Atlas-craftsman 101.07301 Chuck Wobble

E

Ed of all trades

Registered
Registered
Joined
Jun 3, 2014
Messages
141
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
 
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
 
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.
 
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.
 
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
 
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.
 
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
 
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
 
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
 
You must log in or register to reply here.
Back
Top