Compared with a surface-mounted pogo pin, the through-hole structure provides mechanical engagement with the PCB as well as an electrical connection. This makes it useful for charging interfaces, battery contacts, industrial equipment, docking systems, test fixtures, and other assemblies where the connector experiences repeated compression.
The solder joint alone, however, does not determine reliability. PCB hole dimensions, pogo pin alignment, housing material, soldering temperature, flux control, mechanical support, and post-solder inspection all affect the finished connector.
How does a through-hole pogo pin connect to the PCB?
A through-hole pogo pin normally has a termination section extending below the barrel.
During assembly, this tail is inserted into the PCB hole. Solder then forms the electrical and mechanical connection between the termination and PCB.
Depending on the product and production volume, soldering may be performed using:
manual soldering
wave soldering
selective soldering
another controlled through-hole soldering process
Reflow should only be used when the pogo pin assembly, plastic housing, plating, and other materials are specifically designed for the selected reflow profile.
Not every through-hole pogo pin connector is automatically reflow-compatible.
1. PCB hole size needs to match the pogo pin termination
One of the first design parameters is the relationship between the pogo pin tail and PCB hole.
If the hole is too small, insertion can require excessive force.
This can damage the plating, deform the termination, stress the PCB hole, or change the alignment of the pogo pin.
If the hole is too large, positioning becomes less accurate and soldering consistency may be reduced.
For a multi-pin connector, excessive clearance can allow individual contacts to tilt before soldering.
PCB hole dimensions should therefore be specified according to:
finished pogo pin termination diameter
termination tolerance
PCB finished-hole tolerance
plating inside the PCB hole
soldering process
required positioning accuracy
The drilled-hole size and finished plated-hole size are not necessarily the same, so the connector drawing and PCB drawing should use clearly defined dimensions.
2. Through-hole mounting does not automatically guarantee accurate positioning
A pogo pin passing through a PCB hole has better mechanical location than a contact simply resting on a flat pad, but some positional variation still remains.
Final pin position depends on several tolerances:
pogo pin tail diameter
PCB hole diameter
PCB hole position
connector housing dimensions
pogo pin assembled height
fixture accuracy
soldering movement
For a single contact, small deviations may have little effect.
For a high-density multi-pin connector, the accumulated deviation can change pin pitch, coplanarity, or mating alignment.
When contact position is critical, the plastic housing or another mechanical locating feature should establish the connector position instead of relying only on loose PCB holes.
3. The pogo pin should remain perpendicular to the mating surface
Pogo pins primarily work by axial compression.
If a through-hole pogo pin is soldered at an angle, the mating surface may apply side force to the plunger during operation.
This can increase friction between the plunger and barrel and may accelerate wear.
A tilted pin can also create uneven compression in a multi-pin connector.
Assembly fixtures are therefore useful for maintaining:
vertical orientation
correct pin pitch
consistent exposed height
housing alignment
The connector should be held in the intended position while the solder joint is formed and cooled.
4. PCB thickness affects the mechanical design
PCB thickness should be considered together with the pogo pin termination length.
The tail needs enough usable length to create the intended solder connection, but excessive projection below the PCB may interfere with other components, enclosures, or assembly processes.
For compact products, the space beneath the PCB can be just as important as the pogo pin height above it.
The design should check:
PCB thickness
tail length
solder fillet area
bottom-side component clearance
enclosure clearance
routing space
A longer termination is not automatically stronger if the surrounding structure does not require it.
5. Do not let the solder joint carry unnecessary mating force
When the mating surface compresses a pogo pin, an axial reaction force is transferred into the connector.
In a multi-pin assembly, the spring forces of all pogo pins add together.
If the connector is supported only by solder joints, repeated compression can place unnecessary mechanical stress on the PCB connection.
Housing shoulders, locating structures, mounting features, or other mechanical support may be used to transfer part of the load into the connector body or PCB structure.
This is especially important when:
spring force is high
many pogo pins are used together
the connector is pressed repeatedly
the product is exposed to shock or vibration
Solder should provide a reliable electrical connection, but the mechanical design should also control where repeated mating forces are transferred.
