This week, the overall grades of four machinery stocks are lower, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

Luxfer Holdings PLC Sponsored ADR (LXFR) earns an F (“strong sell”) this week, moving down from last week’s grade of D (“sell”). Luxfer Holdings, a materials technology company, engages in the design, manufacture, and supply of materials, components, and gas cylinders. LXFR also rates an F in Portfolio Grader’s specific subcategory of Earnings Surprise. To get an in-depth look at LXFR, get Portfolio Grader’s complete analysis of LXFR stock.

Kaydon Corporation (KDN) earns an F this week, falling from last week’s grade of D. Kaydon designs, manufactures, and sells custom-engineered products for a variety of industries, including aerospace, defense, and industrial. In Earnings Growth, Earnings Momentum, Cash Flow and Margin Growth the stock gets F’s. The stock’s trailing PE Ratio is 37.20. For more information, get Portfolio Grader’s complete analysis of KDN stock.

This week, Rexnord Corporation (RXN) falls to a D (“sell”), worse than last week’s grade of C (“hold”). Rexnord manufactures highly engineered power transmission, aerospace and other precision motion technology products. To get an in-depth look at RXN, get Portfolio Grader’s complete analysis of RXN stock.

Flowserve Corporation (FLS) experiences a ratings drop this week, going from last week’s D to an F. Flowserve designs, manufactures, distributes, and services industrial flow management equipment throughout the world. The stock also gets an F in Earnings Surprise. For more information, get Portfolio Grader’s complete analysis of FLS stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.