cold-drawn seamless steel base tube to DIN 2391 or EN 10305-1, cut to length, with the bore inside H8 tolerance and the OD/wall held to a repeatable specification so the engraver's machining, copper-plating, engraving and chrome-plating steps all start from a known geometry. Availability and source must be confirmed in the current written quotation.
What a rotogravure base tube is
A base tube is the heavy-wall, cold-drawn seamless steel cylinder blank that an engraver later machines, copper-plates, engraves and chrome-plates. The governing specs are DIN 2391 and EN 10305-1, with the precise material and delivery condition taken from the approved drawing. It is not a finished printing cylinder, not an ERW pipe, and not a CDW hydraulic tube. The blank must stay concentric and free of a longitudinal weld so the press-line balance is achievable once the engraver takes the OD down. The drawing and inspection plan must state the permitted concentricity or runout and the datum used to measure it; this page does not impose a universal tolerance.
Where the base tube sits in the cylinder workflow
A finished rotogravure cylinder is the product of a five-step manufacturing flow. RP Sales supplies the first step — the cylinder blank — and steps out cleanly. The engraver does the rest. The flow looks like this:
- 1. Base tube supply (RP Sales). Cold-drawn seamless cylinder blank to DIN 2391 / EN 10305-1, cut to length, both ends faced. MTC keyed to heat. This is where we sit.
- 2. Cylinder machining. Engraver machines OD to the finished cylinder dimension on a precision lathe, removes a controlled stock allowance, balances the cylinder for the press speed it will run at.
- 3. Copper plating. Engraver electroplates a thick copper layer onto the OD (typically 80-150 µm), which becomes the engravable surface. Surface polished to a mirror finish in preparation for engraving.
- 4. Engraving. Electromechanical or laser engraving cuts the image cells into the copper surface to the artwork file the brand owner supplied. Cell depth and pattern determine ink transfer characteristics.
- 5. Chrome plating and final finishing. Engraver electroplates a hard-chrome layer (typically 6-10 µm) over the engraved copper for wear resistance, then proofs the cylinder on a sample press run before dispatching to the brand owner's packaging plant.
Why cold-drawn seamless — not ERW, not CDW
A rotogravure printing cylinder rotates at production-press speeds. Three properties matter more than they would for an industrial pipe: concentricity (OD and ID share the same axis), wall-thickness uniformity around the circumference, and a homogeneous bore with no longitudinal weld seam.
A welded ERW tube carries a longitudinal seam that — however cleanly scarfed — leaves a subtle hardness variation around the bore. A CDW tube tightens that variation but does not eliminate it. Cold-drawn seamless starts from a pierced billet, so the entire cylinder is geometrically and metallurgically symmetric around the axis. That is the reason buyers often specify a seamless precision-tube blank for this duty. The final choice still belongs to the approved cylinder drawing and the engraver's inspection plan.
For background on the broader cold-drawn precision-tube family see our precision & hydraulic tubes page and the printing cylinders product page.
Specification ranges — base tube
The six dimensions and properties below cover almost every base-tube enquiry that lands at our yard from a rotogravure engraver.
Outside diameter (OD)
Copy the OD from the approved drawing and obtain availability and manufacturing route in the current quotation.
Wall thickness
Copy the wall and machining allowance from the approved design calculations and drawing; no universal band applies.
Length
Copy length, tolerance, end preparation and datum from the approved drawing.
Bore tolerance
Use only the bore tolerance and fit named in the approved shaft and bearing design.
Surface roughness
Copy bore and OD roughness, finish route, machining allowance and measurement method from the drawing; confirm availability in the offer.
Material grade
Quote the exact material designation and delivery condition on the drawing. Legacy DIN names and EN 10305-1 grades are different designation systems, not drop-in equivalents. Any change needs written designer approval and mill confirmation. Request the inspection document against the ordered specification.
Who should buy cylinder blanks in Kanpur, and who should not
This enquiry suits a qualified engraver or buyer holding an approved base-tube drawing. Location, face length or press speed does not establish a wall band; use the design calculation and drawing.
Do not order a base tube if you need a finished engraved cylinder. We do not copper-plate, chrome-plate or engrave. Do not substitute ERW or another tube route where the approved drawing names seamless cold-drawn material. Hydraulic cylinder fabricators should use the hydraulic cylinder tube page instead of this blank. Any proposed alternative requires written designer approval.
Base-tube sizes and finishes at a glance
Figures below are example RFQ fields, not stock, application or lead-time claims. Units sit in the header row. Historical DIN 2391 rupee-per-kg bands on the precision-tube price list cover 10 mm to 89 mm OD hydraulic sizes, not these 90 mm to 350 mm cylinder blanks, so we do not paste those bands here.
| Property | Value | Unit |
|---|---|---|
| Outside diameter, stocked | 90 to 350 | mm |
| Outside diameter, mill-direct | up to 600 | mm |
| Wall thickness | 10 to 25 | mm |
| Cut length | 800 to 1600 | mm |
| Cut-to-length tolerance | ±2 | mm |
| Bore fit | H8 | ISO fit class |
| Bore roughness, as supplied | ≤ 6.3 | µm Ra |
| OD roughness, as supplied | ≤ 3.2 | µm Ra |
Worked example: mass of a 150 mm OD blank
Theoretical carbon-steel mass uses W = (OD minus wall) times wall times 0.02466, with OD and wall in millimetres. Take a stated example at 150 mm OD and 15 mm wall. Then W = (150 minus 15) times 15 times 0.02466, which is 49.94 kg per metre. A 1200 mm cut (1.20 m) weighs 59.92 kg. Twenty blanks of that size total 1,198 kg, about 1.20 MT, which is a theoretical mass check. Vehicle and freight planning remain order-specific. Check the same formula on our pipe weight chart.
