QCTP with upside down tools?

[Boucher]

Running tools upside down is sometimes desirable as in the case of cutting a right hand thread away from a shoulder or a rear mounted parting tool.

Will a wedge type QCTP work in these conditions where the cutting force is trying to lift the tool holder?

[TGTool]

I can't speak for the wedge type because I've got the piston lock, but I do use the tools upside down with some frequency. Most often for internal threading without reversing the spindle rotation. I did do a little with a QCTP as a rear post with parting off but the setup was awkward enough I don't have much experience to comment on for that arrangement.

[madwilliamflint]

Running tools upside down is sometimes desirable as in the case of cutting a right hand thread away from a shoulder or a rear mounted parting tool.

Will a wedge type QCTP work in these conditions where the cutting force is trying to lift the tool holder?

The only thing that's really different from that orientation (picturing it in my head) is the height adjustment nut, and that's for placing the tool holder before the wedge is engaged. It's not load bearing.

I'm gonna go with yes, it should work fine.


*crosses his fingers, hoping he's finally helped here*

[dalee100]

Hi,

Speaking from personal experience, no it doesn't cause me problems. I always thread away from shoulders, it's just so much easier. Those light cuts won't be enough to cause movement. In fact, I highly recommend the Aloris #8 tool holder and blade for threading. It allows quick and easy resharpening with quick and easy adjustment for left and right threading.

I will qualify my experience is with Aloris brand QCTP. And not other brands.

dalee

[duckman]

Why not just turn your tool upside down and raise the holder up.

[Black_Moons]

Yes a wedge will hold tools just as well upside down as right side up. The adjusting nut is not designed to carry any load at all, the wedge type have parallel dovetails that 'expand' to lock the tool in place.

Infact, If you look carefuly, you'll see its designed to be able to handle tools upside down, Because it has enough adjustment in the adjusting nut to put an upside down tool on center. (at least, on my lathe it does)

[Toolguy]

You can always add a spacer block under the toolpost to get whatever height you need.

[Boucher]

Getting the threading tools near a shoulder and on center when turned upside down was somewhat problematic. It required a left hand threading tool to get near the shoulder and some modification to get centered. That bridge has been crossed. The threading cuts tend to be light and I have done this enough to be comfortable using the QCTP. I am building a rear post to try the upside down parting off. This supposedly lets the cuttings fall freely from the groove. Based upon current input I am going to set this up to use the QCTP rather than a dedicated cutoff tool holder. I can see some other cases where this might come in handy.