Where to find upside down parting holder?

[magicniner]

Rear tool post parting with an inverted cutter solves some issues encountered with conventional tooling, but no one has mentioned the major issues.

1. A badly adjusted or poorly designed/built spindle with insufficient rigidity or too much sideways free movement can be pushed away by the tool, once the tool is cutting, the work can climb up and into the cutter and the instantaneous increase in tool engagement ends badly as the tool is effectively wedged between opposing forces from bed and work.

2. If a slide has excess backlash then when cutting commences the forces can take up that backlash and that's a short but quick move into the work which, once again, ends badly.

Both of these situations will be made worse by a cutter being set slightly low which will increase the tendency to pull the cutter into the work or being slightly off from 90 degrees to the work axis in X or Y as the resulting friction on the sides of the cut will increase forces on the tool, as will inappropriate feeds and speeds or the lack of cutting fluid where needed.

When I first bought my Myford Super 7 lathe I though there must be a magic parting tool somewhere that would solve all my problems, over time I found that I no longer had any issues parting any materials and all the parting tools I bought which didn't work before, with proper set up and use, now work fine, I have an inverted parting tool for the rear tool post but this is used simply for convenience and speed when making washers, bushes or other quick jobs where it gives me an extra tool without a tool change and without the need to reverse,

- Nick

 

[Downunder Bob]

The eccentric engineering FoR is designed to be used on either the front or rear tool post, that's what the name is FoR front or rear every one who has used one will agree they are great.

 

[P. Waller]

Buy a left handed parting tool and hold it upside down

 

[TORQUIN]

The eccentric engineering FoR is designed to be used on either the front or rear tool post, that's what the name is FoR front or rear every one who has used one will agree they are great.

Thanks for the info. I looked at that but they do not offer the size I need. It just happens, when I was first getting started in this I ran across two Aloris parting tools holders, at different times, that both take 11/16" parting blades. I stocked up on that size, and now I have about 100 11/16" parting blades. This was also when I was running an SB13, and rigidity was a problem, so I was regularly breaking the blades. Now that I have graduated to Monarchs I do not have that problem anymore.
I am thinking I will just make my own, stealing someone else's design.

Buy a left handed parting tool and hold it upside down

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

 

[P. Waller]

Thanks for the info. I looked at that but they do not offer the size I need. It just happens, when I was first getting started in this I ran across two Aloris parting tools holders, at different times, that both take 11/16" parting blades. I stocked up on that size, and now I have about 100 11/16" parting blades. This was also when I was running an SB13, and rigidity was a problem, so I was regularly breaking the blades. Now that I have graduated to Monarchs I do not have that problem anymore.
I am thinking I will just make my own, stealing someone else's design.


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

Many manufacturers produce left hand parting tools, Kennametal, Kyocera, Kaiser, Widia/Manchester and Iscar for example. Many slant bed lathes hold all of the tooling opposite the operator side. Are all of the other tools upside down or on the back?

Most would be considered Left Handed. Look here
https://www.mscdirect.com/browse/tn...rm=left+handed+parting+tools&navid=4287922435

 

[Downunder Bob]

Many manufacturers produce left hand parting tools, Kennametal, Kyocera, Kaiser, Widia/Manchester and Iscar for example. Many slant bed lathes hold all of the tooling opposite the operator side. Are all of the other tools upside down or on the back?

Most would be considered Left Handed. Look here
https://www.mscdirect.com/browse/tn...rm=left+handed+parting+tools&navid=4287922435

What size lathe are you using they make 5 different sizes and claim to fit most lathes. I used one a few years ago, it was brilliant, and I'm now getting ready to order one when my credit card recovers from my last tool purchase.

 

[P. Waller]

What size lathe are you using they make 5 different sizes and claim to fit most lathes. I used one a few years ago, it was brilliant, and I'm now getting ready to order one when my credit card recovers from my last tool purchase.

The tool that you need will be determined by the depth of cut required to part off the the part. The deeper the cut the wider the blade/insert needs to be in order to support the cutting forces, it goes without saying that the work material is also a factor.

As for lathes I regularly run several machines, a 28" X 100" manual, 15" X 40" CNC, a small Hardinge turret and a large W&S turret, each one has different tools for the most part due to the size difference. The Hardinge has a parting attachment that will only hold a maximum of 3/8" shank tools, the others will hold 1 1/4" tools.

 

[Downunder Bob]

The tool that you need will be determined by the depth of cut required to part off the the part. The deeper the cut the wider the blade/insert needs to be in order to support the cutting forces, it goes without saying that the work material is also a factor.

As for lathes I regularly run several machines, a 28" X 100" manual, 15" X 40" CNC, a small Hardinge turret and a large W&S turret, each one has different tools for the most part due to the size difference. The Hardinge has a parting attachment that will only hold a maximum of 3/8" shank tools, the others will hold 1 1/4" tools.

Yes some rather large machines , and then a small one. You are of course quite right in that it is always horses for courses, If the tools don't fit your machines then obviously they are not suitable, They do however fit quite a range and almost every one who uses them says they are very good. in fact I've never heard any complaints.

 

[NortonDommi]

higgite
I can assure you that a blade running upside down and the chuck running in reverse or clockwise the forces are up. I run this setup and sometimes on Mysterium with a heavy feed the tool will suddenly bite in extra deep, the force can be so great as to shift the tool holder upwards on the Aloris style mount, the good thing is it is just a quick reset and carry on. Bit rough and one day I'll make a better one.

 

[rick9345]

I do most of my parting and threading inverted as the chips seem clear out easier and go in chip pan instead of all over. Aliginment of tool always no.1 consideration.After many crashes now do threading left to right. Blind holes always inside to out. Far more relaxing.