This page helps you select a product based on the application needs of your project.
Call or email us for any special needs not shown here.
Problems solved with special screws!

• Vacuum  Updated
• Low Outgas
• Cleanroom Specification
• Chemical Resistance
• Antireflection
• Heat Resistance
• Seizing Prevention
• High Strength
• Tightening Hole Damage Prevention
• Non-Magnetic
• Electrical Insulation
• Lightweight
• Work Process Reduction
• Space-saving  Updated
• Theft Prevention  Updated
• Fixing and Positioning
• Fallout/Loss Prevention
• Vibration Resistant
• Female Thread Reinforcing  NEW
• Prevention of air/liquid leakage
• Decoration  Updated

Note: Values in charts are for reference only. They are not guaranteed values.

Vacuum   Updated

• Bolts with ventilation holes and washers with ventilation grooves support equipment vacuuming.

With ventilation hole/ventilation groove	product
Screws	Screws
Washers	Washers
Clamping Set Screws	SCSS-VF, SCSS-VR
Clamping Cap Screws	SCBS-VF
Miniature Ball Plungers	PVFS
Hexagon Posts	SHVAS, SHVBS

• Hex socket head cap screw incorporating a ventilation hole that has been treated to prevent screw galling and seizing.

• Aluminum alloy and ceramic cover caps prevent corrosion of bolts due to the process gas and plasma in the vacuum chamber.

	product
Cover Caps	SCAP-AL, SCAP-CE
Socket Head Cap Screws for Cover Caps	SNCPS

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Low Outgas

• Screws using material/surface treatment with low outgassing. Outgassing is extremely low even in vacuum environments.

Vespel^Ⓡ＊1

Special Chemical Polish

Cleanroom Specification

• Screws are washed and packed in cleanrooms.

For details, refer to Cleanroom Wash & Packaging Service. ➡ Cleanroom Wash / Cleanroom Packing Service

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Chemical Resistance

• Screws with excellent chemical resistance protect the thread and screw head from chemicals.

Hastelloy^＊2

Metal's chemical resistance

Material	Chemical Resistance	product
MAT21＊1		SNSMT
Hastelloy＊2 C-22 equiv.		SSHH-C22
Hastelloy＊2 C-276 equiv.		SNSH-C276
Monel 400 equiv.		SNSMN
Titanium		Titanium products
Inconel＊3 600 equiv.		SNSI, SHNI
Duplex stainless steel		SNHDS, SHNDS, SWAI-F
SUS316L HiMo		SNSX-88, SNSX-109
SUS310S		SNSJ, SHNJ, SWAJ-F

PTFE（Polytetrafluoroethylene）

Resin's chemical resistance

Material	Chemical Resistance	product
PTFE（PolytetrafluoroethylenＶ）		PTFE(Polytetrafluoroethylene) products
PVDF		PVDF products
PP		PP products
PEEK		PEEK products

＊1： MAT and MAT21 are registered trademarks of Proterial, Ltd.
＊2： Hastelloy is a registered trademark of Haynes International, Inc.
＊3： Inconel is a registered trademark of Special Metals Corporation.

• PTFE (Polytetrafluoroethylene) cover cap protects the screw head from chemicals.

	product
Cover Caps	SCAP-AL, SCAP-CE
Socket Head Cap Screws for Cover Caps	SNCPS

• Bolt head only has PFA Coating with excellent chemical resistance.

	product
Hex head screw (PFA Coating for head)	SNHS-HTF

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Antireflection

• Low temperature black chrome treatment/stainless steel black has a very low spectral reflectance, making it ideal for optical equipment that requires antireflection.

Hex Socket Head Cap Screw

Adjusting Washer

Special Surface Treated Screw	Spectral Reflectance	product
Stainless Steel Black	1.5% or less	SNSS-BK, SWAS-AWBK
Low temperature black chrome treatment	1.5% or less	SNSS-RY

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Heat Resistance

• These are highly heat‑resistant screws even for metal/resin.
  Select according to the operating environment.

Molybdenum

Seizing Prevention

• By reducing the friction coefficient of the threaded surface through plating and coating, the required axial force can be obtained even at low tightening torque. As a result, the generation of frictional heat in tightening can be suppressed, making it effective in preventing galling and seizing.
  ＞＞Galling and Seizing

Gold Coating

Low Temperature Black Chrome Treatment

• Galling and seizing are prevented by curing the screw surface using NBK's own processing technology. There is nothing adhering to the surface, eliminating concerns about contamination due to stripping. Furthermore, it is effective in preventing galling and seizing even at high temperatures.

	product
Surface hardening treatment	SVSL-PN, SNSL-PN

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High Strength

• Screws made of high‑strength titanium, stainless steel, resin and surface treatment.
  For applications that require strength in addition to the properties of the material and surface treatment.

Ti-6Al-4V(Grade 5 Titanium)

Tightening Hole Damage Prevention

• Hexalobular hole shape allows minimal damage from tools compared to hex hole or cross hole.
  It is ideal for repeated use at a high tightening torque.

Hexalobular Socket Head Cap Screws with Special Low Profile

Hexalobular Wrenches for Extremely Limited Access Spaces

Hexalobular Short Bits

Non-magnetic

• Non-magnetic screws with low permeability.
  For FPD manufacturing equipment, semiconductor manufacturing equipment and electronic equipment requiring non-magnetic properties.

Grade 2 Titanium

Phosphor Bronze

Electrical Insulation

• Screws with excellent electrical insulation properties.
  For electrical and electronic equipment and the like requiring electrical insulating properties.

PEEK

PTFE（Polytetrafluoroethylene）

Lightweight

• For applications that require lighter weight such as automobiles, aircraft, aerospace equipment, medical equipment, robots, etc.

