Kit contains parts to produce a rotational joint with either ball bearings or plain bearing.

5mm plain bearing kit (M4)

Contains

4 of M4 flanged brass insert
4 of M4 Shoulder bolt where d= 5mm L= 12mm

5mm ball bearing kit (M4)

Contains

2 of flanged radial ball bearings where i.d.= 5mm
2 of M4 flanged brass insert
2 of 5mm diameter spring washer
1 of M4 Shoulder bolt where d= 5mm L= 18mm
1 of M4 Shoulder bolt where d= 5mm L= 12mm

8mm ball bearing kit (M6)

Contains

2 of flanged radial ball bearings where i.d.= 8mm
1 of M6 flanged brass insert
1 of M6 Shoulder bolt where d= 8mm L= 12mm
2 of 8mm diameter spring washer

Bearing kit parts

name	supplier		Cost category
5mm dia spring washer
5mm dia x 18 mm shoulder bolt (M4)	RS	399-173	B
5mm radial ball bearing	RS	540-277
5mm radial bb (11mm od)	RS	540-277	C
8mm dia spring washer
8mm dia x 12 mm shoulder bolt (M6)	RS	399-173	B
8mm radial ball bearing (12mm O.D)	RS	540-299	C
M4 Threaded insert			A
M6 Threaded insert	RS		A

Shoulder bolts

	shoulder diameter d	thread	Shoulder length L	Head diameter D	head length H	thread length E
5mm kit	5mm	M4	18mm	8mm	4mm	5mm
8mm kit	8mm	M6	12mm

1: Shoulder bolt dimensions (https://www.accu.co.uk/en/socket-shoulder-screws/436257-SSH-M4-5-18-A2)

Flanged Radial Ball Bearing

all unmarked dimensions in millimetres

	d	D	W	FD	FW	Max load
5mm kit	5	11	5	12.5	0.9	276N
8mm kit	8	12	3.5	13.2	0.9	246N

1: The flanged bearing is on the right. Bearing dimensions

M6 Brass insert

Assembly dimensions

For the 8mm kit, it may be adviseable to make the depth of the bearing hole slightly shallower to allow a spring washer or a wire ring (cut down a paperclip) around the bearing. This prevents the outer 'race' from rubbing against the brass insert and head of the M6 nut.

Cost category

A	$<$ 1
B	1-3
C	3-10
D	10-30
E	33-100
F	100-300
G	$>$ 300