Tangential lathe tool holder

For a Myford 7 series lathe, I found I had to crank the toolbit end down 1/4" + to be able to get the cutting edge at centre height, using a qctp.

Dave
The Emerald Isle

Kenneth

Just a thought - don't know if it would work on your lathe - but if you made the tool shank circular in cross-section and then gripped the tool in a split holder, like a boring bar, you could do away with the side ways slope on the slot for the bit and just cut the for and aft slope. Might make machining a bit easier as you wouldn't be milling on a compound angle, also it would allow you to experiment with the side ways angle for the best cutting performance just by rotaating the whole tool in the split holder.

I could certainly go that route on my machines because I can use large tools in the standard toolpost - 1inch hich slot.

Keith

Kenneth - I sawed the blank for the original from a length of 1.5" x 0.5" bar. The 0.5" thickness was not reduced in any way unlike your drawing which shows one side machined at an angle. I chain drilled the basic elongated "L" shape and then hack sawed the shape out.

If you look at my second post on this thread have a gander at the third photo. This clearly shows that the shank is machined as a parallelogram. It is the 12 degree angles incorporated in this parallelogram that cants the tool over to give the tool bit its sideways 12 degree attack angle unlike your drawing.

Aside from that, your 20mm should be 23mm and your 30mm should be 38mm. The latter dimension is particularly critical given the clamp dimensions which I have detailed.

And nit picking here, your drawing shows the clamp screw holes to far away from the tool bit slot. These need to be as near to the slot as possible without breaking through to allow the clamp to bite on the tool bit as near to the longitudinal centre line of the tool bit as is possible.

Hope this helps.

Rik

Keith - There are no compound angles to machine on my version. --- Rik

I just finished my version of tangential toolholder for my homemade QCTP:

And here it is on the QCTP:

And it woorks beautifully!

Sverre

Well done Sverre. Hope you will not mind me pointing out that I think you will find some limitations with your tool due to the very prominent tool bit fixing screw head. From the photo it looks as though the head will foul the first shoulder it comes up against - well before the tool point gets there

This is a problem that is quite difficult to overcome in this design which is why I approached it from a different direction in my version earlier on in the thread.

Rik

Hello Rik;

Yes - I know! I just wanted to get a quick way of trying out a tangential toolholder. The big screw holds the toolbit firmly, but limits the diameter for facing to about 20 mm.

I'll have to finish the holder for grinding the toolbit, thought I would make a jig for grinding it on my new Worksharp 3000 (mostly for sharpening woodworking tools), but will give a very nice sharp edge.

Sverre

This is mine.

Very nice tool Vic what's it made from or is the grey colour some kind of heat treatment?

.

Paul,

I may be wrong, but I suspect it's made from "Ones and Zeroes"

... Whether I'm right or wrong; it's a lovely job, Vic.

MichaelG.

The only Ones and Zeros I know is binary. How would you make a toolholder from binary? I realise you could computer generate an image so are you suggesting the toiolholder is vaporware?

graham.

Graham,

Yes, I'm suggesting it is a lovely piece of image rendering.

MichaelG.

And thought Michael meant CNC by his "Ones and Zeroes" comment.

Les.

Or it's been sandblasted perhaps?

IanT

No, it's the real deal, I made it from some unknown steel but you're right, it's been sandblasted. Here's another pic of it with some other stuff I made.

In use on my Lathe (height setting).

Michael et all

Oh ye of little faith!

Nice work Vic

Norman

Thanks Norman! Couple more pics, how it started out:

Clamp setup.

.

I did cover my options

But I am VERY impressed !!!

MichaelG.

Its so nicely sculpted its almost a work of art my friend mine is nowhere near as nice:

Your Knurling tool is nice too mine is a similar design:

Paul