NAREX MTE - first page
...Expert in Boring


Search site NAREX MTE through Google.

| Home | Czech |












Czech Republic





Office work





Zhb - Safety tapping head NAREX
205bh - Fine boring head NAREX
205bh - Fine boring head NAREX

Favourable actions here ...



Product description Zhb - Safety thread-cutting head


Zhb - legend

Zhb - legend

1 - shank

2 - bush

3 - sleeve

16 - locking bolt

22 - tap

28 - screw


30 - nut

Usage advantages

  • safety clutch protects the tap from the damage

  • possibility of thread-cutting into the blind holes

  • cutting of right- and left-hand threads

  • Range of thread-cutting
    Zhb 21 M2÷M8
    Zhb 31 M5÷M16
    Zhb 41 M16÷M30
    Zhb 51 M30÷M52


Zhb - thread-cutting heads are applicable on drilling machines and lathes.

Head principle:
The tap (22) is clamped into the bush (2) by collet (29) and nut (30). Two opposite locking screws (28) or jaws of the bush NVH engage the tap square and protect the tap against angular displacement in the collet. Bush (tap) provides axial movement – axial compensation of difference lead of screw thread and machine feed.

For leaving tap from carved thread is necessary to change direction of rotations on the machine.

Safety clutch protects the tap against damage and is adjusted on necessary torsion moment which allows to carve thread fluently. Safety clutch is adjusted by sleeve (3) and its arrestment is arranged by locking bolt (16). Transmitted torsion moment is adjusted either during thread-cutting or directly on given value measured by torque wrench. The scale on the circumference of the nut serves for information only.

The shank (1) is part of the body. Safety thread-cutting heads are delivered with shanks MORSE (Mk2, Mk3, Mk4 a Mk5) and with shank WELDON 20 a 25 up to the type of head.

The axial compensation compensates the difference between thread pitch and machine spindle feed for cutting calibrical thread on conventional machines.

Zhb heads are also delivered in design Zhb A for quick change adaptors type NVH (PLASTIC collets) or RVK for wide range collets type RUBBER FLEX JACOBS.




Zhb - Safety tapping head NAREX


Zhb - Safety tapping head NAREX


Zhb - Safety tapping head NAREX

  Zhb models   Zhb 31 WELDON   Zhb 41 Mk4
  Zhb - Safety tapping head NAREX        
  Zhb 31A        





General Dealers Czech Republic


  • M & V, spol. s r.o. (Vsetín)

4. května 288, CZ-755 01 Vsetín

tel:  420-571 484 817

fax: 420-571 413 126

  • TTI, s.r.o. (Brno)

Údolní 40, CZ-602 00 Brno

tel: 420-543 216 868

fax: 420-543 249 300

  • Stim Tools, a.s. (Brno)

Bratislavská 49, CZ-602 00 Brno

tel: 420-545 212 092

fax: 420-545 211 163

  • HOFMEISTER s.r.o. (Plzeň)

Mezi ploty 12, CZ-326 00 Plzeň

tel: 420-377 242 058

fax: 420-377 243 161

  • BOS HK a.s. (Teplice)

Přítkovská 152, CZ-417 12 Teplice-Proboštov

tel:  420-417 560 721

fax: 420-417 560 385

  • HANÁK NÁŘADÍ, s.r.o.

Osvobození 129, CZ-763 16 Fryšták

tel: 420-577 110 711

fax: 420-577 110 733


  • NTV - Naradie, s.r.o.

Farská 86/2

SK-019 01 Ilava

phone: 421-424 466 316

fax: 421-424 464 279

  • M&V, Slovakia spol. s r.o.

Vsetínská cesta 1487-9

SK-020 01 Púchov

phone: 421-424 634 548

fax: 421-424 634 549


Sumracná 27

SK- 821 02 Bratislava

phone: 421-243 338 080

fax: 421-243 335 501


Horská 1311/2

SK-958 06 Partizanské

phone: 421-387 491 373

fax: 421-387 491 373


Frequently asked questions (FAQ)

  • What use is scale on the sleeve by which is torsion moment adjusted?

