Short Thread 6mm Alloy Steel Shoulder Bolts, 8 Pack

Special Shoulder Bolts for Hubmotor Mounting!

NOTE: 8mm length will be restocked late October 2024, there was an issue with the first batch which will be resolved. 

These bolts are perfect when paired with the RDY-5536 Hubmotor, but useful for a range of other situations! These bolts have a 6mm precise shoulder diameter and 5mm long M5 threads. Features a short thread length to avoid damaging coils of the 5536 motor like a standard bolt would.

The 5536 motors have a 6mm diameter pocket for each screw location meaning that all shear forces are directed through the 6mm diameter shoulder of these bolts, rather than the 4.1mm core diameter of the M5 threaded section. This is 2.1 times the cross-sectional area!

Specialty metric bolts can be incredibly expensive in the US (8 pcs from McMaster Carr would be over $40 with shipping!) and often made from weaker materials. So we had these custom-made in bulk to bring the price down to reasonable levels. 

The minimum ultimate tensile strength of the Grade 12.9 Metric Bolts is about 1242 Mpa or 180,000 PSI, making them the highest grade of bolts produced, about 2.5 times stronger than stainless steel.

These shoulder bolts have a precision ground bearing surface and are perfect for use with 6mm inner diameter bushings, bearings, and more.

• Shoulder Diameter: 6mm (actual 5.928-5.990mm)
• Shoulder Length: 8mm or 12mm
• Head Diameter: 10mm +/- 0.2mm
• Head Height 4.5mm+/- 0.2mm
• Thread: M5x0.8, 5.2mm length max
• Drive: 3mm Hex (Same as M5 flat-head and button-head screws)
  
• Weight: 45g (1.78 oz) for 8x 12mm bolts
• Hubmotor not included!

12mm Length drawing: