Confused About Lathe tool holder

[Kidbee]

It has probably been discussed on this forum before- but why is a right hand tool holder curved to the left? Which probably translates to- right is left and left is right. Why is it so??

[bob ward]

Best explanation I can come up with is that if a lathe tool is designed to cut from right to left then its a right hand tool.

[anglesmith]

The best way I could explain it at this time of the morning !, Is to imagine you needed to machine deep shoulders on the left and right ends of long shaft, you would need to use the opposite cranked tool holder on each end to reach in to machine the step. When I was using a line shaft belt driven lathe during my apprenticeship we didn't use tool holders but solid "blacksmith" forged left and right handed "knife" tools !! The shaft itself was machined using a straight forged round nose tool !!
Graeme

[Bryan]

You're right, it's Been Done. Some 'rugged individualists' refuse to accept the convention and I once saw a thread on another forum grow long and unpleasant. But if you're ordering tool holders you might as well use the same nomenclature the manufacturers do. :wink:

FWIW my answers are:
Because it makes a cut that faces right.
To be consistent with threading terminology?
Because it just is. :)

[anglesmith]

It has probably been discussed on this forum before- but why is a right hand tool holder curved to the left? Which probably translates to- right is left and left is right. Why is it so??

Sorry Kidbee It WAS too early in the morning !! I took your question to be a machining query not a terminology question!? As Bryan said the convention just is. It is stating / describing what the tool or tool holder DOES not which way it points or which side the cutting edge is on !
Graeme