Which is the best parting tool ?

[Brian JohnParticipant @brianjohn93961]

Advantage and disadvantages of different types of parting tool.

[Brian JohnParticipant @brianjohn93961]

There are a few different parting tools available on ebay and I would like some opinions as to which is the most useful.

The first one is the standard parting tool and is part of a set (fourth from the right) which I will be buying anyway but it does look a bit fragile. The blade types look like they would give a much neater finish.

**LINK**

**LINK**

**LINK**

[John HaineParticipant @johnhaine32865]

It depends on your lathe. If you have one of reasonable size I wouldn't give any of those house room, to be frank. For my Myford I have one of these: http://www.greenwood-tools.co.uk/shopscr23.html and it works very well. There are similar systems available here:

http://www.jbcuttingtools.com/epages/es461493.sf/en_GB/?ObjectPath=/Shops/es461493/Categories/%22Parting%20Systems%20and%20Blades%22.

I also have a rear tool post style parting tool from Myford which is very good but slightly gets in the way.

[John HaineParticipant @johnhaine32865]

By the way, I'd recommend that you avoid that set of carbide tipped tools. The problem is that when you chip one then it's finished, hard to reshape. I bought some when I started but got very discouraged. A better bet would be either a couple of inserted tip carbide tools or even better a Diamond tool holder from Eccentric Engineering which has an easy to grind HSS tool and works extremely well.

[Bob Brown 1Participant @bobbrown1]

I have used different parting tools and have not had a need to go to carbide tipped as HSS has been fine. The ones I use support the blade along its length **LINK** and have at least three clamping screws, these give better support to the blade. If you have a small lathe pick a parting tool with a thin blade as the wider they are he higher the load and the greater chance of tool chatter and then the greater risk of the tool breaking.

As for regrinding brazed tipped tooling, as long as you use the correct type of grinding wheel they should present few problems but as a parting tool the one shown may be a little too wide.

[IanTParticipant @iant]

Brian, you asked what the "best" parting tool is? In my view none of the tooling you show is the "best" (just less expensive).

I have an elderly Myford Super 7, well past it's first flush of youth and parting larger lumps was a real challenge. I then acquired the set-up below and now I can comfortably part off 2" plus mild steel slices with no problems at all.

I still use my 'earlier' HSS tooling to groove and part smaller diameter sections but this beastie (or something similar) is the one to get for serious parting work. I've also just purchased a smaller/thinner (narrower insert) version of the insert holder shown but I haven't made a suitable tool-post for it yet (as it won't fit the one shown and frankly I'm too cheap to buy another one!)

I couldn't easily make the insert holder itself but the tool-post is doable. Anyway, my advice is go for the better solution rather than the cheaper one – in this instance it's well worth the extra money.

Regards,

IanT

[Brian JohnParticipant @brianjohn93961]

I should have mentioned that I have a Sieg C2 lathe which takes 5/16'' or 8mm cutting tools.

[Jon GibbsParticipant @jongibbs59756]

Hi Brian,

I'd suggest avoiding the cheap brazed tip versions as others have said. In my experience these are too wide and hard to use. So, I've gone down the HSS route and have a similar rear toolpost version to Ian T's but in HSS and I have both thin and thick parting blades for it to cater for small and big parting jobs…

**LINK**

HTH

Jon

[steamdaveParticipant @steamdave]

Once you have got the Best parting tool sorted, you may wish to consider a parting tool for small parts. The large wide tools may be rigid, but they can waste a lot of material.

For small parts, tubes and pieces using up odd ends, a parting tool made from a broken hacksaw blade has much to recommend it. A suitable holder can be made in a short time and can be used at the front or rear position.

[URL=https://imageshack.com/i/31hacksawpartingtoolj][IMG]http://imagizer.imageshack.us/v2/xq90/109/hacksawpartingtool.jpg[/IMG][/URL]

[URL=https://imageshack.com/i/59hacksawpartingtoolbitsj][IMG]http://imagizer.imageshack.us/v2/xq90/189/hacksawpartingtoolbits.jpg[/IMG][/URL]

Dave
The Emerald Isle

[JasonBModerator @jasonb]

As the C2 does not have a slootted cross slide that really rules out all the suggestions for a rear mounted parting tool.

Of your three links the first as you rightly thought do have a nasty habbit of snapping the whole tip off at the narrowest point, I've done that a few times in the distant past.

I have one like the second link amoung others, these are OK for diameters upto about 5/8" (15mm) much more than that and the blade can flex sideways but being only 0.050" thick don't waste a lot of material or put much load on the machine

Link 3 won't fit as the holder is 14mm high

Given the small size of the lathe I would probably use option two and a hacksaw for larger stuff.

J

Edited By JasonB on 24/06/2014 11:21:47

[blowlampParticipant @blowlamp]

I have a C2 lathe AKA as a Clarke CL300.

I have converted the spindle to taper roller bearing and generally made sure there is no slop in any of the slides that may affect its parting-off and general turning potential.

My experience says to use a blade equal to, or under 2mm in width to reduce chatter and jams. I also use GFN style inserts, which can be found with a positive rake, as opposed to the ubiquitous GTN style, which I have only found with negative rake geometry and makes a substantial difference to the ease of cut.