Grade 2 Titanium

Aluminum

Work Process Reduction

• Screws with washers incorporated. They do not require washers to be embedded, simplifying the assembly.

Hex Socket Head Cap Screws with Captive Washer

Washer Integrated Hex Socket Head Cap Screws - High Strength Stainless Steel

Socket Button Head Cap Screws with Flange

Titanium Hex Socket Head Cap Screws with Captive Washers

Phillips Cross Recessed Pan Head Machine Screws with Captive Washers

Hexagon Head Screws with Captive Washer

• Tools that can be used even in limited access spaces.

Low Profile Screwdrivers for Extremely Limited Access Spaces

Hexalobular Wrenches for Extremely Limited Access Spaces

Space-saving  Updated

• Screws with low head. Suitable for reducing the size of equipment and devices.

Hex Socket Head Cap Screws with Special Low Profile

Comparison of low-head and standard screw head heights

Unit:mm

	Hex Socket Head Cap Screw JIS B 1176	Hex Socket Head Cap Screws with Low Profile	Hex Socket Head Cap Screws with Special Low Profile	Hexalobular Socket Head Cap Screws with Extreme Low Profile
M2	2	1.3	1.1	0.5
M2.5	2.5	1.6	1.3	-
M2.6	2.6	-	-	0.6
M3	3	2	1.3	0.8
M4	4	2.8	1.5	0.9
M5	5	3.5	1.5	1
M6	6	4	1.5	1.2
M8	8	5	1.5	-
M10	10	6	1.5	-

• Screws with small head diameter.

Hex Socket Head Cap Screws with Small Head

Small Head Screw	product
Cross Recessed Flat Head Machine Screws with Small Head	SNF-SD-TZB
Hex Socket Head Cap Screws with Small Head	SNS-SD, SNS-SD-EL
Hex Socket Head Cap Screws with Low and Small Head	SLH-SD, SLH-SD-EL
Hex Socket Head Cap Screws with Extreme Low and Small Head	SSH-SD, SSH-SD-EL

Unit:mm

	Hex Socket Head Cap Screw JIS B 1176	Hex Socket Head Cap Screws with Small Head
M2	3.8	3
M2.5	4.5	3.8
M3	5.5	4.5
M4	7	5.5
M5	8.5	7
M6	10	8.5
M8	13	11
M10	16	13.5

• Small-diameter screws of M2.6 or less.

Pan Head Machine Screws for Precision Instruments

Resin Screws
(PEEK / small countersunk screws for precision equipment)

Set Screws for Precision Instruments

Theft Prevention  Updated

• This prevents mounting and removing with commercial screwdrivers or wrenches. Dedicated tools are required for these screws, providing effective theft prevention.

Button Head Cap Screws with Five-Lobe Holes (with Pin)

Flat Head Bolts with Hexalobular Socket (with Pin)
Rosette Washer Set

• Theft prevention nuts and one-sided pan-head screws can be mounted using commercially available tools. Crime can be prevented without compromising the workability of mounting.

Theft Prevention Nuts

One Side Pan Head Machine Screws

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Fixing and Positioning

• Clamping screws with eccentric head are suitable for fixing and positioning. When the screw is tightened, the workpiece is strongly clamped by the head, which is decentered from the shaft center of the screw. The wedge effect creates a large clamping force with low tightening torque.

• Suitable for mounting linear guideway rails. As the decentered head presses the rail against the installation reference surface, precision can be easily achieved when mounting. Also, mounting accuracy is maintained by suppressing warping and misalignment caused by long-term use.

Fallout/Loss Prevention

• Screws and washers suitable for screw fallout prevention. For CE Marking compatibility.

Hex Socket Head Cap Captive Screws

Captive Washers

• Captive processing service is available to provide screws with relief cut and fallout prevention functions.

• Since a flat washer is incorporated into the screw, the washer will not be lost.

Hex Socket Head Cap Screws
with Captive Washer and Ventilation Hole

• M1.4 to M2.6 captive screws for precision instruments.

Pan Head Machine Screws for Precision Instruments
(Miniature Screws)

Vibration Resistant

• Screw components highly effective for prevention of screw loosening due to vibration or seating surface falling.

Ribbed Lock Washers

Hex Lock Nuts

High Intensity Flat Washers

In addition to the above products, an anti-loosening service for screws is available. ➡ Vibration Resistant Treatment Service

• Prevents screw loosening with eccentric lock washers in combination with commercially available hex nuts.

Eccentric Lock Washers

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Female Thread Reinforcing  NEW

• A keyed female-thread reinforcing insert. It is ideal for reinforcing female threads in light metals such as aluminum, castings, or resin, as well as for repairing damaged female threading.
• With high strength compared to coil-type inserts, it is usable for firm fastening or in areas where bolts are frequently fastened and removed.

Mounting is even easier than with coil-type inserts.
Use the dedicated tool SKK.

Prevention of air/liquid leakage

• Plugs and seal washers prevent leakage of gas or liquid.

Hex Socket Pipe Plugs

Seal Washers

• A service is available to improve seal performance by applying fluororesin synthetic composite to the threads.

Decoration  Updated

• The mounting surface has been beautifully decorated with a distinctive color and shape.

Stainless Steel Black

Hexalobular Socket Head Cap Screws
with Extreme Low Profile

Gold Coating

Two Hole Pan Head Machine Screws

Button Head Cap Screws with Five-Lobe Holes
(with Pin)

Consult us if you have any questions.

Note: 60% of special screw purchase orders to NBK are for special screws not listed in this catalog. Many unique customization requests may be possible.