Best Torque Screwdriver for Small Screws: Slip, Non-Slip or Fixed? 12 Japanese Picks
Quick answer: choose a torque screwdriver by screw size first, then by what happens at the set torque
- You must never over-tighten (repeat assembly, small screws): a slip-type (rotary slip) driver. TOHNICHI says its RTD series ratchets freely after the set torque, so turning further adds no torque.
- One or a few screw sizes, simple to use: a fixed-torque bit holder such as the VESSEL TBH series (M3 0.7 N·m to M6 4.6 N·m, ±10% per VESSEL). Tighten until it clicks four times.
- You want a signal but full control: a non-slip (limiting) driver such as the TOHNICHI LTD500CN. It signals at the set torque, but keeps adding torque if you keep turning, so you must stop.
- Range by screw size (TOHNICHI's table for machine screws): about M1.8 → 2–15 cN·m, M2 → 4–30 cN·m, M3.5 → 20–120 cN·m, M4 → 60–260 cN·m, M5–M6 → 100–500 cN·m.
- Units: 100 cN·m = 1 N·m, and 1 N·m is about 8.85 in-lb (MISUMI).
This guide does not rank tools by price or reviews. The more useful questions are which screw you are tightening and how the tool behaves when it reaches the set torque, because those decide the torque range and the type you need. This guide explains the three main mechanisms, matches torque ranges to screw sizes using TOHNICHI's published table, then compares 12 torque screwdrivers and torque bit holders from TOHNICHI, KANON and VESSEL using the specifications on their product pages. Sources are listed at the end.
What a torque screwdriver does
A torque screwdriver tightens a screw to a specified torque, so the screw is tight enough but not over-tightened (Wikipedia). The torque value itself should come from the maker of the screw, part or equipment you are working on. The tool's job is to stop at that value every time.
Three types: slip, non-slip and fixed
| Type | What happens at the set torque | Torque setting | In this guide |
|---|---|---|---|
| Slip-type (rotary slip) | The driver ratchets freely after the set torque, so turning further does not add torque (TOHNICHI RTD). | Adjustable with a scale | TOHNICHI RTD15CN, RTD30CN, RTD120CN, RTD260CN, RTD500CN; KANON CN300LTDK |
| Non-slip (limiting) | You feel the limit and the tool springs back slightly. If you keep turning, it keeps adding torque (Pemro, describing TOHNICHI LTD). | Adjustable (graduation: Not confirmed) | TOHNICHI LTD500CN |
| Fixed-torque bit holder | It clicks at one preset value. VESSEL says to tighten until four clicks. | Fixed per size (cannot be changed) | VESSEL TBH-M3, TBH-M3.5, TBH-M4, TBH-M5, TBH5S set |
The KANON CN300LTDK product page describes it as a slip (idle-running) type: when the set torque is reached, the driver turns freely.
Step 1: choose the torque range by screw size
TOHNICHI lists the screw sizes each RTD model is designed for. Sizes in brackets are as TOHNICHI shows them.
| TOHNICHI model | Torque range | Machine screw | Tapping screw |
|---|---|---|---|
| RTD15CN | 2–15 cN·m | (M1.8) | (M1.4) M1.6 |
| RTD30CN | 4–30 cN·m | M2 (M2.2) | (M1.8) M2 |
| RTD60CN (not in our store) | 10–60 cN·m | M2.5, M3 | (M2.2) M2.5 |
| RTD120CN | 20–120 cN·m | (M3.5) | M3 (M3.5) |
| RTD260CN | 60–260 cN·m | M4 (M4.5) | M4 |
| RTD500CN | 100–500 cN·m | M5, M6 | (M4.5) |
For a fixed value, the VESSEL TBH series is sold by screw size: M3 0.7 N·m, M3.5 1.1 N·m, M4 1.4 N·m, M5 2.6 N·m and M6 4.6 N·m, each with ±10% tolerance (VESSEL leaflet). The M6 holder is included in the TBH5S set.
These tables show which tool is built around a screw size. They are not tightening specifications for your part.