6. Plastic housing temperature limits are material-specific
A common mistake is to state that all pogo pin connector housings can tolerate approximately 240–280°C or a fixed 260°C soldering temperature.
There is no universal temperature specification for every pogo pin housing.
Heat resistance depends on the actual resin, housing geometry, exposure time, soldering method, and connector construction.
Materials used in connector housings may include different engineering plastics, each with its own thermal behavior.
A housing that tolerates a short peak temperature may not tolerate prolonged exposure at the same temperature.
The correct soldering profile should therefore come from the approved material and connector specification.
7. Peak temperature is only one part of the soldering profile
Soldering quality cannot be controlled using maximum temperature alone.
Thermal exposure also depends on:
preheating
heating rate
peak temperature
time at elevated temperature
solder contact time
cooling rate
number of heating cycles
A connector exposed to a high temperature for a very short controlled period can behave differently from one held near that temperature for much longer.
For this reason, specifying only "maximum 260°C" does not adequately define a soldering process.
The full process should be validated on the actual connector and PCB assembly.
8. Heat can travel from the termination toward the pogo pin body
During soldering, heat applied at the PCB termination can conduct upward through the metal structure.
The amount of heat reaching the barrel, housing, or internal parts depends on the pogo pin geometry and soldering process.
Excessive thermal exposure can potentially affect surrounding plastics or other temperature-sensitive materials.
Manual soldering therefore also requires process control.
Holding a soldering iron on the termination for an unnecessarily long time can create greater thermal exposure even when the iron temperature itself is within a commonly used range.
The objective should be to form the solder joint efficiently without applying more heat than necessary.
9. Flux should be kept away from the moving plunger area
Flux is required for many soldering processes, but pogo pins have a moving mechanical interface close to the soldered termination.
This creates a specific contamination risk.
If excessive flux or cleaning residue reaches the barrel opening, plunger, or internal moving area, it can interfere with smooth movement.
After heating, some residues may become sticky or hard.
Possible symptoms include:
sluggish plunger return
increased friction
inconsistent working stroke
pogo pin sticking
unstable electrical contact
Process design should therefore minimize the possibility of flux migrating toward the moving end of the pogo pin.
10. Capillary action can draw liquids into small gaps
Pogo pins contain very small clearances.
During soldering or cleaning, liquids can move into narrow spaces by capillary action.
This is why simply keeping visible flux away from the plunger may not always be sufficient.
Connector orientation, flux quantity, application method, and cleaning process should all be considered.
If the connector manufacturer defines a maximum soldering depth, protected area, or cleaning restriction, those requirements should be followed.
11. More flux does not necessarily create a better solder joint
Excessive flux can create additional contamination without improving the connection.
The correct amount depends on the soldering process, solder alloy, PCB finish, component termination, and flux system.
Flux should primarily act at the soldering interface.
It should not flood the connector body.
For manual production, operator consistency becomes particularly important because excessive manual flux application can vary significantly from unit to unit.
A controlled dispensing or automated process can improve repeatability for volume production.
12. Be cautious when cleaning a soldered pogo pin assembly
Post-solder cleaning may be necessary depending on the flux chemistry and product requirement.
However, the cleaning process itself should not introduce another reliability problem.
Cleaning liquid entering the pogo pin barrel can carry contaminants into the internal moving structure.
Some cleaning processes may also affect plastics, adhesives, surface treatments, or lubricated internal components.
The cleaning method should therefore be compatible with the complete connector assembly.
When possible, preventing contamination during soldering is preferable to relying on aggressive cleaning afterward.
13. Solder should wet the termination, not the moving barrel area
The soldering region should be clearly separated from the mechanical working region of the pogo pin.
Solder flowing too far along the termination can reduce the intended mechanical clearance or interfere with surrounding structures.
In severe cases, solder contamination near a moving portion could restrict the plunger mechanism.
Tail length, PCB position, solder quantity, and connector orientation should therefore be designed so that solder remains within the intended termination area.
