Jovvi Non-Magnetic Titanium Tool Kit for MRI Engineering – Version
6 (Deep Dive: Wrenches, Screwdrivers & Hex Keys)
1. Quality – Material & Geometry Requirements for MRI Tools
Not all wrenches, screwdrivers, or hex keys perform equally in the
MRI environment. Jovvi specifies three critical quality parameters
for each tool type:
| Parameter | Requirement for MRI Safety | Jovvi Titanium Compliance |
|---|
| Magnetic susceptibility (χ) | < 10 × 10⁻⁶ (no artifact) | < 5 × 10⁻⁶ (Grade 5 Ti) |
| Tip hardness (HRC) | ≥ 35 (prevents stripping) | 38–42 HRC (Grade 5) |
| Non‑sparking | Required for oxygen‑rich MRI suites | Yes (Ti does not spark) |
| Corrosion resistance | Withstand contrast media (gadolinium) | Excellent (passive oxide layer) |
Jovvi guarantee: Every wrench, screwdriver, and hex key is 100% X‑ray inspected
for internal ferromagnetic components (e.g., steel core in coated
“titanium look” tools).
2. Application Scenarios – Tool‑Specific Use Cases in MRI
Engineering
Wrenches – For MRI Magnet Cover, Gradient Coils & Cryostat Ports
| Wrench Type | Common MRI Application | Torque Requirement | Jovvi Model | Titanium Grade |
|---|
| Open‑end wrench | Helium vent line nuts (size 14–19 mm) | 10–25 N·m | JOW‑14 to JOW‑19 | Grade 5, 100% Ti |
| Box‑end wrench (12‑point) | Gradient coil mounting bolts (size 10–13 mm) | 15–30 N·m | JOWB‑10 to JOWB‑13 | Grade 5, 100% Ti |
| Combination wrench | Patient table rail fasteners (size 8–15 mm) | 5–20 N·m | JOWC‑8 to JOWC‑15 | Grade 5, 100% Ti |
| Torque wrench (adjustable) | Cryostat port nuts (critical: 8 N·m max) | 1–10 N·m | JOTW‑10 | Grade 23 Ti beam + Be‑Cu spring |
| Socket wrench (ratchet) | RF shield copper mesh fasteners (size 6–13 mm) | 2–10 N·m | JOR‑14 (1/4″ drive) | Ti body + Be‑Cu gears |
| Crowfoot wrench (open‑end attachment) | Hard‑to‑reach cryostat sensors | N/A (for use with torque wrench) | JOCF‑10 to JOCF‑15 | Grade 5, 100% Ti |
Why titanium for wrenches?
Brass wrenches are too soft – jaw spreads under torque >15 N·m.
316 stainless wrenches cause artifacts and become magnetic after
cold working.
Titanium provides steel‑like strength with zero magnetic
susceptibility.
Jovvi ProTip for open‑end wrenches: Always pull, never push. Titanium has slight flex (modulus 110
GPa vs. steel 200 GPa). Pulling keeps the jaw engaged; pushing can
spread the jaw.
Screwdrivers – For RF Coils, Control Console & Accessory Mounts
| Screwdriver Type | Tip Size | Common MRI Application | Shank Material | Handle Material | Jovvi Model |
|---|
| Phillips | #0, #1, #2 | RF coil cover screws, patient table panels | Grade 5 Ti | Brass (knurled) | JOPH‑0,‑1,‑2 |
| Flathead (slotted) | 3 mm, 5 mm, 6 mm | Control console chassis, accessory mounts | Grade 5 Ti | Brass (knurled) | JOFL‑3,‑5,‑6 |
| Torx (star) | T6, T8, T10, T15, T20, T25, T30 | Magnet cover panels, gradient coil fasteners (Tamper‑resistant) | Grade 5 Ti | Brass (knurled) + color‑coded ring | JOTX‑6 to JOTX‑30 |
| Hex (socket) screwdriver | 2 mm, 2.5 mm, 3 mm, 4 mm | RF coil tuning screws, small set screws | Grade 5 Ti | Brass (knurled) | JOHS‑2,‑2.5,‑3,‑4 |
| Precision screwdriver set | Phillips #000, #00; Flat 1.5 mm, 2 mm | Animal MRI coil adjustments, small device repair | Grade 5 Ti | Aluminum (anodized) | JOPS‑4 (4 tools) |
| Insulated screwdriver | Phillips #2, Flat 5 mm | Live electrical work inside MRI console (non‑magnetic insulation) | Grade 5 Ti with ceramic coating | Rubber grip (non‑magnetic) | JOIS‑P2,‑F5 |
Why titanium for screwdrivers?
