# Ideas for tangential cutter tool holder?



## burdickjp (Nov 23, 2014)

I'm looking at putting together a tangential tool holder to suit Norton Patent style QCTP systems. Here's the design I've come up with:




A few disadvantages I can see right from the start: The front face of the holder has a 12 degree angle with respect to the back face. The slot for the holder has a similar 12 degree angle, but should be much easier to accomplish, as it's just a 0.25 inch slot.


Here's what I'm curious about: I'm looking at securing the tool in the slot with a large conical washer for a flat face M4 socket head cap screw. The slot will be ever so slightly less than the width of the tool. I don't think it will be enough, but I'm not sure.


I'm wondering if anyone has a better idea for accomplishing this.


----------



## Bill Gruby (Nov 24, 2014)

If I understand you correctly you wish to know if the Conical washer and Screw will have enough holding capability to keep the tool from slipping down under load? If so, it's iffy. A standard flat washer (Fender Type) might be better. Try it with the Conical, if it doesn't hold use the other.

 "Billy G"


----------



## Rick Leslie (Nov 24, 2014)

I might be stated the obvious, but there's a good bit of info and designs on the tangential tool holder here. Here's the search results. 
http://www.hobby-machinist.com/search.php?searchid=668713

I know that doesn't answer your original question. Like "Billy G" said, you'll just have to give it a try. Please show the project and document the progress, success/failure and mods. I think lots of folks are going to be using these sooner or later. Any info will help.


----------



## burdickjp (Nov 27, 2014)

Here's where I'm at thus far with a clamping-style tool holder. I'm thinking one or the other sides needs a slot so that clamping the tool doesn't work against clamping to the post.




I think it'd be easy to add another tool to the other corners of the holder. Either 1/8 inch or round or whatever.


I'm trying to decide if it'd be advantageous to make the thickness of the holder such that I don't need to adjust height by moving the holder vertically on the post, since the tool can move vertically in the holder.


----------



## burdickjp (Nov 27, 2014)

Here I've made the clamping mechanism different and added a round holder.


I think when I go to make something I'll start with round since it will be much easier to manufacture.
The rest of it honestly looks much more complicated than I want to attempt making. Way too many set ups and processes.


----------



## Bill Gruby (Nov 28, 2014)

By the looks of those prints there is not enough metal holding the tool in place. Look at the others posted on this forum. Your tool looks like it will break right out of there.

 "Billy G"


----------



## burdickjp (Nov 29, 2014)

Bill Gruby said:


> By the looks of those prints there is not enough metal holding the tool in place. Look at the others posted on this forum. Your tool looks like it will break right out of there



I don't think I could get it much smaller. That's set up to mill out the opening on either side with a 3 mm cutter.

I've seen a few similar designs, but I'm looking at another design which may cure that.


----------



## burdickjp (Nov 29, 2014)

So here's a design which may be easier to manufacture than iteration 2, but stronger than the initial design. What do you think?


----------



## chuckorlando (Nov 29, 2014)

How much meat is left on that clamp over the square tool?


----------



## Bill Gruby (Nov 29, 2014)

burdickjp said:


> So here's a design which may be easier to manufacture than iteration 2, but stronger than the initial design. What do you think?




 That is much better. At least here there is something holding the tool.

 "Billy G"


----------



## burdickjp (Nov 29, 2014)

Bill Gruby said:


> That is much better. At least here there is something holding the tool.
> 
> "Billy G"


This was my inspiration for iteration 2:






He has a few other pics in that gallery, and seems to be doing well with it, so I think my iteration 2 would be a viable option, but I think iteration 3 would be easier to manufacture.


----------



## burdickjp (Nov 29, 2014)

chuckorlando said:


> How much meat is left on that clamp over the square tool?


The tool comes to the outer most upper tip of the block and slopes away from it at a 12 degree angle in both directions. The block is 20 mm thick, so by the bottom of the block there's a decent amount of material.

The way I envision making it is cutting the slot in both blocks and then shaving the thickness until they fit just right.


----------



## chuckorlando (Nov 29, 2014)

Now I see it in the drawing. Very faint. I see the meat now.


----------



## burdickjp (Nov 29, 2014)

chuckorlando said:


> Now I see it in the drawing. Very faint. I see the meat now.


It's not much, but it is there.
If I'm looking at it right, an advantage of this is that the torque of the cutter on the post is reduced because it's closer in.

The cutting edge is also much closer to the bulk of the material of the holder than my current tool holders.


----------



## magu (Dec 1, 2014)

I apologize for my ignorance or for it it has been in one of the tangential toolholder threads and I missed it, but what is the point? Is the benefit simply that you pull the cutting point in closer to the fulcrum and better support it?


----------



## burdickjp (Dec 1, 2014)

magu said:


> I apologize for my ignorance or for it it has been in one of the tangential toolholder threads and I missed it, but what is the point? Is the benefit simply that you pull the cutting point in closer to the fulcrum and better support it?


As I understand it, you can use square tool bit stock, grind a single angle, and get good results.
I'm hoping there will also be some repeatability to it; grind it, mount it a certain way, and it will be repeatable to some degree to the next time you grind it and mount it.


----------



## Rick Leslie (Dec 2, 2014)

I think the angle of the cutter greatly reduces the cutter flex. Forces are transmitted downward through the cutter's length as opposed to perpendicular to the cutter. But that's just my guess.


----------



## Bill Gruby (Dec 2, 2014)

Short answer -- The tool is no longer sticking out of the holder perpendicular to the work. By standing it on end it is much more rigid.

 "Billy G"


----------



## magu (Dec 6, 2014)

Thank you all. That is sort of what I expected, but I figured I would ask.


----------



## Jim2 (Dec 8, 2014)

In my opinion, there are several benefits to the tangential tool-holder.

1) As has already been pointed out the rigidity is very good.
2) Sharpening is easy, even trivial.  
3) Properly designed, the tool-holder allows both turning and facing cuts without repositioning.

I've found that the quality of my work has gone up as a result of using a tangential holder.  That's probably due to the fact that I'm more likely to sharpen the bit more often when it only takes a few seconds and it's so easy to get consistently good results.

Jim


----------

