# DIY Toolholders



## Shotgun (Jun 27, 2022)

It seems that every Youtuber machinist has a video on making toolholders.  Take a big block of steel.  Cut the dovetail down the whole thing.  Chop to individual length.  Mill a slot and then drill and tap holes.  Then you use the drilled-tapped holes to clamp a bit holder in the slot.

Those last couple of operations are quite a bit of work.  When using carbide tooling, wouldn't it make more since to mill a landing directly on the nose of the holder for the bit?  The point of making the holders in the first place is so that you can have a separate holder for each tool.  Why not skip the extra steps and end up with a tool that will be much more rigid at the cutting face since it doesn't have to transition through as many connections?


----------



## woodchucker (Jun 27, 2022)

WHAT ARE YOU TALKING ABOUT?  a little more info, maybe a link, maybe a pic, maybe a clue?


----------



## Shotgun (Jun 27, 2022)

I'm talking about making QCTP type tool holders.  Here is This Old Tony's version:  




The question is why make a slot and hold down screws to hold another tool, that in turn holds a bit, instead of machining in a place for the bit directly?


----------



## matthewsx (Jun 27, 2022)

Are you talking about making something like this?




I think the point of the regular toolholders is you have the flexibility to use HSS or a carbide insert holder with the same part.

John


----------



## wrat (Jun 27, 2022)

I think i see what you're saying and I believe they actually exist for the big CNC lathes, but the question would be 'why bother'?
It would seem to be quite a lot more machining, but like you say, once it's done, it's done without all the fiddly bits.
On the down side, there's such a thing as a 'crash'.  Let's say you crash by some astronomically random accident.  Do you wanna replace a cheap, straight holder piece you get off-the-shelf?  or an entire machined holder?
Especially if you had to machine it yourself.
Everything's a tradeoff.


----------



## Shotgun (Jun 27, 2022)

matthewsx said:


> Are you talking about making something like this?
> 
> View attachment 411812
> 
> ...


Yes.  Just like that, except machined as one piece from wedge to the bit bolt down screw.
I agree that the point is the flexibility.  But, then everyone gets tired of swapping out tools, and gets a separate holder for each anyway.  At least, I do.  

I've just recently upgraded lathes, and have gone from an AXA to a CXA toolpost, so all the holders have to be replaced.  I'm thinking what is the quickest way to get the most rigid setup.  Machining a flat out on the nose seems so much simpler than a slot with 3 or 4 tapped holes, and it seems like the rigidity could be significantly higher.


----------



## mmcmdl (Jun 27, 2022)

If you like that holder , give me a shout out . I have Alrois CXAs down the basement that are going out . Or , just make them as you said .


----------



## woodchucker (Jun 27, 2022)

many already put a dovetail in the larger tools already. But larger tools cost more.
And many will have a limited supply of both holders and tools.

Do what you want.. the flexibility remains for folks that want to do different things.


----------



## mattthemuppet2 (Jun 27, 2022)

main reason not to is that you're stuck with that insert and stick out from the toolpost. I often have to change how far a tool is sticking out of the holder to get around other issues.

main reason to do so is more rigid and you do alot of the same sort of op with the same style insert.

which matters more depends on the kind of work you do and I guess how big your machine is


----------



## Shotgun (Jun 27, 2022)

I like that thinking, @mattthemuppet2 .  That would lead me to want just a couple "rigid" holders for rough operations. Maybe cut to use the "waste" corner of CCMT or DCMT bits.  Then the rest would be the more flexible type.

Ok. Make some. Buy some.


----------



## davidpbest (Jun 27, 2022)

The least rigid aspect of your lathe from a toolholder perspective is the compound.  If you want better rigidity using a QCTP, switch to a solid toolpost like discussed *in this thread*.

As far as your idea goes, machining the pocket for a carbide insert is not a trivial undertaking.  They require 10ths level precision, often have difficult profiles to achieve on a manual mill, and complex angles.   I'd must rather machine slots and drill/tap for holding screws than to tackle the complexity of making a pocket at -7° angle for a DCMT insert.


----------



## Shotgun (Jun 28, 2022)

Challenge accepted, @davidpbest .   

I've made several carbide bit holders, and got acceptable performance from them.  But. . . "acceptable" is not, and never will be, a scientific term of merit. I've got the material and desire to build a "QCTP bit holder", and a question of whether or not it will be any better.

Nothing left to do but give it that ol' college try and make some chips. . . just as soon as this new hip upgrade will let me.


----------



## FOMOGO (Jun 28, 2022)

That's a pretty interesting design. Have never seen one before, but looks very versatile. Mike


----------



## matthewsx (Jun 28, 2022)

Aloris makes this one, there are copies out there too.


----------



## Parlo (Jun 28, 2022)

Shotgun said:


> It seems that every Youtuber machinist has a video on making toolholders.  Take a big block of steel.  Cut the dovetail down the whole thing.  Chop to individual length.  Mill a slot and then drill and tap holes.  Then you use the drilled-tapped holes to clamp a bit holder in the slot.
> 
> Those last couple of operations are quite a bit of work.  When using carbide tooling, wouldn't it make more since to mill a landing directly on the nose of the holder for the bit?  The point of making the holders in the first place is so that you can have a separate holder for each tool.  Why not skip the extra steps and end up with a tool that will be much more rigid at the cutting face since it doesn't have to transition through as many connections?


I like the idea of dedicated toolholders. I have the same tools in the same holders for years, which is what you are suggesting. Perhaps you could consider mounting some inserts upright for tangential cutting.


----------



## davidpbest (Jun 28, 2022)

Shotgun said:


> Challenge accepted, @davidpbest .
> 
> I've made several carbide bit holders, and got acceptable performance from them.  But. . . "acceptable" is not, and never will be, a scientific term of merit. I've got the material and desire to build a "QCTP bit holder", and a question of whether or not it will be any better.
> 
> Nothing left to do but give it that ol' college try and make some chips. . . just as soon as this new hip upgrade will let me.


If by ”BIT” you mean industry standard carbide inserts, you might find the following video interesting.






I’ll be interested to follow your progress.


----------



## davidpbest (Jun 28, 2022)

FOMOGO said:


> That's a pretty interesting design. Have never seen one before, but looks very versatile. Mike
> 
> View attachment 411887


That tool is an Aloris #20, which I own and use frequently.  It comes in handy if you have a solid tool post and need to alter lead angle.  
This tool has an articulating head that can be rotated and secured in 12 indexing positions at 15° intervals. The tool consists of a QCTP mounting block and a bolt-on cartridge that acts as the insert toolholder. The tool is proprietary to Aloris and is available in sizes to fit AXA, BXA, and CXA tool posts.

The insert is a triangle shape with zero clearance angle (similar to the WNMG trigon insert), and is double-sided with six total cutting faces. Inserts are available from Aloris and several other manufacturers. Since the insert has a 0° clearance angle, the insert is held in a negative rake, making this tool suitable for aggressive material removal. The rotating head on the cartridge gives this tool unique positioning ability and lead angle flexibility. 

This tool takes a triangular insert with 3/8" I.C., and although it has a zero clearance angle and is held in a negative rake, the TNMP33x variety has a positive cutting edge for use on softer materials like aluminum.


----------



## FOMOGO (Jun 28, 2022)

Thanks for the info David. Cheers, Mike


----------

