16° Tangential Tool Holder

[Rickabilly]

Hiya Larry,
I do like the holder it seems you've thought your way through the project carefully, FYI the angle of the HSS section is actually quite important in that this angle defines the front and side clearance of the tool and as a result the strength and therefore longevity of the cutting edge,

When I was originally taught about tool grinding the front and side clearance angles were set at 7-10 degrees, but that was in heavy industry, the 16 degrees will reduce some as the approach angle is somewhere around 40 degrees from what I can tell but even at 16 degrees it will last well given the lower stress of hobby use.

One thing I really like is how the bit is fully supported in a square hole, so many of these types of holders use a groove with a clamp of some kind and that always looks weak to me, considering that slipping of the tool is not always obvious to the operator, it tends to make me think that finish and indexing wouldn't be reliable on the other designs I've seen.

Regards
Rick

[the artfull-codger]

I wanted on of these a lot of years ago they were advertised in ''model engineer'' but couldn't afford one, they were made in australia,I forgot all about them then a few years ago I got hold of some american magazines [machinists workshop, a good read too!!] & saw them advertised by a firm called bay-com enterprises so I sent for one, myford size [being a little more affluent now!!] it came but the fecin customs stiffed me up for 20 odd quid the ba**ards, & the post office even charged me for wrapping it back up,well a couple of years ago I wanted a larger one for the colchester so I bought it from australia & got it delivered to my daughters house in perth & picked it up when on a visit there, I absolutely love them, cheapo 1/4" sq hss bits from autojumbles & dead easy to sharpen I wouldn't be without mine.[dangerous on brass though] it dragged mine in,should have known better too much top rake.
Graham.

[Rickabilly]

The down side or advantage depending on viewpoint of these holders is that they do make it very easy to grind your own tools, which sometimes means folks don't think about tool design as much as they might if they were grinding all three facets of the tool(incidentally the three facets, 1.front, 2.top and 3.lead) all three "ideal" angles vary depending on material, hardness, tool grade, speeds and feeds among many other lesser factors. As a result it's easy to form a one size fits all to lathe tooling which can cause the sort of thing that happened to Graham.

This is just a friendly caution, there is no "Easy answer" only a compromise, I have the same gripe with indexable carbide tools, on day one it seems like a panacea, but as time goes by you learn that you need to know quite a lot to use them properly, even as a hobbyist, maybe more so as a hobbyist, as many professionals work in one field or material where a hobbyist tends to do a bit of everything not to mention the problems associated with "found" materials.

Best Regards Rick

[LJP]

Rick, there is no question you are correct that this tool is a compromise. But the beginner needs to start somewhere. Tool grinding is a complicated matter, made to look simple by the knowledgable, and held as mysterious by the neophyte. There is an "art" to it for certain. So the beginner struggles by reading books, watching videos and "muddleing through". Mostly what the beginner ends up with, without proper guidence is compromise anyway.
Now, I am not suggesting that this tool should be able to do everything, but it gives good results, quickly. So, someone with the desire to learn "proper tool grinding" can take away some quick positive lessons to apply to the inevitable need for traditional shaped tools. Nothing will discourage a beginner more than repeated poor results.
I would think that even a seasoned proffesional, would sometimes take the quick and easy approach to getting a job done.
Thanks, Larry

[the artfull-codger]

(08-31-2013, 03:16 AM)LJP Wrote: Rick, there is no question you are correct that this tool is a compromise. But the beginner needs to start somewhere. Tool grinding is a complicated matter, made to look simple by the knowledgable, and held as mysterious by the neophyte. There is an "art" to it for certain. So the beginner struggles by reading books, watching videos and "muddleing through". Mostly what the beginner ends up with, without proper guidence is compromise anyway.
Now, I am not suggesting that this tool should be able to do everything, but it gives good results, quickly. So, someone with the desire to learn "proper tool grinding" can take away some quick positive lessons to apply to the inevitable need for traditional shaped tools. Nothing will discourage a beginner more than repeated poor results.
I would think that even a seasoned proffesional, would sometimes take the quick and easy approach to getting a job done.
Thanks, Larry

What I've found is that you tend to sharpen the tool more than you would normally especially after taking a few''bonus cuts'' with purple swarf coming off good style 'cos it's so easy to sharpen,then a quick tittle up dor finishing cuts.
Graham.

