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3:15 PM
June 15, 2010
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Wooly Mammoth
| | South carolina, USA | |
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| posts 134 |
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I understand the concept of 'gibs' to tightenup/true up tailstocks and saddles/cross-slides on lathes. Without even knowing the word, i did the same thing on my wood lathe years ago. :)
So now, with the BGT, there are tiny adjustment screws for the gibs. Should I turn them in to tighten the gibs against the ways until the tailstock, for instance, will only just move with as close to ZERO side play as possible? I want the BGT as precise and tight as practical. I [and I suspect other beginners ] would luv to hear from the 'old hands' here re this. Thanks guys.
– Don "Politically Incorrect, and I don't care…" [sung to the tune of "Jimmy Crack Corn" ] :):)
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8:34 AM
June 17, 2010
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Tyler
| | Seattle, WA | |
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| posts 319 |
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I recently had to adjust the gibs on my cross slide because the slide as a bit loose. Even though my lathe was new (less than 50hrs) my cross slide didn't operate smoothly when the gibs were tightened the way they needed to be. I was puzzled. What I discovered was the gib strip needed to be stoned. It had nicks and burrs that had never been removed by the factory, so the only way to get the cross slide to travel smoothly was to loosen the gibs – which left the cross slide with an unacceptable amount of play.
I removed the gib strip and stoned it carefully to remove all the high spots. Then I replaced it and was able to tighten down the gib so that there was virtually no perceptible play.
For me, I tightened the gib down evenly until I felt a slight resistance when turning the screw to advance the cross slide. Once I felt noticeable resistance, the gib was tight enough to remove any excess play. You don't want to go too tight, because doing so will put unnecessary wear on your screw.
Be careful when you remove the gib strip, sometimes there is a small pin behind the locking screw (the screw or knob used to lock the slide in place). This pin pushes against the gib strip locking it in place, but doesn't rotate, so it doesn't wear a hole in the gib strip over time (like the end of a threaded screw would). Be sure you don't loose the pin, and be sure you put it back together properly.
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8:41 AM
June 17, 2010
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Tyler
| | Seattle, WA | |
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| posts 319 |
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And of course, if you take it all apart to inspect (which you should do occasionally to make sure you don't have chips or other harmful things imbedded against the ways) you should clean everything thoroughly and re-grease the parts before re-assembling. I used to use 1-2-3 oil, then I bought proper "Way Oil" and used that – which seemed to hold up better than 1-2-3 oil (lasted longer). But I just recently came across some high pressure CV Joint grease at the auto parts shop. I'm going to try a thin coat of this high-pressure lube the next time I take my lathe apart for cleaning. If it works well I'll let you know.
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9:05 AM
June 17, 2010
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Wooly Mammoth
| | South carolina, USA | |
| Member
| posts 134 |
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Thanks Tyler. Thast's the sort of 'real-world' advice that I, and probably other beginners really need. And like a llot of others, I understand the basic concepts, just don't have the experience yet, and know enough to realize that I could screw something up, even with the best of intentions.
– Don John Browning invented the .45 auto because ya can't always carry a 12 ga. :)
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9:47 AM
August 11, 2010
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ironring1
| | Vancouver, BC | |
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I followed a tip posted on mini-lathe.com and lapped my gibs using Al-oxide sandpaper, starting with 400grit and working up to 1000. They now have a mirror finish and I can tighten up the gib screws a lot more and still have a smooth feed (e.g. no binding). One thing that has crossed my mind, though, is that scraped ways sometimes are said to trap oil better, so I have though about doing one or two quick passes over 200 or 120 grit paper to put some "oil holding scratches" on the gibs, which otherwise are super flat. Make sure that you clean them REALLY WELL after lapping, though. You don't want any of that abraisive left on them when you reinstall them in your lathe :0
Be careful, though. On my G0704 mill, the gibs are all hand scraped to their corresponding slides. It would be a shame to lap those!
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10:48 AM
August 11, 2010
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Tyler
| | Seattle, WA | |
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| posts 319 |
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Hey IronRing, have you thought about scraping instead of sanding your newly polished gibs? If you don't have a scraper you could make one out of an old file. Scraping would make little pockets for oil to sit in. I'm afraid sanding would just destroy all the hard work you put into laping them.
I'm just wondering, you've already taken your gibs to a higher level than mine, so I'll defer to your judgment. If it works well for you I might consider it the next time I take my lathe apart for cleaning.
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11:17 PM
August 12, 2010
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ironring1
| | Vancouver, BC | |
| Member | posts 19 |
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I do have a scraper; it probably would be a better choice than the sandpaper. I was thinking of just one or two light passes to lightly score it, so I don't think that it would be much different than scraping, though. I can see my reflection in my jibs as they are now, though, and I can't bring myself to scratch 'em up! What I didn't say in my first reply was that I layed the Al-Oxide sandpaper on a pane of glass and rubbed the gibs on that, to ensure that they remained (became?) flat.
-Chris
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