Parting made easy

P

Peacons

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Many may already know this but I tried a new way ( for me anyway) of parting off a part.
I remembered seeing a YouTube video of someone parting off by having the parting tool upside down and then running the lathe spindle in reverse so I decided to give it a try.
What a difference! Cut thru smoothly, no chatter, no digging in.
This will definitely be my preferred method.
 
I should mention that this method is only safe with chucks that are held on with studs not screwed on as this will obviously cause them to unscrew.
 
If you can mount the cut off tool behind the work, upside down, you don't have to reverse the rotation. My Ames turret lathe has one permanently mounted there. It an a chamfer tool I put in front on occasion are the only tools on the "saddle".
 
I have this set up. I tapped the bottom of the parting tool holder and added an adjustable leg. It is so ridgid that I pretty much always use auto feed when parting and it just goes in, doesn't stop, absolutely zero chatter.

SvdqHIz.jpg
 
There was recently a few different threads about this issue in which a "Old" style Armstrong parting tool holder was reintroduced to the gang.
This holder has a relief cut across the tool holder body that allows the tool to "give way" vs digging in and stalling the lathe (pictured in post 16 on the linked thread.) There are more threads with more info about said tool holder but I figured you would search them out if interested.

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Parting

I gather several folks do this and believe there are some tooling setups to do it. For the life of me, I don't understand why it would be any better. Instead of a piece that wants to climb on top of the cutter, now you have a cutter that wants to climb on top of the piece. I must be...
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Man! I can't tell you what crap luck i have parting. I have a HSS & a carbide cut off. Have it on absolute dead center & half raised it a hair, lowered it a hair. I've tried higher rotation, slower rotation. Thicker oil, thinner oil, nothing does a nice clean job...it's a battle i tells ya. I've watched many a video but something just isn't right. Having a live center helps....a little, but thats not always an option. This approaching from the backside is something i haven't tried, but seems you need your compound to go WAY in to approach from back? No? Pictures/videos anyone?
 
If your lathe has somewhere on the cross slide available, skip the compound. Here's a picture of my rear mounted tool holder. It's in front as this is while I was adjusting the height by trimming the bottom on the mill.

IMG_20190806_010043.jpg
 
So if you were to use the stock tool post position, could you get the tool far enough back to approach the part from behind? I’m pretty sure I’d run out of threads on the compound before I was behind the part all the way.
 
GunsOfNavarone said:
So if you were to use the stock tool post position, could you get the tool far enough back to approach the part from behind? I’m pretty sure I’d run out of threads on the compound before I was behind the part all the way.
Click to expand...


Possibly, depending on the part diameter and the lathe in question. But why? It's the wrong tool for the job. It also has flex, particularly on small lathes. That is part of the problem, which is why using a jack on the tool holder can help. One of the best improvements to my lathe has been removing the compound. It's easy to put back if I want a taper. The rest of the time it's flex I don't want.
 
I’m looking at your setup & im not sure what you m looking at. The tool post is raised on a block of aluminum, and there is a block of aluminum next to a diamond shaped cutting tool not a parting tool? I’m unsure how this relates to the parting process
 
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