Uploaded on Dec 28, 2009
This is my Kearns S-Type boring machine. I bought it for £510 off Ebay.
It is a machine specifically built to bore holes into metal, for instance a car engine cylinder.
I have stripped out all the original electrics because they were all wired for 415 volts 3-phase and I only have 230 volts single phase, so I built a system to use 3-phase inverters.
The original main motor, mounted under the machine and impossible to get to, was not suitable for 230 volts operation so I bodged a new one on the side. The new motor is 2 HP 1440 rpm. The old one was about 4 times larger but only 1.5 HP, 3 speed.
The 3-phase inverters allow me to run all the motors on the machine at a variable speed, programmable from 0-200% rated speeds, though the SUDS pump is fixed at 100%.
The table motor was a bit of a problem as it was only wired for 415V Star. I spent 4 hours hacking away at the insulation to access the Star join and rewired it to Delta. so it could be used on 230 volts.
The main motor inverter is an IMO Jaguar VXSM. Cost about £500 new but I bought it 2nd hand for £100. The table motor inverter is a tiny Mitsubishi device, only cost £20 new.
The Suds pump motor inverter is a Brabender unit, found it in a scrap yard. Only about 100 Watts, no torque control or anything, so if the motor doesn't start up 1st time it'll just sit there and buzz, where as the IMO drive will sort the motor out from the feedback it gets.
We've had this device mostly to pieces and given it a good clean up. It was out of Hartleypool college originally. Still has some scratchings of students names in it.
Other than the fact that someone has painted it without keying in the old paint, so the new paint is peeling off, the machine is in good condition.
The machine has an indexing table, meaning you can rotate a job by 90 degrees at a time and have it set very accurately.
The facing chuck basically allows you to slide the tool across the fact of the chuck while the machine is in use. When boring a hole this allows you to increase the diameter of the cut while running the main motor.
The one thing we didn't get was the tail stock. This is a post at the back of the machine to support the boring bar when doing long jobs.
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