Here is a video of me parting 1" diameter mild steel with one hand, whilst holding the camera in the other – no coolant, no jams, no drama.

**LINK**

Martin.

[DustyParticipant @dusty]

O.K. I am going to throw my hat in the ring. Most of our problems with parting off stem from forgeting about speeds and feeds, just because you are doing something that frightens the life out of you is not the reason for slowing the speed right down. That is a receipe for disaster, a slight twitch with your feed hand at 100 rpm is inviting a dig in, the same thing at 400 rpm is not as critical. as has been stated make sure the machine is rigid, reduce all overhang to minimum and make sure your tool is sharp and on centre line or even a few thou above. I only use HSS parting tools and part off at 4/500 rpm.on a regular basis.

[NobbyParticipant @nobby]

Hi Guys
I always part from the back on my S 7 Mk 1 using HSS
Regards Nobby

Edited By Nobby on 24/06/2014 12:52:51

Edited By Nobby on 24/06/2014 12:53:50

Edited By Nobby on 24/06/2014 12:56:23

[Danny M2ZParticipant @dannym2z]

Brian. Your second option works fine for small diameters, depends on what you are cutting.

I have one the same that I use in a QCTP mounted upside down with the tip on the centerline.

Your C2 can then be run in reverse rotation (safe due to bolted on chuck) and the forces are then the same as using a rear-mounted toolpost. Locking the saddle & keeping the gibs tight helps too.

* Danny M *

[michael coleParticipant @michaelcole91146]

Hi Brian

I have good results from the tool in your last link. For best results ditch your top slide and replace with a large lump of cast iron or steel.

Mike

[Bob Brown 1Participant @bobbrown1]

Mike, "For best results ditch your top slide and replace with a large lump of cast iron or steel."

Absolutely crazy idea

[blowlampParticipant @blowlamp]

Posted by Bob Brown 1 on 24/06/2014 17:23:29:

Mike, "For best results ditch your top slide and replace with a large lump of cast iron or steel…

That's not necessary, as can be seen from my video.

Martin.

[Neil WyattModerator @neilwyatt]

Personally I take the same approach as Martin & dusty; roller bearing conversion, keep everything nipped up nicely, and don't be lily-livered about it.

I did break a 1/162 wide HSS parting tool recently – I hadn't realised that the hex I was parting was the worng bar something like EN19T or EN24T.

So, I've just done a trial, I turned a register so I could securely hold a 1 1/2" diameter short-end of EN1A in my CL300M (that's a 4" chuck).

I parted off a slice using a rectangular section 1/16" thick HSS toolbit in my home-made QCTP. Note that this is more overhang than with the standard toolpost. Lubrication froma brush dipped in neat cutting oil.

At 528 rpm, it was parted off in well under a minute.

Note the small, curled 'chips' of swarf, typical of EN1A Pb and showing the tool was cutting properly.

Admittedly this is the 'best' steel for parting off, but I think this proves the point that no hugely special modifications are essential.

Neil

Edited By Neil Wyatt on 24/06/2014 18:05:25

[michael coleParticipant @michaelcole91146]

Bob and Martin

Never heard of the Gibraltar tool post then.

[Chris TriceParticipant @christrice43267]

I agree with Ian T. The blade type with the replaceable tip is the one I reach for most of the time. For thin walled tube I use a HSS tool I’ve ground into a thin blade on it’s left hand side (so you can get right in close to the chuck). I also have a rear toolpost which makes a big difference.

[Bob Brown 1Participant @bobbrown1]

I have seen machines without a top slide, but on my Boxford I fail to see any reason what so ever to remove it of use a rear parting tool.

A lot of people go off on a tangent with regards to actually performing the task when the question was what is the best parting tool.

When you are up to your arse in alligators, its hard to remember the object of the exercise was to drain the swamp.

[blowlampParticipant @blowlamp]

Posted by michael cole on 24/06/2014 18:52:19:

Bob and Martin

Never heard of the Gibraltar tool post then.

I have, but that's for a Myford.

The top slide of my Clarke lathe is probably more rigid than the Myford offering and substituting it for something else has never been necessary. It certainly does not bend (visibly) in the way a Myford does.

Martin.

[Chris TriceParticipant @christrice43267]

Just out of interest, the Emco Compact 5 comes with a solid toolpost block you can substitute for the top slide. It’s basically a mini Gibraltar post. Since small improvements in rigidity can make all the difference depending on the quality of the lathe and how heavy the cut is you’re trying to do, solid posts do make sense in some set ups.

[Chris TriceParticipant @christrice43267]

I will also add I’ve never HAD to use one.

[Harry WilkesParticipant @harrywilkes58467]

I use a Sandvik parting tool with Sandvik N151-2-200-5E inserts andI find it very good ! It came with the Myford S7 and a couple of spare inserts, looking around the internet for inserts I see plenty of N151-2-300-5E inserts and I gather that the difference between -200- and -300- is the seat size how does it differ ? would the -300- still fit the holder ? Would appreciate advice please.

H

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