Another Reason to buy or make a diamond tool holder

[Jdunbar]

I bought a used broach for $30 to make this tool and to make a boring bar. You simply drill an undersized hole and push the broach through using a press or vice and you end up with a perfect square hole. The broach is a piece of HSS that starts out round to fit the pilot hole, and then is a hexagon, then square. It is about five inches long and is tapered the entire length.

 

[Niels Abildgaard]

Due to illness, long projects are not possible but squezed tangential holders are less than 4 hours work.
It is also nessecary to go to my automechanic that has a 25 tons press and this is combined with shopping and all in all give a more pleasant day.
Excuse for making one more is that clamping screw wasted to much power deforming holder and to little for the carbide bit.Not that I have had any slips,but for safety thigthening was violent.
This is much more civilized/nicer in the newest version illustrated here.

I really need to find an evening class with a course in BETTER ANGLEGRINDING

Chatter comes at more or less the same rate of cutting as the CCMT holder shown somewhere else.This means that toolholder rigidity is not the issue anymore,but lathe design is.
Making lathe more rigid is not a four hour job.
Wonder what lathes there are in heaven.Is it too much to hope for swiss Schaublins?

 

[JAndrew]

Hello,

Nice tool holders! I played around with these angles in Sketchup and figured: With a 30 degree ground bit and 12 degree angles on the bit the angle that is being transferred into the work is 83 degrees. So my question is what angles are used for threading with one of these tool holders to get your 60 degrees?

I don't see a real advantage to making a whole separate holder just for threading but it's certainly appealing for turning and facing.

Thanks in advance!
-J.Andrew

 

[Niels Abildgaard]

Hello Andrew

My threading is done by preformed carbide inserts,so hopefully a satisfied Eccentric Enginering Diamond User will answer.
I bought one years ago and gave it away when my homemade ones worked OK.
As I remember it the manual has a way to grind a threading tool.
Or we make a protest movement like in the CocaCola case and demand triangular Crobalt sticks.

 

[charlton]

Hi Niels,

Thanks for all the posts about your TTH across the various forums. Do your tool holders only have a fore/aft angle or do you actually have a compound angle? From the pictures, it seems like you only do the fore/aft thing but I'm not 100% certain.

Thanks!
Charlton

 

[Niels Abildgaard]

Hello Charlton

It has only 12 degree fore and aft angle made as on photos.
This gives around 8.5 degree entrance or clearance angle on the two cutting edges.This is the real important angles in tool grinding and we get them free and ready from toolbit manufacturer.The top plane angle is NOT very important.
Unless it is a foot driven lathe.
Make one,test it and let an old man hear about it.

 

[charlton]

Hello Charlton

It has only 12 degree fore and aft angle made as on photos.
This gives around 8.5 degree entrance or clearance angle on the two cutting edges.This is the real important angles in tool grinding and we get them free and ready from toolbit manufacturer.The top plane angle is NOT very important.
Unless it is a foot driven lathe.
Make one,test it and let an old man hear about it.

Thanks for the clarification Niels. I'm just getting started in metalworking so I have much to learn. It'll probably be a while before I actually get around to making a TTH but I'm trying to soak in as much information as possible. Making square holes is a foreign concept to me (except in wood via chisels) and I don't have access to a big press so it looks like I may have to utilize one of your original two-piece designs.

Thanks for sharing all your knowledge on this subject. It's enlightening to say that least.

 

[Niels Abildgaard]

Hello Charlton

You will enjoy making things with Your hands and head.
I used around 14 tons to press the picture from 15 of April 2013 and then reground the slit.
I should have used a little more of my old brain and less anglegrinder .
The hole for the toolbit is 6.7 mm and the slitholes 5mm.
I do not need 3.35mm times two /14 tons squeze.
3 to 4 tons will give two times 1.5 mm deformation and this is more than enough.
3 tons can be made with a car jack and two pieces of all thread.

 

[james_III]

What about this drawing, this should be doable, not sure is there enough dimensionlines, but will this work?

View attachment SP6X6.pdf

 

[Niels Abildgaard]

Hello James

You will need to remove some jaw material close to the cutting point.
This can be done manually on a bench grinder.
If not You cannot turn and face into a corner.
Having been used to my own creations yours look to flimsy for my taste but try.If working I was wrong and if not everybody learnt something and that small piece of iron is not very expensive.
Give us some words and pictures

 

[james_III]

Yes I agree and I might try to redesign, so cornering is possible, now this is more like chamfer tool for really small outside corners