Diamond tool holder.??

[VicParticipant @vic]

I had to look back through a past build log to see what I was using some years ago. Jogging my memory I happily turned cast iron, bronze and brass with the same indexable insert tool with the same (gold) insert. I also used the same insert on mild steel. Perhaps two years ago I bought another tool holder that took slightly bigger inserts, it was supplied with one "gold" insert which was supposed to be for most materials including mild steel and a very shiny silver insert which was said to be used for Aluminium Alloy and Stainless steel. Not sure this makes sense to me given what's been said! I must say that in spite of what's been said I've never used a zero rake tool on brass, perhaps I should try it and see if it really does work better?!

[Tony Pratt 1Participant @tonypratt1]

Hi Chris,

Well it’s confession time, I did buy a tangential tool holder about a year ago from EBay in a fit of ‘tool envy’ but it was a little too big for my current tool set up so after a quick run out it was put in the drawer for another time, it’s now been found after some hunting, soon to be used in anger.

My current favoured method is to rough with an indexable carbide tipped knife [CCMT 06 tip] tool & finish with a HSS knife tool.

The finishing tool is a general purpose shape as like most people I can’t be bothered to have loads of shapes on the go but I know if I require an excellent finish or size on any particular material the best results are achieved by grinding a tool with geometry suited to that material.

That’s the way I do it & there are many others, as to finishing a shaft with emery I have worked alongside quite a few ‘turners’ who favoured that method, all I can say is that they never impressed me as engineers and they were not interested enough in their job to work out why they couldn’t obtain a good finish or size consistently with a turning tool.

Tony

[VicParticipant @vic]

I must admit that I wasn't very impressed with the way the first one I made cut. I put it aside and continued with some insert tools. It wasn't until I chipped several inserts in a short space of time that I realised how expensive they could be to run. Rather than mess with the one I made I bought one of the commercial Tangential tools and that worked well. Looking back I think I just ground the HSS for my shop made one at the wrong angle. I've since made a couple more of my own and they all work well. Next job for me is an upside down parting tool holder!

[David Carpenter 4Participant @davidcarpenter4]

Posted by Vic on 08/12/2014 16:23:39:

Next job for me is an upside down parting tool holder!

 

Save yourself the trouble and shorten the learning curve here.

Edited By David Carpenter 4 on 08/12/2014 17:25:32

[Neil WyattModerator @neilwyatt]

Or better still just click the eccentric Engineering ad to the right of this thread

Neil

[David Carpenter 4Participant @davidcarpenter4]

Posted by Neil Wyatt on 08/12/2014 17:25:54:

Or better still just click the eccentric Engineering ad to the right of this thread

Neil

Does it for me. Almost.

Edited By David Carpenter 4 on 08/12/2014 17:29:06

[Tony Pratt 1Participant @tonypratt1]

Posted by David Carpenter 4 on 08/12/2014 17:21:08:

Posted by Vic on 08/12/2014 16:23:39:

Next job for me is an upside down parting tool holder!

Save yourself the trouble and shorten the learning curve here.

Edited By David Carpenter 4 on 08/12/2014 17:25:32

I am a big fan of the inverted parting tool design, but if you use this tool in the front position be aware you have to run the lathe spindle in reverse which could be interesting with screwed on chucks.

Tony

[Tony Pratt 1Participant @tonypratt1]

Posted by Tony Pratt 1 on 08/12/2014 17:35:42:

Posted by David Carpenter 4 on 08/12/2014 17:21:08:

Posted by Vic on 08/12/2014 16:23:39:

Next job for me is an upside down parting tool holder!

Save yourself the trouble and shorten the learning curve here.

Edited By David Carpenter 4 on 08/12/2014 17:25:32

I am a big fan of the inverted parting tool design, but if you use this tool in the front position be aware you have to run the lathe spindle in reverse which could be interesting with screwed on chucks.

Tony

Sorry guys it does actually mention this fact in the whole advert for this tool.

Tony

[Nick_GParticipant @nick_g]

.

A point that may be of trivial interest is I rang the UK distributor prior to ordering mine to check stock level.

The UK part of the network is actually the guy in Auzzies sister. Not that it matters.

She posted the order out the same day.

Nick

[VicParticipant @vic]

Posted by David Carpenter 4 on 08/12/2014 17:21:08:

Posted by Vic on 08/12/2014 16:23:39:

Next job for me is an upside down parting tool holder!

Save yourself the trouble and shorten the learning curve here.

Edited By David Carpenter 4 on 08/12/2014 17:25:32

I've already got a couple of blades from Chronos, it won't take me long to make a holder for them.

[Nick_GParticipant @nick_g]

.

May be of interest to some.

Here is a link to youtube showing my recently purchased diamond tool holder with a HSS bit in cutting EN3

**LINK**

Nick

[Neil WyattModerator @neilwyatt]

Don't make a parting tool holder until you have seen the February MEW. There will be something truly different in it.

Neil

[VicParticipant @vic]

When does it go on sale Neil?

[chris stephensParticipant @chrisstephens63393]

Hi Neil, bet you a cup of tea it isn't. Someone, somewhere, almost always got there first..

ATB

c

[VicParticipant @vic]

There was a special offer on an insert parting tool holder set at the Sandown ME show a couples of years ago. Against my better judgement I bought it and found the holder was a poor fit on my lathe. I ended up making my own which is obviously a perfect fit. I should have saved my money and just bought the blade and inserts. The Eccentric one looks nicely made but it's not cheap. I have the steel and it wouln't take that long to make one that's a perfect fit for my machine. Having said that I can wait until February to see what's new!

