Grizzly cross slide removal

B

Brian

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I had a accident the other day with my Grizzly lathe. I crashed the cross slide while facing off a barrel. It crashed into the side nearest me, the dial side. I freed it up but I fear I have damaged the cross slide leadscrew nut. I need to inspect the damage and to do that I must remove the cross slide itself. I have no idea how this thing comes off and before I tear into it I thought I would ask and see if anyone has any experience doing this. Is it supposed to slide off the far end or the dial side end.
 

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Brian, what makes you think you hurt the nut?? .

Most lathes have some sort of safety feature that keeps you from destroying expensive or hard to get to parts. It might be a non metalic gear in the gear train on the back of the lathe, or a shear pin of some sort.

I seriously doubt you hurt the nut.........jackie
 
I'll try to help you. The slide is the basic generic design that many lathes use.

I can not make out the bearing pack very well, but I wouldn't worry too much.
1. remove the handle on the cross slide
2. there is a bearing pack of somekind right behind the handle. Usually held in place by either a Timken bearing nut, Bearhug bearing nut, or a flat looking disc with holes drill in it for a spanner wrench. I would not remove any of these nuts with a hammer and punch, unless you like buying new parts
3. once the bearing pack assembly is removed (keep track of the direct the bearing went on the cross feed screw as this is very important)
4. ontop the slide you will find two or maybe three screws that attach the cross feed screw's nut to the top of the slide. Remove them. Next remove all the gibs, and mark each one for where they came from as in many cases they look the same.
5. I could not tell very well if the was a second bearing pack on the rear of the lead screw. If there is, it will have tobe removed just like the other.
6. Now you should be able to slide the cross slide off the saddle towards the operator's side of the machine
7. you can now remove the leadscrew

Being as the lathe was in a serious wreck, you will want to lightly stone the saddle and slides bearing surfaces with a very fine brown india stone (I'll fine the correct numbers for you). Now you should set the lead screw inside a matching pair of vee blocks on a surface plate. Rotate the screw and check with a dial indicator to see if it's still strait
(less than .0005" TIR). If the screw is strait you'll be OK assuming the nut is undamaged. If it shows a lot of slop in it (can you wiggle it sideways?), I'd replace them both (buy two nuts). Now being as we've taken a serious hit on the slide, I'd go out and buy new bearings (all you need is ABEC 5's so don't let them try to sell you sevens or even nines). Stone the gibs very lightly (are they showing a lot of wear?)

NOW for the bad part! If the head stock took a major hit, it will probably have to be realigned. Does the chuck open and close freely? With no tight spots? If the headstock is cast with the frame you'll be OK as long as you didn't hurt the spindle bearings. Assuming the chuck is OK (check the jaws very closely as they'll probably have to be recut with a spider). Find something that is very smooth and round (I like Thompson rod but drill rod will do in a pinch) and about 1.50" in diameter. You'll need at least a foot long piece and 18" is far better. Chuck it up in the lathe just like you were going to make a cut on it. You'll need a good wand type .0005" dial indicator (I prefer Interrapid, but they don't come cheap). By hand rotate the chuck till you get to the idicators low point of travel, and then set a zero. Now rotate the the chuck slowly till you've made at least four or five revolutions. Hopefully it will read less than .0005". If you have a good tenth indicator now is the time to use it. While rotating the chuck by hand, do you feel any metalic clocks or a tight spot? If you do you got problems. Should everything feel and look go so far, then lets reassemble the slide and screw and nut. Everybody has their own way of tightening the gibs, and here's what I do. First I'll crank the cross slide back and fourth a couple inches while pushing the gibs in with my thumb (not too tight now). Some cross slides have screws on both ends of the cross slide for the gibs. If so you got off lucky assuming you did not remove them. After you have the gibs in all the way and locked down, take a .0005" indicator and put it ontop the slide with the indicator reading agains the saddle. If the reading changles a lot when you crank the slide tighten the gibs till it quits moving (not too tight). when doing this you only need to move the slide a quarter inch at most. Now it's time to adjust the backlast out of the lead screw is you have the three screw nut. The center screw is the adjustment. Otherwise I'd use plastic shim stock between the slide and the nut to push it down (some actually work just the opposite of this, but are not common). After all is assembled lets put the Thompson rod back in the chuck one more time. Rotate it to make sure it's chucked up nice and square. Now you want to sweep the top of the rod with an indicator You may find that you need a gib adjustment on the saddle as well. Make several sweeps along the top without moving anything, and write down what you find. Rotate the chuck 180 degrees and do the samething. Now you know the true error in the chuck as well as the alignment of the head stock. Next sweep the side the sameway. and rotate it. Hopefulling it will come out at less than .001" in 12". If not all is not lost, but the fix will take into another world of fixing machinery.
email me at l1945@sbcglobal.net if you need more help, as I did this for a living half my life.
gary
 
