# Atlas-craftsman 101.07301 Chuck Wobble



## Ed of all trades (May 13, 2015)

I am trying to get my 101.07301 Atlas -Craftsman lathe up and going. Today I watched a Tubalcain video on tail stock alignment and tried it on my lathe. I got nowhere. So I set up my indicators and tested for wobble on my chuck. I put a new 1/2" shank drill bit in the chuck and got over 100/thousands off, I then tested the Back edge of the chuck and got 54/thousands off. I took the chuck off and put the backing plate on and got 12/thousands off. I guess I should have checked the spindle but have not done that yet.  Do I need to throw my chuck in the trash? Or are there other things I could do. When I got the lathe the threads in the chuck were buggered up and I had to chase them to get the chuck on the spindle. the spindle threads look good. Thanks for any help you give. Ed


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## Ulma Doctor (May 13, 2015)

Hi Ed,
i'd indicate the spindle bore, the spindle may be bent.
it's not difficult to bend the spindles on the smaller atlas lathes.
it is possible for the work to run true, and have measureable runout on the chuck.
i'd be most worried about the work running true.
the chuck may be ok, but you'll need the spindle issue straightened out to find out for sure.
if the chuck doesn't register correctly on the spindle , that may cause alignment issues as well.
further inspection of the chuck and spindle will be necessary


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## RJSakowski (May 13, 2015)

That's a lot of runout.  You need to check the spindle runout.  

When you are referring to the backing plate, are you referring to the chuck back plate or the face plate?  If the face plate, radial runout is not important, only axial runout.   The faceplate can be trued on the lathe.  If you are referring to the chuck mounting plate, .012" is a lot.  It may be that the chuck/backing plate came from a different lathe.  Backing plates are usually trued to the lathe they are used on .  You should be able to true the backing plate again.  You will have to re-cut the boss that centers the chuck so it runs true.  This involves refacing the plate to provide enough material to cut the new surface on the boss.  The new boss has to be concentric with, and the face of the backing plate perpendicular to the spindle axis.


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## chips&more (May 13, 2015)

Start with the heart of the lathe, the head stock spindle. Use proper measurement techniques and record your findings. Work your way alone, mounting a chuck(s), making and recording measurements as you go. Repeat measurements to be sure of your findings. Only then, can you find your discrepancies…Good Luck, Dave.


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## brino (May 13, 2015)

Ed,  you have already made the most important discovery......something is wrong.

Thru the great advice above you will find out exactly what. Start with the spindle as Ulma Doctor advises.

Other thoughts:
-I've heard of people rotating the chuck on the backing plate(remove the bolts, rotate one hole, replace bolts and remeasure) to  find the "best" orientation.
-check for burrs on the shoulder of the backing plate and lathe spindle, the surfaces perpendicular to the lathe centre line that tighten together when you install the chuck
-you should also check for any burrs on the back of the chuck

Let us know what you find, there are many smart people here that are generous with their knowledge.

-brino


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## Ed of all trades (May 13, 2015)

RJS  I was talking about a face plate, sorry, Needless to say I have a lot to learn. This chuck just threads onto the spindle.  I assume that the correct way to measure run out on the spindle is to put the indicator just inside the lip of the inside of the spindle and turn by hand. I will try this as soon as I can get out to the shop, should be in a few min. Thanks Ed.


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## brino (May 13, 2015)

Ed of all trades said:


> This chuck just threads onto the spindle.



Are you sure? This post from almost a year ago suggests you got the chuck off the backing plate:
http://www.hobby-machinist.com/threads/how-to-remove-back-plate-on-atlas-chuck.23566/

Different chuck? Different lathe?
-brino


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## Ed of all trades (May 13, 2015)

Bruno same lathe just found out back then that the previous owner had kinda bolted the chuck to the face plate and screwed it on the spindle as well. I just looked up pics of face plates for my lathe to make sure. 
I measured the inside of the spindle and got 1 1/2 thousands run out
face of chuck (toward tail stock) 40 thousands run out
outside of chuck (where the tread would be on a tire)  43 thousands run out
work (NEW drill bit shank, 1/2" from chuck) 97 thousands run out 
                                                                                                              Thanks Guys Ed


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## Ed of all trades (May 13, 2015)

Bruno  It took me a while but I found out that the previous owner had screwed the face plate on the spindle and then screwed the chuck on the spindle and tried to bolt them together. Just looked at old post was trying to get the back of the chuck off of the chuck.
I just went out and remeasured. These are the results.
Inside of the spindle about 1/8 in from lip. 1 1/2 thousands run out.
Face of chuck (toward tail stock) 40 thousands run out
Outer surface of chuck (think tire tread) 43 thousands run out
work (NEW drill bit shank 1/2" from chuck and slid in a good ways. 97 thousands run out.
I did notice that the face plate goes on all the way to the collar and the chuck stops almost 3/16 away from it.
                                                                      Thanks guys 
                                                                                         Ed


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## Round in circles (May 13, 2015)

Perhaps make  long thin pointed angled wire pick & carefully run the point in the whole of thread of the chuck as you may have crud in in the thread form   After the first go give the thread a good spray with WD40  leave it for 1/2 hr or so to soak in and repeat the picking out exercise .
Also clean the spindle threads with a wire brush  rotating it by hand as you do it. 

