Parting tool recommendations

Sandvik Coromant is as well known as anything. Whether it's the best, or only, value for money I couldn't say.

Be aware, that you need a rigid lathe for the carbide part off tools. Seems that you don't need a specific manufacturer. But most recommend inserts of the SP.. type.

I have one, but I'm not fully convinced. Often enough, I prefer the HSS blades. But for 30mm of SS, I'd take the carbide.

Nick

How rigid is rigid though Nick?

I only have a little Myford and I use a carbide parting tool for everything. I bought the Q-cut tool from Greenwood at a show last year, and wouldn't go back to HSS unless i absolutely had to.

Makes parting an absolute breeze.

To be honest I use carbide turning tools almost exclusively on the Myford, except for screwcutting, and one toolholder with a sandvik coromant DCMT insert is practically a permanent fixture on the toolpost.

Mind you I'm a lazy bugger too. I hardly ever alter the spindle speed from the Myford top-end of

640rpm, and cut pretty much everything from 4" diameter mild steel to 1mm silver steel on this speed, all with the dcmt insert, just altering feed and depth of cut.

Peter

Greenwood Tools - Q-CUT Parting Tool. Expensive but certainly works a treat in my boxford.

How rigid is a Myford? I don't know, but I think she isn't as bad as the small Chinese cheapies.

Yep, this type of inserts. And no, below say 10mm I prefer the HSS. The carbide has higher cutting forces and would bend something delicate (say a 2mm round) more than cut it.

Full ACK for something over 20mm or hard to cut like SS. Parting off 40mm with HSS is an adventure, with carbide, it is a snap.

As HSS, I'm using the Komet part off blades. If you stone a small radius on the right edge, they cut really nice. But, they have to be better aligned than the carbide part off tools.

Nick

I can completely agree with that, carbide does require you to be a bit more brutal with the infeed, and would probably bend the smaller stuff.

Again , I just use the hacksaw for the really small stuff, and the bandsaw for the really big stuff.

Peter

In article , Peter Neill writes

I entirely agree with Peter - I have been using the Q-cut for a couple of years on my S7, and you would have to shoot me to take it away.

Yesterday I was parting off some 30mm MS, and forgot to drop down from

615 to 200 rpm (as I would normally) but the Q-cut sliced through without pausing for breath. I have even seen the Myford men demonstrating parting off under PXF using one - something I can't imagine doing with a conventional tool.

The only time I have gone back to conventional tools recently was to part off some nylon bar, where I worked out that my narrow HS tool would

*just* get me 3 pieces instead of 2.

David

In message , Ian writes

[snip]

I have fond memories of a beat-up old Boxford. It was my first lathe and I learned a lot from it. One of the things I learned was the joy of a rear mounted (and upside down) parting tool.

Is there any need/advantage in using carbide parting tools inverted a

the rear of the cross-slide

-- Myford Mat

----------------------------------------------------------------------- Myford Matt's Profile:

this thread:

Thanks for the really useful replies

It was the Q-cut tool I had in the back of my mind but had forgotten its actual name.

My only concern would be the 2,5mm width of cut, I am used to 1.6mm which the Boxford copes easily with, it also reduces wastage. Another advantage of the loose HSS blade type is that only the minimum length of bit need to be projecting which helps rigidity, I have also parted in to about 50mm depth on 150mm diameter Delrin by extending the bit in stages.

Is the Q-cut an adaptation of another manufactures double ended holder I wonder? if so I might buy one from J&L, make two, and see if anyone wants to go 'halves'.

Ian in Cheshire

Ian if you can wait until the Bristol show next month then visit Jenny at JB Cutting tools. She usually has different sorts on the stall at good prices. I bought a double ended on off her for about £30 and the inserts are also double sided and cheaper than the single sided ones like Greenwood sells. This is a 1.6mm wide blade and it cuts great.

Only problem with mine was the blade is tall, no problem to my lathes but for a small lathe you would have to chop it in half then reduce the height but the tip cost would more than pay for the hassle of doing that.

It looks like. You get the double ended holders for ... oops! ... 60.- EUR. Then build your own clamp, because these cost above 130.- EUR. Prices for non-Chinese quality. BTDT:

Hope you can reach the pictures.

The smallest inserts are 2.2mm or you bite the SECO price-tag and you get

1.4mm. SECO inserts are expensive (starting at 9.- EUR / pc), holders are expensive starting at 75.- EUR, clamp costs "just" 200.- EUR. But the holders are made out of HSS. If everything fails, you can regrind them. ;-))

Nick

John

I could wait for the Bristol Show but probably wont, due to impatience. I would definitely prefer something narrower than 2.5mm.

Do you know how machinable are the blades that hold the tip.

Are the double ended tips a compromise over the single types I wonder?

Ian on the Cheshire Plain

The other end will cut (or rub) too at deeper cuts.

Nick

In message , Myford Matt writes

My understanding is that it depends upon the design of the lathe insofar as how and where the cross-slide is constrained in the vertical plane and also the rigidity and overhang of the spindle (does it have measurable flex or lift).

I never thought of that Nick, but you are right.

HSS cutting tools rub fine but my experience with tips on SS is that the cutting edge can break off if the job is rotating in the wrong direction.

Ian

In article , Peter Neill writes

Can't say I have had much problem parting off small sections with a Q-Cut - just have to ensure the part line is close to the chuck. Or, more likely, near the collet. I parted off several sections of 1/8 silver steel yesterday with no problems. I would be surprised if an HS tool would have been easier.

In general (i.e. normal turning, not just parting) I feel the belief that TC tools are unable to take fine cuts is a myth. I find they can shave off a few tenths off FCMS without too much trouble, and tougher stuff with maybe more care to use a sharp (new) tip.

David

Is there any need/advantage in using carbide parting tools inverted at the rear of the cross-slide?

I know it's recommended for HSS. Any opinions?

Cheers

Matt

Does parting off of 35mm with a HSS (Komet blade 1.9mm) under power feed qualify?

Nick