Michael Cox Tangential Tool Holder- MEW 179

[michael howarth 1Participant @michaelhowarth1]

Thanks Chris, but I still have queries…..I have left you a member message asking you to email me. Sorry to be a pain.

Edited By mick H on 02/09/2011 16:21:07

[michael howarth 1Participant @michaelhowarth1]

Thanks for contacting me Chris. You have now explained that the groove angle in the grinding jig is 90 degrees and this has resolved my queries. I shall now get on and make the jig.

[Michael Cox 1Participant @michaelcox1]

Hi mick H,

I have just returned from holiday and caught up with this thread. As Chris has already told you the channel on the grinding jig is a 90 degree groove so there is only one possibleorientation for the tool.

Mike

[michael howarth 1Participant @michaelhowarth1]

Mike….I hope you enjoyed yourself…..we have been talking about you whilst you were away!

I picked up MEW 181 today and I am looking forward to the flycutter article.

[michael howarth 1Participant @michaelhowarth1]

The recommended toolbit grind cuts superbly on BMS and stainless but what about brass. Do you grind different angles? I don’t get the finish I would expect on brass. Can Mike or Chris help on this one?

[Michael Cox 1Participant @michaelcox1]

Hi mick H,

I have not used my tangential tool for cutting brass many times but I have not found any big problems with it. However there are so many grades of brass that maybe my experience is not representative of all brasses.

Normal cutting tools for brass are ground with zero top rake. This could be achieved on the tangential tool by grinding the tool tip at a different angle. This could be achieved by setting up the tool in the tangential tool holder, with some protrusion, and then grinding the tip of the tool parallel to the upper clamping surface of the tool holder shank. A simple jig could be made to hold the tool in the correct orientation during grinding by clamping the upper clamping surface of the shank to a square bar and then just touching the tip against the side of a grindstone.

I hope this helps

Mike

[chris stephensParticipant @chrisstephens63393]

Hi Mick H,

I’m in complete agreement with Mike on this.

I seem to recall that MGJ, another former member, ground his tools with zero rake for brass and if he recommends it then you can be sure it works, although I have not found it necessary but then I don’t use much brass it’s far too expensive.

 

As Mike says all the usual recommendations are for zero top rake for brass because of its chippy cutting characteristics. When you use a middling sort of tool there is a risk that the tool will grab. What I find with my favourite type of tool, with its very sharp edge, is that grabbing is not a problem as it just cuts its way through the metal. If you are getting a less than satisfactory finish, is it that you are working on small diameter stock? Brass is not as stiff, size for size, as steel and will flex and can give a rippled surface. You can improve the finish if you run the tool backwards, while supporting the work with a piece of oiled leather. This might sound very non H&S but can be very effective on small diameters, as with all things lathe if you don’t like the sound of it, DON’T DO IT.

chriStephens

[adyParticipant @ady]

Funny how these things pop up as you do your own thing.

 

I found boring toolholders easy to use and “self sharpening” but struggled with surfacing work.

While final cuts are always best done with “on the money” and established procedures alternative techniques for roughing out big chunks of barstock can be handy.

 

I’ve found that if you don’t cut too deep, then below the centreline at the back or above it at the front can give good roughing results and the workpiece “grinds” the tooltip keeping it in a reasonable working condition until seriously accurate cuts and finish are required.

Works for both carbide and hss.

Don’t go too deep or you might dig in.

Great for auto feed work.

[michael howarth 1Participant @michaelhowarth1]

Thanks for the response. My comment arose as a result of working on a piece of small diameter brass……perhaps that explains it, but I should emphasise I still get a “good” finish as opposed to a “superb” finish on BMS. I shall experiment further.

[Sub MandrelParticipant @submandrel]

Lacking a chunk of metal big enough to make Michael Cox’s toolholder without wasting loads, I’ve just milled a crude copy of the eccentric holder out of some 3/4″ bar.

 

It’s a bit rough as it was very much an experiment to work out how the clamping manages not to foul the work. The answer is ‘with difficulty’, I had to grind a lot of the clamp away. I ground the top of the tool by eye, and tidied it up and out a tiny radius on with a diamond slip.

 

Problem was I made the clamp ‘hooked’ around the front edge of the bar; the eccentric tool squeezes it from the sides. but at least I’ve worked out how to get the angles.

 

I was still able to see what happened on some intractable 1/2″ stainless. And the result – was rather good. At least as good as any other tool I’ve used on what is nasty work-hardening stainless. The swarf came off as a continuous spiral, hot but not blued. Depth of cut was about 20 thou with 4 thou fine feed.

 

Another try needed to make a tool that will face and deal with large diameters, but on the wholea useful proof of concept.

 

Neil

[JohnandeParticipant @johnande]

I read with interest the Fly-cutter by Michael Cox in MEW 181.

I intend to make it as I think it could solve some of my machining difficulties.

 

Rather than use the complicated method of drilling the 12mm hole for

the shaft at the 12 degree angle. Would it be possible to mill the

slot for the tool at 12 degree’s and mount the shaft at 90 to the base plate?

Or are there other things come into play to make this not an option?

 

Regards

 

Johnande

 

[Michael Cox 1Participant @michaelcox1]

Hi Johnande,

Sure you could mill the slot at 12 degrees and keep the base plat at right angles to the shaft but you would then have to modify the clamping screw arrangement because the tool would be in a deep channel.

I agree, my method of drilling the angled hole was overly complex. It would be much easier to drill the angled hole using a slot drill but I did not think of that at the time. Hindsight is wonderful.

Mike

[JohnandeParticipant @johnande]

Thanks for the reply Michael, your dead right, we all

have 20 – 20 vision in hindsight.

 

Johnande

[Anthony KnightsParticipant @anthonyknights16741]

Michael Cox tangential tool holder. MEW 179. I made both left and right handed versions.

[VicParticipant @vic]

This is my tool holder from ten years ago. It was very straightforward to machine. The work on the clamping side including the drilling was all done in one sitting.

[Grizzly bearParticipant @grizzlybear]

Hi Vic,

That's very nice, a masterpiece no less.

Bear…………

[Author]

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