Finally flush the threads on both with WD40. 
 I'd also check to see that that the thread of the chuck is as deep as the spindle thread is long .

I'm following  this thread with great interest


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## Ed of all trades (May 13, 2015)

Round, The spindle threads look great but the chuck threads were messed up when I got the lathe. I chased the threads with a tap just to get them on the spindle more than about a 1/2".  I am beginning to think I need to do that again, maybe I did not go far enough? Lot of questions in my head. Wondering if the threads are so messed up that that is what is causing the problem. Thanks Ed


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## francist (May 13, 2015)

The chuck stops 3/16" away from the spindle collar? This is not right, the chuck must lock up against the collar on the spindle to register. Otherwise you are relying only  on the threads themselves to keep things on spot, and they never will.

-frank


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## mattthemuppet2 (May 13, 2015)

sounds like the spindle is fine. Now you need to get that backing plate threaded on ALL the way so that it sits flush on the spindle register (flat part perpendicular to the threads, closest to the headstock) before doing anything else. Then, once you've done that, face the backplate and recut the chuck register. The chuck "registers" to the back plate in 2 ways. The end of the chuck, where the bolts go, sits flat on the outside portion of the backplate - this is the bit that reduces runout or wobble that increases with distance from the chuck. The inside lip of the chuck sits against the ledge sticking out from the backplate - this is the bit that makes the chuck run perfectly inline with the spindle. If it's off, then the tip of a point held in the chuck with scribe a circle, instead of rotating in place.

Most likely you'll need to recut both. The flat register is pretty easy, the inside register (the last one above) is trickier and takes a lot of care. Also make sure that the bolt holes or even the countersunk holes are not interfering with the chuck bolts as that can throw the chuck off too.

I had to do all of the above with the chuck that came with my 6 x 18, now it shows ~0.001in runout and no wobble. Before it was in the 0.01+ range. Also, even once you've made those changes, you can often lightly tap the chuck while it's loosely screwed to the backplate to get rid of the last couple thou runout (I got mine from 0.004 to 0.001 that way).

If you do all of that and it's not fixed (unlikely from what you've described so far), then the chuck may be shot, but that's the very last thing you should worry about.


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## wa5cab (May 14, 2015)

For the time being, ignore the 3MT taper inside the spindle nose.  Although important, it has nothing to do with chucks, backing plates or face plates.  The register actually consists of two parts.  The cylindrical unthreaded area to the left of the threads, and the face of the flange to the left of that.  Unless it is oversize, which is unlikely, you can only make matters worse.  Measure the runout on the cylindrical part.  That controls chuck runout (if the chuck is otherwise perfect).  And measure the axial variation in the face of the flange.  That affects wobble.


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## Ed of all trades (May 14, 2015)

CONFUSED  The spindle is threaded to within 3/16" or so of the flange BUT the chuck is threaded all the way so that it has to stop app. 3/16" from the flange.  Am I missing something? Is there a part I don't have? ??????   Is this the wrong chuck for my lathe? It is an Atlas chuck.


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## wa5cab (May 14, 2015)

The back of the chuck (or if it has a separate one the back plate) should be counterbored to a depth of about 3/16" (just slightly greater than the length of the unthreaded register on the spindle) and a diameter of at a guess 1.0006"/1.0001".  The spindle register diameter is probably 1.0000"/.9995".  That's based on the register dimension on the larger spindle in the 10" and 12" machines.  If it isn't counterbored, that is why the chuck won't screw all the way onto the spindle and probably accounts for most of the horrendous runout you reported.  Note that it is not unusual to see just the very tip of the thread cutting across the surface of the counterbore.  Because the major diameter of the female thread must be larger than the major diameter of the male thread or it would be an interference fit.

FWIW, few if any of the original 3" through 8" chucks sold by Atlas (or Sears) had separate back plates.


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## GWH (May 14, 2015)

You might want to check the size and tread count on that Atlas lathe. I just made a 4th axes and removed my 3 jaw chuck from my atlas lathe to be used on it, and it had 1" 10 tread count which is not standard size with any of my taps & dies sets. When I made my new spindle i just threaded to fit the chuck 1" 10 tread. The run out is okay for what I want to do with it. The new setup has a stepper NEMA 23 motor with a 4 to 1 ratio.


