Manufactured by Grüdelbach & Schütter, Prazisionsmaschinen, Buschhütten in Kreuzta, near Siegen, Germany, this remarkable "portable" radial-arm drilling machine was intended for use in machine shops that dealt with large workpieces where it could be used to tackle awkward jobs. In order to reach into otherwise inaccessible places, especially where machining subsequent to assembly had to be carried out, the drilling head could be swivelled in two planes, the supporting arm moved in and out and elevated.
Made in twelve models: B25, B30, B40, B50, B60, B80, B100, and B200 and sub-variants, the B-Series machine had drilling capacities in steel from around 13/8" to 39/64" (35 to 80 mm) and in cast iron from 13/4" to 4" (45 to 100 mm). The spindles used a Morse taper fitting, ranging in size from a No.3 to a No.5, with the drive motors starting at 3 h.p. for the Model B30 and finishing at 11 h.p. for the B200.
Various mounting bases were available to suit almost any application, divided into two main types: flat and round.
A similar machine, though much smaller and not as versatile, was the Model UB2 by Oerlikon, a company that used the Grüdelbach & Schütter portable drill in their own machine shops. 
The full specifications of the Grüdelbach & Schütter can be found below.