Gentlemen and Trolls I am in the final stages of reassembling a vast old flat-belt drilling machine (about 7' tall) and would appreciate some advice. The socket is 3MT and it will be mostly used for 1/2"-1" with the occasional foray up to 2". What range of quill speeds should I aim for and how many horses will the motor need. I have 3 phase. The machine carries no markings but is of massive and timeless design and the threads are metric. If anyone wishes I could stick a pic on my website. regards
Drilling machine
Nov 06, 2003
3 Replies
I'd plump for 75rpm to 300rpm (assuming that you're not spending your life on Ali or Brass) - Depends upon what range of steps on pulleys that you have. Without resorting to Machinerys Handbook and doing the maths on motor size I'll use crude comparison. As a guide my lathe with a 2HP motor will happily let me push a 1.5" drill from the tailstock into a workpiece. My Victoria MO horizontal mill is very happy eating metal with 1.5HP. It too has a 2" flat belt somewhere deep inside and belt slip is the limiting factor, not motor power.
Charles
A possible guideline:
20" Denbighs were 118-428 rpm over 4 speeds " " " 22-428 rpm over 8 speeds with back gears. Both were 3MT and used a 1-1/2 hp motor.Tom
Thanks chaps. Primarily for Tom I've stuck three pics up
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one know what it is and a rough date? Confusingly its a mix of metric and BSW threads/flats. However the table (missing) socket is 60mm so I'm guessing non-UK origin. With the 4 speeds (1.38, 0.84, 0.52, and 0.38) and the 18:27 bevel reduction it looks like a layshaft input of 6:1 reduction from a 1400 ish rpm motor would be about right. ttfn Roland
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