Tangential tooling

I have been thinking about making some tangential tool holders for the lathe. I found this which shows one design. There are many other similar designs.

http://theamateurmachineshop.com/index.php/projects/13-tangential-lathe-tooling

Has anyone used this type of tooling and if so there must be some rules on how to grind the tool bits? Any insight welcome before I try making this.

Starting at 7:18 this video from Eccentric Engineering shows sharpening:

Gordon, looking at the drawing on the link it appears there is no side clearance/rake on the design ? Forward rake is 16deg but it shows zero side rake.
Here is a photo of one I made a while back -- I copied the design form another chap's photo of one he made. No drawings --yet !! but it has 12deg rake for both front and side. One photo is as machined and the other are hardening
View attachment 088E16A1-B572-423C-88B9-7E9B48EE00A5.jpeg

OK Thanks. That is what was confusing me. I know that it needs both side and rear rake so I was wondering if the rake was generated in how the tool bit is ground. I will keep looking for another design or make my own. The $100 price plus shipping for the eccentric seems kink of steep. Also I have plenty of time to make my own.

Sort of a Request.........

I have had it in my head for years that I would like to make one of these, but the other "Round To-its" have been keeping it in the background.

I followed the late Chuck Fellow's experiments back in those days, but did not save his posts, and what he did was not exactly what I was thinking at the time.

Anyway........,

If I make an attempt at this I will post my adventures with it and I would hope ayone else making one of these or a variation of it might post some detailed information that might help us all. I am having a particularly difficult time getting my head around the orientations of the bit necessary to make the sharpening jig that would be required to grind HSS toolbits for this use.

I am using a 7x mini-lathe and have grinders and belt sanders for sharpening and protractors plus angle plates with surface plate for measuring: So, old-school tools and techniques.

Or, If someone knows of a free source for build information (hopefully with plans) I would like to know where to find it.

Thank You for listening,

--ShopShoe

Gordon said:

OK Thanks. That is what was confusing me. I know that it needs both side and rear rake so I was wondering if the rake was generated in how the tool bit is ground. I will keep looking for another design or make my own. The $100 price plus shipping for the eccentric seems kink of steep. Also I have plenty of time to make my own.

Click to expand...

Blondihacks has one that she demonstrates.

I made one many years ago for my 12.5 x 30 Cincinnati TrayTop lathe, and I use it all the time. Grinding the bit is simple a matter of holding it so that it presents to the grinding wheel as a diamond shape - i.e., rather than the flat sides being horizontal and vertical, the corners are aligned vertically and horizontally. Tip it about 10 degrees and grind the bit, leaving a high spot on one corner of the face, sloping back to the opposite corner. Hone lightly and it is ready to go. Note that I also prepare the bit by slightly rounding the whole corner that will be used for the high spot / leading edge.

Age old question. Buy the tool and have it to use, or make one and save the $ at the expense of time and other projects?

While I have been slowly learning to grind my own HSS bits, the simplicity of these would be a big advantage. The time saved by "fixing" my grinding would probably make up for the time spent making the holder.

Another 'round tu it'....

I have the Diamond tool holder from Eccentric Engineering and it is absolutely brilliant with either HSS or Crobalt. Yes postage is expensive now - I often buy things from the USA or UK and sometimes the postage costs more than the item.

Model T Ford said:

I have the Diamond tool holder from Eccentric Engineering and it is absolutely brilliant with either HSS or Crobalt. Yes postage is expensive now - I often buy things from the USA or UK and sometimes the postage costs more than the item.

Click to expand...

Postage is why I bought the Diamond holders, bits, etc. at the same time as the Flexi-Vise (with spares as well): incremental postage was minimal.

Village Press (The Home shop Machinist, Machinist’s Workshop & Live Steam) used to sell Diamond Tool Holders (they still sell the FoR Cutoff Holder and some Crobalt bits), but IIRC it was actually cheaper to buy them direct, even with the postage.

Just visited their site. Prices are high enough but you can't get a shipping charge without starting through the checkout process.
Deal killer for me.
Guess I will be making my own. At those prices I can afford to scrap some metal in the process.

Obviously I am not the only one who has a problem figuring out how the bits are sharpened. I have seen variations of the holder in right hand and left hand and also with the bit set at 45 deg.point forward and also with a round bit. All of these would require a different grind. I am thinking about making a RH and a LH. If I have those it should be easier to visualize the proper grind.

The Eccentric Engineering tangential tool is very nice and easy to sharpen. That is also what Blondihacks uses.

