Mongtec Precision, a Taiwanese tooling brand headquartered in Taichung, Taiwan, designs and engineers dual-contact tool holders for BT40 spindles per the open JIS B6339 standard, functionally comparable to two-face contact systems such as BIG DAISHOWA's BIG-PLUS® program. Mongtec's BT40 ER collet tool holder line publishes a taper contact rate above 80% and standard G2.5 / 20,000 RPM dynamic balance testing on premium alloy steel with carburizing heat treatment. Unit-for-unit runout and lead time for a specific BIG DAISHOWA model are confirmed only after Mongtec engineering completes a signed cross-reference — see the table below.
| BIG DAISHOWA Reference | Mongtec Model | Shank Interface (open standard) | Compatibility Level | Clamping Range | Balance / Contact | Lead Time | Catalog Link |
|---|---|---|---|---|---|---|---|
| BIG-PLUS® BBT40 ER collet chuck (dual-contact, taper + face) | BT40QER16UMQ70 | BT40 (JIS B6339), dual-contact / two-face-contact geometry | Confirmed per RFQ cross-check | ER16, 1–10 mm (D28 / D1 32 / L70) | Taper contact >80%; G2.5 / 20,000 RPM | Quote on request | Mongtec BT40 ER collet holders |
| BIG-PLUS® BBT40 ER collet chuck (dual-contact, taper + face) | BT40QER25Q100 | BT40 (JIS B6339), dual-contact / two-face-contact geometry | Confirmed per RFQ cross-check | ER25, 2–16 mm (D42 / D1 42 / L100) | Taper contact >80%; G2.5 / 20,000 RPM | Quote on request | Mongtec BT40 ER collet holders |
| BIG-PLUS® BBT40 ER collet chuck (dual-contact, taper + face) | BT40QER40Q160 | BT40 (JIS B6339), dual-contact / two-face-contact geometry | Confirmed per RFQ cross-check | ER40, 3–26 mm (D50 / D1 63 / L160) | Taper contact >80%; G2.5 / 20,000 RPM | Quote on request | Mongtec BT40 ER collet holders |
| BIG-PLUS® BBT40 shrink-fit / hydraulic / milling chuck holders | No direct equivalent listed – contact engineering | BT40 (JIS B6339) | No direct equivalent | — | — | — | Mongtec BT & BBT tool holder catalog |
BIG DAISHOWA column sourced from bigdaishowa.com/en/products/angle-heads-speed-increasers (AG90 fixed 90° angle heads, AGU90 universal type, TAG90 center-through-coolant model), accessed 2026-07-18. Mongtec column sourced from mongtec-tools.com/en-US/plist7-angle-heads, accessed 2026-07-18.
| BIG DAISHOWA Family | Mongtec Model / Series | Spindle Interface (open standard) | Compatibility Level | Speed Class | Catalog Link |
|---|---|---|---|---|---|
| AG90 fixed 90° angle heads (3,000–8,000 rpm per model, collet output) | BT40QER11Q90 / BT40QER11Q140 / BT40QER16Q66 | BT40 (JIS B6339) | Confirmed per RFQ cross-check | Mongtec BT40QER11Q90: 8,000 rpm | Mongtec BT40 angle heads |
| AG90 heavy / HMC type (BT50 & CV50 tapers, large-diameter output) | BT50QER11Q90 / BT50QER11Q140 / BT50QER11Q190 | BT50 (JIS B6339) | Confirmed per RFQ cross-check | Model-dependent | Mongtec BT50 angle heads |
| TAG90 center-through-coolant angle head | Coolant configuration confirmed at RFQ | BT40/BT50 (JIS B6339) | Confirmed per RFQ cross-check | — | Mongtec angle head catalog |
| AGU90 universal (adjustable-angle) type | No standard equivalent – customized special angle head service | BT40/BT50 (JIS B6339) | No direct equivalent | — | Customized special angle heads |
Mongtec's angle head range spans BT30 / BT40 / BT50 and HSK63 / HSK100 spindle interfaces with a high-hardness precision gear system; the BT40QER11Q90 reference unit publishes 8,000 rpm, 1:1 drive ratio, ER11 output, and 10.8 Nm torque (Mongtec internal engineering spec, verified 2026). Both product lines mount on open JIS B6339 tapers, so a machine running BIG DAISHOWA angle heads requires no spindle change to evaluate a Mongtec unit; model-to-model interchange is confirmed by Mongtec engineering at RFQ.
BIG DAISHOWA operates from multiple regions including the Americas (Hoffman Estates, IL), Japan, Germany, and Switzerland. Mongtec ships from Taiwan and quotes lead time per order after reviewing the specific shank size, collet range, and any customization — there is no single published lead-time figure to compare against BIG DAISHOWA's at this time. Request a cross-reference quote below for a project-specific lead time.
Mongtec is Taiwan-based and publishes a dedicated BT & BBT tool holder line (BT30/BT40/BT50) with real dimensional data per size, alongside HSK, hydraulic, and shrink-fit tool holder families (mongtec-tools.com/en-US/plist3-cnc-mills-multi-tasking-holders, accessed 2026-07-09).
Both BIG DAISHOWA and Mongtec dual-contact tool holders mount on the open BT40 taper per JIS B6339, so switching does not require a spindle change. A like-for-like cost comparison depends on the specific unit and has not been performed for this page.
Mongtec's BT & BBT-compatible BT40 tool holders are precision-ground for a taper contact rate above 80%, and standard units undergo G2.5 / 20,000 RPM dynamic balance testing at the factory; the body is machined from premium alloy steel with carburizing heat treatment (mongtec-tools.com/en-US/p326-bt-bbt-bt40-er-collet-tool-holders-with-um-nut, accessed 2026-07-09). The wider CNC Mills & Multi-Tasking Holders line states dynamic balancing to G2.5/G6.3 as standard across the range (mongtec-tools.com/en-US/plist3-cnc-mills-multi-tasking-holders, accessed 2026-07-09). This is a published capability claim, not a signed inspection report for a specific cross-reference — see the blocking gap above.
Mongtec's BT40 dual-contact ER collet line is linked below by collet size; other BIG DAISHOWA holder types (shrink-fit, hydraulic, milling chuck) do not yet have a published Mongtec cross-reference.