The Diamond Tool Holder

[peak4Participant @peak4]

Posted by Vic on 21/01/2019 18:08:47:

Quick picture of mine, more in my album.

I'm using something similar I knocked up for the Myford a few years ago, but am about to make a bigger one for the Warco GH1330.
In my initial trial one, I used 12° for both angles; what's yours?

Cheers

Bill

[Howard LewisParticipant @howardlewis46836]

Yes, the articles in M E W called for 12 degrees in all planes. My problem in making the original design with the compound angles was getting one angle right and then cutting the other the wrong way round. Checking that I'd got it right took longer than the machining when I was sure!

Glad that I read the articles and made some, (1/8 as per drawing, followed by another to take 5/16 toolbits, – which has seen a lot of work..

Howard

[VicParticipant @vic]

Yes, I used 12° for both angles. If I remember correctly I swung my main vice around 12° then mounted the workpiece in a smaller vice held in the bigger one at 12° if that makes sense. My main milling vice is a fairly standard looking 4” one but I also have a 2” screw less vice.

[peak4Participant @peak4]

Posted by Vic on 24/01/2019 20:51:27:

Yes, I used 12° for both angles. If I remember correctly I swung my main vice around 12° then mounted the workpiece in a smaller vice held in the bigger one at 12° if that makes sense. My main milling vice is a fairly standard looking 4” one but I also have a 2” screw less vice.

Thanks Vic (and others)

Fortunately I have a small 3 axis universal vice, which i used to make my prototype, so I could set all the angles at once. It's only a 2" one and not all that rigid, but i was only using an 1/8" cutter to make the 3/16" slot for the tool bit.
Still making grinding wheel arbours for my recently acquired part built Quorn at the moment, but a bigger diamond holder's probably the next job.

Bill

[Howard LewisParticipant @howardlewis46836]

Like peak4, I used a 2" three way vice. O K unless you want to take heavy cuts. So slowly slowly catchee monkey. Got there in the end, just don't watch everything flexing!

It did the job and introduced me to easy machining, sharpening and setting.

As you may gather, a great fan.

Howard

[LathejackParticipant @lathejack]

I have been reading with interest all the comments about the Eccentric Engineering Diamond Toolholder, and they inspired me to nip into the workshop to dig out my hardly used example that I bought from the UK supplier maybe six years ago, it cost just over £60 from the Harrogate Show I think.

My Diamond Toolholder has a trailing cutting edge when the tool is mounted at 90 Degrees to the lathes axis. In order to be able to turn and face at the same setting I have to swivel the toolpost, which is just daft. Surely a cutting tool designed to turn and face should just simply mount at 90 degrees and only swivelled round if a trailing cutting edge is required. This aspect of the tool has always annoyed me which is why I have only used it a handful of times over the years. Other than that I agree it is an excellent tool.

So do I have a dud? Is mine made incorrectly? Or are there other examples out there made like mine? The first two photos I have posted show how my tool holder cutting edge trails when mounted at 90 Degrees, and also the angle it needs to be set in order to be able to turn and face at the same setting.

…………..I then found a test of the Eccentric Engineering Diamond Toolholder by Roger Bunce on the Model Engineering website. In it he does state that the original design had been modified by increasing the crank of the tool to allow it to turn and face when mounted at 90 Degrees. I don't know the date of the article or when the design was modified.

The last photo shows an image from Eccentric Engineerings website. With the cutter set to turn and face, the tool shank can just be seen and appears to be set at similar angle to mine. So maybe I was sold an early version.

Edited By Lathejack on 25/01/2019 20:27:38

[VicParticipant @vic]

Yes, the design was changed some time ago after several comments, mine included, that you had to set the tool at a funny angle to both turn and face. As far as I know the current versions allow the tool to be set at 90°. It was this original design “feature” that prompted me to make my own Tangential tool. I still use the Eccentric one though because it takes round tool bits, particularly carbide which is good for hard stuff.

[John ReeseParticipant @johnreese12848]

I wanted to try a tangential tool but didn't like the price from Eccentric. I decided to build my own. I was working at the mill without drawings when I realized I was making a left hand tool. Damn. I had to start over and make a right hand tool. I really like the way they cut and the finish I get.

I hadn't realized that Eccentric put a radius on their bits until I read it here. Thanks for that information.

The fishtail threading gauge (60*) makes a great gauge for grinding the bit.. I grind freehand. I have a tool & cutter grinder but it isn't worth setting up for that simple grind.

[LathejackParticipant @lathejack]

Vic

Thanks for your reply. I feel a little better knowing that I am not really the only person to have one like this.