[Nick_GParticipant @nick_g]

.

They are not too shabby at facing off either.

Here is a link to youtube taking off a 1mm cut to remove excess material in an interrupted cut on an eccentric for the James Coombes I am building.

**LINK**

Nick

[MuzzerParticipant @muzzer]

On the subject of upside down parting tools, there aren't many lathes that are designed to withstand a lifting of the slides (including the saddle) by the cutting force, so I concluded that for my Bantam at least, any rear-mounted parting tool should be operated with the lathe in reverse and the tool not inverted.

If you look at the assembly drawing / exploded parts list for your machine, you will see what arrangement is used to restrain the saddle against this vertical (upwards) movement. It's usually fairly minimal and primarily intended for locking the saddle at a single point. Unless you have this saddle lock adjuster tightly nipped up (which isn't ideal in terms of wear), there has to be vertical slop in there and the horizontal location by the bed Vee's will also suffer from any such vertical movement .

On the cross slide, there is a firm and direct contact between the horizontal underside faces of the slide and its base in the "normal" direction. With cutting forces in the reverse (upward) direction, the slide is instead held by the angled gibs with some slop ie much less well defined and rigid.

I can only assume that in some cases, the additional slop and springiness resulting from running the tool upside down actually helps to reduce the likelihood of judder, most likely combined with light cuts. However, if you were asked to demonstrate exactly how the tool position is positively defined / constrained, I suspect you'd struggle. Generally speaking, rigidity and control seem to be the safest way to prevent "rubber pants" moments during heavy parting operations.

Murray

[VicParticipant @vic]

Posted by Nick_G on 12/12/2014 10:38:04:

.

They are not too shabby at facing off either.

Here is a link to youtube taking off a 1mm cut to remove excess material in an interrupted cut on an eccentric for the James Coombes I am building.

**LINK**

Nick

No stringy swarf on that, what material is it? Lovely finish on it as well.

[Nick_GParticipant @nick_g]

Posted by Vic on 12/12/2014 13:17:39:

Posted by Nick_G on 12/12/2014 10:38:04:

.

They are not too shabby at facing off either.

Here is a link to youtube taking off a 1mm cut to remove excess material in an interrupted cut on an eccentric for the James Coombes I am building.

**LINK**

Nick

No stringy swarf on that, what material is it? Lovely finish on it as well.

Hi Vic,

It's EN3

Nick

[chris stephensParticipant @chrisstephens63393]

Hi Murray, I also have a Bantam and agree about the forces involved, When people talk about lifting and tool post bending etc they tend to forget the weakest part of the set up that is the parting tool itself, which is going to bend long before the tool post. On a Bantam parting is no problem in the conventional manner but some top rake helps with the peel effect.

Have you tried a tangential parting tool? They have a limited depth of cut, depending upon design, but within its range they work great.

chriStephens

[MuzzerParticipant @muzzer]

Chris

No, I bought a 3mm Korloy Sawman indexable parting tool as you can see from this album. Works really well. I use a few hundred rpm and power feed with coolant and it doesn't flinch. I'd forgotten that I made a Youtube video of it.

I wouldn't go back to HSS now except for very narrow grooving. I also wouldn't try to operate it upside down! I am going to get some "H01" grade inserts for parting aluminium and light alloys – although it parts these OK with the steel cutting inserts, the material sometimes doesn't clear fully, resulting in snagging and poor finish. Cutwel sell single inserts online.

I also have a Korloy KGT tool which not only parts and grooves but is also designed for normal turning operations. I've got inserts for both steel and light alloys and it's pretty darned good.

I have to admit I often use an indexable boring bar for both internal and external turning. The internal operation is pretty obvious – but for external turning I move the tool behind the centre line and reverse the machine. In this way, when you have the top slide at 45 degrees for chamfering, you can use the same setting for both internal and external chamfers. That avoids having to keep swinging the topslide back and forth. You need to swap out the boring bar for a proper turning tool when you have more than an inch or two of overhang or if you want to make proper heavy cuts.

When using the machine in both directions like this I like to sanity check that the power feed is the correct direction. I always try to use the power feed and feed stops where possible so I can get a decent finish and a reasonable rate of material removal.

Murray

Edited By Muzzer on 12/12/2014 20:50:33

[Martin King 2Participant @martinking2]

Hi all,

Really interesting thread!

Can someone please tell me the correct size to get for an ML7 using the Chronos QCTP holders?

The War Office, (aka the missus) has promised to get me these for Xmas!

Cheers and Season's Greetings to everyone.

Martin

[VicParticipant @vic]

Details here Martin.

http://www.eccentricengineering.com.au/index.php?option=com_content&view=article&id=6&Itemid=19

[Nick_GParticipant @nick_g]

Posted by Martin King 2 on 20/12/2014 19:13:07:

Hi all,

Really interesting thread!

Can someone please tell me the correct size to get for an ML7 using the Chronos QCTP holders?

The War Office, (aka the missus) has promised to get me these for Xmas!

Cheers and Season's Greetings to everyone.

Martin

If you are using e.g. 12mm tools presently get a 12mm version.

Nick

[chris stephensParticipant @chrisstephens63393]

Hi Martin, might I suggest you get the later version that allows you to keep the tool post square to the work, so you don't have to keep re-squaring it when, for instance, parting.

The original has to be kept angle, a compromise for threading, which is something not discussed under this title so far. For starters a tangential threading tool does cut very freely and cleanly especially with flank feed threading, if that happens to be your preferred method. Anyone else tried this tool for threading?

chriStephens

[Author]

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