INSIZE SCREW THREAD MICROMETER (CODE – 3281)

Code:

▪Measure pitch diameter of screw threads
▪Graduation 0.01mm
▪Non-rotating spindle
▪Ratchet stop
▪Supplied with 60° setting standards
▪Optional accessary: 55° setting standards

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INSIZE SCREW THREAD MICROMETER (CODE – 3281)

Product Overview

The INSIZE Screw Thread Micrometer (Code 3281) is a precision measuring instrument designed specifically to measure the pitch diameter of screw threads. It features a non-rotating spindle and a ratchet stop for consistent, repeatable measuring force. The instrument is available in two main configurations: Series 3281-A (where measuring tips are optional) and Series 3281-S (where measuring tips are included).

Key Features & Capabilities

Application: Designed for measuring the pitch diameter of screw threads.
Graduation: 0.01mm
Spindle Type: Non-rotating spindle
Stop Mechanism: Ratchet stop
Standards: Supplied with 60° setting standards (except 0-25mm models)
Optional Accessory: 55° setting standards

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Technical Specifications

Measuring Tips Optional (Series 3281-A)

Code	Range (mm)	L (mm)	b (mm)	55° setting standard (optional)
3281-25A	0-25mm	42	26	–
3281-50A	25-50mm	67	38	3281-SP1
3281-75A	50-75mm	92	50	3281-SP2
3281-100A	75-100mm	117.6	62	3281-SP3
3281-125A	100-125mm	143	70	3281-SP4
3281-150A	125-150mm	168.2	82	3281-SP5
3281-175A	150-175mm	192	94.5	3281-SP6
3281-200A	175-200mm	217	107	3281-SP7
3281-225A	200-225mm	242	130	3281-SP8
3281-250A	225-250mm	267	142	3281-SP9
3281-275A	250-275mm	291	155	3281-SP10
3281-300A	275-300mm	317	167	3281-SP11

Measuring Tips Included (Series 3281-S)

Code	Range (mm)	L (mm)	b (mm)	Measuring tips (included)	55° setting standard (optional)
3281-S25	0-25mm	42	26	6 pairs of measuring tips: metric and unified thread (60° thread angle) 0.4-0.5mm/64-48TPI, 0.6-0.9mm/44-28TPI, 1-1.75mm/24-14TPI, 2-3mm/13-9TPI, 3.5-5mm/8-5TPI, 5.5-7mm/4.5-3.5TPI	–
3281-S50	25-50mm	67	38	3281-SP1
3281-S75	50-75mm	92	50	3281-SP2
3281-S100	75-100mm	117.6	62	3281-SP3
3281-S125	100-125mm	143	70	3281-SP4
3281-S150	125-150mm	168.2	82	3281-SP5
3281-S175	150-175mm	192	94.5	3281-SP6
3281-S200	175-200mm	217	107	3281-SP7
3281-S225	200-225mm	242	130	3281-SP8
3281-S250	225-250mm	267	142	3281-SP9
3281-S275	250-275mm	291	155	3281-SP10
3281-S300	275-300mm	317	167	3281-SP11

Accuracy of Micrometers with Tips (mm)

Pitch	Range
	0-25	25-50	50-75	75-100	100-125	125-200	200-225	225-300
0.4~0.5	±0.01	–	–	–	–	–	–	–
0.6~0.8	±0.01	±0.013	–	–	–	–	–	–
1~1.25	±0.012	±0.015	±0.017	±0.017	–	–	–	–
1.5~2.0	±0.014	±0.017	±0.019	±0.019	±0.020	±0.023	±0.025	±0.028
2.5~3.5	±0.016	±0.019	±0.021	±0.021	±0.023	±0.025	±0.028	±0.031
4.0~7.0	–	±0.021	±0.023	±0.023	±0.025	±0.028	±0.031	±0.033