Right, having done nothing on this for too long, I decided I've procrastinated long enough. Having taken the armature to a chap who's got a lathe (& knows how to use it), only to discover the unit + casting is too big to go on it... we figured out the threads on the pully holes, and today I went to my local "bits" supplier & bought a metre of 5/16ths BSF stud, 6 nuts, and some cutting oil... to make my pulley puller.
So, here's what I used:
1) A piece of scrap bucket blade (from a big digger) gave me the ideal start point. I needed (ideally) a circle around 8" diameter. Circles are too hard for me, especially in 1/2" thick steel, so I used the plasma cutter to cut out a square. Well, squareish... this is the thickest stuff I've cut with the plasma, and it was only just up to it (or maybe
I was only just up to it... this is entirely possible). A few good belts with a lump hammer freed the square from the blade scrap, with an old bolt hole roughly in the middle. I considered tidying the piece up, but figured it was a waste of time...
2) Next, located a piece of bar. Unfortunately, the bar was far in excess of the pulley shaft diameter (this figures later), but using the chop-saw I cut a couple of inches anyway. This was welded into rioughly the centre of the square - and by roughly, I mean
rough! This is only the second thing I've ever MIG welded in my entire life. It surprised me somewhat that it stayed on at all.... although you couldn't accuse it of being even remotely close to level.
3) Now I needed to drill the holes for the bar. Fortunately, I have the use of a massive pillar drill; unfortunately, it took a good hour to clean all the crud off it to make it usable (it's not been used in ages). Using uber-crude methods, I marked the location of the holes (note to self: Need some calipers & a scribe...), broke out the 3/4" drill, mounted it up & got cutting. Power feed is ace! Until the work piece rides straight out of the vice & up the drill bit and you can't find the stop button! No harm done, luckily.
4) The end result is this - the ugliest puller known to man (click on pix for the big version):
Apply it to the pulley:
Add the nuts & start cranking down on them:
Remember that over-sized bar stock? Well, when the pulley face got flush to the shaft, and it still wasn't going to wiggle off, I had to add a spacer. Some of the threaded bar I had left over was ideal, so I used the chop-saw again to whizz off an inch, added this between the puller nose & the shaft, and resumed cranking:
In all, I had to make three spacers, each about twice as long as the last, before I got enough length to pop the pulley over the edge of the shaft. It fought every last damn 16th/inch of the way... but at least I didn't have to call a man in... Cost me £15 in bar & nuts, plus a total of about 4 hours time.
The end result:
(that pic shows the insane angles everything was at... I really must learn to weld straight)
So, in the end, no heat, no fancy welding, no clever stuff. Just brute force & patience... And the growing realisation that I really can't do without a lathe & a milling machine: The pillar drill just isn't in the same league.
