Sardar Mill Store handles precision shaft, hardchrome shaft and linear-motion bearing enquiries from Delhi and across India. Send a complete drawing or old part code when possible. Our team can discuss a match, but material, finish and availability must be confirmed for the exact order.
What should I specify for a precision shaft enquiry?
Provide the diameter, length, tolerance, material, finish and end drawing, plus the mating bearing code. A diameter alone cannot establish whether the shaft will fit or last in the machine.
- Nominal shaft diameter, overall length and required diameter tolerance.
- Material, hardness, surface finish and whether hard-chrome plating or another treatment is required.
- End machining, threads, keyways, holes and a drawing of both ends.
- Mating linear bushing or bearing code, housing details and machine application.
- Quantity, required delivery location and any inspection or certification requirement.
Do not assume that every same-diameter shaft has the same surface treatment or load life. In particular, a THK SF LM shaft reference is not automatically a hard-chrome shaft specification.
THK SF shaft size reference
THK publishes the following standard LM shaft nominal diameters and corresponding LM bushing sizes. These are manufacturer catalogue references, not a Sardar Mill Store stock list. The full shaft code also includes tolerance, length and optional treatment or material symbols.
| Shaft model | Nominal diameter | THK matching bushing | Shaft model | Nominal diameter | THK matching bushing |
|---|---|---|---|---|---|
| SF 3 | 3 mm | LM 3 | SF 4 | 4 mm | LM 4 |
| SF 5 | 5 mm | LM 5 | SF 6 | 6 mm | LM 6 |
| SF 8 | 8 mm | LM 8 / LM 8S | SF 10 | 10 mm | LM 10 |
| SF 12 | 12 mm | LM 12 | SF 13 | 13 mm | LM 13 |
| SF 16 | 16 mm | LM 16 | SF 20 | 20 mm | LM 20 |
| SF 25 | 25 mm | LM 25 | SF 30 | 30 mm | LM 30 |
| SF 35 | 35 mm | LM 35 | SF 38 | 38 mm | LM 38 |
| SF 40 | 40 mm | LM 40 | SF 50 | 50 mm | LM 50 |
| SF 60 | 60 mm | LM 60 | SF 80 | 80 mm | LM 80 |
| SF 100 | 100 mm | LM 100 | Confirm length and configuration for the exact part. | ||
Source: THK Linear Bushing catalogue, Standard LM Shafts table, page B-460. THK lists shaft tolerance and standard lengths separately. This table does not represent local stock, interchangeability or a coating claim.
Shaft and linear bushing: check the whole assembly
The shaft and bushing must be chosen together. The shaft diameter must match the bearing bore, but the bearing outside diameter, length, seal arrangement and housing fit also matter. A worn shaft can damage a new bushing, and a replacement bushing cannot correct an unsuitable shaft finish or tolerance.
For a quick enquiry, send a photo of the bushing marking, the measured shaft diameter and a sketch of the housing. If the assembly is safety-critical or load-sensitive, use the machine maker's drawing and current manufacturer data for final approval.
Common buyer questions
Is an SF shaft the same thing as a hardchrome shaft?
No. THK's SF designation identifies an LM shaft family. Hard-chrome plating is a separate surface-treatment requirement and must be confirmed for the specific shaft supplied.
Can you match a shaft if the original code is missing?
Share diameter, length, end machining, photographs and the mating bearing code. A drawing is best where tolerance, straightness or surface treatment matters.
Can I choose a linear bushing by shaft diameter alone?
No. Check its outer diameter, length, seals, housing fit and load conditions as well as the shaft diameter.
Continue the product comparison
Prepared by Sardar Mill Store, 43 Main GB Road, Delhi. The selection advice reflects details our team asks buyers to confirm. The model table is transcribed from the linked THK catalogue and is provided for comparison, not as an availability or authorisation statement.