C7 vs C5 Ball Screw: Which One Should You Choose?

Quick answer

For most standard machines, repair replacement, distributor stock, and general automation, start with a C7 rolled ball screw. Consider C5 only when the drawing specifies it, the axis needs higher positioning and repeatability, or the machine requires ground-level accuracy. Do not choose by grade alone; put application, travel, speed, load, budget, lead time, and inspection needs into one RFQ.

How to decide between C7 and C5

| Decision point | C7 is more common | C5 is a better fit | | --- | --- | --- | | Purchase target | Cost, lead time, standard replacement, batch stock | High positioning accuracy, repeatable motion, drawing requirement | | Typical use | Packaging machines, woodworking CNC, repair, distributor inventory | Precision automation, inspection equipment, key axes, demanding OEM projects | | RFQ focus | Diameter, lead, length, nut, end machining | Accuracy grade, preload, inspection report, drawing tolerance | | Related parts | BK/BF support units, couplings, linear guides, linear bearings | Support units, guides, module structure, and machine accuracy checked together |

Do not leave out the application

C7 and C5 describe accuracy grade, but the final choice also depends on installation structure and machine target. If the buyer also needs linear guides, linear modules, support units, or couplings, include those relationships in the same RFQ so the supplier can judge end machining, nut preload, and inspection level.

FAQ

**Is C7 always worse than C5?** No. C7 is the better practical choice for many standard machines and batch purchases because cost and delivery are easier to control. C5 adds value when higher accuracy and stricter inspection are truly needed.

**For repair replacement, should I follow the old part or redesign it?** If the original machine structure stays the same, follow the old part dimensions, end machining, and nut style first. If the machine is being upgraded, confirm accuracy, load, speed, and related guides again.

**Can I ask for both C7 and C5 quotations?** Yes. Put both options in one RFQ and state target price, lead time, and whether an inspection report is required.

RFQ checklist

Send diameter, lead, overall length, and thread length.
Describe machine type, travel, speed, and load.
Confirm nut type, preload, or backlash requirement.
Attach support model or end drawing when machining is needed.
Include related needs for linear guides, linear modules, support units, linear bearings, or couplings.

Next step

Turn this guide into an RFQ

When the specification direction is clear, send the details below together with quantity, lead time, and packing requirements.

Include these details

Model, diameter, lead, accuracy grade, or target application.
Load, speed, travel, mounting method, and matching rail or support-unit needs.
Quantity, lead time, packing, and whether inspection records or shipment photos are needed.

Send accuracy requirements View standard parts and bars