Atlas 618 bent spindle threads??

J

jster1963

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Hey guys,

I changed over to a link belt, but wanted to save the old belt. So I removed the spindle. My lathe was not mounted in it's final spot before I removed the spindle, but I don't remember it having a wobble.

With the spindle mounted in the headstock, the shaft runs true. However, with a chunk, faceplate, or dead center mounted, there is a significant runout. On the flat part of the spindle that sticks out, the runout is less than .0005". That is measured on the vertical and horizontal axis. It runs as bad as .008"-.012" with a dead center.

I posted a youtube video on how to remove the spindle. It shows the runout about 6:00 into the video. I did run the lathe in back gear without putting oil in the hole in the pulley. It got hot. Do I need a new spindle? Is it something that I'm missing? I could use any help.

Thank you.......ps. I posted this on the yahoo atlas 618 group too
http://www.youtube.com/watch?v=ATNTYnJ5IwI
 
sssfox said:
You are measuring in two different places. The first measures the runout of the external surfaces of the spindle. The second measures the runout of the MT socket and the dead center. Since you have no runout on the external, it probably isn't the spindle.

It could be the dead center or it could be a piece of crap or rust on the MT socket. If you know the dead center is accurately machined, get a brush, clean out the socket and try again..

By the way, you will get better results if you preload the bearings.

Steve Fox
Click to expand...

Thank you Steve! I'll check the MT socket and the center, but the chuck wobbles too. That is why I thought it was another problem. Do you think that I should put everything back on and go through the preload procedure? Could that help with the spindle wobble?

Thanks again Steve......
 
Steve,
The chuck is not threading all of the way onto your spindle. The chuck must bottom out against the shoulder at the back of the threads. The smooth part of the spindle past the threads and the shoulder that is 90 degrees to the threads is known as the register. That is what makes the chuck square to the spindle. The threads just snug everything against the register. You can see daylight between the back of your chuck and that shoulder in the beginning of your video. Don't just crank down on the chuck, find out why it isn't threading all of the way on. I have a 618 where someone decided to thread a 1" x 8 chuck onto a 1" x 10 spindle. It wasn't pretty. The early 618s were 1"x8 and the later models 1"x10.
HTH,
Chrispy
 
Actually, the first 618 model (Craftsman 101.07300) had 3/4"-16 spindle nose threads. Spindle part number L9-31. But it was only made for about a year (late 1937 and 1938) before being replaced with the model with 1"-10 threads (Craftsman 101.07301). Spindle part number L9-31A. Both of these models had split bronze sleeve bearings. The latter was produced until late 1956. Beginning early 1957, the final 618 model with Timken bearings and 1"-10 spindle nose threads came out (Craftsman 101.21400). Spindle part number M6-31.

All that aside, as Chrispy said the chuck or faceplate must bottom against the flange face or all bets are off. The diameter of the register should be 1.0000/.9995". Do NOT put a lathe tool on the diameter and I wouldn't touch the face of the flange until I was absolutely certain it was part of the problem. And even then only after I was certain that the cross slide was dead nuts right. A new spindle is expensive.

Robert D.
 
wa5cab said:
Actually, the first 618 model (Craftsman 101.07300) had 3/4"-16 spindle nose threads. Spindle part number L9-31. But it was only made for about a year (late 1937 and 1938) before being replaced with the model with 1"-10 threads (Craftsman 101.07301). Spindle part number L9-31A. Both of these models had split bronze sleeve bearings. The latter was produced until late 1956. Beginning early 1957, the final 618 model with Timken bearings and 1"-10 spindle nose threads came out (Craftsman 101.21400). Spindle part number M6-31.

All that aside, as Chrispy said the chuck or faceplate must bottom against the flange face or all bets are off. The diameter of the register should be 1.0000/.9995". Do NOT put a lathe tool on the diameter and I wouldn't touch the face of the flange until I was absolutely certain it was part of the problem. And even then only after I was certain that the cross slide was dead nuts right. A new spindle is expensive.

Robert D.
Click to expand...

EXCELLENT info Mr.D! I looked into a new spindle from Clausing and it runs $189 plus shipping. I sure hope I don't have to go that route. I do have the headstock back together and show the 3 jaw chuck about .017" runout with and end mill bit. I will post another vid shortly of my results. For some reason, I can't get my 3 jaw to bottom out on the spindle. There is about 1/16" gap. I cleaned both parts very well too.