Looking at the tool holder there is no reason why it could not have been formed with the end cranked over a little more, so it does appear to have been a bit of an error in the original design.

Despite being very annoyed and irritated by it all these years, it is only after first reading this thread a couple of days ago that I thought to investigate and ask questions about it.

So rather than attempt to make another I am going to put this one right with some careful cutting, bending and Tig welding. I can then banish all the ill feeling I have for it, then use it much more often and finally get my money's worth out of it.

Edited By Lathejack on 26/01/2019 02:41:39

[Chris TriceParticipant @christrice43267]

Posted by Lathejack on 25/01/2019 20:22:23:

I have been reading with interest all the comments about the Eccentric Engineering Diamond Toolholder, and they inspired me to nip into the workshop to dig out my hardly used example that I bought from the UK supplier maybe six years ago, it cost just over £60 from the Harrogate Show I think.

My Diamond Toolholder has a trailing cutting edge when the tool is mounted at 90 Degrees to the lathes axis. In order to be able to turn and face at the same setting I have to swivel the toolpost, which is just daft. Surely a cutting tool designed to turn and face should just simply mount at 90 degrees and only swivelled round if a trailing cutting edge is required. This aspect of the tool has always annoyed me which is why I have only used it a handful of times over the years. Other than that I agree it is an excellent tool.

Almost word for word my experience too. Similarly bought about six years ago and equally frustrated by the bizarre choice of head angle. As a result, it's spent most of its time on the shelf. Since I have nothing to lose, I might cut part way through the shank, bend it to a better angle and then mig weld it.

[Niels AbildgaardParticipant @nielsabildgaard33719]

Posted by Chris Trice on 26/01/2019 03:44:38:

Posted by Lathejack on 25/01/2019 20:22:23:

I have been reading with interest all the comments about the Eccentric Engineering Diamond Toolholder, and they inspired me to nip into the workshop to dig out my hardly used example that I bought from the UK supplier maybe six years ago, it cost just over £60 from the Harrogate Show I think.

My Diamond Toolholder has a trailing cutting edge when the tool is mounted at 90 Degrees to the lathes axis. In order to be able to turn and face at the same setting I have to swivel the toolpost, which is just daft. Surely a cutting tool designed to turn and face should just simply mount at 90 degrees and only swivelled round if a trailing cutting edge is required. This aspect of the tool has always annoyed me which is why I have only used it a handful of times over the years. Other than that I agree it is an excellent tool.

Almost word for word my experience too. Similarly bought about six years ago and equally frustrated by the bizarre choice of head angle. As a result, it's spent most of its time on the shelf. Since I have nothing to lose, I might cut part way through the shank, bend it to a better angle and then mig weld it.

Why not make a new and better tangential Yourself?

Edited By Niels Abildgaard on 26/01/2019 06:58:46

[thaiguzziParticipant @thaiguzzi]

Posted by Clive Foster on 20/01/2019 13:53:00:

ega

If downwards projection of the toolbit is an issue with tangential holders the simple answer is to switch to an Armstrong style!

As the video linked in the first post implies, but doesn't actually state, at the cutting edge tangential and armstrong tool holders are functionally identical devices. The only primary difference is that the armstrong bit requires two grinds for most tool shapes whilst the tangential bit gets away with one. If you have the grinding jig. The armstrong bit also consumes its cutting edge at every grind so it gets narrower and shallower over time whilst the tangential tool regenerates the edge in the same place with every grind. Of course an armstrong bit does not need a jig, although a simple angled fence can be helpful, and sharpening on the front of the wheel using the hollow ground method is trivially simple.

The real genius behind the Eccentric Engineering tangential toolholder was the realisation that the toolholder and uber simple sharpening jig combination added up to a price / performance / perceived value ratio corresponding to a successfully marketable product. Realising that there was also a touch of "new to this generation" novelty to provide serious marketing impact and keep the idea fresh was important too.

Well done that man. Seriously. Heck I almost bought one.

Fact is an equivalent simple, one universal angle, sharpening jig can be devised to use with armstong holders. With equally effective results given a simple half page instruction sheet explaining the hollow grind on front of the wheel method and how to hone the tool to keep it sharp. Possibly a footnote on packing up for various rake angles too. Which pretty much don't matter for the home shop guy so long as the thing is sharp and has some clearance.

But no one has ever made a go of a lathe tool sharpening jig for home shop guy. Southbend tried but theirs was too clever and too complex. Good tho'. Price / performance / perceived value being all wrong for a commercial product especially with everyone saying its dead easy to grind an ordinary tool. Which it is if you have someone to show you but un-mentored and working from books is a different matter if things don't click quickly. Especially if you don't know how much of a cut you ought to be able to peel off with a sharp tool. I've yet to see a written description of basic lathe tool sharpening that rates better than not very good from the solo novice viewpoint.

