# Help me evaluate head stock bearing wear on SB 8x42



## RRT (Sep 6, 2011)

Greetings. I know very little about lathes, so please bear with me. I got this lathe in a trade and have very little into it so far. It has more than paid for itself already in the ranch shop. Im trying to decide how worn out it is before I start spending money on tooling that need. This lathe is used in a ranch shop for ag machine repair and low level gun projects and suppressors (legal of course). 

The head stock shaft has noticable play in it when pulled side to side. 
As set up in the pic I get 0.010" when I pull (40lb ? at the end of the 18" bar) and 0.005 when I push. 

There is no noticable play when forced up and down and I couldnt figure out how to set up my indicator properly.

The bearing faces have some gouge marks from running dry. The shaft faces are in much better condition.



The question is ......will I go crazy trying to get repeatable accuracy with this level of wear?

Will a refurb by a knowing individual cost more than a used but good lathe?

Any comments appreciated.


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## pjf134 (Sep 6, 2011)

RRT,
 Try taking the chuck off and do the lift test on the spindle only and see what you get. Take your readings on both ends of spindle. I see it is a top oiler and most likeky from the 30's but I have seen worst from newer lathes and still give good products. Use a round bar thru spindle for your test as the bar you are using can rock on the points I would think. I think after 10 posts you can get into the download area at top and you can get a lot of info from there for checking wear and how to add shims ect., but for now do a lift test and go from there.
 Paul


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## Tony Wells (Sep 7, 2011)

Don't get too worked up over a little clearance. You need it for oil. The scuffing I see is minimal. Overall, you look to be in good shape.


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## RRT (Sep 8, 2011)

Thanks guys.  I pulled the chuck and set indicator on top center of the spindle and used a 3/4 round bar pulling about 30 lb at 24" from spindle. 

With "0" at rest, I get -0.002" when I lift and +0.001" on push down. 

With indicator on side center I get +0.003" pushing and 0.002" pulling.

From your comments I feel better about buying the tooling.  The tail stock is a no 1 morse and I need centers and chucks and I figured it would be wasted money if I had to get another lathe in the future. 

Thanks


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## Tony Wells (Sep 8, 2011)

You should also bear in mind that clearances change when things warm up. If you run at high speed, especially if you use incorrect oil, those clearances will disappear, or close up considerably. This is all about compromise, really. Zero clearance and nothing moves, too much and poor performance results. Somewhere in the middle is room for lubrication, and minimal excess to allow oscillations of the spindle that show up as chatter and ugly on the work. Sometimes people will attempt to compensate for excess clearance with heavier oil. This can help, but it's not a real solution.

So you must have clearance, and the proper lube for things to work out as the manufacturers intend.


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## brucer (Sep 10, 2011)

i agree with tony, I always run a lathe for a warm up period, like 10minutes or so...


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## RRT (Sep 10, 2011)

Thanks again for all the good info guys. 
Now if I can only find a chest full of tooling on craigs list.....


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## RRT (Sep 11, 2011)

1200rpm link=topic=3439.msg25380#msg25380 date=1315747913 said:
			
		

> up and down is all you can adjust so don`t worry about side to side
> push the bar down and zero indicator
> then pull up on the bar and get a reading
> also don`t worry about trying to determine what the clearance is for both up and down. you only need one number- the total clearance.
> ...




Well duh. I feel stupid that I never thought of that. Thanks. I'll get busy and try to find one or get mine modified?


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