Hey Squeakie
All he did was accidentally bottom out the cross slide and jammed it. He did not get in a automobile wreck with it on the back of a truck. Unless, that is, he rigged some type of power source and was facing off a barrel while heading to a match.:D
I would bet he hasn't hurt anything on his lathe.............jackie
 
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.0005" TIR run out on the lead screw? Do you have too many zeros I can't believe a lead screw in a Chines lathe is going to be that straight.
 
Hey Squeakie
All he did was accidentally bottom out the cross slide and jammed it. He did not get in a automobile wreck with it on the back of a truck. Unless, that is, he rigged some type of power source and was facing off a barrel while heading to a match.:D
I would bet he hasn't hurt anything on his lathe.............jackie

when you run a cross slide into a rotating chuck you need to do a check. If nothing else, the chuck. There's nothing funny at all about a chuck failure while you using it (often fatal). The fellow asked how to remove the crss slide and I hope I got him started. Had I been the one checking it out, I would not have pulled the slide unless I detected something amiss. The slide I was not all that worried about, but the chuck and headstock I was. Lastly, I've been unfortunate to have worked on a couple of that brand of lathes in the past.
gary
 
.0005" TIR run out on the lead screw? Do you have too many zeros I can't believe a lead screw in a Chines lathe is going to be that straight.

how many lead screws have you changed in your lifetime? Or better yet how many have you inspected (including the nuts)? I've probably done over two hundred. How many chucks? I've probably rebuilt over a hundred. .0005" is not that bad for a short screw, but when you take the .0005" and double it (the error in the screw will double each revolution) from a plus to a minus (in otherwords become .001". This causes the nut to wear out faster.
There are two things that causes the screw and nut to wear out prematurly. Missalignment is number one. Number two is a wreck. Lack of lubrication is usually number three. I might add here that if the cross slide screw is bent; you can straiten it in an arbor press (assuming it's in the middle). But no matter what; it wants to be strait
gary
 
Gary I agree with everything you said for a high dollar high precision lathe. I have one of these lathes and find it to be good piece of equipment for a weekend hobbiest. This is a machine built in China, most likely goes through a chines trading company, landed in the USA, goes through a machine tool dealer, and is sold to the end user for $2900.00. For that kind of money you are not going to get the same quality as you would in a machine selling for $30K. I agree the screw should be that straight, but in the real world for that money your not going to find it.
 
when you run a cross slide into a rotating chuck you need to do a check. If nothing else, the chuck. There's nothing funny at all about a chuck failure while you using it (often fatal). The fellow asked how to remove the crss slide and I hope I got him started. Had I been the one checking it out, I would not have pulled the slide unless I detected something amiss. The slide I was not all that worried about, but the chuck and headstock I was. Lastly, I've been unfortunate to have worked on a couple of that brand of lathes in the past.
gary


Squeakie.....First of all, thank you for replying. I appreciate it. However, you misunderstood the scope of the accident I had. I did not crash the cross slide into the chuck at all. I was using the power cross feed and let the cross slide crash into the end closest to me. It froze the dial and when I finally freed it up I found I had a full rotation of backlash that I can't seem to get out. I was told by a friend who is more experienced with a lathe that I may have trashed the lead screw nut.
 
