Member postings for Erik Christiansen

There's quite a range of Al bronze alloys, and some of them can also chill cast, becoming quite hard. Many years ago, I alloyed some that was approximately Cu9Al2Fe, and the ~7 mm thick sections were clearly chill cast, because a big angle grinder skated across the surface without much effect, and I had to regrind a new HSS drill after drilling 1.5 times through the section. I think I was drilling it dry, on the basis that "bronze is bronze, right?"

These days I'd just use TCT tooling, and google for cutting speeds & feeds. (I use some German TCT drills on brass, for their zero rake, and on the lathe, the crumb-like swarf pours out the flutes like sawdust - at a rate of knots. It would be fun to try them on Al bronze, not just the lathe/mill tooling.)

Ah, I pasted the link in the email version of your post, Michael, which was their home page.

Now I see that there's a diferent link on the forum. I'll grub through that now.

Thank you very much.

Erik

Yup, it was still open in the browser, after my friend google found it. From there, I've scouted the "Examples of Use", "Detailed Description", and "News" links, without finding anything useful. As it was explicitly mentioned in the article, I had hoped it'd save some net trawling. And being 99% programmer/1% machinist, it's the mechanical tips I've bought the magazine for, these last 20 years.

The Arduino Indexer article in MEW 249 lacks all details on reducing backlash in the rotary table, but suggests that there are tips at DivisionMaster. I've just looked there, and find nothing remotely resembling a tip of any kind, so hope to find some prior art before embarking on taking out the slop in my Vertex 6" rotary table. (Doing things again, to get them right, is no big deal when developing software, but it is a distinct pain on the mechanical side.)

Can't help wondering what the backlash would be if I just made an indexer with double toothed belt reduction. If the practical limit is 5:1 per pulley pair, then 25:1 * 200 gives nearly 14 steps per degree, or 28 at half stepping. Then there's no worm slop and better tooth engagement. (But the rubber teeth can deform under load.)

As a machine installer, I'm a beginner, but have found that lathe levelling was very wortwhile, and dead simple to do. My (AL-1000) 3/4 tonne Taiwanese lathe doesn't seem to be as rigid as David Fenner finds on p56 of MEW 205 - fortunately, I think, in retrospect. It wouldn't turn as precisely parallel as a "toolroom quality" lathe should, even after tweaking the tailstock alignment. My heart sank when I measured 0.48 mm (0.019" twist in 1160 mm of bed length, using a spirit level with laser shining on a wall 5.8m away. How was I ever going to straighten that out?

A chinese machine level, with each division equal to 0.02 mm in a metre, was not too expensive. It resolves 0.0027 mm (.0001" across the 133 mm shears on my lathe. With its help, and a jacking screw in one leg of the machine stand, I now have the bed ends parallel, with a bit of twist in the middle, amounting to 5 scale divisions (0.1 mm in 1 m = 0.013 mm across the 133 mm bed). That's half a thou in the old money, and it'll have to do.

I made no attempt to make the machine level, just parallel, which is all that is needed, I figure. Packing was placed under one end of the level, to make it read level at one end of the bed when sitting on the flat top of the cross-slide. Winding the saddle to the other end, the screw was adjusted for the same reading. Bed ends parallel - job done. (Ten minutes to fiddle suitable packing, since one thicknes of newspaper sent if off-scale. Then five minutes to level the machine, cranking back and forth a few times to check how much the other end had moved, after waiting for the bubble to settle. A few degrees of screw rotation are more than enough for the final adjustment.)

It's a very nice machine now. But I figure I'll give it a quick check summer and winter in the first year, to see how much it has moved, even though it's on a steel stand on a thick reinforced concrete floor.

If there's already a thread on this topic somewhere, then my apologies.

Having bought every MEW issue from 20 to 189, which has just arrived Down Under, I've thoroughly enjoyed the halcyon years when Harold Hall's delightfully informative articles, and Peter Rawlinson's wide-ranging technicalities made MEW the world's premier workshop magazine. Currently, new bandsaw tweaks in 187, rotary broaching in 185, the interesting single-tooth broach in 184, all the recent Al casting articles, the Accurate CNC Axis in 175-182, making a custom tap in 182, the hydraulic press in 183, and the Hot-Wire cutter in 184-185, are current gems amongst the "How to put new belts on a myford", "Renovate yet another Raglan", and "How to paint a myford" style background filler, which provide ambience, without ever needing to be read.

What has been bringing this reader back for decades is thoughtful writing on _What_ is being done overall and at each stage, and insight into _Why_. It is timely for the long series of Tom Senior endplate drawings to taper off as the more varied Stepperhead drawings come on stream. Alan Jackson's use of the "Overview" box to actually give something of an overview of his goals, what we're in for, and how it might be utilised, is so much more informative than the average "Non-Overview" sometimes provided there.

The place for regular beginner articles over the years is well understood, and more welcome than another "How to oil a myford." Workshop tips are a winner, I think, and prior appearance in ME is no obstacle, because we haven't seen them.

But compensating for the dwindling stock of workshop articles by filling the magazine with modelling hoo-ha, is the bitter end. That's when I seriously rethink my decades-long standing order which has been passed from owner to owner at the local newsagent over the years. Or is it the case that ME also lacks sufficient articles, and the magazines need to be merged to survive? Cannibalising ME readership by beginning the process in MEW would seem to just bring on that outcome.

So please put me down as a "No" vote for losing the plot. (Even slightly, just for now.)