Brazed Carbide Tool Selection Chart
Which brazed carbide lathe tool does which job - each ISO 243 tool plus pulley and bull nose tools shown cutting, right and left hand, shank sizes, carbide grades, regrinding and problems.
Download PDF (2 pages, A4)Shop brazed tools
Tools shown from above on a stylised bar in the chuck - right-hand tools, feeding towards the chuck.
Tool types
| ISO 243 | Tool | Hand | Use it for |
|---|---|---|---|
| ISO 1 | Straight rougher | R / L | Roughing and general turning |
| ISO 2 | Chamfer tool (cranked 45°) | R / L | 45° chamfers; also turning and facing from one setting |
| ISO 3 | Corner tool | R / L | Turning right up to a shoulder and facing it |
| ISO 4 | Broad (wide) tool | - | Finishing with a broad flat edge at low feed; flat-bottom grooves |
| ISO 5 | Wide facing tool | R / L | Facing ends and shoulders |
| ISO 6 | Side tool | R / L | Turning and facing to a square (90°) shoulder |
| ISO 7 | Necking (parting) tool | R / L | Parting off, necking and grooving |
| ISO 8 | Inside rougher | R / L | Boring through holes |
| ISO 9 | Inside corner tool | R | Boring blind holes and to an inside shoulder |
| ISO 12 | Threading tool (DIN 282; Denas ISO 13) | R / L | 60° external threads (55° for Whitworth) |
| ISO 13 | Inside threading tool (DIN 283; Denas ISO 14) | R | 60° internal threads |
| - | Pointed finishing tool | - | Light finishing cuts and vee grooves (80° point) |
| - | Pulley tool | - | Form tool for V-belt pulley grooves (34 - 38° included) |
| - | Bull nose tool | R / L | Cranked head with a round nose - turning, facing and 45° chamfers |
Hand, geometry, sizes and grades
Shank sizes
| Shank h x b mm | Length L mm | Typical lathe |
|---|---|---|
| 8 x 8 | 90 | Mini and hobby lathes |
| 10 x 10 | 90 | Mini lathes, tool and cutter work |
| 12 x 12 | 100 | Bench lathes, 200 - 250 mm swing |
| 16 x 16 | 110 | Centre lathes up to 300 mm swing |
| 20 x 20 | 125 | Centre lathes 300 - 400 mm swing |
| 25 x 25 | 140 | Centre lathes 400 - 500 mm swing |
| 32 x 32 | 170 | Heavy lathes |
| 16 x 10 | 110 | Rectangular - more height for the same width |
| 20 x 12 | 125 | Rectangular |
| 25 x 16 | 140 | Rectangular |
| 32 x 20 | 170 | Rectangular |
Carbide grades
| ISO grade | Shank colour (usual) | Material | Duty |
|---|---|---|---|
| P10 | Blue | Steel, cast steel | Finishing, higher speed |
| P20 | Blue | Steel, cast steel | General turning |
| P30 | Blue | Steel, cast steel | Roughing, interrupted cuts |
| M10 / M20 | Yellow | Stainless, manganese and heat-resistant steel | General |
| K10 | Red | Cast iron, aluminium, brass, plastics | Finishing and general |
| K20 | Red | Cast iron, hard woods, non-ferrous | Roughing, interrupted cuts |
Regrinding a brazed tool
| Step | How |
|---|---|
| 1 Relieve the steel | Grind the steel shank under the tip on an aluminium oxide wheel, 10 - 12° clearance, so the carbide wheel only touches carbide |
| 2 Rough the carbide | Green silicon carbide wheel, 60 - 80 grit; 6 - 8° clearance - more makes the edge weak |
| 3 Finish | Diamond wheel (D91 - D64) or diamond lap for a sharp, long-lasting edge |
| 4 Hone | A light touch with a diamond file takes off the wire edge |
| Never | Dip hot carbide in water - it cracks the tip and the braze |
Problems
| Problem | Likely cause | Fix |
|---|---|---|
| Tip chips on the edge | Grade too hard, tool above centre, chatter | Tougher grade (P30 / K20), set to centre height, shorter overhang |
| Tip cracks or comes off | Overheated grinding or quenching; heavy interrupted cut | Grind gently, let it cool in air; lighter cut |
| Rubs, no chip, burns | Blunt, too little clearance, too low feed | Regrind 6 - 8° clearance; more feed |
| Built-up edge, torn finish | Speed too low for carbide | Speed up - carbide wants 3 - 5 x HSS speed (see the cutting chart) |
| Pip left in the centre when facing | Tool not on centre height | Pack the tool to centre - check against the tailstock centre |
| Chatter | Too much overhang, too big a nose, loose gib | Shorter overhang, smaller nose radius, tighten the slides |