R8 Tool Change

[Overloaded]

Greetings,
Considering a tool changer for a Bridgeport R8 spindle. An older manual machine.
I assume it will have a spindle index disc with 1 slot.
How is the spindle typically made to always line up the key in the spindle to the keyway in the holders ?
A VFD , slow RPM to index slot and a brake, all in the macro ?
My friend said to remove the key....I told him to leave.
Thanks,
RC

[Graham Waterworth]

Have a look at this post.

http://www.machsupport.com/forum/index.php/topic,1942.0.html

Graham.

[Overloaded]

Ahhh....interesting.
Thanks Graham,
RC

[Chaoticone]

Hey RC,
    I have lots of ideas on R8 tool changers. Will try to make you some drawings. One way Poppabear suggested in Galesburg that sounded good for the draw bar was this. Get a large collet, 7/8 or so. Make toolholders with a 7/8 shaft. Put a nut on the drawbar, then the collet. once you have the length figured out, use the nut as a jam nut on the collet and locktite. Can use an air cylinder to actuate the drawbar. Since you will now be going in a collet, the key is of no concern or orentation. Can make a disk type tool holder to hold the tools.

Brett

[Graham Waterworth]

Have a look at this post.

http://www.machsupport.com/forum/index.php/topic,6119.0.html

Graham.

[Overloaded]

That's a keen idea Brett.
Would be good for light to moderate cutting. Heavy cutting with a collet has its problems.
I can open your dxf in LCam, but cannot open it in ACLt98.
I can open some dxf's posted in the forum, but most I cannot. (see pic.)
Do you know if there is a way to do this on my end ?
A friend sent drawings that I could not open, he then saved them with an older format and they opened fine here.
Of course he was using the latest AC full blown version.
I'd like to open all files so I can follow along in the forum posts without having to buy a bunch of cad prgms.
Thanks Brett,
RC

Hey Graham,
That is one of the topics that spurred this topic.
Joel's is pretty complex. I guess he is powering the knee for Z axis otherwise he could drop the quill to do the changing. Or the change stations are too close for the quill to clear the neighboring holder.
This example is what makes me wonder how the key typically gets lined up.
Thanks,
RC

[Chaoticone]

Rc, I use Autosketch. It is inexpensive and I can open most any file, not solids of course.

Brett

[Ian Ralston]

RC

If you have an older Bridgeport R8, it is unusual for the keyway pin to have survived! It is only a grubscrew that has been turned down and a second screw to lock it in position. It is usually wrecked by not tightening the collet or collet chuck enough and the peg gets broken off. The spindle needs a stripdown to replace it, so instead, for the collets, if needed, a "spanner" with three small tongues to fit into the collet slots is used to hold  against the drawbar torque. The peg is not there to provide any driving torque, so you can get away without it and the problems of indexing the spindle.

My little Denford Novamill has a BT 30 spindle with pullstuds and a spring loaded retainer. To fit a new toolholder, I have rigged up a direct acting air cylinder to release it. There is a carousel toolchanger that came with the machine. It consists of a rotary air cylinder to swing the tools into position and a DC motor to index the six toolholders. For the small, uncomplicated, short runs that I use the machine for, manual change is simple and quick enough.

Ian

P.S. DesignCad can import DWG, DXF, IGES, WMF, HPGL and XYZ (?).

[Overloaded]

Great Info.....
Thanks Ian,
RC