metalmagpie
Titanium
- Joined
- May 22, 2006
- Location
- Seattle
I'm working on a motor mount for an antique 1hp GE motor patent date 1912. On the machine, it had all kinds of washers and shims stuffed underneath it because the machine's cast motor mount is nowhere near flat. To further complicate matters, the motor is larger than the factory mount so an extension plate must be used.
I have learned enough to know that if you want an electric motor to run right and run quiet, you need to mount it on a flat level base.
So I scrounged up this piece of cast iron. It's about 7/16" thick, and it isn't anywhere near flat either. If you bolted it down to a mill table with clamps you'd probably crack it because it has a big hump in the middle, maybe .080" high. Maybe I could figure a way to bed it in pitch or something but I decided what the heck. I'll scrape the auxiliary plate flat on one side and then I can use it to spot the factory motor mount so I can scrape that flat too. Finally, with the aux plate flat on the bottom, I can clamp it down and mill the top to something approaching flat, then scrape it in the rest of the way.
That was my battle plan, anyway. Well, as someone said, no battle plan survives contact with the enemy army. I realized right away that I'd be scraping for months to get that huge hump out. So I moved to plan B. I'm "scraping" it using a coarse flap wheel on an angle grinder. I'm careful not to let it gouge too deep. In half a day and innumerous trips to the surface plate, it's approaching the point where I can start scraping.
I believe I heard Richard King say he's used an angle grinder for heavy removal prior to scraping before. That's where I got the idea. Anyway, so far it's working. And if I screw it up, well, it's my time and sweat but very little money so in my book no big deal.
metalmagpie
I have learned enough to know that if you want an electric motor to run right and run quiet, you need to mount it on a flat level base.
So I scrounged up this piece of cast iron. It's about 7/16" thick, and it isn't anywhere near flat either. If you bolted it down to a mill table with clamps you'd probably crack it because it has a big hump in the middle, maybe .080" high. Maybe I could figure a way to bed it in pitch or something but I decided what the heck. I'll scrape the auxiliary plate flat on one side and then I can use it to spot the factory motor mount so I can scrape that flat too. Finally, with the aux plate flat on the bottom, I can clamp it down and mill the top to something approaching flat, then scrape it in the rest of the way.
That was my battle plan, anyway. Well, as someone said, no battle plan survives contact with the enemy army. I realized right away that I'd be scraping for months to get that huge hump out. So I moved to plan B. I'm "scraping" it using a coarse flap wheel on an angle grinder. I'm careful not to let it gouge too deep. In half a day and innumerous trips to the surface plate, it's approaching the point where I can start scraping.
I believe I heard Richard King say he's used an angle grinder for heavy removal prior to scraping before. That's where I got the idea. Anyway, so far it's working. And if I screw it up, well, it's my time and sweat but very little money so in my book no big deal.
metalmagpie