View Full Version : What are these toolholders?

07-22-2009, 07:21 PM
Please tell me they are not a proprietary product. :P

I have 4 of them, all with the same "shank", this one holds a 3/8 shank bit with set screws, another holds a 1/4", 1 holds a shell mill and the last holds ER16 collets.

They came off of an Emco PC Mill 125, my tool turret has 6 more open spots and I would like to buy more toolholders though if they are an Emco only thing im sure the cost will be quite high. Thanks guys!

07-23-2009, 11:23 AM

07-23-2009, 12:00 PM
Looks close to an ISO 30


Andre' B
07-23-2009, 12:45 PM
The taper may be standard but with that bearing inplace of the flange and the integrated draw stud it is likly somthing special.

What does the bearing do?
Does it change tools while the spindle is turning?

07-23-2009, 12:51 PM
Havent run the machine yet so I am not sure if it pauses the spindle to change the tools or not. All 10 tools remain in the turret, and the spindle simple seats on top of one and spins, no removing of the tools takes place.

They are referred to in the manual as SK-30 tool holders

07-23-2009, 01:08 PM
Given that, I searched:


07-23-2009, 01:10 PM

Look at this pic and compare the measurement


07-24-2009, 07:25 AM
The bearing looks like a critical part of the toolholder

Check out YouTube - IES-SEP Mollet del Vallès. Grabado escudo del BARÇA-- you only need to see the first 10 sec. for the toolchange

While looking around found this - YouTube - paradoxical gear set 1,2,3 teeth--or is it a worm ?? which do you think :rolleyes:

07-24-2009, 09:48 AM
Wow! Sorry, but I can't help getting in on this threadjack... COOL GEARS! I would say those are helical gears, not worms. The helix is used to keep the single tooth in contact with the others for 360 degrees of rotation.

Again... very cool!

07-25-2009, 09:23 AM
Because of the sliding action, I'd call them worms. Worms are actually "screws", worm wheels "nuts". Gears roll against each other. Thats why the involute form of the teeth.

Dick Z

07-27-2009, 01:11 AM
This "motive force transmission assembly" is difficult to define with traditional terms. I would still consider them gears rather than worms, because they break fewer of the rules for gears. The only rule I see them breaking for the definition of a gear is that the number of teeth is extremely low, and that's not really part of the rules, it's just traditionally been a matter of practicality. As far as the sliding motion goes, gear teeth do slide against each other as the point of contact moves along the line of action. In this case the effect is accentuated by the extremely low number of teeth. And those teeth are curved - whether it's actually involute or not isn't really material, it could be cycloidal or something else I've never heard of, but it's appears to be curved in a fashion that provides constant linear conjugate action - a property of gear teeth.

Worms on the other hand have straight flanked teeth, unless they are of a double enveloping type - and none of these fellows seem to actually envelope one another. Also, as you noted, a worm (screw) meshes with a worm wheel (nut). So which one's the nut? And why is it's axis parallel to the worms?