Rolled Ball Screw

Tianjin OuNaiDa Transmissions Technology Co., Ltd. is one of the leading manufacturers and suppliers of Rolled Ball Screw in China. If you're going to buy high quality Rolled Ball Screw, welcome to get more information from our factory. Also, custom service is available.

Ball Screws for CNC and Automation - Supplied as a Matched Set

Most ball screw problems do not start with the screw itself. They start at the two ends.

A customer sends us a drawing for a 1605 screw, we quote it, and two weeks later the machine still will not run smoothly - because the shaft ends were machined for one support unit series and the brackets on the shelf are another. The screw is fine. The match is not.

That is why we quote ball screws together with the nut and the end machining, not as a loose part number.

Available Series

We supply four series from stock and to order:

SFU - Flange Type Single Nut
The standard workhorse. Round flange with 4 or 6 bolt holes, internal return system. Used on CNC routers, engraving machines, Z-axis assemblies, and general automation.

SFNU - Strong Dust-Proof Type
Same mounting concept, longer nut body with improved sealing. Worth the extra cost in woodworking, stone cutting, and any environment where dust reaches the nut.

SFY - Big Lead Type
For applications where travel speed matters more than resolution - pick-and-place, gantry transfer, long-stroke positioning.

SFK - Mini Type
Small diameter screws for compact equipment and limited installation space.

Specification Range

Common Sizes - Actual Dimensions

Dimensions in mm. Left-hand thread available on request.

Dust-proof SFNU equivalents share the same mounting dimensions - SFNU1605, SFNU2005, SFNU2505, SFNU3205, SFNU4005, SFNU5010 and others are available on the same lead range.

About C7 Accuracy

C7 is a rolled-thread grade with a travel deviation tolerance of 0.05 mm per 300 mm of thread length, as specified under ISO 3408 / DIN 69051. It is the practical grade for CNC routers, plasma tables, engraving machines, and general positioning work.

If your application needs tighter positioning - die-sinking, grinding, metrology stages - tell us the required deviation over your actual stroke rather than only the grade letter. Ground-thread screws in higher grades are made to order.

One point worth making plainly: a higher accuracy grade will not fix a mounting problem. If the screw axis is not parallel to the nut mounting surface, C3 will run no better than C7. Alignment first, grade second.

Shaft End Machining

This is where most replacement orders go wrong.

The shaft ends must match the support units you intend to use. Critical dimensions:

• Fixed-end journal diameter and bearing shoulder
• Thread specification and lock nut size
• Supported-end journal diameter
• Overall shaft length and each journal length

Too short and the lock nut will not fully engage - bearing positioning cannot be set correctly.
Too long and you get interference with the coupling or end cover.

We machine both ends to your drawing. If you do not have a drawing, send us the support unit models (BK/BF, FK/FF, EK/EF) plus your stroke, and we will produce the shaft-end drawing for your approval before cutting.

What to Send Us for a Quotation

To quote accurately the first time:

1. Screw diameter and lead - or the model number if you know it
2. Total shaft length and required effective stroke
3. Nut type - SFU flange, SFNU dust-proof, or a sample photo
4. Accuracy grade, or the positioning tolerance you need
5. Shaft-end drawing, or the support unit models you plan to use
6. Quantity

Replacing an existing screw? Photos of the front view, the nut, and both shaft ends alongside a ruler will get you a faster and more accurate match than a written description.

Manufacturing

Tianjin OuNaiDa has been producing precision transmission components since 2008 - 20 years of manufacturing and 15 years of export experience, supplying over 300 overseas distributors.

Our workshop runs CNC lathes, CNC grinding machines, thread rolling, tooth-hardening equipment, and inspection machines. Production is held to CE and ISO 9001:2015 standards.

We also supply the matched components for a complete linear axis: BK/BF, FK/FF and EK/EF support units, shaft couplings, and linear guideways - so the axis arrives as one matched set instead of four separate purchases.

OEM and ODM accepted. Samples available. Technical support 24 hours.

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