Buy Imperial Jobber Drill Sets Online in Australia
Imperial Jobber Drill Set Selection — Quick Reference
Imperial jobber drill sets for workshops + toolrooms requiring fractional + number + letter series drill bits. AIMS sets from Sutton Tools + Bordo + Saber + P&N cover the imperial drilling range for US-origin equipment + automotive + tap drill matching.
| Imperial Drill Set Type | Best For | Range |
|---|---|---|
| Fractional Set (1/16" - 1/2") | Standard imperial workshop drilling | 1/16" / 5/64" / 3/32" up to 1/2" |
| Fractional Set (1/16" - 1") | Larger imperial drilling — extended range | 1/16" up to 1" |
| Number Drill Set (#1 - #60) | Small precision drilling + tap drills | 1.02mm - 5.79mm range |
| Letter Drill Set (A - Z) | Larger precision drilling + UNC/UNF tap drills | 5.94mm - 10.49mm range |
| Combination Set (Fractional + Number + Letter) | Complete imperial workshop coverage | ~115 bits total |
| HSS Standard | Mild + low-alloy steel + aluminium | Workshop default |
| HSS Cobalt (M35/M42) | Stainless + tough alloys | Premium option |
| TiN-Coated (Yellow Gold) | Production + extended tool life | Premium coating |
| Indexed Case + Bit Stand | Workshop organisation | Slot-per-size case |
Critical for tap drill matching: Imperial tap drill sizes often fall between fractional sizes — number + letter drills fill those gaps. E.g. UNC 5/16"-18 tap drill = letter F (0.257"); UNC 3/8"-16 tap drill = 5/16" fractional. See threading tap chart for full reference. Brands: Sutton Tools, Bordo, Saber, P&N. Companion: drilling, jobber drill bits, cobalt drill bits, threading.
Imperial Jobber Drill Sets
AIMS Industrial sells imperial jobber drill sets for workshops and toolrooms requiring fractional, number and letter series drill bits. Our sets from Sutton Tools, Bordo, Saber and P&N cover the full range from No.60 wire gauge through to 1" diameter in HSS and HSS-Co for demanding alloy and stainless steel applications.
Imperial Drill Size Series
- Fractional inch sets: 1/16" to 1/2" in 1/64" increments — the most common imperial drill set for general workshop and maintenance use in Australia.
- Number gauge sets (1–60): Wire gauge drills for tapping clearance and pilot holes in imperial fastener applications — essential in precision engineering and toolroom work.
- Letter size sets (A–Z): Fill the gap between number gauges and fractional sizes — used for specific clearance hole requirements in inch-dimensioned engineering drawings.
- Combined sets: Fractional, number and letter series combined in a single case — the complete imperial drill reference for toolroom and maintenance facilities.
- HSS-Co cobalt sets: 8% cobalt content increases red hardness for drilling stainless steel, heat-resistant alloys and work-hardening materials.
Selection and Maintenance
- Jobber length: Standard jobber length (OAL ~9–14× diameter) suits most drilling applications; longer series bits are available for deep-hole and through-plate drilling.
- Point geometry: 118° split point for general materials; 135° self-centring split point for harder materials requiring reduced feed force.
- Resharpening: Quality HSS jobber drills can be resharpened multiple times with a bench grinder or drill grinder — preserving the geometry is critical for accurate hole sizing.
- Storage: Indexed drill cases prevent bit-to-bit contact damage and allow fast size selection during high-volume drilling operations.
Australian Business, Local Supply: As a proudly Australian business since 1988, we stock locally and work with trusted local Australian manufacturers and distributors to ensure fast, reliable supply.
Expert Support: Need help buying the right product for your application? Contact our team for application-specific advice or request a quote.
Also see our Hand Tools and Power Tool Accessories for complementary products.
People Also Ask — Imperial Jobber Drill Sets
Q: What's the difference between number, letter and fractional imperial drill sizes?
Fractional sets run 1/16" to 1/2" (or up to 1") in even fractional steps — the everyday imperial range. Number drills (#60 up to #1) fill in small precision sizes for tap drills and pilot holes. Letter drills (A-Z) sit above the number series and below the larger fractional sizes, covering the gap for specific clearance-hole requirements on inch-dimensioned drawings.
Q: Why would I need a letter-size drill instead of a fractional one for a UNC tap?
Imperial tap drill sizes often fall between fractional sizes, and letter (or number) drills fill those gaps exactly. For example, a UNC 5/16"-18 tap drill is letter F (0.257"), not a fractional size at all — while a UNC 3/8"-16 tap drill does land on a fractional size, 5/16".
Q: What's in a combination imperial drill set, and why buy one instead of three separate sets?
A combination set bundles the fractional, number and letter series into a single case — around 115 bits covering the complete imperial workshop range. For a toolroom or maintenance facility needing full coverage, one combination set is simpler to stock and reach for than managing three separate sets.
Q: Does point geometry matter on an imperial jobber drill?
Yes — a 118° split point suits general materials, while a 135° self-centring split point reduces the feed force needed on harder materials and starts more accurately without walking, which matters when drilling to a marked centre.
Q: Can imperial jobber drills be resharpened, and does that affect accuracy?
Quality HSS jobber drills can be resharpened multiple times on a bench grinder or dedicated drill grinder. Preserving the original point geometry through each resharpen is critical — a poorly resharpened point drills an oversized or off-centre hole even though the drill still cuts.