[G59]

I think Bob is talking of a different type of tool holder. Big air cylinder wouldn't do much on a draw bar system. Petal or ball clamping system used in industrial VMC, yes of course.

[Bob La Londe]

No. I think engaging a wrench to a nut in this manner is very elegant. I certainly didn't mean to denigrate your creation. In fact as soon as I saw it I decided I would employ part of it for a different purpose. On my other larger mill (Hurco KMB1) the pneumatic disc brake on the spindle motor slips if I have to use real force with a spanner to release the spring lock nut on the quill. I made my own spanner for the nut, but that didn't eliminate the problem with locking the quill. An auto retractable spline nut engaged from the top for tool changes would solve that.

I am still curious about what catastrophic failure would be dangerous by a using spring washer stack. A tool coming out could hit the polycarbonate shields, but more likely it wouldn't with much force as a pull out would likely have it engaged in the material. Maybe even partially chip welded to cause the pull out. I can't see the spring washers themselves failing. The draw bar could strip out I guess, but unless it actually snapped it wouldn't send washers flying. If the hardware on the pneumatic failed for the most part it would just not work. I suppose if the upward constraining bolts broke it could fall over and break your foot if the enclosure doors were open. The thing is there should be no force on those. The constraining force should be on the bottom of the stack when actuated.

I am also curious about the comments on balance. I don't see how having the spring stack inside a spindle would make them inherently any better balanced. They still have to have room to move in order to work.

[Hirudin]

Brokt disc springs probably wouldn't kill you, but you don't want something on your machine to spontaneously stop working.

[G59]

Bob, you lost me. Your talking spring washers and air cylinder and...... What system do you have?

[Bob La Londe]

Bob, you lost me. Your talking spring washers and air cylinder and...... What system do you have?

I must have lost you on the very first post then. On the machine I posted this on I have none of the above. It currently has a kwik 200 master holder. It has a gear head, and I will shortly be converting it to belt drive. When I do that I plan to remove the master holder, and install some type of TTS setup.

My original post was asking how much spring pressure was required to hold a TTS holder securely.

For those of you who have setup your own quick change system around the TTS style tool holder... How much spring pressure do you need to be able to push a 1/2" or larger end mill with decent loads without slipping?

Along the way some said or implied it was unsafe and/or would be unbalanced using belleville spring washers. I wanted to know exactly how it would be unsafe, and how other systems that do use bellevile spring washers were balanced.

Right now on the machine in question my "quick change" system is a spline wrench and a Kwik 200 spindle spanner.

[G59]

From what I have experience with, KwikSwitch300, It will be interesting to see what you come up with. What is holding the KS200 master?
On the old Tree mill I worked with, the KS was part of the spindle shaft. I take it yours isn't.
Also, nowhere on this thread do you mention what machine you plan to modify.I had to do my own research into your threads to figure things out, and from what I have gathered, it's for the CO machine.
It helps knowing what machine you have and what taper the spindle has in it for the tool holder, so others can envision what you are trying to do..
Again, I will guess R8?
Mentioning Bellville washers with a link to it seemingly suggests to most that you have a cartridge spindle.
But now, knowing all this( the above), we now know that is not the case, as it is destined to be used on a CO machine with R8 taper.
Phew, and you wonder how I got lost????

[Bob La Londe]

Summary from this thread.

My application is a converted ZX-45 with a 2HP spindle motor.

The base machine is one of the many XX-45 Chinese mills.

I'm running a master holder right now, but I'ld like something that is faster and doesn't stick down as far. I had to turn that draw bar to put the master holder in.

A draw bar is holding the master holder.

When I do that I plan to remove the master holder, and install some type of TTS setup.

The master holder will go away when I convert to something faster.

I've got a few other machines in the shop from toys to halfway serious, so I can see how references to some of my other machines could confuse things.

This is what I was thinking of when I started this topic. He's running 2700lbs of springs, and a 3 stage 4" pneumatic cylinder with apx 36.1 inches of piston surface. It places effectively zero load on the spindle bearings. 2700lbs seemed like an arbitrary number so I asked others with more experience what they thought the necessary holding force would be.

ZX45 Power Drawbar - YouTube

I did mention a lever arm. I was not thinking of bolting a door hinge the the back of the head and just hanging down off of it. I was curious if there was a simple compound lever somebody had used that pressed up and down simultaneously like the air system in the video does. I did look at one CAM type lever somebody had designed and didn't like it. It is easy to operate, but does not lift up on the bottom of the washers.

[Hirudin]

The design in the video looks good. If you have the room for a 7" cylinder, I'd say "go for it!". The slip fit collar is something I considered for fear of the same thing that he talks about, the bellevilles sliding around. What I did was make a long nut that had about the same diameter of the bellevilles' ID. I was thinking some kind of ridgid-ish rubber could be slipped around the whole stack which would help keep them concentric and could also possibly retain lubrication.