Sorry to dig this up, but wouldnt you figure i would find this thread after my run-in with the "hobby-machinist" forum. Anyway, here is the info on this tool from there website. I purchased one a week ago and will be testing it out as soon as it comes in the mail! Happy Reading!!
The Diamond Tool Holder was originally developed in Australia by Des Burke in 1985 and manufactured by him until 2006. At the age of 80 Des finally hung up his production overalls to spend more time in his shed on hobby engineering .
Since Des started the Diamond Tool Holder many thousands have been sold across the world, the majority in Australia and the USA where our distributor, Bay-Com, handle our sales.
UK customers can now order direct from our distributor. Click here for details
Unlike conventional lathe tools the High Speed Steel (HSS) tool bit is held at a tangential angle to the work piece.
Tangential tool angle Conventional tool angle
Holding the tool bit in this position provides all the clearance angles required for general cutting purposes. Leaving only the top rake to be put on using the grinding jig that comes with the kit.
Due to this tangential angle, all the cutting forces will be transferred down through the length of the tool tip. This together with a body cast in 4140 heat treated steel makes for a very rigid tool.
The Diamond Tool Holder utilises a standard piece of square section 1/4" HSS, inexpensive and easily available from any engineering supplies. One tool bit blank is supplied with each kit.
Resharpening is fast and simple using the supplied grinding jig. Just clamp the tool bit in the jig and run it across a regular bench grinder. Due to the design of the holder, this is the only face that needs grinding.
Using the same jig, it is easy to grind the angles for a 55 or 60 degree screw cutting tip by using the V groove at the front of the jig. The holders will also accept 1/4" diameter round HSS for use as a round nose tool and the jig will sharpen this too.
For more information on the Diamond Tool Holder click the Features and Tips button, or watch the video of the tool in action. For information on how to select the correct size tool for your lathe, click the Sizes and Ordering button.
The Diamond Tool Holder is available in five sizes, from 8mm - 16mm tool height.
The original design for the tool meant that the shank had to be angled at 12 degrees so that it could slide and surface at the same setting. This design is a compromise to make the tool easier to use when screwcutting, so that the shank doesn't get in the way as much when cutting a thread close to the chuck. See the images below for more detail.
The 8mm, 9.5mm, and 12mm tools have been redesigned so that the tool tip can face and surface when the shank is at 90 degrees to the mandrel. This makes the tool much more convenient to set up when used in a quick change or 4-way tool post. The 8mm, 9.5mm, and 12mm tools are also available in a left hand version for cutting towards the tailstock and left hand shoulders. The left hand tool also gets around the problem of the shank getting in the way of the chuck when cutting threads.
To select the correct size tool holder for your lathe, take a measurement from the base of the tool post where the holder will sit on, to the centre height line of the lathe.
This measurement is the lowest setting that the tool bit can go down to, but the tool tip can be moved up or down for fine adjustment to get the point on centre. Of course you can always put a piece of packing under the holder to bring it up higher for a bigger lathe.
If you are using an adjustable tool post, set it close to its lowest point before measuring.
Once you have decided which tool holder is best for your lathe, use the online shop to purchase.