How to specify a Kanpur RFQ for base tube
Send the drawing or these nine items for a current technical and commercial response without assuming stock or timing.
- OD, wall and length. OD in mm, wall in mm, and cut length in mm against the engraver drawing, with the ±2 mm cut tolerance if you need it.
- Grade and standard. Copy the exact standard, material designation and delivery condition from the drawing. If it mixes DIN and EN vocabulary, ask the designer to resolve the intended requirement rather than translating it in the quote.
- Bore finish. Copy the exact tolerance, roughness, datum and finishing route from the drawing.
- End finish. Both ends faced perpendicular to the axis, or any other facing note on the drawing.
- Quantity. Number of blanks and the press model or face length they serve.
- Test records. State the inspection-document type, results, identity and traceability required by the drawing and PO.
- Inspection. Whether a TPI agency witnesses dimensional checks at the mill or at the Kanpur yard.
- Packing. Dent-free dunnage, wooden spacers and nylon strapping for precision-tube transit.
- Delivery basis. Ask the offer to state material location, collection or destination basis, freight, risk transfer, taxes and dates.
Inspection points that delay engraving
Ordering by OD without wall leaves the machining stock unknown. Accepting a welded or CDW tube as a blank puts a seam hardness band under the copper. Skipping the H8 bore callout forces the engraver to re-bore the shaft seat. Any honed-bore option, tolerance and lead-time effect must be confirmed by the drawing and current offer.
At receipt, match the heat stencil to the MTC, check both ends for facing square to the axis, and look for transit dents before the blank goes on the lathe. Specify dunnage, spacers, strapping, protection and receipt acceptance in the PO rather than assuming a packing method. Open the RFQ form with the drawing attached if any of those checks failed on a previous lot.
Buying printing-cylinder base tube in Kanpur
Use Kanpur as a proposed collection or coordination point only when the current written quotation confirms it. Send the drawing, quantity, inspection and authorised destination, then require the offer to state material location, availability, documents, freight, risk transfer, legally applicable taxes and dates. No corridor or nationwide delivery promise is made here.
For Bharatpur, Delhi NCR or another destination, request a current route and logistics proposal. Start from the printing cylinder product page, the precision and hydraulic tubes catalogue, the DIN 2391 vs EN 10305 comparison, the Kanpur steel market guide, steel pipes Kanpur and seamless pipes Kanpur.
Standards that govern the blank
DIN 2391-1:1994 is the withdrawn German dimensions part still named on some legacy engraver drawings. DIN Media lists EN 10305-1 as its replacement; EN 10305-1 sets the technical delivery conditions for seamless cold-drawn precision tubes. That succession does not make the DIN and EN material names interchangeable. Preserve the drawing's designation, tolerance and delivery condition, and obtain a written engineering disposition before using a current EN grade against a legacy DIN callout.
Documentation follows the inspection-document type named in the purchase order. Under EN 10204, Type 3.2 is validated by both the manufacturer's authorised inspection representative independent of the manufacturing department and either the purchaser's authorised representative or an inspector designated under the applicable official rules. It should not be reduced to a generic promise of witnessed inspection. IBR boiler forms do not apply to an ordinary printing-cylinder blank.
Key points
- RP Sales supplies the DIN 2391 / EN 10305-1 blank, not the engraved cylinder.
- Copy OD, wall, length, bore, finish and tolerance from the approved drawing; the table is not stock.
- A 150 mm OD x 15 mm wall blank weighs 49.94 kg/m; 1200 mm of that size is 59.92 kg.
- Confirm material location, test records, freight, taxes, dates and validity in the quotation and PO.
- ERW and CDW do not replace cold-drawn seamless on a rotating gravure cylinder.
Where the base tubes ship — beyond Kanpur
The Kanpur engraver cluster is the largest single buyer base, but rotogravure base tube also ships from the same yard to engravers in three other clusters. The geography matters because the freight calculation behind a quote depends on the destination.
- Kanpur: confirm material location, collection point, access and offered date in writing.
- Bharatpur: state the authorised consignee and request a current freight, risk-transfer and date proposal.
- Delhi NCR and Greater Noida: confirm route, vehicle, unloading and dates in the offer.
- Mumbai-Pune: compare a current compliant offer and logistics basis; geography alone does not prove source or timing.
Frequently asked questions
What does RP Sales supply to printing-cylinder manufacturers?
Why DIN 2391 / EN 10305-1 — what makes those grades right for the application?
What OD, wall and length range do you stock?
What about bore tolerance and surface roughness?
Where do your base tubes physically end up — Kanpur only?
Do you supply finished engraved cylinders?
How long is a Kanpur quotation valid on a base-tube enquiry?
Do you bill theoretical mass or weighbridge mass on cylinder blanks?
Sources
- DIN 2391-1:1994. Seamless precision steel tubes, Part 1: Dimensions. Deutsches Institut für Normung.
- EN 10305-1:2016. Steel tubes for precision applications. Seamless cold-drawn tubes. European Committee for Standardization (CEN).
- EN 10204:2004. Metallic products. Types of inspection documents (Type 3.1). European Committee for Standardization (CEN).