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## wa5cab (May 14, 2015)

If the machine is a 101.07301, as the first post says, it will have 1"-8 spindle nose threads.


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## Ed of all trades (May 14, 2015)

It has 1"-8 threads on the spindle and the same on the chuck, the problem is the unthreaded part of the spindle and a fully threaded chuck won't allow the chuck to go all the way on to the spindle.
Wa5cab  so I need to take my chuck to a machine shop and have 3/16 or so of the threads cut out?


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## francist (May 14, 2015)

You have a faceplate, yes? You could mount the backing plate backwards on your faceplate, mount faceplate to lathe, and then take the offending threads out yourself. Just a thought until Robert replies.

-frank

Sorry, thought the "faceplate" referred to earlier was an actual faceplate and not the back of the chuck. Could you do the same process though but with the chuck back?

-frank


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## wa5cab (May 14, 2015)

Ed,

Short answer is yes, if the 1"-8 female threads on the back of the chuck come all the way out to the surface, they must be cut away.  The problem is that the counterbore is what centers up the chuck to the spindle.  So it MUST be concentric with the jaws.  If the jaws are in good condition, what I would do is to take a piece of precision ground steel solid round just small enough to fit through the hole in the front chuck body and mount it in a 4-jaw and indicate it in to zero TIR.  Then clamp the chuck to the round with its jaws. 

But before we get into that, it still isn't clear to me whether the chuck is a solid-back, as most were, or has a back-plate.  Easiest way to answer that is to take and post rear and side view photos of the chuck.  I can't understand why the back of the chuck (whichever variant it is) doesn't have the register counterbore as I can't imagine it shipping from the factory like that.


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## wa5cab (May 14, 2015)

I forgot to add that if the chuck does have a back plate, you could, if you have a large enough 4-jaw or if you can figure a way to solidly attach the back plate to a face plate, do the counterbore yourself.  But you would want to confirm that the axial runout of the face plate was essentially zero first.  But I think that all around, as you are still working on the machine and don't know how accurate the rest of the machine is yet, you would be better off getting the counterbore fixed on a larger heavier machine.


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## randyc (May 14, 2015)

wa5cab said:


> ....If the jaws are in good condition, what I would do is to take a piece of precision ground steel solid round just small enough to fit through the hole in the front chuck body and mount it in a 4-jaw and indicate it in to zero TIR.  Then clamp the chuck to the round with its jaws...



That's a good way of doing it !  The following photo shows that identical operation on a backplate into which an ER-40 collet chuck has been shrunk.  I put a 1 inch piece of drill rod in the three-jaw and then turned it to 15/16 so the diameter is now true with the spindle axis.  With a 15/16 collet installed in the ER-40, I secured it over the turned diameter of 15/16 then machined the backplate register.  The backplate is shown in a stage of partial completion:


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## Ed of all trades (Jun 12, 2015)

Thanks to everyone.  For some reason my computer to a strong dislike to Hobby Machinist, it would let me go anywhere but here. When ever I tried it said page not available.  Well back now.  Thanks for the info, I think I will try to find someone to cut out 3/16 of the threads on a bigger lathe. I would hate for this to be the first thing I have ever turned that mattered.  I played with a lathe in high school, but the teacher knew nothing about it and said you can try it if you want, and I have many hrs on a brake lathe. Thanks again, will update when I get this done, will take a little while as work is kinda crazy now.  If I did try this how would I center the hole on the lathe? I can see how if it was not threaded but being threaded??? Ed


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## wa5cab (Jun 12, 2015)

Ed,

I'm not sure that I understand your question.  Normally, a back plate is bored out to the minor diameter of the threads.  Then it is counterbored to the nominal diameter for a short depth.  This larger bore is the part that centers up on the spindle register.  Finally, the plate is threaded to a major diameter maybe half a thou larger than nominal, shown in the thread tables as the max major diameter of the female threads..  So the final pass will leave a barely visible score in the register counterbore.  This ensures that the spindle register and not the threads are responsible for centering the chuck.


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## Ed of all trades (Jun 13, 2015)

Wa5cab  My chuck has never been counterbored and because of this the chuck is threaded all the way and can't reach spindle register.  I need to take my chuck apart, it does not have a back plate, and attach it to the face plate and center it on the lathe and cut out the threads so it can register on the spindle.
How do you center something that has a threaded surface to measure against? Also is what I am planning to do a good idea?


