Member postings for gerry madden

The other way of putting very fine radii on components (such as bearing rollers and raceways) is to plunge-grind them using a grinding wheel that has been dressed at an angle to its axis. A staight cut made this way will infact produce a parabola but it's as near as dammit a radius and was always described as such. Inspection of a surface made in this way was done by simply measuring the 'drop' at a given distance with precision gauges. No one attempted to prove it was actually a radius, or even a parabola as there weren't many other shapes it could be.

Gerry.

Thanks all for your interesting input to this thread. I am 90% of the way through making an HH rest and soon to be thinking about wheels and motors. Just one point I have not seen mentioned.... what does one use to dress a diamond wheel ? Does the fact that they have metal location bores mean that runout is less and therefore dressing not necessary ?

Gerry

In lathe and mill slides there is often a tendency to get slightly tight and loose spots which must be due to the normal geometric inaccuracies of the mating parts. Adjustment of the gib strips doesnt really solve this. Removing any slackness just results in increased friction elsewhere because there is no compliance (or very little) in the structure. So Im wondering, why aren't the gibstrip adjustment screws made with some built in compliance to help them ride over the 'tight spots' ? I was thinking that the grub-screws could be drilled and fitted with short length of plastic rod to create a kind of spring preload effect ? Any thoughts on this ?

Thanks all for your comments and apologies for taking so long to reply. There dont seem to be any major risks so I will give it a try.

As for the anodising, I thought I may try to do it myself - there was an article on it in MEW. Keeping the current low gives a fine finish. I dont plan to use any lubricant in the finished product and hope that the anodic coating will prevent scuffing and keep the friction down. But as one of you said, I need to avoid small machining ridges on the teeth or they will create high localised stresses.

Regards

Gerry

Chaps,

I plan to make a clock at some stage and hope to incorporate some ideas of my own. One is to use aluminium for the gears. I have not seen this suggested before. Are there good reasons not to do this ?

I can think of positives (light weight, easy machining, cost) but only one negative and that is the potential for wear. However to counteract this, I was thinking of anodising. This will give a coating harder than the steel and will reduce friction as well.

But I have probably forgotten something obvious and would appreciate your thoughts.

Gerry