My guess is that your parting tool isn’t dead square to the face of the chuck. If you go in at an angle it will almost certainly grab.

I suggest you use a parting blade with a carbide insert.  The insert is wider than the blade and gives clearance to the supporting blade.  Another suggestion is to be bold with both spindle speed and feed rate.

Rod

The usual, and very good, advice is to have the tool on exact centre height. However, I’ve found – possibly due to a bit of flex in my setup due to wear – having it a fraction higher than centre helps. Not a lot, of course, maybe up to 5 thou.

Rob

I also like the 2.2mm wide GTN-2 inserts, this is a bit of 30mm EN3 on an Amadeal 210E lathe, nicer swarf than Rods😉😉

Same tool on the Warco 280 cutting a 1.5mm slice off a 70mm diameter iron casting

The rules for parting off are:

Slower than normal turning or facing.

Part off as close to the chuck as possible.

Minimal overhang of the parting tool.  You need to have everything as rigid as possible.

The face of parting blade should be perpendicular to the lathe axis. (A parting blade ground at an angle will produce swarf that is wider than the groove, and likely to jam)

This where the raplaceable carbide tips score. They generally have a central groove, so that the tool mproduces two harrow streams of swarf, which curl minwards and are unlikely to jam in the groove.

Keep a slow steady feed, DON’T rush, but don’t let the tool rub! (This means that you need to have the basic skill of providing a steady feed of the tool, whatever task you are underaking on the lathe). If in dounbt, go slow!

If you can arrange a steady, if only a drip feed, supply of lubricant (Soluble or mineral oil) this will help. Machine brass and copper alloys dry, lubricate ferrous materials, but not cast iron.

If you can fit (make?) a rear toolpost, an inverted parting tool in it will improve matters (The swarf falls away, so less likely to jam)

Needless to say, the parting tool needs to be sharp (I do not use top rake; and am now so brave /over confident that I often part off under power cross feed of about 0.002″ per rev wihich leaves hands free to apply lubrication.

This is my take; others may use other methods, but H T H

Howard

I just braved the hot workshop, hopefully this not very good photo will show th edufference feed rate can make.

1″ EN1A, 250rpm, GTN-1 Insert.

On the right was a fine power fee dof 0.00075″ on the left the feed was double at 0.0015″ which has not only been folded far more but also broke up into smaller pieces.

I would expect a heavier lathe like Julie’s to fold the swarf even more