Gary I agree with everything you said for a high dollar high precision lathe. I have one of these lathes and find it to be good piece of equipment for a weekend hobbiest. This is a machine built in China, most likely goes through a chines trading company, landed in the USA, goes through a machine tool dealer, and is sold to the end user for $2900.00. For that kind of money you are not going to get the same quality as you would in a machine selling for $30K. I agree the screw should be that straight, but in the real world for that money your not going to find it.

No I agree with everything in your post 200%! But here's the ticket in my eyes. He simply said he had a wreck on a Grizzley lathe. Not actually knowing whatkind of chuck and just how hard he was running the machine I responded as I would have with any crash. It's not how many dollars and cents he spent, but a saftey issue with me.
The fellow wanted to know how to pull the slide, so I helped him as best I could without being in his shop (if he was close by I'd have fixed it for him as long as he had a twelve pack of ice cold Becks). I'd help most any one of you all out in the same manner. If you called me up at ten in the evening asking me why your Bridgeport clone won't work; I'd be right there. I think in life one needs to extend a hand a lot more than he does right now.
just me anyway
gary
 
Squeakie.....First of all, thank you for replying. I appreciate it. However, you misunderstood the scope of the accident I had. I did not crash the cross slide into the chuck at all. I was using the power cross feed and let the cross slide crash into the end closest to me. It froze the dial and when I finally freed it up I found I had a full rotation of backlash that I can't seem to get out. I was told by a friend who is more experienced with a lathe that I may have trashed the lead screw nut.

I read that before I had my coffee! The lathe probably is just fine, but don't force the handle on the screw trying to move it! Loosen the gibs and the nut a little bit. Reason why is that the far ends of the slide will be much tighter than the middle due to wear. By loosening the nut just a little (maybe one turn on the screws holding it) and the gibs just a little bit it will move easier. I might add here for all you guys using a lathe a good bit, that it's a good idea about once a year to pulle the gibs and flush out the pockets where they reside. (don't use an air hose!) Then coat the gibs with a light bearing grease before reinstalling them. Your slide will last a lot longer this way. Anytime I can help you, just send me an email (same for all of you).
gary
 
No I agree with everything in your post 200%! But here's the ticket in my eyes. He simply said he had a wreck on a Grizzley lathe. Not actually knowing whatkind of chuck and just how hard he was running the machine I responded as I would have with any crash. It's not how many dollars and cents he spent, but a saftey issue with me.
The fellow wanted to know how to pull the slide, so I helped him as best I could without being in his shop (if he was close by I'd have fixed it for him as long as he had a twelve pack of ice cold Becks). I'd help most any one of you all out in the same manner. If you called me up at ten in the evening asking me why your Bridgeport clone won't work; I'd be right there. I think in life one needs to extend a hand a lot more than he does right now.
just me anyway
gary


Twelve pack of Becks, I'm gong to keep you in mind for machine repairs you work cheap. Have a good one Gary.
 
Twelve pack of Becks, I'm gong to keep you in mind for machine repairs you work cheap. Have a good one Gary.

You know it's not a beer so much as doing a favor for a friend. I do have one buddy that has a small shop with five or six machines in it. He'll call me up in the morning asking me to look at one of them, and I tell him to put his wife on the phone. I'll ask her what's for dinner as this single male hasn't had a good home cooked meal in eons! When I drop by to see what's wrong (he's got one Bridgeport that would make a quality boat anchor in my book!) he'll call his wife up to send her to the liquor store. Now that's a good woman! On the otherhand I can take a race hemi head over to Marc and have him perform his magic on it without the slightest problem (he drinks cheap beer too). It's just what friends are for. If you were in Indiana I'd drop by to help you thru the latest headache without a second thought.
gary
 
Brian,
Bring the cross slide all the way to the near end, so it is closest to you. Remove 2 hex screws that hold a small plate on the back side of the saddle. Next remove the hex screw that is in the middle of the saddle right behind the compound(this holds the pinch nut that is on the cross slide screw). Now rotate the hand wheel like you are trying to move the cross slide away from you, watch the back side where you removed the plate, the pinch nut will start to come out that end. You can keep rotating the hand wheel until it comes off. Catch it with your other hand before it drops off. You can tighten the pinch nut to take out some of the slack, take care though. If you tighten it too much it will cause premature wear. Re-assemble in reverse order.

James
 
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