TTS style tool holders for Sherline Mill

[macardoso]

Hi All,

I set my buddy up with my old CNC Sherline mill. Was teaching him the basics on my G0704 CNC conversion and the conversation came up about adding toolholders to that machine which work similarly to the Tormach Tooling System holders on my machine. This is a dual contact toolholder that adds quick change/ATC functionality with a 3/4" R8 collet and straight shank tools or tool holders.

https://littlemachineshop.com/images/gallery/instructions/u10044m_tormach_tooling_system.pdf

My question would be, why not apply these principles to a Sherline? It would need to be much smaller since the largest MT1 collet holds a 1/4" shank, but could it work?

I'm thinking of some precision 1/4" OD, 1/8" ID ground steel tubing (if available) which has the wider collar pressed over it and a set screw drilled and tapped from the side.

I see collet adapters available that must have good concentricity, but they all have a slit on the side. I'd like some tubing that is just like this but solid.


Alternatively they could be machined in one operation on a lathe using a reamer for the precision bore. Straightness of the initial drilled hole would be tricky... Maybe a carbide drill?

EDIT: this all comes back to having tools with preset tool length offsets in the CNC control.

 

[macardoso]

Also, the holder would need to be the minimum possible length since the Sherline has so little Z travel.

For larger 1/4" tools, the collar could be pressed on directly to the tool.

I guess if you don't mind changing collets, you could just press the collars onto the tools and only use the tool shanks.

 

[mikey]

I guess if you don't mind changing collets, you could just press the collars onto the tools and only use the tool shanks.

Or you could make tool holders with a 3/4-16 thread to spin onto the spindle. They could be end mill holders with set screws to hold tools or heat shrink type if best accuracy and rigidity is required. This would minimize loss of Z-travel, ensure the greatest degree of accuracy in the tool holder, be pretty fast to change out tooling and you cannot get a better reference than the spindle's register.

Another option is to make or buy separate ER collet chucks that screw onto the spindle and change chucks (with tools fixed in them) at need. You lose some Z but a column riser will offset that.

And there is always the option of making custom spindles with whatever configuration you desire. Couple that with deep groove ABEC 3 bearings and you'll have a pretty accurate set up.

 

[macardoso]

All great ideas Mikey, thank you!

 

[Karl A]

...
My question would be, why not apply these principles to a Sherline? It would need to be much smaller since the largest MT1 collet holds a 1/4" shank, but could it work?

I'm thinking of some precision 1/4" OD, 1/8" ID ground steel tubing (if available) which has the wider collar pressed over it and a set screw drilled and tapped from the side.
...

The largest MT1 milling collet from Sherline holds a 5/16" shank. Part number is 3088.