Lathe turning tool nomenclature

[JAParticipant @ja]

Once upon a time a “left hand knife” turning tool cut towards the lathe head stock (ref: Myford Series 7 Manual by Ian Bradley). Now Myford supply insert holder for cutting towards the head stock as “right hand”. Why the change or is it just to confuse old people like me?

JA

[JasonBModerator @jasonb]

I have always termed a L/H tool as one that cuts from left to right, so insert holders are no different. mybe Mr Bradley is to blame

 

Harrold Hall has it as I learnt at school

[Bill PhinnParticipant @billphinn90025]

This was puzzling to me as well once.

Just remove your focus from the direction the angled tip points in and consider only the direction it cuts from relative to the operator. Then all will become clear.

The handedness of boring tools follows the same pattern as long as we assume (which I think we safely can do) that the operator uses them whilst facing the chuck rather than looking across the bed as in the first case.

 

[JAParticipant @ja]

I have just dig out my copy of Sparey’s “The Amateur’s Lathe”, first published in 1948. He clearly says a left hand knife tools cuts towards the headstock. I am no longer going to look for my apprentice notes.

JA

[Bill PhinnParticipant @billphinn90025]

I’m looking at a copy of Sparey now. On page 77, in figure 63, he shows a drawing of an HSS turning tool that today would be universally described as a right-hand tool. His description says: “The illustration shows a right-handed tool for cutting towards the chuck”.

I can only assume there must be different editions of Sparey saying different things on this subject.

[JasonBModerator @jasonb]

You must have a different edition of Sparey than me JA

On page 77 it clearly shows and stated a R/H too cutting TOWARDS the chuck

[Roderick JenkinsParticipant @roderickjenkins93242]

My edition of the Bradley Myford series 7 manual says this:

Rod

[egaParticipant @ega]

An analogy from woodturning might help: imagine the turner working a skew chisel towards the headstock – his right hand naturally grips the blade and the reverse is true for the other direction.

[ega]

On ega Said:

An analogy from woodturning might help: imagine the turner working a skew chisel towards the headstock

That might not be a good analogy as with a woodturning tool, BOTH hands are involved in its use.

It is only by convention that (if what you say is correct) we hand the tool by the one that touches the steel part and not the one that touches the wooden handle.

One could draw an equally poor analogy with guitars: they come in both left and right handed, but the defining one is the one that does the strumming not the one that frets the notes.

[JA]

On JA Said:

I have just dig out my copy of Sparey’s “The Amateur’s Lathe”, first published in 1948. He clearly says a left hand knife tools cuts towards the headstock. I am no longer going to look for my apprentice notes.

JA

Sorry. I messed up my reply. I should have said right hand.

Humble pie.

JA

 

[old martParticipant @oldmart]

I have always known a right handed lathe tool to be normally used to face off the right side of the workpiece, and vice versa for the left tools.

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