I made my own. Not perfect, but works very nicely.
BUT I use it less and less, as "traditional" tool shapes cover lots of different access issues that would need multiple "Eccentric" tool holders. And it was a big lump on the rotating 4-tool post (After setting-up, this is much quicker for multiple tool changes on a job than the demountable tool holders, that sell like hot cakes at shows!). But it sits close and handy if I need just a simple tool equivalent of a "RH KNIFE". I made a simple jig for sharpening bits by filing a 90degree Vee in a small block of steel with a clamp - like the one in the eccentric photo. Easy to sharpen tools correctly. Though they rarely need sharpening, now I am back to mostly using regular tooling.
I have no problems sharpening tools "by hand and eye" as I was taught and doing it as a teenager in a proper machine shop, So actually, it is of little benefit if you can develop sharpening skills.
For me, the hobby is as much about developing new skills, and utilising old knowledge, as my career was on paper not machines, after my Teenage apprenticeship. So while it was a project to make the eccentric tool holder, like most projects, it sees little use for me. I "wanted" to use it after making it myself, but after a couple of years it isn't on my tool-post of regular tools.
Others may use it a lot though, but "You pays ya money and makes ya choice"... etc.
Toolmaking for me is for the "specials", not the "regular" tools that are readily available.
Conclusion:

• YES it does what it says.
• Yes, it is easy to re-grind tools to a sharp edge = but that is the only significant advantage.
• Changing from a "square" to "round" bit can be done. (but set-up time is longer than swinging the tool post around to another different shaped tool!).
• Setting tool cutting point height is relatively simple, but not easy until you have practiced - which you will do if you want one holder to do both square and round tool jobs.
• YES it does go from machining face to diameter readily, but so can many regular tools, anyway.
• Yes, it is clever, but I find it unnecessary on my tool-post.

Making one can be the pleasure of making something, but improved "usefulness" isn't always achieved...
Each to his own.
K2

Over the years I have made 5!!! of these one with a round toolbit. the round version and one square one have TC toolbits I tend to use them for difficult materials. One of the great advantages of them is they will remove large quantities of material in one pass making the stock sizing ooperation less onerous. One complaint is that its difficult to face large diameters without turning the toolpost to the right. The round version ( which uses broken 6mm shank cutters) gives a fantastic finish on stainlessView attachment S11A7071.JPG

Not just for these tools, but for many tools I re-use broken taps, milling cutters, masonry drills (tips), carbide tips, etc. to make tipped tools that I grind to suit the lathe. especially when I want a special boring bar or something, a rod with a tip brazed on is a good starter.
K2

ChazzC said:

Postage is why I bought the Diamond holders, bits, etc. at the same time as the Flexi-Vise (with spares as well): incremental postage was minimal.

Village Press (The Home shop Machinist, Machinist’s Workshop & Live Steam) used to sell Diamond Tool Holders (they still sell the FoR Cutoff Holder and some Crobalt bits), but IIRC it was actually cheaper to buy them direct, even with the postage.

Click to expand...

I got one of those several years ago. I thought they worked pretty good.

Jon K

Yes, I can definitely take a much deeper cut with the tangential tool. Tool height is pretty easy with the tangential holder in a dedicated tool holder. I just made a "shim" of the right thickness such that I turn the holder over on a flat surface with the shim giving the tool bit the correct height when slid to touch. Tighten the lock screw for the bit and done.

To me, the only negative is that you lose the super easy sharpening if you grind in a chip breaker. So it is pretty easy to get very long chips.

A long thread
Homemade tangentials

And Video

Tungsten carbide Blue Swarf

Spring Hollow. I like the "inverted tool and shim" idea to jig the tool height setting. Simple and effective. Maybe I'll make a setting block... because I can. I find it pretty easy to set the tool height anyway, as years of practice makes life relatively easy. And I found it is for changing from a square bit to round bit that I changed the tool more often than for re-sharpening.
But after the novelty wore off I am back to pre-set traditional tools in a 4 post tool holder anyway...
For those, I set to a height gauge (for convenience) and when I have the set of correct shims simply assemble into the tool post - with a dab of loctite between each shim and the next and tool. But No loctite on the tool post! Then when I remove the tool to fit a different one, (like a special, boring bar or Tangential tool or other) then the "Frequent use" tool with shims attached can be re-fitted and needs no resetting. The shims only need changing after a re-grind.
Hope this description is clear enough?

K2