How to stop juddering

[Peter Simpson 3Participant @petersimpson3]

Hi All,

I need to reduce the diameter of a 14″ long piece of tube.

The material in Bright mild steel 13mm OD and an approx ID of 3mm.

I have it secured in a collet chuck at the head stock end and secured at the tail stock end with a rotating centre. Taking quiet shallow cuts under power feed I get a horrible juddering type of cut as the tool approaches the 7″ position Do you need to use a traveling steady for this type of work, would a sharp HSS tool be better than an indexable tool ?

[JasonBModerator @jasonb]

Sharp tool either HSS or **GT type insert with 0.2mm corner radius.

You don’t say how much to come off or what sort of finish is required but you could do it in short lengths of say 30mm, moving it further out the collet once the previous section is down to size. This would also be the quickest way to rough it down to size then do a full length finish pass with a travelling steady.

[Peter Simpson 3Participant @petersimpson3]

 

 

 

 

 

 

 

 

 

 

 

 

 

The final OD will be 11mm and a good finish is required.

 

 

 

 

 

 

 

 

 

The finished diameter will be 11mm and a good finish is required.

 

 

 

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[Andrew CrowParticipant @andrewcrow91475]

I would agree that a travelling steady is essential for any chance of good finish and accurate size at that length of such a slender bar.

Andy.

[old martParticipant @oldmart]

As Jason mentions, very sharp tools and the –GT inserts made for aluminium of HO grade along with very small depths of cut. Try different speeds and steadies are a great help.

[Author]

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