Parting tool help

[savarin]

Rigidity is the key, since I removed the top slide and replaced it with a solid block

Plinth For Qctp On 9 X 20 Lathe

In my never ceasing search for more rigidity in my lathe I decided to make a plinth for the qctp. In its normal configuration I can often see the complete top slide assembly flex slightly. (I think I punish my lathe a bit) After seeing Bill G's plinth I felt it was time to go. I forgot to take...

www.hobby-machinist.com

my 9x20 parts like a hot knife through butter.
I use "T" shaped HSS parting blades now, a quick touch up with a diamond hone before starting and cut as close to the chuck as possible.
Blade tip on dead centre, but I often just eyeball the blade at 90', sometimes I'm a bit out so the cut curves slightly but its never been a problem.
On large diameters I will start parting then withdraw and move over half the blade width and continue a bit deeper and keep swapping back and forth for faster chip clearance.

 

[ChazzC]

Like others said, on center and dead nutz 90 degrees to the work. Also important is a taper on the tool for relief or chips will bind the tool up when the cut gets deep. Make sure the tool is vertical as some holders taper to match a factory tool taper and some don't.

Vertical is important: you may need to shim the bottom of the blade in the holder to make this happen.

 

[GT-6 Racer]

I use T-shaped empire blades on my Hardinge lathes. Very happy with them too.
Blades with GTN 2 inserts work really well too.
best cut off is my horizontal band saw though.

 

[Parlo]

I assume that rear mounted tools have the spindle in reverse to direct the cutting forces into the machine bed.
The benefit of having a rear mounted parting tool is that it can be set and kept there permanently. I don't think it is much more rigid than a properly locked toolpost and compound slide & the same as a solid toolpost.

 

[GeneT45]

I assume that rear mounted tools have the spindle in reverse to direct the cutting forces into the machine bed.
The benefit of having a rear mounted parting tool is that it can be set and kept there permanently. I don't think it is much more rigid than a properly locked toolpost and compound slide & the same as a solid toolpost.

The setups I've seen all run the lathe forward and mount the parting tool 'upside down'. There is the advantage of perhaps improved rigidity, as well as the convenience of leaving the tool set up for much of your turning.

GsT

 

[Parlo]

The setups I've seen all run the lathe forward and mount the parting tool 'upside down'. There is the advantage of perhaps improved rigidity, as well as the convenience of leaving the tool set up for much of your turning.

GsT

I was taught that also. Another benefit being that the swarf falls directly into the chip pan.

 

[ChazzC]

I was taught that also. Another benefit being that the swarf falls directly into the chip pan.

And the forces tend to lift the cutting edge away from the work so it doesn't dig in.