Thanks for the info and more to come......
 
Jster,

Do you have a faceplate? If so does it screw up to the register shoulder?

Most chucks can be disassembled (and probably should be every decade or two as "stuff" gets inside that doesn't belong there). If the faceplate or another chuck screws all of the way on, then the problem is probably with the chuck and not the spindle. Taking the troublesome one apart should allow you to easily look at and clean out the blind end of the threads.

On the 2MT spindle taper, sometimes they get nicked or scored or the big end can get damaged. In another thread an owner reported having both problems.

Robert D.
 
sssfox said:
I don't have a 618, I have a 12" Atlas.

I had the same problem that you are having. I ended up getting an inspection mirror and a dental pick to remove aluminum swarf that was "welded" to the internal threads in the chuck. I have 1-1/2" threads, so It will be a little tougher for you since you have 1" threads . The mirror I have is 1" wide. I guess you need a smaller mirror. Also, you could use a small, internal boring bar instead of a dental pick.

Robert is correct, there is never a need to shave the diameter of the spindle. It won't help anything.
It also won't do any good to resurface the face unless you indicate it and it is out.

My three-jaw chuck is old and worn and has from .003 to .005 runout, depending on the size of the work installed in it. If I need anything more accurate than that, I use my four-jaw chuck.

Even with a four-jaw chuck, if it isn't seated correctly, you will still have runout issues. If the axis of the work isn't parallel with the axis of the spindle(wobble), when you indicate the work true at one point, it will still be out everywhere else. The assumption with a four-jaw chuck is that the gripping surfaces of the jaws are each parallel to the spindle axis. A crooked chuck won't give you that. That's why it is so important to get the chuck up against the face on the spindle, three-jaw or four-jaw.

Steve Fox
Click to expand...

BRILLIANT Mr. Fox! That was a question I had today. I put it back together and preloaded the bearings. I got the runout on my 4 jaw with an end mill to .0005". That was my fist time centering up a round piece in a 4 jaw. So I think it's dead true! With the end mill in a collet, the runout is .002-.003". So it's not the spindle, right?

I still have the wobble with my 3 jaw. So I think my 3 jaw has the problem. I still for the life of me can't get it to "seat" to the spindle. I used a pick and cleaned all the threads. There is still a 1/16" gap. It really is clean, so I'm clueless (well that goes without saying).

I'm really scared to try to force it anymore onto the spindle. I'll do some measuring it tomorrow.

Thank you again for all of your help......
 
wa5cab said:
Jster,

Do you have a faceplate? If so does it screw up to the register shoulder?

Most chucks can be disassembled (and probably should be every decade or two as "stuff" gets inside that doesn't belong there). If the faceplate or another chuck screws all of the way on, then the problem is probably with the chuck and not the spindle. Taking the troublesome one apart should allow you to easily look at and clean out the blind end of the threads.

On the 2MT spindle taper, sometimes they get nicked or scored or the big end can get damaged. In another thread an owner reported having both problems.

Robert D.
Click to expand...

Thank you very much! My chuck does not have a faceplate. However, I do believe it is my 3 jaw chuck that is the problem. I got the 4 jaw to get an end mill to .0005" runout, so it has to be the 3 jaw. The 4 jaw chucks seats right up to the spindle. I think I try to take the 3 jaw apart tomorrow.

Thanks again.....
 
Jster,

It (the makeup problem) has to be the 3-jaw because the 4-jaw will make up to the register flange. Not because you got the runout near zero with the 4-jaw at one point on the end mill. With a four jaw, runout at a single point is mainly subject only to the skill or patience of the operator. Unless there is something badly wrong with the bearings, which isn't the case here. The collet runout could reflect minor damage to the taper in the spindle nose.

Robert D.
 
sssfox said:
Make sure you check the runout in two places on the endmill, as far as you can from each other because of the explanation I gave earlier. The longer the endmill, the better.

By the way, a faceplate is different from a chuck. Do a search on faceplate and see what comes up. It could give you a better answer or not, depending on the accuracy of the faceplate, but it's definitely easier. It is also easier to true up if it is off.
Click to expand...

Unfortunately, I don't have a long end mill. I did use my faceplate a couple of times, but didn't show it in the last vid. I posted a new video on this issue and I think it is my 3 jaw chuck that is my problem. However, I'm so new to this game I'm not 100% sure. Thanks so much for the help!
http://www.youtube.com/watch?v=RKceUsFTRFc
 
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