Product Knowledge Views: 35

Shank size specifications and selection: The shank diameter determines which collet holds the tool - a key parameter. Part 1 - Common shank sizes: 1) Metric - φ3, φ4, φ5, φ6, φ8, φ10, φ12, φ14, φ16, φ20, φ25mm; 2) Inch - 1/8in (3.175mm), 3/16in (4.76mm), 1/4in (6.35mm), 5/16in (7.94mm), 3/8in (9.53mm), 1/2in (12.7mm), 5/8in (15.88mm), 3/4in (19.05mm); 3) Most common - φ6, φ8, φ10, φ12, 1/4in (6.35mm), 1/2in (12.7mm). Part 2 - Scenarios by size: 1) φ3-5mm small - a) micro countersinks (head under φ6); b) small drill presses, watch-machine tools, engraving machines; c) weak rigidity - small diameters, light cuts only; 2) φ6 - a) one of the most common: heads φ6-12mm; b) ordinary drill presses, mills, machining centers - ER11/ER16 collets; c) good value, full range; 3) φ8 - a) heads φ10-16mm; b) ER16/ER20; c) more rigid than φ6; 4) φ10 - a) one of the most common: heads φ12-20mm; b) ER20/ER25/ER32; c) rigid, versatile; 5) φ12 - a) one of the most common: heads φ16-25mm; b) ER25/ER32/ER40; c) rigid, large diameters and heavy cuts; 6) φ16+ large - a) large countersinks (heads φ25+); b) ER40/ER50 or Weldon holders; c) most rigid, heavy cutting; 7) 1/4in (6.35mm) - a) common on US-standard machines, especially imports; b) close to φ6 but NOT interchangeable (0.35mm difference); 8) 1/2in (12.7mm) - a) US-standard machines; b) close to φ12 but not interchangeable. Part 3 - Selection principles: 1) match the machine collet - the basic rule: use what the collet holds; e.g. ER32 holds φ3-20mm, commonly φ10 or φ12; 2) thicker is better - within collet limits, thicker shanks are more rigid: less vibration, better finish, longer life; same φ16 head, φ12 shank far more rigid than φ6; 3) match shank to head - shank about 1/2 to 2/3 of head diameter: φ16 head - φ10 or φ12 shank; φ25 head - φ12 or φ16; 4) avoid reduction sleeves - they reduce rigidity and add runout; use the direct shank size; 5) metric vs inch - NOT interchangeable: φ12 vs 1/2in (12.7mm) differ 0.7mm - a loose fit can fling the tool out - dangerous; 6) standardize - one factory should keep 1-2 shank sizes (e.g. φ10 and φ12) to reduce collet changes and raise efficiency. Part 4 - Common collet ranges: 1) drill chucks - usually φ0.5-13mm: small countersinks only; high runout, weak - not recommended; 2) ER collets - the most common: ER11 φ1-7, ER16 φ1-10, ER20 φ1-13, ER25 φ1-16, ER32 φ3-20, ER40 φ4-26, ER50 φ6-32; 3) Weldon holders - large shanks (φ12+): rigid, but one holder per size; 4) shrink-fit holders - highest precision and rigidity: high-precision work, needs a shrink-fit machine; 5) hydraulic holders - precise, rigid, easy, pricier. Part 5 - Common problems: 1) shank too thin - weak, vibrates, poor finish, short life; thicker shank; 2) shank too thick - collet will not grip; change collet or use a sleeve (not recommended); 3) metric/inch confusion - will not grip; confirm the system; 4) worn collet - precision drops, runout rises; replace; 5) long overhang - weak; shorten. Part 6 - Advice: 1) ordinary factories - keep φ10 and φ12 to cover most needs; 2) small machines - φ6 or φ8; 3) large machines/heavy cuts - φ12, φ16 or larger; 4) imported machines - watch for inch shanks (1/4, 1/2in); 5) high precision - shrink-fit or hydraulic holders with precise tools; 6) unsure - tell us the machine and collet and we will pick the shank. Shank selection looks simple but strongly affects quality and life: thicker is better, match the collet directly, avoid sleeves. Our countersinks come in many shank sizes - ask us.