14. Tail plating needs to support the soldering process
The pogo pin head and barrel may use a plating system optimized for electrical contact and wear.
The termination region also needs a surface condition suitable for the intended PCB attachment process.
The same finish does not necessarily need to perform the same function across the entire component.
The contact head requires stable repeated electrical contact.
The PCB termination needs reliable solderability or another defined connection method.
For custom pogo pins, plating areas and thicknesses can therefore be specified differently according to function.
15. The current path should be designed through the complete connector
A through-hole tail can provide a direct PCB connection, but the current does not depend only on the solder joint.
The complete path may include:
mating pad → pogo pin plunger → internal contact interface → barrel or conductive structure → termination → solder joint → PCB copper.
For higher-current applications, engineers should evaluate the complete path.
Important factors include:
pogo pin conductive cross-section
internal contact resistance
termination size
solder-joint quality
PCB copper area
via structure where applicable
ambient temperature
number of parallel power contacts
Increasing the amount of solder cannot compensate for an undersized pogo pin or inadequate PCB copper design.
16. High-current pogo pins may need additional PCB consideration
When a pogo pin carries higher current, the PCB connection becomes part of the thermal design.
A small plated through-hole connected to a narrow PCB trace may become the limiting part of the system even when the pogo pin itself is capable of carrying more current.
The PCB designer should therefore coordinate the connector current requirement with copper thickness, trace width, pad area, thermal spreading, and the number of power contacts.
Temperature-rise testing should be performed at the intended working compression and electrical load.
17. Plastic housing design should account for soldering and mating load
The plastic housing serves several functions.
It can control:
pin pitch
contact alignment
assembled height
electrical insulation
connector orientation
mating position
Its design should therefore consider both soldering and operation.
If the housing is too close to the soldering zone, it may receive unnecessary thermal exposure.
If the housing does not adequately support the contacts, pogo pins may move during soldering or under repeated compression.
For multi-pin connectors, housing dimensional consistency also affects coplanarity and final working stroke.
18. Do not compress the pogo pins during soldering unless the process requires it
The connector should generally be assembled in the condition specified by its manufacturing process.
Unnecessary compression during heating can apply load to the spring and surrounding assembly while the solder joint is being formed.
Fixtures should hold the body or dedicated locating features rather than using the moving plunger as an assembly clamp point.
The plunger head should also be protected from impact, solder splashes, and fixture damage.
19. Manual soldering needs operator controls
Manual soldering is useful for prototypes, repairs, and smaller production quantities, but process variation can be large.
Common variations include:
iron temperature
contact time
solder quantity
flux quantity
operator angle
fixture positioning
A defined work instruction should specify the approved process for the actual connector rather than relying entirely on operator experience.
After soldering, the pogo pin should still move freely through its intended stroke.
20. Wave and selective soldering need connector-specific validation
Through-hole pogo pins can be compatible with automated soldering, but the complete connector must be evaluated.
Process development should consider whether solder or flux can reach the moving portion of the pogo pin and whether the housing can withstand the thermal exposure.
Connector orientation relative to the solder wave or selective nozzle can also affect contamination risk.
A successful solder joint alone is not sufficient. The spring-loaded mechanism must still operate correctly after soldering.
21. Check plunger movement after soldering
One of the simplest post-solder mechanical checks is to confirm that the plunger still compresses and returns normally.
A pogo pin that feels rough, sticks, or returns slowly may have experienced:
flux contamination
solder contamination
housing deformation
side loading
barrel damage
assembly misalignment
These issues may not be visible by inspecting the solder joint.
For volume production, the inspection method should be defined according to the connector's risk and application.
22. Inspect more than solder-joint appearance
Visual inspection is useful, but a good-looking solder joint does not confirm complete connector performance.
Depending on the application, post-solder verification can include:
connector position
pin verticality
assembled height
solder wetting
solder bridging
plunger movement
spring return
continuity
contact resistance
High-current or reliability-sensitive products may require additional electrical and mechanical testing.
