A lot of Thanks giving the answer 

In your According ,is it possible do the measure every day  from inch to gram because my company produce every day 400 Pcs ,there are 15 inch use in some product ,and there are 50 inch use in some product 

I set it in my odoo

Unit Of measure - Gram

Type - Smaller than the reference unit of measure

Ratio - 100 

Unit of measure - Kg

Type - Reference Unit of measure for this category

ratio  - 1

To address the situation with your product "Chain," which is purchased in kilograms but received in grams and used in inches for manufacturing, follow these steps:
- Determine the conversion rate between grams and inches, considering factors like thickness, materials, and density. Ensure accurate conversions by manually checking the actual weight per length.
- Create a new "WeightLength" UOM category in your system to combine weight and length measurements. Alternatively, use an existing UOM category in older systems.
- Choose either grams or inches as the reference unit for the "WeightLength" category to serve as the base unit for conversions.
- Define the conversion factor based on the relationship between grams and inches.

Following these steps will help you effectively manage the different units of measure for your "Chain" product and maintain consistency in your systems.