Where to find upside down parting holder?

[NortonDommi]

I still wonder ...can you just use a parting tool holder and turn the blade upside down?

As long as you can get the tip on center then no problem. As noted by several people if a relief clearance is needed with HSS or a cast blade like a Crobalt then again no problem as long as it is the right way up/down.
My opinion for the little it is worth is that running the blade with the cutting edge at the bottom has so many advantages I try to do this as often as possible. Threading away from the chuck is so safe it is my preferred method. Even plain turning particularly with something like Brass I like all the chips going down. Once you get used to it it is like everything else you will swop back and forth depending on the work. The only kicker being to always remember which way to push the control lever.

 

[mikey]

I have a Multifix toolpost coming tomorrow and I will decide if that is what I am going with after I examine it. I still wonder ...cna you just use a parting tool holder and turn the blade upside down?

The two key parameters that will determine if you can use the tool upside down is the angle the blade is held at (must be horizontal) and whether or not you can get the tip of the tool at center height. This is the one sold by HHIP on Amazon:

The first criteria might be okay; not sure if the blade will hold solidly with the bottom of the slot at an angle, though. Not sure about the center height thing.

 

[NortonDommi]

Best bet is when your Multifix arrives take whatever blade you would like to use or something of that size and hold it in place against a mounted toolholder. This will give you a good idea of where to proceed. One thing we have to thank our Chinese friends for is making bits and bobs affordable to the masses so if necessary put aside qualms and start carving.

 

[Headrc]

With Mikey and Ddickey's help I believe what I am going to do is pursue a DIY solution. It will be cheaper and teach me more about machining. That is one of the reason's for this newly found hobby ... making more tools to make more tools!

 

[P. Waller]

Problem with that is most QC, and other, holders are angled up, to give the blade a lot of positive relief and won't work backwards. If they were zero-relief, yes, I would just flip one upside down.

Thanks,
Chris

Why exactly can you not turn the tool upside down?
This is a blade parting tool, just clamp it into the QC tool holder upside down. The rake angle is built into the insert pocket not the entire tool.
The blade adjusting screws will be on the bottom of course but this is QC so simply remove the tool block and adjust as needed.
https://www.machines4u.com.au/view/...Tool-Kit-Insert-Type-16mm-Tool-Height/188823/

 

[cjtoombs]

Metal Lathe Accessories sells a kit for making a rear toolpost for small lathes:
http://www.statecollegecentral.com/metallathe/MLA-6.html

 

[NortonDommi]

Why exactly can you not turn the tool upside down?

The problem is that the tip is not on center with an insert blade. For example a 32 mm blade has the tip center /cutting edge at 26 mm from the base.
This means that when you turn the blade upside down you cannot raise the blade high enough. I struck this problem which is why I made a holder. Perhaps if I had a narrower blade it would be possible say a 19 or 25 mm blade.