Saturday 21st February 2009
For the second day running I didn’t manage to stay out in the workshop for as long as I would have liked. However I did manage to pin the leadscrew and fit it permanently to the lathe so that was a positive. Even better was the smooth and free turning nature of the leadscrew after final fitting.
I decided that to cheer myself up, I would connect up the gear train and run the lathe at various speeds to ‘run in’ the new bearings of the counter shaft and leadscrew. However I was soon to discover that the gear wheel changing on this 1953 version of the ML7 had a really frustrating gear change set up! On my much loved ML10 (and the same for the ML7 according to the later manual I have) you simply unscrewed the retaining screw on the end of the pillar on which the gears seat. Not so my lathe! The screws on the end are in fact bolts on mine. They fit into two bolts with indents that fit into the rear of the gear casting. The hollow pillar through which the bolt goes then has another keyed bush that fits inside the keyway cut gear. The length of the pillar is more than the width of two gears and the screw is the same outside diameter as the inner pillar. So if you want to change gears you have to take the whole bolt, pillar and special nut off the casting.
Since there isn’t a lot of room between the casting and the lathe body this is a fiddly (bl*&^^y frustrating!!!!) job. I now understand why many owners either bought or built gearboxes! I will have to sort the problem out, but for now I have packed the gap with two large washers to fill the gap (about 3/16”) and a smaller washer for the bolt head to seat against. This works fine but it isn’t an ‘engineered’ solution (see I am getting posh now). It may be a simple case of reducing the overall diameter of the pillars (cant see that Myford would have allowed this situation so there must be something wrong –let me know) or buying a pair of ‘modern’ replacement fittings from Myford.
It may be just a ‘bodge’ from a previous owner which I suspect is the true reason for the discrepancy. However the gears were eventually fitted after discovering my driver gear may be an accessory rather than the standard gear. After much head scratching I found a set of gears that I had and would give a fine feed. I need another gear to get the finest feed, but I just wanted to get the leadscrew to turn over for now. And turnover it did, after all the oil nipples were given a generous amount of Myford recommended oil I rand the motor on a slow speed at first, in both forward and reverse directions, before speeding up, then varying the speed. The whole gear end of the lathe (I believe the tumbler gears are known for there noise) is a lot noisier than my ML10…….
However that may change with the gear cover on. The leadscrew seemed to run as true as it should with the naked eye. So I would consider the whole exercise a success in regard to making the new shafts and leadscrew. My thanks go to members of the HMEM forum for their ideas and support during this project and in particular to Peter who told me about a supplier for the leadscrew threaded rod. Whilst it is not finished, all the large ‘engineering’ tasks have been done leaving just a few items outstanding waiting for parts from Myford. I would say it is 90% finished and less than a days work left.