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## T Bredehoft (Jun 13, 2015)

Ed, what's your level of experience? This is something for a well versed amateur or a professional to do.  Normally, with chucks that are sold ready to run the purchaser expects a run out of .002 to .003. Do you think you can locate your chuck on a faceplate that accurately?  I'd look for help if I were you.


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## Ed of all trades (Jun 13, 2015)

I have little to no experience with a lathe. I have a many hours of work on a break lathe, but that won't help much.   I just hate to take my chuck to a machine shop and spend $_____ on a chuck that I am not sure will work.  The threads were messed up when I got it and I had to chase them with a tap just to get it to thread on at all.  Thanks T Bredehoft


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## T Bredehoft (Jun 14, 2015)

I made a collet holder for my new lathe, messed up the threads myself.  I bored them out, and pressed an insert in, put a couple of 5-40 set screws in the joint between the insert and the mounting flange and chased new threads, with the proper locating collar.  You might try that.


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## wa5cab (Jun 14, 2015)

Ed,

I'm out of town for a funeral and fighting an extremely slow connection.  And probably paying roaming charges.  So this will likely be my only reply until I'm back in Houston.  But I agree with Tom.  You need to get a local opinion from someone competent to give one.  I can't imagine a reputable chuck manufacturer selling an unfinished chuck.  So there is something amiss here.  If you can find someone local who is willing to look into it and not charge you more than a decent new (to you, it can be used if good) chuck would cost, he might be able to salvage it.  If not, you are probably better off scrapping it instead of throwing good money after bad.  I know what I would do but I'm not going to write out detailed instructions as anyone who CAN fix it will know HOW to fix it.

I don't specifically recall which lathe you have and with my connection problem tonight it might take me an hour to find out.  But assuming that you have an Atlas built 10" or 12", the factory specs on the diameter of the register are 1.5000"/1.4995".  I got that from Jolene last year.  Pass that on to whomever you enlist to help.


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## wa5cab (Jun 14, 2015)

Ed,

In the aftermath of trying to send my previous, I finally caught the thread title and see that you have a 618.  So the spindle register dimensions are 1.0000"/0.9995".  Not 1-1/2" nominal.  Sorry.


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## Ed of all trades (Jun 14, 2015)

Wa5cab
 Thanks so much for the time and effort you put into this. I will try to get a local to help me. just not sure who.


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## wa5cab (Jun 15, 2015)

You're welcome.  Good luck.


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## Ed of all trades (Jun 16, 2015)

I took the chuck to a local machine shop my neighbor told me about.  Turned out to be my wife's 1 1/2 cousin.  I didn't even have to tell him what I wanted he took one look at the chock and told me.  I gave him the measurements I took on the spindle and he said he would call me in a couple days and then came out to the car and had a long talk with my wife.  I am excited that I might get this thing working soon.  Ed


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## wa5cab (Jun 17, 2015)

Sounds good.

What is a 1-1/2 Cousin?


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## Ed of all trades (Jun 18, 2015)

My father in laws first cousin is my wife's 1 1/2 cousin because the change is only on one side of the family.  If you step down on both sides you have 2nd cousins.  ( two first cousins have children their children would be 2nd cousins)  My wife is Mennonite and they have kin figured out to the .00000001".  I never knew any of this until I married her.


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## MikeMc (Jun 18, 2015)

I just got through monuting a new chuck to my machine so have been dealing with similar issues. Rather than take the backplate to another machinist you can make a 1/4" sleeve carefully filed and sanded to have parallel faces that would allow the backplate to 'snub up'. Holding a piece of 1" ID tubing in the steady rest, face off the end then part off a 1/4" ring. Now the faces are parallel but will need touching up for precision. This between your backplate reversed will allow you to remove the offending threads. Be sure to get enough, I skimped and wasn't quite snubbing up to the spindle shoulder but didn't realize it until the chuck wasn't true. I had to go back and do it again. You might want to take a look at this thread: machinistweb.com/forum/showthread.php?t=3580
MikeMc


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## wa5cab (Jun 18, 2015)

Ed,

OK.  I would have called him her 2nd cousin I guess.

Mike & Ed,

The counterbore depth is not critical so long as it is deep enough.  But the diameter of the counterbore is critical.  Regardless of who does the machining, I would expect to see a faint outline of the threading tool left in the counterbore when it is the correct diameter.


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## Ed of all trades (Jun 18, 2015)

The guy knew exactly what I wanted before I asked and I know He will do his best.  H said he thought 2 thousands over the spindle size would be good.  He is going to cut it to 5 thousands deeper than the shoulder.  He should call before to many more days, and then we will see what I have.   A chuck or an anchor.