Ceramic screwdrivers are non‑magnetic but brittle – tips chip
easily.
Brass screwdrivers are too soft – tip deformation after 50–100
uses.
Titanium screwdrivers maintain tip geometry for thousands of
cycles.
Jovvi design feature: Tang‑through construction – the titanium blade extends the full
length of the brass handle, allowing high torque without handle
separation. Many “titanium” screwdrivers from competitors have
steel tangs (hidden ferromagnetic risk).
Hex Keys (Allen Wrenches) – Most Frequently Used MRI Tool
Hex keys are the most common tool in MRI engineering – used for
magnet covers, RF coils, gradient panels, patient table
adjustments, and accessory mounts.
| Hex Key Type | Size Range (metric) | Common MRI Application | Jovvi Model | Special Feature |
|---|
| L‑style (standard) | 1.5, 2, 2.5, 3, 4, 5, 6, 8, 10 mm | General service – covers, panels, mounts | JOHL‑9 (9 pcs) | Ball end on long arm (allows 25° angle entry) |
| L‑style (short arm) | 1.5, 2, 2.5, 3, 4, 5, 6 mm | Tight spaces (inside RF coil housing) | JOHL‑S7 (7 pcs) | Short arm 25 mm, long arm 75 mm |
| T‑handle | 2, 2.5, 3, 4, 5, 6 mm | High‑torque applications (stubborn screws) | JOHT‑6 (6 pcs) | Ergonomic grip, 150 mm shaft |
| Hex bit (1/4″ hex drive) | 2, 2.5, 3, 4, 5, 6 mm | For use with ratchet or torque wrench | JOHB‑6 (6 pcs) | 25 mm length, color‑coded rings |
| Extra‑long (200 mm shaft) | 2, 2.5, 3, 4 mm | Deep recessed screws (cryostat access) | JOHX‑4 (4 pcs) | Ball end on long arm only |
| Micro hex keys | 0.7, 0.9, 1.3 mm | Animal MRI coil tuning, small device repair | JOHM‑3 (3 pcs) | Precision ground tips |
Why titanium for hex keys?
Brass hex keys strip within 10–50 uses (brass hardness 20–25 HRC
vs. titanium 38–42 HRC).
316 stainless hex keys are harder (55 HRC) but:
Become weakly magnetic after use (work hardening)
Cause artifacts if dropped near bore
Risk of ferromagnetic fragmentation if broken
Titanium hex keys offer the “sweet spot”: non‑magnetic, durable,
and safe.
Jovvi ProTip for hex keys: When using ball end at an angle, apply only 50% of normal torque.
The ball end has smaller contact area – overtightening will strip
the screw head, not the hex key.
3. Tool Variety – Detailed Specifications by Tool Type
Jovvi Wrench Specifications
| Parameter | Open‑End Wrench | Box‑End Wrench | Combination Wrench | Torque Wrench |
|---|
| Material | Grade 5 Ti | Grade 5 Ti | Grade 5 Ti | Grade 23 Ti + Be‑Cu spring |
| Finish | Bead blasted | Bead blasted | Bead blasted | Polished beam |
| Jaw angle | 15° offset | 0° (straight) | 15° open end, 0° box end | Fixed head |
| Length (size 10 mm) | 120 mm | 120 mm | 140 mm | 200 mm |
| Thickness (jaw) | 4 mm | 5 mm (wall) | 4 mm / 5 mm | N/A |
| Marking | Size laser‑etched | Size laser‑etched | Size laser‑etched | N·m scale engraved |
| Max torque rating (size 10 mm) | 30 N·m | 40 N·m | 35 N·m | 10 N·m |
Jovvi Screwdriver Specifications
| Parameter | Standard (Phillips/Flat) | Torx | Precision | Insulated |
|---|
| Blade material | Grade 5 Ti | Grade 5 Ti | Grade 5 Ti | Grade 5 Ti + ceramic coating |
| Handle material | Brass (knurled) | Brass + color ring | Aluminum | Rubber over brass |
| Handle length | 90 mm | 90 mm | 70 mm | 100 mm |
| Blade length | 100 mm (standard), 150 mm (long) | 100 mm | 50 mm | 100 mm |
| Tang construction | Full tang | Full tang | Full tang | Full tang |
| Max torque (#2 Phillips) | 5 N·m | 5 N·m (T20) | 1 N·m | 4 N·m |
| Insulation rating | N/A | N/A | N/A | 1000 V (non‑magnetic) |
Jovvi Hex Key Specifications