Step 2: read the units
The TOHNICHI and KANON tools in this guide are labelled in cN·m (centinewton-metres): 100 cN·m = 1 N·m. If your specification is in in-lb, MISUMI gives 1 N·m = 8.8507 in-lb, so multiply N·m by about 8.85. TOHNICHI also sells metric models in kgf·cm; for example, its table lists the 1.5RTD at 0.2–1.5 kgf·cm alongside the RTD15CN at 2–15 cN·m.
The 12 tools compared
Specs are copied from each product page. VESSEL's tolerance is from VESSEL's own product pages and leaflet.
TOHNICHI RTD15CN Slip-Type Preset Torque Driver, 2-15 cN·m
TOHNICHI RTD30CN Slip-Type Preset Torque Driver, 4-30 cN·m
| Model | Type | Torque | Graduation | Accuracy | Length / weight |
|---|---|---|---|---|---|
| TOHNICHI RTD15CN | Slip | 2–15 cN·m | 0.1 cN·m | ±3% | 101 mm / approx. 50 g |
| TOHNICHI RTD30CN | Slip | 4–30 cN·m | 0.2 cN·m | ±3% | 101 mm / approx. 50 g |
| TOHNICHI RTD120CN | Slip | 20–120 cN·m | 1 cN·m | ±3% | 132 mm / approx. 160 g |
| TOHNICHI RTD260CN | Slip | 60–260 cN·m | 2 cN·m | ±3% | 149 mm / approx. 270 g |
| TOHNICHI RTD500CN | Slip | 100–500 cN·m | 5 cN·m | ±3% | 155 mm / approx. 320 g |
| TOHNICHI LTD500CN | Non-slip | 100–500 cN·m | Not confirmed | ±3% | 155 mm / approx. 330 g |
| KANON CN300LTDK | Slip | 40–300 cN·m | 1 cN·m | Not confirmed | 157 mm (without bit) / 214 g |
| VESSEL TBH-M3 | Fixed | 0.7 N·m (M3) | — | ±10% | 75 mm / 36 g |
| VESSEL TBH-M3.5 | Fixed | 1.1 N·m (M3.5) | — | ±10% | 75 mm / 36 g |
| VESSEL TBH-M4 | Fixed | 1.4 N·m (M4) | — | ±10% | 75 mm / 36 g |
| VESSEL TBH-M5 | Fixed | 2.6 N·m (M5) | — | ±10% | 75 mm / 36 g |
| VESSEL TBH5S | Fixed, 5 holders | M3, M3.5, M4, M5, M6 | — | ±10% | 75 mm each / 183 g set |
All TOHNICHI and KANON tools here tighten clockwise (right-hand) according to their product pages.
Best torque screwdriver by job
Electronics and very small screws (about M1.6 to M2.2)
- TOHNICHI RTD15CN: 2–15 cN·m in 0.1 cN·m steps, 101 mm and about 50 g.
- TOHNICHI RTD30CN: 4–30 cN·m in 0.2 cN·m steps, the model TOHNICHI lists for M2 machine screws.
Assembly with M3.5 to M4 screws
KANON does not publish screw sizes for the CN300LTDK on our product page; choose it by its 40–300 cN·m range.
- TOHNICHI RTD120CN: 20–120 cN·m, with a resin handle listed as an accessory.
- TOHNICHI RTD260CN: 60–260 cN·m, with a resin handle and a preset hook spanner listed as accessories.
- KANON CN300LTDK: 40–300 cN·m slip type that comes with No.1 and No.2 Phillips bits (SB type), so you can start without buying bits. The product page does not state its accuracy.
M5 and M6 screws
- TOHNICHI RTD500CN: 100–500 cN·m slip type for M5 and M6 machine screws.
- TOHNICHI LTD500CN: the same range in the non-slip type. The product page lists M5 and M6 machine screws as a reference. Choose it only if the person using it will stop at the signal.
One screw size, or with a low-speed electric screwdriver
- VESSEL TBH5S: five fixed holders (M3 to M6) in a storage case. The holders fit screwdrivers that take 6.35 mm hex bits. VESSEL also allows electric drivers of 7.2 V or less at 250 rpm or less, but not impact drivers.
- Single holders: TBH-M3, TBH-M3.5, TBH-M4 and TBH-M5, if you only work with one size.
VESSEL states that the holders are for tightening only, can be used up to 10,000 times, and are not supported with repair or calibration certificates.