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## Ed of all trades (Jun 24, 2015)

OK guys it is time to say I TOLD YOU SO.  You guys told me to measure the spindle for run out, but I knew that the problem was in the chuck.  I got the chuck turned out to fit the spindle and I still have 60 thousands wobble on the face of the chuck.  I measured the spindle and the shaft behind the threads has 5 thousands run out and the face of the collar has around 40.  I know I could buy a spindle but right now I feel like using it for a boat anchor.


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## wa5cab (Jun 24, 2015)

Next step should be to remove the spindle from the headstock, set it on V-blocks, and determine what is wrong with it.Your wife's 1-1/2 Cousin should know how to do that.

Fortunately, the work that he did on the chuck isn't necessarily wasted.  If you can get the spindle problem sorted out, the chuck should be usable.

Based on your most recent figures, my guess would be that the machine suffered a terrible crash.  And probably not with the chuck you just got fixed.
.


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## Ed of all trades (Jun 25, 2015)

Thanks Wa5cab  I will see what I can do.  My wifes cousin told me that the threads were not just messed up they had been changed.  I assume that my chuck was once a 1" 10 thread and was converted to 1" 8 to fit my lathe.  With that info your statement about a "terrible crash and probably not not with the chuck you just got fixed."  sounds dead on.  will follow your advise and see what he has to say, thanks again Ed


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## wa5cab (Jun 25, 2015)

OK.


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## Round in circles (Jun 25, 2015)

I wonder if someone has been lifting the lathe with a large eye bolt in the  chuck as the lifting point .

Don't despair Ed .. My son  ran a four day old £ 550 ( $750 USD )  32 inch cut petrol rotatory  self powered petrol mower over some surface roots  because he decided to ignore what I said and put the cutting height down to one inch instead of leaving it at 2.5 inches  whilst in the orchard .    . I realised the mower had stopped , looked out the window and saw him on his knees trying to start the mower ..which is quite difficult when the crankshaft has been bent a good half an inch .

 I stripped it out and gave it to my pal Paul who had a fly press and various home made Vee blocks , he straightened it as near as he could ,then took it to his work place where they have various laser testing & measuring machines that can make differences in nano meters . The apprentices were so happy to have a real bit of engineering to do instead of set test pieces etc. 
They check Paul's work and said that's excellent....... about as good as when it was brand new .. a few jigs and machines later it was deemed to now be aircraft engine quality true & balanced .

In the  late 1960's as an engineer I had to true up con rods and crankshafts for 1, 2, 3, 4, 5, 6 & straight 8 cylinder engines myself in engine repair bay  . They all worked OK when put back in the various engines .


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## Ed of all trades (Jun 25, 2015)

Thanks Round in circles
  I emailed Closing and they wanted $405.00  for a new one, so I guess that is out.  I will try to get to the machine shop tomorrow if work allows.  Hopefully they can fix it.


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## wa5cab (Jun 26, 2015)

I've no idea what used spindles go for on eBay but you should probably check over the past 60 days (that's as far back as eBay records seem to go these days) so you'll have a baseline to compare to what the machine shop says that they'll charge for straightening and versus what you know that a new one would cost.


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## Ed of all trades (Jun 26, 2015)

Thanks wa5cab
I also checked Ebay and saw one for $100. Just hate to buy one and find out that it has problems too.  I am trying to work within my $$$$$, as things are tight for a little while but I also worry that they will do it for nothing like they did the chuck.  It feels strange to have people you just met do something for you for free.
                                                               Ed


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## Ed of all trades (Jun 26, 2015)

Just got back from the machine shop and put the spindle back in the lathe, put on the chuck and it is no better.  They said about the only thing they could do was turn the shoulder true.  O well I got my moneys worth.  I have been there two times and they would not take a dime.  Now to figure out what to do next.  Think I'll just sit down and   it beats  or .  might as well make the best of it.


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## wa5cab (Jun 27, 2015)

Ed,

Did they check runout in the taper?  If so, what was it?  And did they get the same 5 thou runout on the register that you did?  Did they say anything about the spindle being bent?

In any case, under the circumstances you can probably at least eliminate most of the wobble on the face of the chuck by facing off the front surface of the spindle flange  Be very careful not to touch the register area.  There is actually a way to fix the register, too.  But it would probably cost more than a new spindle.  So I would face the flange.  But check dimensions on where the thread in the chuck starts and make sure that when you screw the chuck onto the spindle, it stops firmly against the flange and not because it bottomed out the threads in the chuck against the end of the threads on the spindle.  Having done this, if you chuck a piece of fairly accurate drill rod (it's pretty cheap) and check the runout near the chuck and farther away from the chuck, you should get the same number.  If that is the case, you can still do accurate work if you use a 4-jaw, or if you use a 3-jaw and do not remove the part from the chuck until it is finished.

