# Supermax surface finish issue



## sasanifab (Apr 30, 2022)

So I sold this 1338 supermax to a guy in Maine , I'm in ct, I never had surface finish issues when I was using the lathe. He is having issue with surface finish when using the feed mechanism. The first half was cut using the hand wheel , the other with the feed mechanism. What would be causing those lines in the finish ? The carriage appears to be moving smoothly. The headstock needs to be adjusted as there is taper, I didn't think that made any difference with this issue.


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## jwmelvin (Apr 30, 2022)

Did someone lift by a strap that was around the feed screw, bending it? (i.e., does the pitch of the surface finish match the pitch of the feed screw?)


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## sasanifab (Apr 30, 2022)

jwmelvin said:


> Did someone lift by a strap that was around the feed screw, bending it? (i.e., does the pitch of the surface finish match the pitch of the feed screw? The shaft does have teeth , it has a groove that indexes on a gear  inside the saddle ... Facing looks great.


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## Janderso (Apr 30, 2022)

Since you aren’t there to make sure his feeds are set correctly?
Is he maybe feeding with the lead screw?
Looks like .100” per revolution.
I’m just speculating here.


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## jwmelvin (Apr 30, 2022)

Does the pattern change with different feeds?


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## markba633csi (Apr 30, 2022)

How deep and how fast? What type of tool and material?


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## jbobb1 (Apr 30, 2022)

My question would be how much experience he has running a lathe. Looks like operator error to me.


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## JimDawson (Apr 30, 2022)

This is pretty common.  Depends on the material.  Looks like not enough feed/rev, and maybe not enough spindle speed.  Could be tool setup also.


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## matthewsx (Apr 30, 2022)

If he's not already a member invite him to join and ask for help here.

If he just wants you to solve this issue maybe hobby machining isn't for him. I doubt you provided a guarantee of good finishes on every material without any effort on his part.

John


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## sasanifab (May 1, 2022)

matthewsx said:


> If he's not already a member invite him to join and ask for help here.
> 
> If he just wants you to solve this issue maybe hobby machining isn't for him. I doubt you provided a guarantee of good finishes on every material without any effort on his part.
> 
> John


This supermax I learned on and basically rebuilt by myself , I worked great for me. He got the lathe leveled but there was still a lot of taper which he was starting to remedy. I was worried that the lathe got damaged in transport or while lifting it. The carriage moves smoothly though so ‍


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