Run out problem

Obvious to me

deadgearplyr said:
I bought a mini-lathe recently and I have been practicing doing tips. I got a few collets and ferrules from Chris H. and have been tinkering with retipping.

I am experiencing some problems with run out somewhere on either my chuck or the back end, or something. When I put the collet in it seems to wobble. When I take it out it seems to be fine. I can rotate the shaft and it will do it less, but I know there is some minor thing I am overlooking.

I stuck a rod into the jaws and it seems to run fairly true with minimal run out. When I stick a shaft in there with a collet is when I get problems.

On a few of my tip jobs one side of the tip is being shaved more than the other side and it is really sloppy looking. I know some of you more experience ones out there are probably laughing at me, but that's ok. Laugh it up, fellas. I am prepared to go through all the beginner's steps. I just need pointing in the right direction. please :help:
Click to expand...

Ok I am going to give you some good advice. Get a drill blank or something you know is straight that will fit in the chuck. Tighten it down put the dial indicator on it at the chuck and then out 1" and then out 2" or 3" does it get worse? I bet it does. Get a good carbide tipped tool. Take the chuck off of the spindle and take a skim cut off of the face. Then off of the shoulder only gonna take a couple thou off so that you get a continuous cut the whole way around. re mount the chuck and indicate the sucker back in. And Wa-laa now you have an accurate machine. As a side note make sure your gibs are snug so there is no play when you take the skim cuts. This will make your cut not be accurate. With this said you will only be as accurate as your least accurate component. Chuck, collet, tool post, gibs with slop, cross slide with slop. I have had a couple of these little lathes. From the box to a good machine it takes me about 3 hours to degrease, true up and mount to the bench. IMO time well spent.
 
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RocketQ said:
Ok I am going to give you some good advice. Get a drill blank or something you know is thraight that will fit in the chuck. Tighten it down put the dial indicator on it at the chuck and then out 1" and then out 2" or 3" does it get worse? I bet it does. Get a good carbide tipped tool. Take the chuck off of the spindle and take a skim cut off of the face. Then off of the shoulder only gonna take a couple thou off so that you get a continuous cut the whole way around. re mount the chuck and indicate the sucker back in. And Wa-laa now you have an accurate machine. As a side note make sure your gibbs are snug so there is no play when you take the skim cuts. This will make your cut not be accurate. With this said you will only be as accurate as your least accurate component. Chuck, collet, tool post, gibbs with slop, cross slide with slop. I have had a couple of these little lathes. From the box to a good machine it takes me about 3 hours to degrease, true up and mount to the bench. IMO time well spent.
Click to expand...

Yes. It does get worse the further I go out. I am grateful for your comments, but do what now? Skim where and gibb what? You have to remember that I know jack about this stuff. What is a gibb? I can only guess that you want me to take the chuck off and cut into what is behind the chuck and shave it oh-so-slightly. Yes? I am going to take a look back behind the chuck, but I am going to wait for your reply before I actually skim any gibbs. :scratchhead:
 
There is a lot of good advise being given here, but I think you're going to have to do your part in doing a little research so that you understand what is being said. The Internet is a terrific resource. Just try Googling "gibb" or "lathe maintenance" etc, and have some fun learning more about your new hobby.
Mr H
 
In the 2nd last pic from dave38 the pic showing the chuck and a nut at the back of the chuck. I use belville washers under the nut.These are like a spring washer that is bent in a curve. They hold quite alot of pressure. Then if there is some clearance between the chuck and the spigot of the chuck, the chuck can be tapped into position. When running where you want it, tighten up the nuts. Of if there is not alot of heavy or interupted cuts, it will stay where it is from the preload of the washers.
Joey has some good links too.
Neil
 
RocketQ said:
Ok I am going to give you some good advice. Get a drill blank or something you know is straight that will fit in the chuck. Tighten it down put the dial indicator on it at the chuck and then out 1" and then out 2" or 3" does it get worse? I bet it does. Get a good carbide tipped tool. Take the chuck off of the spindle and take a skim cut off of the face. Then off of the shoulder only gonna take a couple thou off so that you get a continuous cut the whole way around. re mount the chuck and indicate the sucker back in. And Wa-laa now you have an accurate machine. As a side note make sure your gibs are snug so there is no play when you take the skim cuts. This will make your cut not be accurate. With this said you will only be as accurate as your least accurate component. Chuck, collet, tool post, gibs with slop, cross slide with slop. I have had a couple of these little lathes. From the box to a good machine it takes me about 3 hours to degrease, true up and mount to the bench. IMO time well spent.
Click to expand...

Tightened the gibbs, took almost everything else apart, and got to the face plate, and the carraige doesn't move far enough left to take a skim cut... I put the chuck back on and readjusted the studs in the back of the chuck and it seems to spin a tiny bit truer.

Thank you all for your help, I apologize for any of my ignorance, I know I sounded like it. It seems like now that I have taken it apart and put it back together now, I can run the thing like an old pro. Wish me luck.
 
deadgearplyr said:
I bought a mini-lathe recently and I have been practicing doing tips. I got a few collets and ferrules from Chris H. and have been tinkering with retipping.

I am experiencing some problems with run out somewhere on either my chuck or the back end, or something. When I put the collet in it seems to wobble. When I take it out it seems to be fine. I can rotate the shaft and it will do it less, but I know there is some minor thing I am overlooking.

I stuck a rod into the jaws and it seems to run fairly true with minimal run out. When I stick a shaft in there with a collet is when I get problems.

On a few of my tip jobs one side of the tip is being shaved more than the other side and it is really sloppy looking. I know some of you more experience ones out there are probably laughing at me, but that's ok. Laugh it up, fellas. I am prepared to go through all the beginner's steps. I just need pointing in the right direction. please :help:
Click to expand...

Have you checked the chuck with something like the back end of a drill bit in the chuck and a dial indicator? The major problem is, a chuck is meant to self center under pressure, more pressure then you would ever squeeze a cue shaft with so even a very good chuck will often have run out with soft materials. There is a technique that you learn in a machine shop or if you take a course in machining that I will teach you in a PM a little later when I have the time to write. There is no need for a bunch of collots, just a piece of leather so you don't mark up the shaft.
 
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RocketQ said:
No problem. How did that work out??
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I ran out of room on the carriage. I couldn't crank it far enough to the left to get contact. I may rotate the cross slide 45 degrees and try it again. I didn't think about that before. I really do appreciate your help. I will say it again, I would probably be sitting in my shop scratching my head wondering what in the hell to do if it wasn't for you guys.

After I put it back together, it seemed to have slightly less run out than before. It is a good little machine.
 
If you get crank the compound out a good way to where it is still stable you can use regular tool or a boreing bar and cut the spindle that way.
 
RocketQ said:
If you get crank the compound out a good way to where it is still stable you can use regular tool or a boreing bar and cut the spindle that way.
Click to expand...

Ah, yes. I will try that. TY
 
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