23. Multi-pin connectors require coplanarity control
In a connector containing several pogo pins, the individual contact heights should remain within the intended range after assembly and soldering.
If one side of the connector sits higher than the other, the pins will not have equal working compression when the mating surface is installed.
Some contacts may be over-compressed while others have insufficient force.
This can create intermittent contact even though all pogo pins pass individual inspection.
PCB flatness, connector housing dimensions, soldering fixtures, and pin-height tolerance should therefore be considered together.
24. Common cause of a stuck pogo pin after soldering
A stuck plunger is sometimes immediately blamed on an internal pogo pin defect.
The actual cause may be external to the spring.
Potential causes include:
flux entering the barrel
solder contamination
housing deformation
barrel-opening damage
connector tilt
side loading
foreign particles
The failure should therefore be inspected before deciding that the internal spring is defective.
Replacing the spring without correcting the soldering or assembly process can cause the same problem to return.
25. Common cause of unstable electrical performance after soldering
If contact resistance becomes unstable after PCB assembly, the investigation should cover the entire current path.
Possible issues include:
incomplete solder wetting
poor PCB through-hole connection
contamination
pogo pin misalignment
insufficient working compression
damaged plating
internal contamination
cracked or stressed solder joints
The measurement should also be performed at the actual working compression.
Testing an unloaded pogo pin does not represent its final operating condition.
26. Common cause of plastic housing deformation
Plastic deformation should not automatically be attributed to a single temperature number.
Possible causes include excessive peak temperature, prolonged exposure, unsuitable resin, uneven heating, repeated soldering cycles, or mechanical loading while the material is hot.
The approved soldering profile should therefore be matched to the actual connector material.
If the manufacturing process must use higher thermal exposure, a different housing resin or connector construction may be required.
27. Through-hole, SMT, and solder-tail structures solve different assembly problems
A through-hole pogo pin should be selected because it matches the PCB and mechanical architecture, not simply because it is perceived as stronger.
Through-hole mounting can provide good PCB positioning and mechanical engagement, but it consumes board-hole space and may restrict routing or components on the opposite side.
SMT pogo pins can be useful where automated surface-mount assembly and PCB routing are priorities.
Solder-tail or solder-cup structures are useful for direct wire connections.
The termination style should follow the product architecture and manufacturing process.
28. Custom through-hole pogo pin design
A standard through-hole pogo pin may not fit every PCB or enclosure.
For a custom project, useful design information includes:
PCB thickness
finished PCB hole size
pogo pin installed height
mating distance
required working stroke
spring force
current and voltage
pin quantity and pitch
available top- and bottom-side space
soldering method
expected mating cycles
operating environment
Based on customer drawings, samples, PCB layouts, or 2D/3D models, the termination diameter, tail length, barrel dimensions, plunger geometry, working stroke, spring force, plating system, plastic housing, and multi-pin arrangement can be adjusted for the actual assembly.
This allows the PCB, pogo pin, soldering process, and mating structure to be designed as one connector system rather than treating the pogo pin as an isolated component.
FAQ
1. What is a through-hole pogo pin?
A through-hole pogo pin has a termination that passes through a PCB hole and is soldered to the board. It is often used where PCB positioning and mechanical support are required in addition to the electrical connection.
2. Can every through-hole pogo pin connector withstand 260°C soldering?
No. The permitted soldering temperature and exposure time depend on the pogo pin structure, housing resin, plating, and specified manufacturing process. The approved thermal profile for the actual connector should be used instead of applying one universal temperature limit.
3. Why can a pogo pin become stuck after soldering?
Flux or other contamination entering the barrel is one possible cause. Housing deformation, side loading, solder contamination, barrel damage, or incorrect alignment can also restrict plunger movement. The complete assembly should be inspected before identifying the internal spring as the cause.
4. What should be checked after soldering a pogo pin connector?
Inspection should verify the solder connection as well as connector position, pin alignment, plunger movement, spring return, and electrical continuity. Depending on the application, contact resistance, temperature rise, working compression, and other reliability tests may also be required.
