Screw Down Mounted Balls— Optical Table Mounted Balls— Threaded Mounted Balls— Kinematic Hex Balls

Thread mounted balls are an excellent method for mounting high quality spheres for kinematic couplings and optical table bread boarding. The contact spheres are made from a very high quality Martinsetic stainless steel balls that are hardened to 58 HRC minimum. This ultra fine grained material has a very high tensile strength of 285,000 psi. In order to keep a low profile, these contact balls are truncated to form a hemisphere. This hemisphere is epoxy glued over a pin into a shallow counterbore in the top of a hex head bolt. The thread of this bolt is a 1/4 inch (slightly over 6mm) diameter with 20 threads per inch.

This mounting method provides extremely high shear strength to the assembly. The shear strength of the balls is as strong as the bolt itself. The one quarter inch twenty mounting thread is three hundred thousandths of an inch (0.300”) [7.62 mm] long ( ¼-20 X 0.300” ) . The head of the hexigonical shape body of these devices is one quarter of an inch (0.250”) [6.15 mm] thick. The bodies are black oxide coated to provide corrosion resistance.

Part Number 50TM-B has a one half inch (0.50”) [12.7mm] diameter hemisphere, that has an overall height of one half of an inch (0.50”) [12.7mm]. This part has a one half inch (0.500”) [25.4mm] hexigonical head.

Part number 62TM-B has a five eights of an inch (0.625”) [15.9mm] diameter hemisphere, that has an overall height of five hundred and sixty two thousandths of an inch, (0.562”) [14.3mm]. This part has a five eights of an inch (0.625”) [15.9 mm] hexigonical head.

Part number 75TM-B has a three quarters of an inch (0.750”) [19.05mm] diameter hemisphere, that has an overall height of five eights of an inch (0.625”) [15.9mm]. This part has a three quarter of an inch (0.750”) [19.05 mm] hexigonical head.

Part number 100TM-B has a one inch (1.00”) [25.4 mm] diameter hemisphere, that has an overall height of three quarters of an inch (0.750”) [19.05 mm]. This part has a one inch (1.00”) [25.4 mm] hexigonical head.

Dimensions & Pricing

Part Number	Ball Diameter Overall “A”	Height “B”	Thread “C”	Thread Length “D”	Head Thickness “E”	Hex Head	Price
100TM-B	1.00” ± 0.0001 25.4 mm	0.750” +0 -0.020” 19 mm	1/4” x 20	0.300” ± 0.020” 7.62 mm	0.250” ±0.010” 6.15 mm	1.00” ±0.020” 25.4 mm	$36
75TM-B	0.750” ±0.0001” 19 mm	0.625” +0 -0.020” 15.9 mm	1/4” x 20	0.300” ± 0.020” 7.62 mm	0.250” ±0.010” 6.15 mm	0.750” ± 0.020” 19.05 mm	$34
62TM-B	0.625” ±0.0001” 15.9 mm	0.562” +0 -0.020” 14.3 mm	1/4" x 20	0.300” ± 0.020” 7.62 mm	0.250” ± 0.010” 6.15 mm	0.625” ± 0.020” 15.9 mm	$33
50TM-B	.0500” ±0.0001” 12.7 mm	0.500” +0 -0.020” 12.7 mm	1/4” x 20	0.300” ± 0.020” 7.62 mm	0.250” ± 0.010” 6.15 mm	0.50” ± 0.020” 12.7 mm	$32