D22/34/43/57/66/88 Rubber Coated Rare Earth Round Counterbore Neodymium Pot Magnets

Product Description

Product Description

This is a type of rubber encapsulated pot magnet with high-performance neodymium iron boron (NdFeB) magnetic core. A central counterbore through-hole is reserved on the magnet body, which allows flat-head screws to pass through for flush mounting. Unlike threaded versions (internal/external thread), it uses penetrating screws for direct fixation, leaving no protruding studs or bolts after installation.

 

Magnet Shape	Disc Shape
Dimensions	Shown in the chart below
Magnet Material	Neodymium N35 or Customized.
Tolerance	+/-0.1mm
Plating/Coating	Rubber Coated
Magnetism Direction	Axially Magnetized
Country Of Origin	China

 

 

Size Information

 

 

MODEL	D (mm)	d1 (mm)	d2 (mm)	H (mm)	Attraction (Kgs)	Net Weight (gs)
NRBD22	22	4.5	8.6	6	2	8
NRBD34	34	4.5	8.6	8	6	20
NRBD43	43	4.5	8.6	6	9	27
NRBD57	57	5.5	10.6	8	18	77
NRBD66	66	6.5	12	8	20	100
NRBD88	88	8.5	19	8.5	42	182

 

Core Advantages & Main Application Fields

• Advantages

1. Flush & Flat Installation
Flat-head screws fit perfectly into the counterbore cavity. The magnet sits tightly and evenly against mounting plates with no raised parts, saving space and presenting a neat appearance.

2. No Damage to Workpiece Surfaces
The soft rubber outer layer avoids scratches, paint peeling and indentations on car paint, stainless steel, aluminum alloy and polished metal panels. It leaves zero traces after removal.

3. Anti-slip & Vibration Resistance
High-friction rubber prevents sliding on vertical metal surfaces, stable enough for equipment under continuous vibration.

4. Waterproof & Anti-corrosion
Sealed rubber layer blocks moisture, splash water and light salt mist, protecting the inner NdFeB core from oxidation and rust for long service life in damp workshops or semi-outdoor environments.

5. Shock-absorbing & Low Noise
Rubber cushion eases impact when attaching to metal, preventing brittle neodymium magnets from cracking and lowering collision noise.

6. Simple & Flexible Assembly
Just run flat-head screws through the counterbore hole and fasten onto brackets, frames or equipment directly; no nuts or threaded adapters needed.

• Applications

1. Machinery Equipment: Fix sensors, positioning jigs and small tool brackets on machine tool frames

2. Automotive Industry: Concealed installation of inspection lights, camera mounts and warning signs on vehicle bodies

3. Advertising & Display: Flat-mounted light boxes, acrylic signs and retail display racks on iron walls

4. Hardware & Furniture: Hidden magnetic fixing for cabinet fittings, lamp holders and storage supports

5. Construction: Temporary positioning of measuring tools and safety markers on steel beams

Technical Data

 

Neodymium Magnets Production Process

Neodymium Magnets Performance Datasheet

Neodymium Magnets Magnetization Directions

Neodymium Magnets Surface Treatment

Surface Treatment	Process	Thickness	Color	SST	PCT
		(μm)		(Hours)	(Hours)
Nickel	Ni	10 ~ 20	Bright Silver	> 24 ~ 72	> 24 ~ 72
	Ni+Cu+Ni
Black Nickel	Ni+Cu+Ni	10 ~ 20	Bright Black	> 48 ~ 96	> 48
Cr3+Zinc	Zn	5 ~ 8	Bright Blue	> 16 ~ 48	---
	Cr3+Zn		Shining Color	> 36 ~ 72
Sn	Ni+Cu+Ni+Sn	10 ~ 25	Silver	> 36 ~ 72	> 48
Au	Ni+Cu+Ni+Au	10 ~ 15	Gold	> 12	> 48
Ag	Ni+Cu+Ni+Ag	10 ~ 15	Silver	> 12	> 48
Epoxy	Epoxy	10 ~ 20	Black/ Grey	> 96	---
	Ni+Cu+Epoxy	15 ~ 30		> 120	---
	Zn+Epoxy	15 ~ 25		> 120	---
Passivation	---	1 ~ 3	Dark Grey	Temporary Protection	---
Phosphate	---	1 ~ 3	Dark Grey	Temporary Protection	---

