Mike BR

If it were me, I’d buy a case of cheap drop ceiling tiles and some hot melt glue, and see what worked.

Indeed, balsa wood is a hardwood, but hardly a hard wood.

I suspect sabotage.

According to Wikipedia, the first uses of roots blowers were blast furnaces and mine ventilation. Centrifugal blowers that big sound kind of scary. Anyway, it might just have been a matter of having a neat idea and trying it out on different products.

I'm home from work, so here it is (I hope). Thinking about it, a roots blower should have made pressure at lower RPM than a centrifugal, so that that might have seemed like a better idea for a hand-cranked blower. And maybe it even was a better idea until the Champion came out with its compound gearing. (Not that I know what else might have been on the market before the 1905 Champion patent.)

Not sure how to post a link from my phone, but if you google 1885 roots blower, you’ll find an iforgeiron thread. It even has pictures of the blower before it got left out in the rain

You can see the fire scale on copper disappear in a reducing atmosphere, which may suggest you don’t need flux to dissolve it.

Thanks! A lot more informative then the Wikipedia article.

And a lot of railroad steel has high manganese levels so precisely so it does work harden. Make sure you sue enough feed pressure so you’re making chips and not just hardening it more.

This is far from your biggest challenge, but the difference between cast iron and pig iron is that cast iron is made into a product and pig iron is made into steel. There's probably pig iron that doesn't meet any known spec for cast, but it should be safe to think of cast iron scrap as pig iron that made an intermediate stop.

Should be safe here. They’ve had solar compactors on the street corners for years.

And unless the dew point’s 22C or lower, your bare feet will feel wet as well. . .

Neat blog, but it isn't really correct (or at least incomplete) to call osmond iron "furnace-cast iron." Rather, it's sort of pre-wrought wrought iron. Pig iron was remelted in a small hearth. As the carbon was burned out, the melting point increased, and lumps of (roughly) pure iron were collected into "osmonds." After export of this intermediate product was prohibited, Sweden started building the hammers necessary to forge it out into wrought iron. There's a short description here: https://en.wikipedia.org/wiki/Osmond_process (it doesn't mention the decarburization, but it would be pretty silly to melt pig iron into pig iron.)

A bad ground (chassis ground strap or the like) can cause some pretty odd problems. Probably not that odd, but might be worth checking.

Yep, 12kw. But CCA is cold cranking amps, so seconds (or tens of seconds?) rather than hours. Still a lot longer than my life expectancy would be with 1000 amps running through me . . .

It’s ultimately current that kills, but voltage is what determines how much will flow through your body. Ever touch the terminals on a 1000 CCA car battery? Also, the HF itself will tend to protect you, through the skin effect. The start circuit on a TIG has a much higher voltage, but the HF keeps it from being dangerous.

If my math’s right, 18 degrees would mean it would take a sideways pressure of about 30% of the anvil’s weight to tip it. Depending on what you plan to bend in the hardy hole, of course. . . .

Yes -- that's what I was thinking. I've done similar things with small hand wheels, and a bronze gear for a Champion blower (that had a solid hub with a web from light plate, then a steel ring on the perimeter with a bronze "tire" silver soldered to that).

They make fluxes for joining aluminum. Might be worth looking into those.

For welding, I ordered the cheapest glasses I could find in my reading prescription. (I guess strictly speaking, I should have bought prescription safeties, but figures I'd live dangerously behind the helmet.) I think some of the online stores have specific options for reading glasses, but I just (mathematically) added the distance numbers from my bifocal prescription to the reading adjustment it showed. I've also plussed up the numbers a little further for close (non-hazardous) work; you could probably back off some for medium distance welding if you wanted.

You could probably forge and fabricate a steel blank, if the machinist’s up with turning that.

I’d check what Frosty said, too. If blade isn’t set up right, it will wander no matter how well you mount the saw

Work hardened mild steel springs can work well. I've only made much smaller springs that way myself, but have had good luck with those.

Another submarine power solution is stirling engines (which NATO now has).

It seems like running the armature of a universal motor below rated voltage should have the same effect as running a permanent magnet motor at reduced voltage—the motor happily runs at reduced speed. But even if I’m right, that’s probably not what you want.