StrayAlien
Cast Iron
- Joined
- Aug 18, 2014
- Location
- Melbourne, Australia
Hi all,
I've watched maybe very scraping vid there is, but, time to tool up and get some practice in before loosing myself on a machine. When I'm happy, this old girl will get some treatment. She is running, but, to do the job for real, she needs a proper recondition.
https://www.practicalmachinist.com/...own-sharp-2-surface-grinder-back-life-363506/
My first attempts have not been great. Terrible actually, and maybe that is an understatement. Chatter and scratches. So, seeking some advice to help me get over this beginner's hump. The following pic has some random stuff and experiments but gives the idea. I am going one pass diagonal, then another at 90 degrees, and other stuff just to see what is what.
I'm using carbide in a hand scraper. 60mm radius, and also tried 90mm. I've jimmied up a slow speed grinder in the guise of a fine grit 6" diamond wheel set on a backing plate (which is a gear) on a shaft and in the lathe 3 jaw chuck. Seems effective.
I'm grinding into the carbide so as not to chip the edge, the wheel is lubed with wd40. About 300 rpm. I've tried 5 degrees and 8 degrees negative angle. The 8 degrees made some small improvement I think. The material is cast iron and, from what I understand, not too bad quality. It is a piece from the last scraping class in Melbourne a few years ago.
The carbide edge has no flaws that I can feel, and it'll shave my fingernail just fine. The surface on the carbide looks good. I've tried heavier scrapes, lighter, shallow angles and steeper angles, long strokes and short strokes.
I've not managed anything I'm happy with.
All comments and advice appreciated.
Greg.
I've watched maybe very scraping vid there is, but, time to tool up and get some practice in before loosing myself on a machine. When I'm happy, this old girl will get some treatment. She is running, but, to do the job for real, she needs a proper recondition.
https://www.practicalmachinist.com/...own-sharp-2-surface-grinder-back-life-363506/
My first attempts have not been great. Terrible actually, and maybe that is an understatement. Chatter and scratches. So, seeking some advice to help me get over this beginner's hump. The following pic has some random stuff and experiments but gives the idea. I am going one pass diagonal, then another at 90 degrees, and other stuff just to see what is what.
I'm using carbide in a hand scraper. 60mm radius, and also tried 90mm. I've jimmied up a slow speed grinder in the guise of a fine grit 6" diamond wheel set on a backing plate (which is a gear) on a shaft and in the lathe 3 jaw chuck. Seems effective.
I'm grinding into the carbide so as not to chip the edge, the wheel is lubed with wd40. About 300 rpm. I've tried 5 degrees and 8 degrees negative angle. The 8 degrees made some small improvement I think. The material is cast iron and, from what I understand, not too bad quality. It is a piece from the last scraping class in Melbourne a few years ago.
The carbide edge has no flaws that I can feel, and it'll shave my fingernail just fine. The surface on the carbide looks good. I've tried heavier scrapes, lighter, shallow angles and steeper angles, long strokes and short strokes.
I've not managed anything I'm happy with.
All comments and advice appreciated.
Greg.