I?m not going to mention the techniques of bluing up a part as imho these will never change. Or even mention that bluing is an art in its self. This thread will only cover the uses of a hand scraper or not as the case maybe. My method will probably make my old grandfather turn in his grave (he was a scraping hand up until he retired) and the purists cringe into their boots.
A brief explanation about how my alternative method came about.
Trying to keep this as brief as possible; I recently bought a Chinese bench top mill. All in this tread and includes some brief posts on my scraping method (start at page 4 about scraping). http://www.factorydaily.com/forums/showthread.php?t=40213 (XJ20 what do you think please?)
As only to be expected with a Chinese mill it was in need of some serious scraping. So off I set scraping the ways of my machine with my old hand scraper (old file modified) and the usual other tools. It wasn?t until I got to scraping the ways of my column that I stopped to think ?there has to be an easier way?. Added to the fact that I had a lot of bearing area to scrape was the fact that there is a 0.09mm (0.00354?) of bow in the column. So I sat and pondered ?do I take this somewhere and have it skimmed on a surface grinder or just dig in and do it by hand?. Well the thought of taking it and the price got to me (tight Yorkshire man that I am) so how was I going to remove all that metal without loosing a week of my life. I then thought about the fact I had been using a Dremel type tool to remove some burrs on the castings so I put on a round belt sander type thing (see picture) and proceeded thrashing off metal off either end of my column after a quick blue so I could see where I was removing it. I realised very quickly I was removing metal far quicker and easier than I would have been with my scraper. So I stopped and wondered could this make my scraper obsolete? I went to the bench and picked up my X-Y saddle (already hand scraped) and blued it up on my surface plate. Very nervously to start I removed some of the blue (did a re scrape of the surface) and to cut this story short it worked a treat. Where before I had my surfaces within +/-0.005mm (0.0001968?) of each other I now cannot measure the error as my DTI pointer barely moves while all set up on my surface plate.
The hand scraper is not quite obsolete yet as the sanding bobbin is to large to get right under the dovetails but I have a plan. I remembered seeing some one with a narrow file sander (see here http://www.axminster.co.uk/product.a...file=1&jump=60 ) and know this will work as a scraper if the front drum is small enough to fit right under the dovetail. If I were doing a lot of this scraping (absolutely no plans to) I would look into modifying (if needed) the nose of the file sander but for a one off job I will probably just stick to my hand scraper to get where the sanding bobbin can not get.
This may all sound like crazy talk to the purists and all I will say is that with the right technique and a little practise IMHO I can do an equivalent job as the above average hand scraper as fast (if not faster), as accurate (if not more accurate) and far easier on the back so don?t knock it until you have tried it.
Before anybody decides to take a sander to their ways I would highly recommend a practice on an unimportant part of their casting as it is not as easy as it sounds. It requires a light touch (which varies as the job gets close to finished) and the tool at just the right angle or you will very quickly remove to much metal and spoil your bearing.
Ok guys get the out I got my asbestos suit on and what can?t speak can?t lie (that would be my X-Y axes saddle).
I?ll post some pictures of my saddle blued up if anyone is interested when I get a minuet?
EDIT: Please see post #41 Page 4 before reading the rest of this thread. :END EDIT