The Home Machinist!

One way to look at your furnace; If it was an older ham radio, you have to tune the transmitter to the antenna. This is what the output stage, with the capacitors, of your induction is; the tuning stage.

Jim B

Patio used that as an example when he was explaining the operation of the furnace to his brother, who is a ham radio operator.

H

Just for fun, here is a couple of pictures of Harold's furnaces. Harold can speak about them if he wants, I am just providing pictures.

Patio wrote: ↑Wed Jan 06, 2021 1:34 am Just for fun, here is a couple of pictures of Harold's furnaces. Harold can speak about them if he wants, I am just providing pictures.

Bravo!

Looking good!

It has been a long and difficult chore getting the induction furnace operational. I had issues with overheating the power supply, which have now been resolved. It requires a water temperature no greater than 90° at the inlet, otherwise it shuts down because the return temperature from the motor/generator cooler will exceed 130°F. It now discharges well below a safe limit. The problem was solved by adding a heat exchanger and changing the fan system. The fan is powered by a three horse motor. It's noisy, but it works. I also provided for an overflow in the coolant tank so cool water can be added, which is introduced at the bottom. Those changes completely eliminated the problems I was having.

Not having any experience in casting iron, each and every move has been a new experience. My first attempt resulted in failure, as I was unable to preheat the ladle adequately. Turns out there was a restrictor in the fuel supply hose that limited the amount of fuel it could deliver (propane). That has been altered to permit greater flow. I suspect that I will now be able to preheat the ladle adequately to provide a longer interval between filling and pouring.

Tuesday of this week, with the help of my good wife, I ran the furnace. I poured three flasks. The third flask, which was a mold for a casting weight (placed on top of the mold to prevent the cope from floating due to internal pressure) chilled before the flask was full, so it is not a complete casting, although it's still functional. The other two flasks were identical, a casting to replace the missing indexing pawl for the index head for my #2 Cincinnati cutter grinder. I poured two to ensure I'd get one that was useful, or in case I scrap one in machining.

Here's a picture of the first one poured.

Here's a picture of the one I have cleaned up and intend to machine.

Here's a picture of the remaining two flasks. The one to the right is the other casting for the index head, with the one to the left the flask for the weight. The two open face molds seen to the left are to be used for emptying the ladle when all of the metal is not used. They were not needed.
H

Very impressive, Harold.

Looks good!

One thing I don't understand;
" in case I scrap one in machining."

Please tell us that doesn't happen to you, or the rest of us might despair!

Fantastic outcome, and of course when you don't use a casting it can just go back into the crucible.

liveaboard wrote: ↑Fri Sep 03, 2021 8:48 am One thing I don't understand;
" in case I scrap one in machining."

Please tell us that doesn't happen to you, or the rest of us might despair!

Heavy sigh!
I last ran my machines for gain back in '83. At that point in time, making errors was exceedingly rare. As an example, I provided (difficult) work on a regular basis for Litton Guidance & Control. In my 16 years of doing so, I had only five rejections. I was quite competent.

Sadly, those skills die if they are not exercised regularly, and they haven't been. I now make stupid mistakes that wouldn't have happened then. So, I am not pleased to report that I no longer can walk on water.

Fantastic outcome, and of course when you don't use a casting it can just go back into the crucible.

For which I am eternally grateful, as the learning curve is quite steep if one hopes to produce sound castings, and I do. There is much that one must know, and, like machining, there is no substitute for experience, which I lack entirely. That said, I have a firm conviction and will, hopefully, overcome my shortfalls.

Thanks for your comments.

H

Well, for a guy with no experience, that's a pretty nice looking casting. I've seen MUCH worse from people that do have experience. Nice work Harold.

Ted

Thanks, Ted.

H