Doesn't help that the Americans never officially seemed to twig that the rocker in their obnoxious lantern tool posts is unnecessary when an armstrong is used. Simply roughly shim and change the tool bit projection for fine height adjustment. So the poor old armstrong system got tarred with the lantern brush.

Clive.

Edited By Clive Foster on 20/01/2019 13:54:32

As always, Clive is right on the money.

I have a Bison QCTP (Dickson clone with 19 holders) that is on my lathe 96% of the time. I have the original 4 way tool post that is used 1% of the time and a home made lantern tool post sans rocker holding an Armstrong holder for those awkward lack-of-space jobs or one-off tool bits for the other 3%.

As you can see, i find the lantern/Armstrong far more useful than the 4 way.

[I.M. OUTAHEREParticipant @i-m-outahere]

Has anyone tried using the tangential tool with a brazed carbide on a square tool shank ? I have a couple of these tool holders from eccentric but rarely use them as I use carbide insert tooling for the most part but have always wondered if a chunk of carbide brazed onto the end of a piece of square stock then ground the same as the tool steel bit would work .

[John HaineParticipant @johnhaine32865]

In this thread **LINK** a few years back I gave details on how to work out the angles to get different clearances. Thanks to Michael Gilligan I can now find old posts!

[VicParticipant @vic]

Posted by XD 351 on 26/01/2019 07:21:35:

Has anyone tried using the tangential tool with a brazed carbide on a square tool shank ? I have a couple of these tool holders from eccentric but rarely use them as I use carbide insert tooling for the most part but have always wondered if a chunk of carbide brazed onto the end of a piece of square stock then ground the same as the tool steel bit would work .

Not sure, it might work. Someone gave me several broken 1/4” solid carbide end mills so I tried one of those once ground in the Eccentric tool and it works great on hard stuff. I turned some HSS with it the other week.

[John PParticipant @johnp77052]

I silver soldered this 1/8 inch carbide shank into a suitable size square piece,the edge is milled out about half the diameter and the piece soldered in ,it seems to work best if left as a round shank.The round piece fits neatly between the clamp.

The one on the left is ground to conform the the square shank ,because carbide chips easily when ground to the acute angles of the diamond tool a shallower angle is needed at the top and both the sides need a little grinding for clearance.

Useful for harder materials and maybe cast iron.

John

[mark costello 1Participant @markcostello1]

I have made a carbide tool bit to use in a tangential tool holder. I have used it on hard plastics. I have not used it on steel yet.

[John ReeseParticipant @johnreese12848]

With that high rake angle I bet it cuts very well in the beginning but will not last long. Sharp points like that on carbide are prone to chipping.

[John McNamaraParticipant @johnmcnamara74883]

Hi John Pace.

GMTA I made the same toolbit using the carbide shank from a PCB drill, PCB drills are so tiny to hold up they are made from very fine grain carbide. Tough too.

I milled a piece of key steel of the correct size and silver soldered in place.

Been using it for a couple of years. The ten degree angle you normally use for the Diamond tool can be reduced to around 5 deg by angling the template. More robust for heavier work. However it will work fine as standard.

Regards
John

[John PParticipant @johnp77052]

Posted by John McNamara 7/01/2019 13:23:07

Hi John Pace.

GMTA I made the same toolbit using the carbide shank from a
PCB drill, PCB drills are so tiny to hold up they are made from
very fine grain carbide. Tough too.

I milled a piece of key steel of the correct size and silver
soldered in place. Been using it for a couple of years. The ten
degree angle you normally use for the Diamond tool can be reduced
to around 5 deg by angling the template. More robust for heavier work.
However it will work fine as standard.

Regards
John

Hi John,

I don't use the supplied fixture to sharpen the toolbits,some while ago
I bought 10 off 1/4 square toolbits from J&l supplies they were on offer
at about 80p each 10% cobalt.
Both ends are sharpened as can be seen in the photo .I had this process
scribbled out on a piece of paper and have tidied if up here for use
on the Quorn grinder or tool grinders with similar axis. This may be useful
for others wishing to do this.The self centering 2 inch four jaw chuck is
from Chronos and makes this much easier to do.

Having 20 ground ends if one is dulled it goes in the grind box and
a fresh one fitted.

The carbide tips that are ground similar to a CCMT shape only need regrinding
on the top until the are worn down enough that the sides need doing again.
Grinding the carbide is best done towards the cutting edge to avoid chipping.
These days the tangental toolholder gets the most use.

John

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