Seven VDI guidelines form the most complete standard system of any single machining process. They define what a deep hole is (bore diameter 0.2–2000 mm, depth usually more than three times diameter), classify the gun-drilling, BTA single-tube and ejector double-tube methods, and carry ready-to-use cutting-value tables, coolant flow and pressure diagrams, drive-power calculations, machining-center guide values, and machine acceptance test procedures. Written by the Association of German Engineers, they are the de-facto reference for deep hole drilling in process planning worldwide.
VDI stands for Verein Deutscher Ingenieure — the Association of German Engineers. Its Richtlinien (guidelines) are technical rules written by volunteer committees of engineers from industry, research, and public administration. Unlike ISO or DIN norms they are not legally binding, but they codify the recognized state of the art in German-speaking engineering practice and are treated as authoritative in process planning, tool selection, machine procurement, acceptance testing, and quality documentation.
For deep hole drilling the VDI has produced arguably the most complete standard system of any single manufacturing process. The series takes you from method overview and terminology (VDI 3210) through the two dominant production processes — gun drilling (VDI 3208) and BTA/ejector boring with external coolant supply (VDI 3209 Blatt 1) — to finishing (VDI 3209 Blatt 2), machining-center application (VDI 3211), and machine acceptance testing (VDI 3212). The companion VDI 3397 series covers the metalworking fluids (coolants) the processes depend on.
| Standard | Latest Edition | Title | What It Governs |
|---|---|---|---|
| VDI 3210 Blatt 1 | 2006-03 | Deep-hole boring (overview) | Definitions, terminology, method classification, machine types, space requirements |
| VDI 3210 Blatt 2 | 1986-10 | Deep-boring equipment — form for enquiry, quoting and ordering | Standardized RFQ / equipment-specification form |
| VDI 3208 | 2014-04 | Deep hole boring with gun drills | Gun-drilling process, tools, coolant concepts, cutting-value tables |
| VDI 3209 Blatt 1 | 2024-01 | Deep hole boring systems with external supply of coolant | BTA single-tube and ejector double-tube methods, cutting data, coolant diagrams |
| VDI 3209 Blatt 2 | 2019-01 | Approximate values for skiving and roller burnishing of bores | Finishing parameters, surface-finish prediction, tool selection |
| VDI 3211 | 2015-01 | Deep hole drilling on machining centers | Tool types, machine requirements, guide values, method selection |
| VDI 3212 | 2014-07 | Acceptance test requirements of deep hole drilling machines | Geometric accuracy testing of one- and multi-spindle machines |
| VDI 3397 (series) | 2007–2016 | Metalworking fluids (MWF) | Selection, maintenance, and disposal of cooling lubricants |
The foundation document: definitions, method classification, machine types. CURRENT · CONFIRMED 2013
VDI 3210 Blatt 2 (1986-10) defines a standardized form for enquiring, quoting and ordering deep-boring equipment. It is a compact 6-page document and is available in German only, but it remains genuinely useful when writing RFQs: it forces the buyer and supplier to state machine type, bore range, spindle arrangement, coolant system, and acceptance criteria in a uniform way.
Gun drilling — the most common deep hole drilling method. CURRENT · 2014-04
The newest revision in the series — the BTA and ejector methods. CURRENT · 2024-01 REVISION
Finishing deep-drilled bores. CURRENT · 2019-01
Complete machining in a single setup. CURRENT · 2015-01
| Abbreviation | Tool Type | Typical Use |
|---|---|---|
| WTB | Twist deep-drilling tools | Medium-depth holes, conventional machines |
| ZLB | Double-lip gun drilling tools | Higher feed rates on gun-drill diameters |
| ELB | Single-lip gun drill tools | Classic gun drilling, highest straightness |
| Ejector / BTA | Ejector double-tube and BTA tools | Larger diameters with external coolant |
| Special tools | Process-specific deep drilling tools | Tailored geometry and coating variants |
Verifying the machine, not just buying it. CURRENT · 2014-07
| Method | Diameter | Typical L/D | Chip Removal | Coolant Supply | Covered By |
|---|---|---|---|---|---|
| Gun drilling (single-lip, ELB) | 0.5–50 mm | up to ~300:1 | Through external V-flute | Internal, high pressure | VDI 3208 |
| BTA single-tube (STS) | 6–2000 mm | ~200:1 | Through the boring bar | External, pressure head | VDI 3209 Blatt 1 |
| Ejector double-tube (DTS) | 18–250 mm | ~100:1 | Through inner tube (Venturi) | External, no face seal | VDI 3209 Blatt 1 |
| Skiving & roller burnishing | Finishing | n/a | n/a | Flood | VDI 3209 Blatt 2 |
| Machining-center drilling | Varies | 3:1–20:1 typical | Method-dependent | Through-spindle | VDI 3211 |
| L/D Ratio | Classification | Typical Process |
|---|---|---|
| ≤ 5:1 | Standard hole | Conventional twist drill |
| 5:1–10:1 | Semi-deep | Peck drilling, through-coolant drill |
| 10:1–20:1 | Deep hole | Gun drilling or short BTA |
| 20:1–50:1 | Very deep | Gun drilling or BTA with steady rests |
| 50:1–100:1 | Ultra-deep | Specialized gun drilling or BTA |
| > 100:1 | Extreme | Gun drilling with whip guides |
A systematic workflow that reads across the whole series.
Record diameter D, depth, L/D, material group, required tolerance and finish. VDI 3210 gives the definitions, terminology, and the method overview to start from.
