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View Full Version : Hello. Blind Pig here...



QSIMDO
06-26-2011, 01:20 PM
Found an acorn yesterday and thought I'd share since it's a rather common problem.

Thanks to new lighting on my low cost import lathe I was suddenly aware of a significant amount of vertical movement on my cross slide while trying to part some SS.
I could now see the way oil squishing in & out from under the cross slide.

This movement had heretofore gone undetected but my parting operations were as scary as others have reported so I just thought parting was a b***h and that's the way of it.

Tightening the gib strip made no improvement whatsoever so off with the cross slide and onto the surface plate where bluing showed a total of maybe one lousy square inch total of contact over the entire area!

Before reading further, understand I'm a hobby machine operator who just enjoys making swarf and occasionally finding something useful left in the chuck, OK?
OK, so, with no surface grinder of accuracy available to me and scraping skills best suited for layers of of paint I did what turned out to be a damn good solution.

Sand paper and the surface plate.

Worked a TREAT!

I can now part nearly as fast as I can turn the handle, absolutely no ripples when normal turning or any tool dragging when cranking back.

No recommendations here, just a happy guy reporting what worked for me!

RB211
06-26-2011, 01:43 PM
I have a feeling that almost every sub 2000$ import lathe on the market needs to be inspected the same and have done to it what you did. Scary to think just how "off" some of these machines can be!

Black_Moons
06-26-2011, 04:55 PM
Sandpaper on a surface plate is a good way to get stuff flat.. However ,May not get stuff into alignment. take GREAT care with such methods. And idealy wipe the hell outta the surface afterwards to get as much grit outta the cast iron as yo ucan.

DATo
06-26-2011, 05:20 PM
Congrats on a job well done! For a "hobby machine operator who just enjoys making swarf" it appears you have a natural talent for this trade. Stay with it, expand your talents and most of all ... ENJOY !!!

sasquatch
06-26-2011, 08:00 PM
Congrats,, just wondering,, what type of sandpaper????????????

uncle pete
06-26-2011, 09:18 PM
Well done, I could only add that an intelligent and well thought out plan of use should be done. It's far too easy to make things worse if you have no idea of what your doing. Obviously this doesn't apply to the OP but if your not well experienced then I'd reccomend the Connley book Machine Tool Reconditioning. It would be $100 well spent.

Pete

J Tiers
06-26-2011, 11:46 PM
That can and will work. Evidently it did. it may not be the best way to do the job.

If you have a surface plate, then all you really need to do a quality job of flattening that surface is a scraper (can made from an old file), and some high-spot blue to show the problem areas.

Looks like you may have the blue.

Scraping is easy to start doing. All you need is to scrape off the marked spots, stone or burr-file the burrs off, and spot again.

After a while the contact spots get bigger until they are over the whole surface, and evenly distributed. basically you can stop there. Much more controlled than sandpaper, and doesn't leave grit possibly embedded in the part.

Whether that leaves the part in a good alignment is another question, but that question is the same either way, scraping or sandpaper. With that sort of part, often a mic will tell you if you are parallel, and then if you are scraping, you can fix it. With sandpaper, maybe, but it will be much harder to do right.

A dial indicator on a surface gage will also do the check, and may be more convenient than a mic, depending on how the cross-slide is made.

Sandpaper seems to have worked, so you don't need to sweat it for now. But scraping is a useful enough skill that is worth learning just to fix dumb stuff like that. You learn by doing... you know what you want, you just need to make it happen.

Yow Ling
06-27-2011, 02:43 AM
So a flap wheel on the angle grinder is out then?

J Tiers
06-27-2011, 09:26 AM
So a flap wheel on the angle grinder is out then?

if you are a true artist with it, knock your socks off... ;)

A.K. Boomer
06-27-2011, 09:59 AM
I would (and have) forgo the sand paper (due to it forming a mild wave action even with the best surface plate) and just use a precision fine grain stone to lap it in - it's how I set up my mill when I first bought it - like you I did not like the limited contact surface area...

just my 2 cents