[Rickabilly]

(08-31-2013, 03:16 AM)LJP Wrote: Tool grinding is a complicated matter, made to look simple by the knowledgable, and held as mysterious by the neophyte.


I would think that even a seasoned proffesional, would sometimes take the quick and easy approach to getting a job done.
Thanks, Larry

Rest assured help is at hand regarding tool grinding and with our policy of "no such thing as a silly question"

I'm pretty sure I posted heavily here in the early days with a guide to HSS tool grinding, so it's probably lost in time, My aim is to pass on as much knowledge as quickly as possible as I can't bear to see the new professional machinists, "trained" if you can call it that, by sitting them in front of a CNC and believing that HSS and hand ground tools are a throw back from the stone age.

As a pretty experienced guy I'll admit to taking shortcuts wherever I can and really like your holder as it is well designed and appears to be nicely made, the problem with short cuts and "Newbies" is that they tend to cause the learning through near misses or actual harm to machine or flesh, If I can help reduce that harm in any way, I'd like to.

So, please accept my offer of assistance "where required" on the subject of tool grinding, also I'd like to say that my comment was more aimed at warning that when it comes to hand ground tools a single design is always a compromise, rather than a dig at your tool.

regards
Rick

[Mayhem]

I had thought that Tom did a good video on sharpening HSS tools but I cannot seem to find it, so perhaps I'm mistaken.

[Rickabilly]

I didn't do a video, more an explanation on why the angles matter and what happens if you get them wrong on various materials, sort of a FAQ thing to help the newbies work through the learning process.

I'll have a look for it later, might still be of value to some,
Rick

[LJP]

Rick, we are on the same page!
I went to work in a large custom cabinet shop as an engineer and project manager in the office, my first "desk job". This shop has an excellent reputation for quality work, and frankly has been able to overcharge for its services. The skill level is pathetic. You will not find a block plane in the place, a 55 man shop, where no one knows how to sharpen a chisel. I bought India and Arkansas stones and brought 10 or 12 of the best guys together to teach them how to do the basics of sharpening. Everything is cut on a cnc, the simplest curve, that really only needed a quick cut on a bandsaw, and sanded to a line on an edge sander, needed drawings generated that were just absured. It got to the point that I just went downstairs and made the parts because it was quicker and easier than doing the drawings. I stayed there for 6 years until I just could not take it anymore!

I welcome your advice and your criticism! I am here to learn this craft, from those that are willing to teach. Thank you for both, because I do understand that both are necessary parts of the teaching process.

I must say that I have found an unusually high level of skill on some forums, and a willingness to share knowledge and experience that is there for the asking. Please be assured, I appreciate, and will take advantage of the generosity of your offer. What we really need, is for the "20 something" generation, to understand the importance of learning from experience.

Best regards, and thanks for the welcome to this forum! Larry

[Rickabilly]

I do love CNCs too, I was trained on them as an Apprentice and until a few years ago owned a shop with good CNC capability, but a "machinist" should be able to manually machine, have a good general engineering knowledge base and a deep respect for hand tools, I have noticed that the young folk sitting at the controls of CNCs rarely develop any of these things.

So it seems to me that the Hobby world is the only place left to maintain these skills.

I think the education system is destroying the spirit of kids with technical tendencies these days, the "Degree Culture" meaning anyone working blue collar has "failed" before they even start. This attitude is super prevalent here in Cambridge, 7 out of 10 of the checkout operators here in our village supermarket have good sound degrees from good universities! not that they can add up without their computer system running.

Rick

Regards
Rick