Question 1

What are spiral dowel pins and how do they differ from slotted pins?

Accepted Answer

Spiral dowel pins (also called coiled spring pins) are hollow pins manufactured by tightly coiling strip steel into a tight spiral, creating a hollow tube. Unlike slotted pins which have a single split, spiral pins distribute load evenly around the circumference. When pressed into a drilled hole, the spiral compresses, then springs back to grip the hole walls uniformly. This provides: superior fatigue resistance, excellent shock absorption, higher shear strength, and better reliability in high-vibration applications. Industries prefer them for heavy machinery and critical assemblies.

Question 2

When should I use spiral dowel pins vs. slotted spring pins?

Accepted Answer

Use SPIRAL PINS when: load is high and sustained, vibration is severe, fatigue life is critical, shear strength matters, or for repeated assembly/disassembly (better reusability). Use SLOTTED PINS when: budget is limited (slotted cheaper), load is moderate, installation force must be minimal, or simplicity is preferred. Spiral pins cost 30-50% more but deliver 2-3x longer fatigue life. For automotive engines, gearboxes, pumps, or heavy machinery, spiral pins are the better choice despite higher cost.

Question 3

What hole sizes should I drill for spiral dowel pins?

Accepted Answer

Spiral pins fit standard drilled holes - typically 0.05-0.2mm smaller than the pin nominal diameter. For example, a 6mm spiral pin fits a 5.95-5.90mm hole. DIN 7343 standards specify exact hole sizes for each pin. Standard drilled holes work (no expensive reaming), but precision drilling (±0.05mm) gives better results. Under-sized holes make installation harder and can split the pin; over-sized holes reduce grip force. We provide installation charts with every order. Holes drilled on CNC mills are ideal.

Question 4

Are spiral dowel pins reusable, and how many times?

Accepted Answer

Yes - excellent reusability compared to slotted pins. They can be removed and reinstalled 10-20+ times without losing grip if handled carefully. Use a puller for removal (never hammer out). As long as the coil isn't cracked or permanently dented, spring force remains. This makes them ideal for: adjustable machinery, tooling fixtures with frequent changes, or equipment undergoing regular maintenance. Slotted pins lose tension faster with reuse, but spiral pins maintain consistent grip through multiple cycles.

Question 5

What materials are spiral dowel pins available in?

Accepted Answer

Standard: high-carbon spring steel (economical, suited most applications). Options: stainless steel (corrosion resistance), alloy steel (extreme strength for heavy loads), beryllium copper (electrical grounding). Material choice depends on: load requirements, environment (dry vs wet), temperature range, reusability needs. Spring steel suits 95% of applications. Stainless costs 40-60% more - essential for marine, food processing, pharmaceutical equipment. We customize materials for specific requirements.

Question 6

What installation equipment do I need?

Accepted Answer

Use a mechanical press (5-50 ton capacity depending on pin size) or hydraulic press for controlled installation. Pneumatic presses work for high-volume assembly. Never use a hammer - impact loading can crack the spiral. Proper installation is smooth, controlled pressure without hard binding. Under-pressing leaves the pin loose; over-pressing can damage the spiral. For small operations (1-100 pins), manual press or press tool costs $100-500. Our technical team can recommend equipment for your volume.

Question 7

What are your specifications for lead time, sizing, and pricing?

Accepted Answer

We stock standard DIN 7343 spiral pins (1-20mm diameter, various lengths). Lead times: 5-7 days for standard spring steel, 10-14 days for stainless. Minimum order: 1000 pieces per size for standard, 100 for stainless. Pricing: $0.15-0.35 per piece (spring steel), $0.25-0.60 (stainless) depending on size. Bulk discounts: 1000+ = 10% off, 5000+ = 20% off, 10000+ = 30% off. Send us: diameter, length, material, quantity for instant quote with delivery timeline.

Parameter	Details
Standard	DIN 7343 / ISO 8351
Product Type	Precision Fastening Pin
Range	Diameter (2–20) mm x Length (10-200) mm
Material Options	Spring Steel · Stainless Steel · Alloy Steel
Coatings	Phosphate · Zinc Plated · Plain
Quality Assurance	ISO 9001:2015 · Dimensional Reports · COC Available
Packaging	Polybag · Box · Bulk — as per requirement

Spiral Dowel Pins

Spiral Dowel Pins

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