However, before you do that, answer my questions in the first paragraph.


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## Ed of all trades (Jun 27, 2015)

Thanks again Wa5cob
  They did not check the spindle, they just faced the flange as you suggested in the above post.  I an to the point of buying a used spindle off of ebay.  I also suspect the chuck and am thinking of getting a 4 jaw at the same time.  I will need a 4 jaw anyway and I can stop fussing with this thing and get on with putting it together and making some chips.  Good idea?
                                                            Ed


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## wa5cab (Jun 27, 2015)

OK.  If they faced the flange, they probably held the spindle with a 4-jaw clamping on the front bearing journal area.  If the spindle is bent, it is probably bent between the two journal areas.  Chucking on the front journal and facing the flange won't have helped any.  Check the flange runout with the spindle mounted in the headstock.  If it is about the same as before, face it and see whether or not that helps (it should).  If it is better than before, mount the chuck and with a .002" or .003" feeler gauge, probe the interface between the flange and the chuck, looking for a gap.  If there is a gap, the chuck is stopping before it gets to the flange.


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## Ed of all trades (Jun 27, 2015)

Thanks  Wa5cab
I don't have the lathe up and running yet. I still need to get a motor, get it mounted to the bench and get some tooling.  Will have to wait for a while for the cash flow to catch up.  Thanks  ED


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## wa5cab (Jun 28, 2015)

OK.


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## Ed of all trades (Jun 28, 2015)

I got over my  and went out to the shop and measured the face of the flange and it is out about 1/3 of 1 thousands.  I have a feeler gauge somewhere but at the present time it is MIA.  The chuck looks tight but when I hold a little LED flashlight behind it I can see light in the crack between the chuck and the flange.


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## Ed of all trades (Jun 28, 2015)

I went back out to the shop and tried the old paper feeler gauge and it is not going up against the flange.  I keep looking at the threads in the chuck and am thinking about just getting a new chuck. ( I think it was 10 tpi and someone tapped to 8 tpi )   Is that a good idea or am I running ahead of my self again?


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## JimDawson (Jun 28, 2015)

Ed of all trades said:


> I went back out to the shop and tried the old paper feeler gauge and it is not going up against the flange.  I keep looking at the threads in the chuck and am thinking about just getting a new chuck. ( I think it was 10 tpi and someone taped to 8 tpi )   Is that a good idea or am I running ahead of my self again?



It could be the chuck, but I would eliminate all of the other possibilities first.  Normally I would have started with checking the spindle every way I could think of before doing any machining on it, or anything else.  It is best to identify the root cause of a problem before trying to find a solution.  Any troubleshooting is an excersize in logical problem solving, methodically following a path so see where it leads.

If a problem was found with the spindle, then correct that before proceeding to the chuck.  This would give you a known good baseline for the rest of the process.  The ''perfect'' spindle would have no runout on any working surface relative to the spindle bearing journals.  The perfect spindle does not exist, so we try to get it as close as we can measure.  This checkout should include the spindle bore.

If no problem was found with the spindle then the next step in the progression would be to the chuck.  Given that the chuck won't register properly, the question is why.  Does the spindle nose bottom out in the threads before the chuck registers on the flange?  Maybe the bore in the chuck needs some relief in the bottom?  Is chuck register only touching on one side of the flange?  Any other possibilities?  The chuck does not register on the threads (at least it shouldn't), but if the threads are cockeyed then that could cause a problem.

You are just going to have to work through it step by step to find the actual problem.

I hope this helps.


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## Ed of all trades (Jun 28, 2015)

Jim, Thanks for your post.
I hope that is what I have done, with a lot of help from all of the replies I have received here.  This is very new to me so I am kinda feeling my way like a blind man who lost his stick.  Actually the blind man would do better.  I am to the point with the spindle where the three measurements I know to make are down to 1/2 a thousands or less.  The register between the flange and the threads is out just a little less than 1/2 a thousands inside the taper is around 1/3 of a thousands and now that I had the flange turned true it is a little less than 1/3 of a thousands out.  I don't know what else to measure or how to measure more accurately I think I am right to say that one line on a dial indicator is 1 thousands of an inch.  I do know that the threads on the chuck are a mess and I wonder if I could get them right how long they would stay that way.  That is why I feel like getting a new chuck would be a good idea,  I am asking because I know that there is much I don't know and I might have missed something else.  Other than what I have understood from you all.


