For more than 40 years, Dan-Kar Corp. has combined precision machine-shop work with custom plastic and metal fabrication for biomedical, laboratory, scientific, and other specialty markets. The Woburn small business also develops its own distinctive lab equipment, including mouse tail illuminators and patented RapidThaw defrosting blocks, alongside made-to-order components ranging from prototypes to large production runs. Its acquisition of BT Engineering added manufacturing capabilities through the newly named Dan-Kar Engineering, LLC.