The Eldorado M75-30T, designed and built by Kays Engineering (Marshall, MO), is a twin-spindle gundrilling machine with a redesigned counter-rotation fixture. To maximize the effectiveness of the gundrilling operation, it is ideal for the workpiece to be rotated in the opposite direction of the drill rotation. This improves the straightness of the drilled hole and reduces drill drift. The new counter-rotation fixture on the M75-30T features an improved gearbox and motor mount that reduces vibration. The new design also introduces automatic advance/retract of the entire counter-rotation assembly via a programmable servo, which simplifies part loading and unloading and reduces cycle time. Specifically:
- The M75-30T has a 0.75 inch (19 mm) diameter drilling capacity and a 30 inch (762 mm) maximum drilling depth.
- It has two gundrilling spindles utilizing independent spindle control, which enables it to perform two independent drilling cycles at the same time.
- The machine also incorporates flame-hardened and ground cast iron box ways and hand-scraped spindle housings (instead of linear guide ways and milled surfaces). This results in superior vibration damping and extended tool life.