Levelling a lathe..yes that old chestnut again

This topic has 31 replies, 18 voices, and was last updated 24 March 2018 at 13:59 by thaiguzzi.

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4 March 2018 at 16:29 #344400
Journeyman
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@journeyman
Chris, I don't think you will get a result with all these turning tests until you have a firm foundation to work from i.e. the lathe is in it's final position and the cabinet stand bolted firmly to the floor. Only then can you start to make adjustments, if necessary, by shimming the lathe feet. At the moment any changes you make will simply distort the stand to fit the lathe!.

John
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4 March 2018 at 16:55 #344404
ChrisB
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@chrisb35596
Like John says, even bolting the lathe to its stand will give you variations, in fact I when I bolted my lathe to its stand I had to take multiple cuts and adjust the tension on the bolts to get it to cut within an acceptable tollerance.
21 March 2018 at 23:10 #347029
Jon Cameron
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@joncameron26580
I recently did a test cut having left my lathe all winter in the dark shed. (She was tucked up). I was 2thou out. Will adjust one of the feet my ML4 is setup on and hopefully get it a little closer, the tenth of a thou is approxmate I can only measure 1thou with my dial indicator.
22 March 2018 at 08:11 #347044
Speedy Builder5
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@speedybuilder5
Quite impressive, but the surface finish doesn't look so good. I think I would attend to surface finish before I made other adjustments for run-out.
BobH
22 March 2018 at 09:22 #347049
ASF
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@asf
Posted by Jon Cameron on 21/03/2018 23:10:55:

I recently did a test cut having left my lathe all winter in the dark shed. (She was tucked up). I was 2thou out. Will adjust one of the feet my ML4 is setup on and hopefully get it a little closer, the tenth of a thou is approxmate I can only measure 1thou with my dial indicator.

Why do you use a dial indicator to test for parallel turning? I thought the test was turn both parts of the bar and use a micrometer to measure.
22 March 2018 at 09:38 #347052
Journeyman
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@journeyman
Posted by Jon Cameron on 21/03/2018 23:10:55:

I recently did a test cut having left my lathe all winter in the dark shed. (She was tucked up). I was 2thou out. Will adjust one of the feet my ML4 is setup on and hopefully get it a little closer, the tenth of a thou is approxmate I can only measure 1thou with my dial indicator.

I am not quite sure that you can measure a taper using a dial indicator, surely if set in the toolpost it will simply follow the same path as the toolbit and therefore will show no difference from end to end as the carriage is moved. You would normally measure with a micrometer or at a push with a dial/vernier/digital caliper. Once the lathe is turning parallel then a dial indicator could be used to make measurements.

John

Edit: Typo

Edited By Journeyman on 22/03/2018 09:39:32
24 March 2018 at 13:59 #347365
thaiguzzi
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@thaiguzzi
Posted by Speedy Builder5 on 22/03/2018 08:11:50:

Quite impressive, but the surface finish doesn't look so good. I think I would attend to surface finish before I made other adjustments for run-out.
BobH

I'm sorry to have to agree. That finish is appalling. To such a degree it probably affects "tenths" in a reading.
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