Remarks:
1. The SST results differ from coating. In general, Salt Spray Test result for the magnets with barrel plating (normally for small size of magnets), is better than the ones with rack plating (normally for big size of magnets).
2. Salt Spray Test (SST) condition: 5% NaCl, 35°C, continuously spray a certain time, test whether there is corrosion on plating/coating surface.
3. Pressure Cooking Test (PCT) condition: 2 atm, 95% RH (Relative Humidity), 121°C to test the plating/coating adhesion. (Zinc, Passivated/Phosphated, and Epoxy not suitable for PCT).
4. Other test methods for plating/coating: Drop Test, Cross Cut Test, Heating and Spilling Test, Constant Temperature, Humidity Test, etc. 

 

Physical Properties of Neodymium Magnets

Curie Temperature (°C)	310~380
Maximum Working Temperature (°C)	80~230
Electrical Resistivity (µ.cm)	110~170
Hardness (Hv)	560~580
Density (g/cm3)	7.4~7.8
Relative Recoil Permeability (µrec)	1.05
Saturation Field Strength (kOe/kA/m)	(30-40)/(2,400-3,200)
Temp. Coefficient of Br (T.C.α (Br)) (%/°C)	-0.12 ~ -0.10
Temp. Coefficient of Hcj (T.C.β (Hcj)) (%/°C)	-0.6

 

Packing & Shipping

 

Packing

Shipping

-When the gross weight is below 50kgs, we recommend to send it after packed in magnetism shielded cartons by express. 

-When the gross weight is between 50-100kgs, it can be sent by express or air. 

-When the gross weight is over 100kgs, we recommend to ship it by sea.

Remarks: We have good contract prices with FedEx, DHL, UPS and TNT. Of course you can choose freight collect with your international courier's account no. For air and sea shipping, we have an experienced logistics team to handle the delivery and our own forwarders that we have been cooperating with for many years. If you would like to ask your forwarder to deal with the delivery, it is also okay with us.

 

Company Information

 

Hangzhou Shengyuan Machinery Co., Ltd. is specialized in manufacturing permanent magnets and magnetic assemblies. Our main products include neodymium magnets, SmCo magnets, AlNiCo magnets, ferrite magnets, pot magnets, magnetic hooks, fishing magnets, magnetic lifters, magnetic rods & grates, magnetic pushpins, magnetic tool holders and magnetic chucks, etc. We have a professional R&D team with plenty expertise and a sales team with rich experience in overseas business. Furthermore, all our products are manufactured with advanced equipment and strict QC procedures in order to ensure high quality. Our company's core value is "Building A Good Reputation With Quality Products And Excellent Service". 

With the advanced management concepts and experienced team, we have exported our products to many countries and regions all over the world, especially to North America and Europe. Our products enjoy a good reputation among our customers. 

We welcome customers, business associations and friends from all parts of the world to contact us and seek cooperation for mutual benefits. 

 

Add.: No. 66, Leda Rd., Xiaoshan Economic & Technological Development Zone, Hangzhou City, Zhejiang Province, 311200 China.

 

 

 

Why Choose Us

 

1. Factory direct price makes our customers more competitive in the market. 

2. OEM and customization is welcome.
3. Quick response to customers.
4. Professional R&D team with extensive expertise in the area of magnets and magnetic assembies . Most of our engineers at least have 10 years experience.
5. Advanced production and inspection equipment.
6. Strict quality control system. ISO9001:2015 and RoHS
7. Experienced logistics team to deal with FOB, CIF and DDU terms. 

 

FAQ

 

-What information should I provide in my inquiry?
1. Model No. 2. Order quantity. 3. Any special requirements for the packaging and transportation? 

 

-How soon can I expect to get your reply?
Normally you can receive our reply within 1 hour during our work time 08:00 - 18:00(UTC-8).

 

-How will you ship the samples to me?

We will use international express such as FedEx, DHL, UPS and TNT. We have a good contract price with them.

 

-What is the normal delivery time?

The normal delivery time is about 15 days.

 

-How about the payment methods?

We accept T/T, PayPal, Western Union and L/C