Found a good'un, here: https://archive.org/details/foundryworkpract01stim Does one of the better jobs of explaining things I've seen, thus far. Good for Nübs, too. Oh, my! Look at the pouring basin on page 39 (in the PDF document!) Figure 22! It looks just like some I've seen here!
Thanks Dennis, I just downloaded it! Looks like it is going to be good. Lets see what those guys from 1916 can teach us. Patrick
You can get them on ebay for around 100 bucks. I bought two little air chisels for 20 bucks that I am going to convert and use for small molds.
Amazon has them, also. There was talk (here?) that the cheap ones didn't work, or something similar - something like "if it doesn't cost at least 500+, It's junk."
I haven't tried it, but I have tried similar things which I was told would not work and found that they worked well enough for my needs. Sandblasting with a puny air compressor? It works, not great, but in small bursts it's entirely usable...and that's all I needed.
FWIW, I've used both a cheap air hammer and a professional grade one, there is a very significant difference. The next air hammer I buy will not be a cheapie.
I have used our professional ones a long time ago. There was nothing I particularly liked about them then and will probably like the cheapy that I may purchase even less.LOL But hey....if it saves me time and sore muscles than it will be an improvement. As for the professional molders....we had guys that did it for a living argue about which ones were better and certain molders had to have certain rammers...guess it is a matter of choice and which one feels more comfortable to you in the end when you are using them everyday day in and day out. Some did not even like them at all.
IMO, there are a lot of handy books in the public domain on a variety of topics. My reading of "The Calculation of Change-Wheels for Screw Cutting on Lathes, by DeVries (1908)" was quite handy in writing a script to compute change gears for my lathe of the same era. Calculates for US Customary and metric. I've done both, so I know it's working. Sure change gears aren't much of a thing these days, but when your equipment and methods are from the ancient past it sure is handy.
Note that the small(er?) H-F lathes use change gears to cut threads. Theirs are plastic - which, surprisingly, do not "go south" in a hurry when used! Still, though - I may try to get module one cutters so as to make my own (non-standard) gears of sae 1117 stock, followed by light case-hardening. Only thing better would be to make a species of quick-change add-on box.
I 3D printed a gear for mine, figured it wouldn't last for but a single use, but it has help up admirably. I am almost embarassed to say that of all the machinery I have (not a lot, but more than most) the 3D printer does the lion's share. Back onto change gears for a moment, I prefer change gears over a quick change gear box. Sure the QC is faster to select, but change gears allow you to do more threads and to do things that the designers very likely never anticipated. CNC is nicer still, no doubt, but I won't likely have one of those for another 100 years.
The quick-change box in question is intended to supplement the existing setup, not supplant it, e.g. it allows quick(?) selection of, say, 20/24/28 threads per inch for threading; Then, it gives further reductions than is possible with just the change gears alone. The intent of this last is to advance the carriage slower during fine finishing cuts using fresh-honed cobalt tool bits.