Scale does not say anything about torsion moment. It identifies place of sleeve on the body of the head.

  • Is it possible to use heads RTH and Zhb to forming screwing taps clamping?

It is possible, but ATTENTION! Especially by heads RTH can not be diameter of forming screwing tap bigger than is half of head work range. For example: we do not clamp forming screwing tap to head RTH 22 but to RTH 32. It is because of the big beats during reverse revolutions what makes for premature attrition or head destruction.

  • What revolutions are suitable for thread cutting heads?

Revolutions are chosen according to recommended cutting speed which is given by producer or supplier of screwing taps. Each thread cutting head has only narrow maximum revolutions.

  • Is it possible to cut threads in impassable slots to the bottom with these heads?

YES it is possible, both types RTH and Zhb have skidding clutch, so if it is correct adjusted, the screwing tap can not be break off. But WE DO NOT RECOMMEND this way of using, it is too fierce and not safe everytime. Especially by bigger diameters of screwing taps.

  • Is for screw tap clamping to the head better collet RUBBER FLEX or plastic collet?

Collet RUBBER FLEX simultaneously centralizes and clamp screw tap. Plastic collet only centralizes screw tap and with worse accuracy. Anyway collet RUBBER FLEX is more favourable though it is more expensive.

  • What is the best way of adjusting the skidding clutch of tapping head?

Procedure is described in instructions for use. The best way is experimentally. Stepwise is torsion moment increasing to the time when screwing tap is fluently cutting thread and can be easily screw out from the thread.

  • Slip on the skidding clutch is fluent or fitful?

In all cases except head Zhr 21 is slip fitful.

  • Are plastic collets used on now produced thread cutting heads?

They are used only on exchangeable chucks NVH 2 and NVH 3, which are designed for thread cutting heads type "A" for fast tools exchange.

  • What collets are used on head Zhb 51?

On this thread cutting head are not used any collets. Screw tap is centralized and clamped by adapter bush and is ensured against turn 360 degrees by two opposite setscrew like in all other heads. In basic head accessories is set of 8 pieces of adapters. The biggest diameter which can be clamped is 40mm.

  • Can be these thread cutting heads used on lathe?

Heads Zhb - YES, heads reversible RTH - NOT.


Product repairing


NAREX MTE standardly provides repairs of produced and delivered products. There are guarantee repairs or normal non guarantee repairs. During repair is product dismounted, there are found defective parts and up to it is determined range and price of repair. After customer´s repair price confirmation are defected parts exchanged, product is again mounted and tested.

Repair speeding

For repair speeding and lower price is suitable to enclose to repair order letter with information about problems (during which conditions defects occurs or indicate required range of repair).

Repair ordering

For repair ordering you should send product for repair, order of repair and specifications of defects on our address:


sales department

Moskevska 659/63

CZ-101 00 Prague 10
Czech Republic

Information about repair

About repair you will be informed by e-mail or by phone, with any questions you can contact export department on phone: +420 246 002 249, e-mail:, fax: + 420 246 002 335


NAREX MTE s.r.o.

Moskevska 659/63

CZ-101 00 Prague 10
Czech Republic




+420-246 002 321

+420-246 002 249

+420-246 002 335

+420-246 002 343



  Technical support is at the disposal of you on phone +420 246 002 249 or you can contact us by e-mail: or by fax: +420 246 002 335.


Basic technical information you can find also on reference service.


NAREX MTE s.r.o.

Moskevska 659/63

CZ-101 00 Prague 10
Czech Republic




+420-246 002 321

+420-246 002 249

+420-246 002 335

+420-246 002 343


  Catalogue of Tapping heads  -  Download (PDF)
  • Catalogue of Tapping heads (PDF)




  RTH - Catalogue (PDF) NAREX
  • Reversible thread-cutting heads RTH (PDF)





  Zhb - Catalogue (PDF) NAREX
  • Safety thread cutting heads Zhb (PDF)




Display of products lines (quick reference)
  • Display of products lines (quick reference)

| Contact us | mexin - Spain | Sitemap | © 2016 NAREX MTE® s.r.o. All rights reserved .