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## wa5cab (Jun 29, 2015)

Ed,

If as you suspect, the chuck was originally threaded 1"-10 and was re-threaded 1"-8, the threads should look pretty much a mess.  However, it should still work OK if the unthreaded bore and the face are OK.  You haven't said and probably you don't know how much the cousin and a half took off of the spindle flange.  But if there is a visible gap between the face of the flange and the rear face of the chuck, that is the next problem.  That usually would indicate that when you screw the chuck onto the spindle, it is stopping on the threads, not against the flange as it should.  You can cut the threads a little deeper or you can grind a little away from the first thread in the chuck.  If you had a 1"-8 die nut, I would use that, but it's highly unlikely that you do.  Assuming that your hands are still pretty steady (mine aren't), use a Dremel tool with a 3/4" dia. flat faced stone to grind away about 0.010" of the first thread.  Chock the chuck on the bench with the start of the first thread at 6:00 o'clock (12 hour system) so that it can't move.  It may be wise to tape the chocks to the bench.  Position the Dremel parallel to the chuck axis (thread axis) and tilt it up at 30 deg.  Grind 0.010" off of the thread face (this will be flat, not curved as the thread will be).  Remove by grinding the sharp edge of the end of the thread.  Make sure that there are no burrs on the edge of the thread by running your finger over it very lightly (don't want to cut your finger).  If there are, remove them with a small piece of sand paper (220 grit or finer).  Fit the chuck to the spindle.  The gap should be gone or at least less.  If it's gone, fine, if it's less but not gone, take another 0/005" off of the first thread in the chuck and see if that fixes it.  But if the gap is still as bad as it was originally, then the spindle nose thread must be bottoming in the chuck.  Report back for options.


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## Ed of all trades (Jun 29, 2015)

Thanks Wa5cab
I wonder if that would work because it appears to me that the gap is only on one side of the chuck, I now, I should have said that in my post. sorry.  The chuck is pretty tight on the flat register behind the threads but it is spinning fast enough to lock in place on the flange.  imho. Could it be that whoever changed the thread did it a little off of "plumb"?


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## wa5cab (Jun 29, 2015)

Ed,

The threads could be a little off of plumb.  However, they will have some clearance.  Is the gap always at the top.  Do you have a 4-jaw chuck?  And I've forgotten, for certain, but is the 3-jaw a 6" or smaller?


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## Ed of all trades (Jun 29, 2015)

Wa5cab
The gap rotates around the spindle as the chuck is turned.  In other words the chuck is tight on the spindle and not moving around.  The chuck is a 4" 3 jaw Atlas chuck.   

                                                                                               Thanks Ed


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## wa5cab (Jun 30, 2015)

Do you have a faceplate or anything else that fits the spindle?  Be sure that there isn't any step in the register from where they faced the flange surface back.

You didn't answer my question about whether or not you had a 4-jaw chuck.


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## Ed of all trades (Jun 30, 2015)

Wa5cab
 Thanks again, Yes I do have a face plate,  there is no gap when I mount it on the spindle. I have noticed that it is not running true, can't recall how far it was out, but it was not just .005 or something it was a good bit out. 
 When they faced the flange they did it from outer edge toward the center in one pass then did it over again all the way across the flange.  I don't see how there could be a step but I will check when I can.  
 Sorry I did not answer your question, I only have a three jaw chuck and a face plate. 

                                                                                   Thanks again  Ed.


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## wa5cab (Jul 1, 2015)

If they didn't face it in far enough, there would be a step remaining.

The threads in a chuck are generally fairly loose.  The chuck is centered up on a combination of the register and the flange.

The faceplate can be trued up by simply taking a facing cut across it.  However, I wouldn't do that until you are sure that you are not going to replace the spindle.

On your 3-jaw chuck, if it were mine, I would carefully grind about 0.010" off of the thread start.  And see whether or not that would get rid of the gap.  If it doesn't, you haven't hurt anything.  At leas so long as you didn't get the stone into the unthreaded bore.

If you were to get a 5"4-jaw chuck, you can probably check the trueness of the 3-jaw chuck body.  Just be sure you don't crank any of the jaws out far enough to hit the bed.


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## Ed of all trades (Jul 1, 2015)

Thanks Wa5cab
I will try to get a small grinder and try that, as you said it can;t hurt.  
I don;t understand your last statement, would I want a 5" chuck on a 6" lathe ? Are you saying chuck my 4" three jaw in the 5"  four jaw and chuck a piece of drill rod in the three jaw to test it?  
                                   Thanks again  Ed


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## wa5cab (Jul 1, 2015)

That wasn't actually what I was thinking of.  And yes, a 5" chuck is marginally too large for a 6" lathe.  However, if you are careful never to run the jaws more than about 3/8" outside of the chuck body, It would allow you to safely chuck a little larger part than you could do with a 4".  For example, If you were to chuck a your 4" 3-jaw in a 4" 4-jaw, the jaws might be a little farther out of the chuck body than is good practice.  And especially for trying what I was thinking of.

