And there are many trying to cash in on the mistique. I got one cd that seemed to offer enlightenment but it was really just junk. I did use it to make a run at my crosslide and compound and they were greatly improved by my very modest attempt. I was very very careful and didn't shoot for perfection, just knocking down the very badly butchered high points and I learned a lot. Then I caught wind of Machine Tool Reconditioning by Connelly and found a copy. Very enlightening and yeah quite a tome at 500+pages. But just reading the spots that are pertinent cut down on the wade. You already have DI's, height gage and surface plate, all you need equipment wise is a good carbide tipped scraper. I bought cheap ones the cd recommended and that was the main reason I struggled. Bought a good Anderson scraper and actually got something done! I'm certainly not advocating everybody do it, but it's a good skill to have even if it's a huge time sink.
Last edited by C-Bag; 05-14-2017 at 07:30 AM.
This why many refrain from toolpost grinders. The problem is some think a pile of rags filter grit and metal fines. NO! Oiled brown paper or plastic wrap are far better suited when properly draped.
Scraping can be viewed as a cutting or finishing operation, per time invested. As machinery is typically cast iron scraping is superior to lap for several reasons. Surface of iron isn't very dense, trapping detrimental particles. The result is wear seen in well used machines. Scraping does not produce a 'flat' surface as such. Ideally, it presents 18 to 25 contact points per square inch. They are surrounded by 'divots' intended retain lubrication. With two such surfaces in contact, it is very nearly hydroplaning on lube, and isolated metal to metal. Properly cleaned and maintained, scraped-in work has incredible longevity. it also presents less stiction, the resistance to movement being initiated. Evidence of this relates to bumping a lathe carriage handwheel to transit the ways a few desired thousandths. All sliding surfaces have it in different degrees; generally desirable if consistent across entire range of travel. Automated equipment use linear guides to increase positioning speed and accuracy.
There are a variety of epoxy-like materials bedded to worn surfaces to supplant traditional metal to metal. Rebuilders use it with varied results, but an industry standard for quite some time now. Generically, they are known as "TurciteŽ"
...we'll learn more by wandering than searching...
I have watched a few youtube videos of scrapping process. I can see I don't want to personally go that path. My read of the CNCZONE post is about taking low cost import machines and improving the slide of the ways.
My "minds eye" sees that putting a grit on the ways, and sliding it back and forth will produce parallel ridges of peaks and valleys at a microscopic level. It will sand away high spots. I would not do that process to my machines, mainly my read (many authors including your post) that lapping grit is left in the surface metal.
It's been a few years since I used my tool post grinder. I found it burned a hole through the cloth towel, and realized during this operation that the grit was not stopped by this porous material. I finished the task using 22gauge sheet metal to protect the ways of the lathe. It's is not an operation I've done much of. I'm not to worried about excess wear on my machines for the time I have left. My 2 lathes were purchased new, both 'affordable' imports. And they both are 'pre-assembled' kits. They do have many hours of rework to improve their operation.
C-bag said it all, Scrape. You will learn a new skill and can accurately align the ways. You can also surface to retain lube. Win win.
There is a U-tube by a,(Swedish?),bloke who goes into great detail on blueprinting slideways by scraping, it's absolutely brillient but if I bookmarked it I can't find.
The best out of many takeaways I got from the Connoly book was measuring, understanding and mapping out what was wrong and what needed to be done before you even get out the scraping tools. That was THE major sin that junk cd never addressed. Like it never occured to me because of that, that the major problem of drag on the crosslide could be misalignment of the feed screw. If it's was too high, then scraping could help as scraping would help to bring it into alignment. If too low you'd only compound the problem. In my case I was lucky as this was one of the problems besides crudely machined surfaces.
But my mill and lathe were both used and in the case of the mill I think several people had a go at it butchering things. Luckily it was the things easy to get to like the gib. Some guys seem to revel in this but I didn't understand I might spend all my time fixing stuff instead of doing actual projects. For me it paid off in being able to actually fix the problems and not make them worse. And that was sheer luck as I now see that these problems were the reason they were so cheap.
Projects improve empirically when the implements improve. And experience benefits from both.
CD's are often self generated, by self appointed experts, whose real talent is just copy/ paste. A CD burner, label stomper and a few boxes of blank disks, they are publishing tycoons. The webay and humazon are chock full of them.
Except, minus the critical proofreading of real experts, or decades being established as "the" standard reference.
Last edited by Toolmaker51; 05-13-2017 at 09:40 AM.
...we'll learn more by wandering than searching...
Little things like marking(I use a silver pencil) on your surface plate so you can get an accurate way to reposition the work to recheck and using an old dull file instead of a stone to shave down burrs made a world of difference in my application of the process. I also see major booboo's like moving the scraped piece in large repeated sweeps on the surface plate and other things in the vids which fly in the face of the original process.
It so reminds me of music where people idolize the present musician but ignore who they listened to. Looking up those originals taught me so much and in more than one instance made me realize these folks were pale imitations of the originals like Django and Howlin' Wolf.
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