Gun drill for small diameters and maximum straightness; BTA single-tube for medium-to-large bores with internal chip removal; ejector for large diameters on conventional machines without a face seal; machining-center drilling for complete machining. Use the VDI 3210 classification and VDI 3211 selection guidance.
Take Vc and feed per material group from VDI 3208 (gun drills) or VDI 3209 Blatt 1 (BTA/ejector). Treat them as starting points — VDI 3208 explicitly warns that values may need adjustment on the job.
Read coolant flow vs. bore diameter and coolant pressure vs. diameter (with L/D) from the VDI 3209 Blatt 1 diagrams. Use VDI 3397 for fluid type, concentration, and maintenance.
Use the drive-power diagrams and power-calculation methods in VDI 3208 and VDI 3209 Blatt 1 to check the spindle and pump can deliver.
Apply the tool-geometry guidance (clearance angles, land widths, chip breakers) and the WTB / ZLB / ELB / ejector / BTA classification from VDI 3211 when ordering or designing tooling.
If the required Ra is below the as-drilled value, apply the skiving and roller burnishing approximate values in VDI 3209 Blatt 2 — burnishing also adds a compressive residual-stress layer.
On machining centers, follow the VDI 3211 guide values and the G73 / G83 pecking cycles, and respect the auxiliary equipment requirements for through-spindle coolant.
Apply VDI 3212 acceptance tests when purchasing a deep hole machine, after long service, or whenever non-conforming bores suggest a geometry problem.
All current deep hole drilling guidelines are published by VDI and distributed through its own shop and through DIN Media (formerly Beuth Verlag). Most are issued as bilingual German/English editions, with the German version declared authoritative.
| Channel | Details |
|---|---|
| vdi.de — official VDI shop | Guideline pages with abstract, edition date, page count, and price; secure online ordering in German and English. |
| DIN Media (dinmedia.de) | Distributes VDI guidelines worldwide; credit card or invoice; quick delivery by download; English editions available. VDI 3209 Blatt 1:2024-01 lists from €89; VDI 3208 ~€81.50; VDI 3210 Blatt 1 ~€117–120. |
| Standards Flat Rate VDI | Subscription model that lets you download a set number of VDI guidelines as PDFs within 12 months — much cheaper than buying individually. Conditions: already-issued standards only, download editions only, one flat rate per company per period. |
| International distributors | Intertek Inform, GlobalSpec, standards.ie and similar shops list and sell VDI standards for teams outside Europe. |
| Manufacturer handbooks | Tool-maker technical handbooks (for example the ISCAR Drilling Handbook) quote extensive excerpts from VDI 3208 and VDI 3209 cutting data — a free way to get the key values in context. |
VDI guidelines sit alongside — and deliberately defer to — the binding ISO and DIN norm system. DIN/ISO standards define the enforceable technical requirements; VDI guidelines fill in the application knowledge that norms do not cover. Deep hole drilling in particular is served by VDI because conventional drill standards stop where the deep hole world begins.
| Standard | Scope | Relationship to VDI Deep Hole Series |
|---|---|---|
| ISO 286 / DIN 7154 | ISO tolerance system for holes | Used to specify deep hole tolerances and tolerance grades |
| DIN 1835 / DIN 6535 | Shank dimensions for drills — parallel and Morse taper | Defines the tool-holding interface for deep hole tooling |
| ISO 513 | Classification of cutting tool materials | P/M/K/N/S/H material groups used in VDI cutting-value tables |
| DIN ISO 230-1 | Test code for machine tools — geometric accuracy | Base standard invoked by VDI 3212 acceptance testing |
| DIN 4000-95 | Part data sheet for gun drills | References VDI 3208 content for tool data exchange |
| DIN EN 12717 / DIN EN 12348 | Safety of drilling machines | Safety requirements surrounding VDI process guidance |
| VDI 3397 (series) | Metalworking fluids: selection, maintenance, disposal | Companion series to the deep hole drilling guidelines |
| VDI 1000 | Principles for creating VDI guidelines | Governs how the whole VDI guideline system is administered |
| Term | Meaning |
|---|---|
| VDI | Verein Deutscher Ingenieure — the Association of German Engineers. |
| Richtlinie | A VDI guideline: a voluntary technical rule representing the recognized state of the art. |
| Blatt | “Sheet” / part number within a guideline series (e.g., VDI 3209 Blatt 1, Blatt 2). |
| Tiefbohren | German term for deep hole drilling / deep hole boring. |
| Gun drilling (ELB) | Single-lip drilling; coolant fed internally through the drill, chips returned along the external V-flute. |
| BTA (STS) | Single-tube system; chips removed through the boring bar with external coolant supply via a pressure head. |
| Ejector drilling (DTS) | Double-tube system; a Venturi effect draws chips back through the inner tube, requiring no face seal. |
| WTB / ZLB / ELB | VDI 3211 tool classes: twist deep-drilling tools / double-lip gun drilling tools / single-lip gun drill tools. |
| L/D | Length-to-diameter ratio of the bore; the defining measure of drilling depth. |
| Vc | Cutting speed in m/min; feed f in mm/rev — the core process parameters tabulated by VDI. |
| Skiving | Finish machining of a bore with a carbide blade to correct form and finish. |
| Roller burnishing | Cold-working a bore surface to low roughness while adding compressive residual stress. |
| Self-piloting | A deep hole tool steers itself along its own bore axis via guide pads, giving straight holes without a pre-machined guide bore. |