Correct Usage.

[armscor 1]

Acquired this left hand boring bar.
Do I use it upside down with Lathe in reverse or correct way up on the far side of bore with Lathe in reverse?
Never used one and are there any advantages?

[GlennW]

Either would work as long as the cutting edge is on center.

A lathe with a threaded spindle may not like running in reverse though. If the tool digs in it could unscrew the chuck and make a bit of a mess.

[LIALLEGHENY]

Left hand bars were designed for shops South of the Equator where everything runs backwards!

All kidding aside, if used upside down, ideally the chips will fall away from the cut, rather than sitting on top of the bar clogging up the works. Most conventional lathes don't have enough travel to run them on the backside if the bore is large enough. There are several issues to consider, (1) don't use it if you have a threaded spindle,(2) when running in reverse the bar will be lifting up on the compound/ cross slide and may give you false readings ( bars like to flex as it is).

Nyle

[armscor 1]

I run backwards, from Australia, also heard the rifling in gun barrels must be opposite twist.
My lathe has a D1, 3 spindle nose so no fear of coming loose, will use it upright on opposite side of bore, plenty of travel.
Thanks Guys.

[pete]

Those L/H bars are also for use in the horizontal cross holes most boring heads will have for doing bores larger than the head diameter.