You have been indicating the face of your 3-jaw and apparently finding enough runout that the chuck shows visible wobble when you mount and rotate it.  What I had in mind was finding out whether the front of your 3-jaw is parallel to the back, and whether it was parallel to the area around the threads.  This would take some time as you would need to make a jaw tension ring to get the 4-jaw's jaws tensioned like they will be with the 3-jaw held in it.  Anyway, supposing that you had a 4-jaw, pull the jaws out of your 3-jaw.  Turn the jaws in your 4-jaw around so that the tallest part is toward the outside.  Temporarily mount the 3-jaw in the 3rd (tallest) step of the 4-jaw and get it roughly centered.  Remove the 3-jaw and measure the diameter to the 2nd step.  Make a ring of that diameter (you'll probably have to turn the jaws back around).  Set the ring against the 2nd step in the 4-jaw's jaws and tighten them.  Set up your indicator to read the flats in front of the 3rd step.  Set the indicator to zero on jaw #1 and read and record the readings on the other three jaws.  Remove the ring and re-mount the 3-jaw in the 4-jaw and center it.  Rotate it (if necessary) so that there aren't any screw heads in the way over the spots where you just read the offset of the 4-jaw's jaws.  Read and record the readings at the same spots as previously read.  If the 3-jaw's back is perfectly parallel to it's front you would get about the same readings as before (if you were using a 5" 3-jaw they would be the same if the 4" is perfect but if you bought a new 3-jaw, I would be inclined to forget your present 3-jaw)..  Now move over to the center of the chuck and check the runout on the face that should contact the spindle flange.  And check the runout of the unthreaded part down in the hole.

If you actually ever do all of this, at this point leave everything as is and report back.

As justification for buying the 4-jaw, you will eventually need one anyway, regardless of the outcome with your present 3-jaw.    Most things that you can do with the 3-jaw you can also do with the 4-jaw.  The 4-jaw does some things that the 3-jaw can't.  Like holding square or octagonal stock.  About the only thing that you can't with it do is hold hexagonal stock.


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## Ed of all trades (Jul 2, 2015)

All of that is way over my ability.  I haven't cut a single chip sense high school and the teacher just let me play with the lathe then. I think I will just get a 4 jaw and see how that goes. Thanks for all of the help. I think I would have sold the lathe and bought an import.

                    Thanks to all of you.
                                  Ed


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## wa5cab (Jul 2, 2015)

OK.  You would have eventually needed the 4-jaw anyway.


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## Ed of all trades (Jul 5, 2015)

I am thinking that I might just get a 4 jaw and see what I can do with that. I still wonder if I am dealing with both a bad Chuck and a bad spindle.  Thanks again for all your help.. Will keep you posted..     Ed


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## wa5cab (Jul 6, 2015)

Ed,

I would agree.  With it (assuming that you get a decent one), I think that you can eventually figure out whether there is a problem with your spindle or not.


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## Ed of all trades (Jul 6, 2015)

Thanks again for all your help with this.
 Ed


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## Birt (Jul 20, 2015)

Ed,
I'm new to the forum but have read this thread with great interest (as I am also a novice and suspect a spindle problem on my Atlas). Did you ever get anywhere with at least isolating the problem?
John


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## Ed of all trades (Jul 21, 2015)

I have had a very intense few weeks with my work and am also trying to deside if we are going to build a house and a couple shops or buy a place or.....  I think it is that the chuck is threaded at an angle, but I wonder if it is both the chuck and the spindle.  When I get more time i will try to figure out what I am going to do. I am tempted to just buy a new lathe and work on this one later.  Wish you luck  Ed


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## Round in circles (Jul 21, 2015)

Ed of all trades said:


> I am thinking that I might just get a 4 jaw and see what I can do with that. I still wonder if I am dealing with both a bad Chuck and a bad spindle.  Thanks again for all your help.. Will keep you posted..     Ed



May I suggest that you get a face plate for your lathe  as it's cheaper initially , you can still turn some things on the lathe and it will help you decide where to go once you've fitted it , measured up any play or variations etc. and thought things out .


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## wa5cab (Jul 21, 2015)

Ed,

The 101.07301 does not have a common history of having bent spindles (although it could happen)  But with it, determining whether or not that is a part of the problem is pretty trivial.  Remove the spindle again and reinstall it without the gears or pulley.  Mount a dial indicator and measure the runout on the generally never touched surface that lies between the two pulley bushings.  It should be close to zero.


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## Ed of all trades (Jul 23, 2015)

Wa5cab
Thanks, That is what I needed to know. Will check it out when I get the time. Like I said my work is crazy and on top of that we are planning to build a house and a shop, plus an equipment shed.  2 much going on.


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