Diamond tool holder.??

What impresses me most about tangential tool geometry is that it seems to cope with large depths of cut more easily than conventional tool geometry. On my minilathe I can take a 1 mm deep cut without too much trouble using the tangential tool.

I also have a small X1 mill. This has only a 150 watt motor. Using a conventional fly cutter it would really struggle to make a 0.1 mm cut in steel. I tried all sorts of tip geometry to try to improve this. I then made a tangential tool flycutter (see: http://mikesworkshop.weebly.com/tangential-tool-flycutter.html) and the difference was amazing. Cuts of 0.4 mm were possible.

What I cannot figure out is why the tangential geometry allows these much better depths of cut. I have tried conventional flycutters that present the tip in exactly the same way to the metal being cut as the tangential tool cutter but the depth of cut ( and surface finish) is always inferior. I think it must be something to do with the rigidity of the tangential tool mounting.

Mike

One of my last purchases before the workshop succumbed to the North Sea 'surge' was a Diamond tool-holder. Quite impressed with the results. Just previous to that I bought a used Myford tool holder which I have not seen elsewhere. Presented in a 'tailored' box, it was approximately 2" x 1" x 1/2" with an angled through hole in one corner to take 'Eclipse' type round HSS rod. The end was ground to match the surface of the tool-holder, providing clearance and rake and making height setting particularly easy. Again, very easy to sharpen, (single flat surface) and the results were superb (by my standards!!). As said above, not seen elsewhere nor have I read of anyone else using them.

Rgds

Bill

PS First bricks laid for the house rebuild yesterday!!!

Sorry for the multiple posts. As Geoff was saying a couple of posts back you hit the post button and nothing happens. I kept hitting the button in the belief that nothing had happened and ended up wit three postings. Can one of the moderators remove the excess postings to leave just one?

Thanks

Mike

Hi Tony, and I beg to differ, as I stated for home user, for in industry HSS doesn't even show on the radar any more. I must assume that you have not yet tried a tangential tool as if you had you would not have dismissed my statement in such a cavalier manner. One tool really can do for just about any metal or plastic, save for those where HSS is inappropriate as stated in earlier post. As for getting the best out of your lathe, I tend to think you might have that backwards. I really do urge you to have a go with one, they are NOT all hype, and, as anyone who knows me will doubtless attest, I do have a "modicum of mechanical aptitude". I also have an enquiring mind and am willing to try anything new, old or different to improve my turning, not quote the same old guff that has been passed down the line since who knows when, at least not without proving it for myself first.

What I hope we can agree on is that there are numerous ways of doing just about anything and if you get the results you set out to achieve, then that is all that matters. I have watched some very experienced proffesional turners who turn things down to a couple of thou oversize and then file and emery to size, I seem to be able to turn to the size I want and get a good finish, though in truth I might polish with grey scotchbright to finesse the surface slightly. Some methods are better than others for sure, and not all of us have the same equipment or experience, so we have to make the best of what we have. My mantra is the more I know, the more options I have. That goes for tooling too.

ATB

chriStephens

Well said Chris. This is pretty much what L.H.Sparey says in his book "The Amateurs Lathe". He says even production shops eventually realised they could get the job done with only a few types of Lathe tools. Are there really folks out there with hundreds of basic Lathe tools with slightly different grinds or is it just folks repeating outdated information? When I first started out I saw all those late 19th century and early 20th century lathe tool charts and was thoroughly confused. Especially as so many of them contradicted each other! I gave up and learned to grind my own tools with a profile that worked. I soon found out you only need a few different tools. As a hobbyist I'm by no means an experienced machinist but I have managed to turn quite a lot of different materials on my modest Lathe with largely the same tools.

Obviously there's nothing magical about a tangential toolholder that somehow allows one set of cutting angles to work for all materials. If you were to try machining brass with a tool that is ground for light alloys, you'd want to be wearing your best rubber pants. It's possible you could get away with it if you take tiny cuts and have your slides nicely nipped up but why would you bother? With a tangential tool, you can have a toolbit ground for brass etc (zero top rake) and one for light alloys (perhaps 20 degrees or so) and swap them over in seconds.

Indexable tooling is pretty rugged and forgiving but even so, they have quite different cutting angles according to the material being machined. Same with HSS twist drills for brass (slow or zero helix) and light alloy (fast helix).

I don't have a tangential tool myself, so perhaps I'm not qualified to comment!

Murray

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?!

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

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!

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

Neil

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

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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

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

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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

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

Neil

When does it go on sale Neil?

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

ATB

c

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!