Bits includedKANON CN300LTDKSlip type, 40–300 cN·m, Phillips No.1 and No.2 bits included.
View CN300LTDK
Why look at Japanese torque screwdrivers?
We sell Japanese tools, so this guide covers Japanese brands only. Here is what they offer, based on what the product pages and maker information state rather than general claims about quality:
- Published screw sizes per model. TOHNICHI lists the machine and tapping screw sizes each RTD model is designed for, which makes the first choice easier.
- Stated accuracy. The TOHNICHI product pages in this guide state ±3%. VESSEL states ±10% for the TBH holders and publishes the tolerance range for each size.
- Two mechanisms from the same maker. TOHNICHI makes both the slip-type RTD and the non-slip LTD; for example, the RTD500CN and LTD500CN both cover 100–500 cN·m.
- Country of origin. The VESSEL TBH product pages list Taiwan. The TOHNICHI and KANON product pages do not state it (Not confirmed).
What we do not claim: that these tools are more accurate or last longer than American or European torque screwdrivers. We have not found a test that compares them.
How to use a torque screwdriver
- Find the torque value for your screw from the part or equipment maker.
- Set the tool. On the TOHNICHI RTD, set the value on the scale and use the lock; TOHNICHI says all RTD models have a locking mechanism that stops the setting from changing during use. On the TOHNICHI LTD, set the value as described in the maker's instructions. On the VESSEL TBH, choose the holder for your screw size.
- Fit the bit and seat it fully in the screw head. TOHNICHI RTD drivers take standard 6.35 mm hex bits; the KANON CN300LTDK uses SB-type bits.
- Tighten until the signal, then stop. With the slip-type RTD, the driver ratchets freely once the set torque is reached, without adding torque. With the non-slip LTD, stop as soon as you feel the limit. With the VESSEL TBH, tighten until four clicks.
FAQ
What is the difference between a torque screwdriver and a torque wrench?
Both tighten to a set torque. The torque screwdrivers in this guide top out at 500 cN·m (5 N·m) and are held like a screwdriver for small screws. For larger bolts, use a torque wrench; see our torque wrench buying guide.
Is a slip-type or non-slip torque screwdriver better?
It depends on the user. A slip-type driver ratchets freely after the set torque, so turning further does not add torque (TOHNICHI). A non-slip (limiting) driver signals at the set torque but keeps applying torque if you keep turning, so the user must stop.
Can I loosen screws with a torque screwdriver?
VESSEL says the TBH holders are for tightening only. The TOHNICHI and KANON tools in this guide are listed as right-hand (clockwise) tightening tools.
Do these come with a calibration certificate?
VESSEL states that the TBH holders are not supported with calibration certificates. Our TOHNICHI and KANON product pages do not mention a certificate (Not confirmed). If you need one, email us before you order.
How do I convert cN·m to in-lb?
Divide cN·m by 100 to get N·m, then multiply by about 8.85 (MISUMI gives 1 N·m = 8.8507 in-lb).
Related guides
- TOHNICHI Torque Wrench & Torque Driver Buying Guide: QL, CL, MTQL, RTD and More
- Torque Wrench Buying Guide: How to Choose the Right Type, Range & Drive Size
- Japanese Screwdrivers by Job: VESSEL, ANEX and ENGINEER Picks
- VESSEL vs ANEX: Which Japanese Screwdriver Brand Should You Buy?
- Japanese torque screwdrivers
- All Japanese torque wrenches and torque tools
Find your torque screwdriver
Browse torque screwdrivers and torque bit holders from TOHNICHI, KANON and VESSEL.
Shop torque screwdriversSources
- TOMAC (TOHNICHI distributor), RTD Rotary Slip Torque Screwdriver: features, ranges and applicable screws
- Pemro, TOHNICHI LTD adjustable limiting torque screwdriver
- VESSEL, Torque Bit Holder leaflet (TBH-M3 to M6, TBH5S)
- VESSEL, Torque Bit Holder 5-Piece Set No.TBH5S
- VESSEL, Torque Bit Holder No.TBH-M4
- Wikipedia, Torque screwdriver
- MISUMI USA, Nm to in-lbs converter
- Product specifications: each linked product page in our store (TOHNICHI, KANON, VESSEL).
Last reviewed: October 2026.
