My Take on a Tangential Tool Holder

[rleete]

I've been wanting to make one of these for quite a few years. Thanksgiving week finally gave me the opportunity to make one. First, I cut a block out of some steel I got as scrap. Had to buy a new bandsaw blade, as the old one just wasn't cutting it (pun intended).

Next, I made a P.V.C. angle block using my engineer's protractor. Then I set the part in the mill and cut the top and bottom faces parallel. Then I drilled a hole for the HSS tool bit. Plan was to simply file it out square. Unfortunately, my square file leaves far too large a radius in the corners, so I resorted to a combination of broaching using the tool bit and filing with needle files. It was a lot more effort than anticipated, and I have new appreciation for those old time apprentices that had to make stuff by hand.

Next step was to drill and ream a cross hole for the clamp. Then I set it up (as shown in another thread) for cutting the chamfers on the nose. Finally, I stuck it in the soft jaws and filed the whole thing smooth and even, adding the radii where I thought it needed more clearance. A quick wipe on the deburring wheel resulted in this:


Now I needed a way to clamp the tool in place. I decided on split cotters, as they are quick and easy to make, and have a surprising amount of clamping force. This was the result of that endeavor:


And all assembled:

 

[timo_gross]

Did you already try the tool? How does it work?

 

[trlvn]

Beautiful! To get an idea of scale, what size of tool bit is it designed for?

Craig
(PS Great photography. Are you using a light box?)

 

[PeterDRG]

Bravo ! One of my memories of Cherry is being presented of one by her husband, Ivan. He liked making tools.

 

[rleete]

Did you already try the tool? How does it work?

Yes, I tried it. Using mild steel, I was able to take a .010" deep cut with no chatter. Very nice surface finish. This is using the standard 7x minilathe.

 

[rleete]

Beautiful! To get an idea of scale, what size of tool bit is it designed for?

Craig
(PS Great photography. Are you using a light box?)

I use 5/16" tooling almost exclusively.

As to pictures, I use a table saw covered in a sheet of white paper from a poster frame, with an LED light right above it.

 

[kiwi2]

Hi,
I've had a pair of tangential tool holders from Eccentric Engineering for years and am a big fan. I'm useless at grinding the top relief needed on tool steel cutters for turning steel and used to avoid doing so whenever I could. Grinding the cutters for a tangential tool is dead easy using the Eccentric Engineering grinding jig and now I prefer cutting steel rather than brass.
You (rlete) went to a lot of trouble cutting the square hole to hold the square tool steel cutters. It may have been easier to drill a round hole to accept round tool steel. A round cutter gives a really good surface finish (better than square cutters) but can be a problem if you are turning up to a shoulder. If that is the case, it's fairly easy to cut two faces at right angles on the side of the cutter on the ground end.
I have found that round cutters in a tangential holder are excellent for turning wood. Even cutting across the end grain gives a smooth finish with no tearing out of the fibres. I made a tangential tool (round) holder for my ball turning attachment for making wooden balls which require no further finishing before varnishing.
Regards,
Alan C.

 

[Steamchick]

Maybe I'll make a round tool holder? But as I usually work with around 0.020" ~0.040" radius for corner radii where a square corner is not needed, that would be 1 - to 2 mm diameter tool -- Hmmm, not so good!
But I like your idea for wood. What diameter bit do you use? I have a piece of 1/4" for a tool bit.
K2

 

[kiwi2]

Hi K2,
I use 1/4" dia. round tool steel to cut wood. The clean cuts you get using a tangential cutter are also useful when cutting threads. I used to have to clean up single point turned threads with a die nut but now they are good to go straight off the lathe.
Regards,
Alan C.

 

[Steamchick]

Thanks Alan, Interesting advice.
Personally, I finish threads with a chaser, as I have a couple of metric (60degree) thread tools, but other threads are not 60 degrees, and my "hand ground tools" are not perfect, compared to the proprietary chasers. (But I rarely need to turn a thread, as I have many dies).
A question. A tangential tool would normally use a square or round tool bit, but for thread turning you must be grinding the tool to the thread angle. Can you post a photo so we can see your tool please, with the thread profile? It will help explain to all I think.
Thanks,
K2

 

[ChazzC]

Thanks Alan, Interesting advice.
Personally, I finish threads with a chaser, as I have a couple of metric (60degree) thread tools, but other threads are not 60 degrees, and my "hand ground tools" are not perfect, compared to the proprietary chasers. (But I rarely need to turn a thread, as I have many dies).
A question. A tangential tool would normally use a square or round tool bit, but for thread turning you must be grinding the tool to the thread angle. Can you post a photo so we can see your tool please, with the thread profile? It will help explain to all I think.
Thanks,
K2

Some info from Eccentric Engineering:



https://www.eccentricengineering.com.au/products/diamond-tool-holder/the-diamond-tool-holder


https://www.eccentricengineering.com.au/products/diamond-tool-holder/features-and-tips

 

[Henry K]

The Eccentric Tool holder is great for turning and threading. It clearly put much less strain on the lathe and makes it very good for non professionals. I supervise machine shop labs for a University with a BSME program (among others) and bought 2 out of my own pocket because it makes machining so much easier for the total newbees I have in my labs. (We train degreed Engineers, not machinists)
Threading angle is perfect with included sharpening fixture which has a different setup for perfect grinding of turning tools weather square or round.