Adjusting Gibs.

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gcarsen
Posts: 575
Joined: Sun Jul 08, 2007 7:39 pm
Location: Tigard, Oregon

Re: Adjusting Gibs.

Post by gcarsen »

My take on adjusting gibs,
first thing that was worked into our daily routine, oil the machine good, and then manually move all the axis by hand back and forth the full length of travels about 4 times. this insured everything and everywhere needed was lubed. second it helped clean the ways to and extent, helped spread the lube. plus it helped spread the wear on the ways all over instead of being concentrated in the center 6 inches or so! help prolonging the hour glass wear in the center of the ways.
then next big question to answer before adjusting gibs on a milling machine, what set up does your ways use. this is important. older all metal scrapped ways need to be very close but as said you dont want them locking up tight either. i was shown by the oldtimers to run the table all the way to the end tavels, lock the knee and saddle . on the long end sticking out from the saddle mount an indicator against the side of the table , now with your waist lean in and push and pull on the end , you only want to see about a .001 movement, rough math shows that you then have about .0005 clearance on the gibs, adjust to you get this number, with good lube its nice and smooth with out noticeable slackness or tightness, run down and check other end.this will give you as about as tight as you can run, using travel lock to make up for the center worn area. then lock table and loosen the saddle and repeat . if you get them too tight you can gall the ways up very quikly!
now if your ways are set up with the turcite inserts , PLASTIC , sheets that are mounted on top and bottom of the saddle, this is a different deal! that turcite has some spongeness and self lubricating tendancies. and this is only with the late model or ones converted over to turcite or one of the other "plastic" insert ways. on a cnc mill with this setup you run the travel back and forth the full length and tighten the gibs to a given electrical load on the servo or drive motors that is specked out. on a manual, set up the indicaters on edges of the table with indicators. tighten the gibs up till all play is gone on the ways. need to still becarefull that you can manually crank the axis back and forth!
ball races, or cages are whole nother matter!
lathe saddles generally have a keeper going around to the back side of the front and rear of the ways. either solid or spring moutn, adjust these to they have about .001 clearance over thightest spot along the bed.
Grant
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