The Diamond Tool Holder

This is my height gauge. Easy to make from a small length of scrap bar.

I wonder - we have here a tool which is held in another tool and clamped to a third. Would it make sense to combine the first two - The square-bit holder and the cutter holder? A slab of steel with the angled clamp-slot at one end and a dovetail slot in the middle to match your QC? And if you did that, what is to stop you making it double ended? In this case the two ends would have to be opposite hands - one downwards and the other upwards - to avoid the second end from fouling the top slide as you change its position.

There would be one clear advantage for some of us - once set up, it would avoid that awkward delay when we needed to change tools but couldn't remember where we had put the next one.

If I have a go at making one of these, would EN1A be OK or should I go for something a bit up-market, and if so what?

Regards, Tim

My idea for the Cowells is to take off the topslide (it's always in the way) and make up a plate to fit in the hole with a spike for one of those split block tool holders, and have the tangential tool part of it, not too distant from Tim's suggestion. If I could remember the official name for the tool holder this might make more sense.

One of the advantages of the Tangential tool is that it has built in height adjustment. No need for shims or a QCTP, in fact it’s likely more rigid without the latter.

Remembered it, Norman Toolholder see **LINK**

As Vic says I won't need the adjusting screw on the tangential one, but will for other tools

Duncan

Have a look at what John Haine built recently: **LINK**

https://www.model-engineer.co.uk/forums/postings.asp?th=132573&p=1

MichaelG.

That looks nice and solid Duncan.

Duncan, Norman toolholder is standard on Drummond M topslide, so I made one to bolt onto the crosslide, made several holders for different tools with height adjusting screw, easy QCP. Also holders fit both slides. John

The standard Eccentric Engineering toolbit has a small radius ground on the cutting edge to improve the surface finish.

It is only small, but combined with a fine feed rate, gives a good finish, especially with a little neat cutting oil added..

I tried doing the same thing to an ordinary toolbit, did it badly so that it did not extend the radius far enough down. The tool rubbed and the finish was terrible!

Howard

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

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

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

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

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

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.

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.

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

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