I have been in the process of renovating a pillar drill for a while now (PhD work kept getting in the way). I thought I would share some of this drill press jazz. After drilling and tapping innumerable holes in thick steel by hand (all be it a Bosch powered hand;) while I was engrossed in the wood lathe project, I can see the value of a pillar drill.  This would have been soooo useful, it seems ironic that I am doing this now.

The original Meddings Drill Press

The idea was that by getting a second hand three phase drill, it is possible to get a really high quality and functional machine, if you are willing and able to convert it to run off single phase electricity supply. Three phase drills tend to be better quality machines suited to industrial use. Unlike a lot of the modern drill presses that are imported you can get a really solid piece of kit.

I picked up a Meddings bench-top M4 Drill Press off e-bay (it was being sold from a school DT department).

I did use the drill in this state, to drill holes in my PhD thesis.  No, I had not gone completely mad, they were careful and considered holes, needed to bind the finished work together (I thought it fitting that I make my own binding after 4 years of research and writing).  To use it like this I made it ‘Sam powered’ – that is, I got Sam to stand on a stool and spin the pulley with gloved hands, while I operated the press mechanism.

Out with the three phase electrics.

As you can see a fair bit of paint has come off round the edges of the table and the coolant trough, which we will fix up later.  First to sort out the holes left from accidental and over keen drilling.  I have filled some of them already with JB Weld – it is good and solid and can be sanded flush to the table when dry. Also notice the rust still on the right of the table, which would mark and stain some work pieces.  As long as it is not too terrible it can be removed with some light abrasion and a bit of time spent rubbing.

Mixing up the JB Weld

One test hole filled with JB Weld and ready for sanding down flat.

A close up on some of the table repairs.  Seems to work well enough – a little air hole in one bit but nothing major.

Not being able to rely on Sam to be at beck and call of the drill at all times, I had to sort the motor.  Originally my plan was to convert the three phase motor, and make it a capacitor run type (There is an excellent description and instructions for such conversions in Jim Cox’s book on electric motors – it is a tad old, but a classic). Anyway, after some poking around I discovered that the original motor only had three connections rather than the usual six.  This made any conversion a whole lot more complicated, requiring a whole lot of re-winding of the copper coils.  I already had in mind an alternative though…

The ‘new’ scavenged treadmill motor I have had knocking about for some time is mounted up. Here you can see its credentials: 1.8 Horse Power continuous duty (Not bad!), 4800 revs per min.  More than ample for this application.  The real bonus is the speed controller that comes with it, which is capable of putting out tremendous torque at consistent low speeds.  

Here it is after a spot of matching green hammerite paint. Ok, so I do need to stick the rating plate corners down, they look terrible.

Here is the new speed adjustment dial (in the middle of the pic).  It is just a good quality variable resistor taken from a scrapped radio. 

Most treadmill speed control boards have an arrangement in which the speed is adjusted by a separate complex computer unit.  Luckily for us though the output from the computer is usually simply a certain resistance, so that we can substitute the computer, with all its elaborate exercise programmes and training systems, with a simple potentiometer.

The treadmill speed control board still retains its nice ‘gentle start’ features, and excellent speed regulation properties.  As you can see I have managed to retain most of the switch gear, that is, the well designed start and stop buttons and the contactors that go with them.

I have started making some hold down clamps using the drill, which is exciting. Will post soon..

Posted: 11|2|09 at 12:33 pm. Categorically squeezed into: Tools.

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