| Parameter | L‑Style (Standard) | T‑Handle | Hex Bit | Micro |
|---|
| Material | Grade 5 Ti | Grade 5 Ti (shaft), Brass (handle) | Grade 5 Ti | Grade 5 Ti |
| Long arm length (size 3 mm) | 100 mm | 150 mm | 25 mm (bit only) | 80 mm |
| Short arm length (size 3 mm) | 25 mm | N/A | N/A | 20 mm |
| Ball end | Yes (long arm) | Yes (optional) | No | No |
| Finish | Bead blasted | Polished shaft | Bead blasted | Precision ground |
| Color coding | None (laser size) | Handle color by size | Ring color by size | None |
| Max torque (size 3 mm) | 6 N·m | 8 N·m | 5 N·m (with ratchet) | 2 N·m |
4. Production Assurance – Tool‑Specific Testing
Jovvi performs tests beyond general ferromagnetic screening for
each tool category:
Wrench Testing
| Test | Method | Pass Criterion |
|---|
| Jaw spread (open‑end) | Apply rated torque × 1.5 for 10 seconds | Permanent deformation < 0.1 mm |
| Box‑end wall flex | Apply rated torque × 2.0 | No cracking |
| Torque wrench calibration | 5 points across range (1, 3, 5, 7, 9 N·m) | ±5% of reading |
| Corrosion (salt spray) | ASTM B117, 48 hours | No red rust (titanium unaffected) |
Screwdriver Testing
| Test | Method | Pass Criterion |
|---|
| Tip hardness | Rockwell (HRC) on 3 samples per batch | 38–42 HRC |
| Tip torsion | Apply increasing torque until failure | Failure > 2× rated torque |
| Tang pull test | Pull tang axially with 500 N force | No separation |
| Magnetic susceptibility | SQUID magnetometer (ASTM F3042) | < 5 × 10⁻⁶ |
Hex Key Testing
| Test | Method | Pass Criterion |
|---|
| Corner radius inspection | Optical comparator (50× magnification) | Corner radius < 0.05 mm |
| Torque to strip | Insert into Grade 5 Ti test screw, apply torque | Stripping occurs at screw, not hex key |
| Ball end retention | 1000 cycles at 25° angle, 50% rated torque | No ball end deformation |
| Dimensional accuracy | Micrometer measurement across flats (size 3 mm) | 2.98–3.02 mm |
5. Selection Guide – Which Tool for Which MRI Fastener?
| Fastener Type | Fastener Material | Recommended Jovvi Tool | Why |
|---|
| M3–M6 socket head cap screw (steel) | 316 stainless | Hex key (L‑style) | Titanium on steel – no galling |
| M3–M6 socket head cap screw (titanium) | Grade 5 Ti | Hex key with anti‑galling paste | Ti‑on‑Ti requires lubricant |
| Torx flat head (M4) | Steel | Torx screwdriver (T20) | Torx resists cam‑out |
| Phillips #2 (M4) | Brass / plastic | Phillips screwdriver (#2) | Low torque – brass handle sufficient |
| Hex nut (M8–M12) | Steel | Combination wrench | Open end for starting, box end for final torque |
| Cryostat port nut (14 mm hex) | Invar (low thermal expansion) | Torque wrench + socket | Precision torque critical (8 N·m max) |
| Set screw (M2–M3) | Stainless steel | Hex key (2 mm, 2.5 mm) | Short arm for access |
6. Common Mistakes When Using Titanium Tools
| Mistake | Consequence | Prevention |
|---|
| Using Ti hex key in Ti screw without lubricant | Galling (cold welding) | Apply Jovvi anti‑galling paste every 10 insertions |
| Pushing on open‑end wrench (instead of pulling) | Jaw spread | Always pull toward open end |
| Using ball end of hex key for final torque | Stripped screw head | Use straight end for final tightening |
| Overtorquing cryostat nut (torque wrench not used) | Thread damage – helium leak | Always use torque wrench (JOTW‑10) |
| Using Phillips screwdriver at angle | Cam‑out, tip damage | Keep driver aligned with screw axis |
| Storing hex keys loose with steel tools | Ferromagnetic contamination | Store in Jovvi ABS case |
