Hi Dan, I see what you mean. I thought I maybe could use round pins in a radial config in place of the tapered bosses. Say 8 positions.
Bolt the pins to the "base" and let the tool plate latch to it.  ? ?
Whaddya think ? I'll try to draw it.
Russ

Hi Russ, yes Hyd pressure is all that keeps it clamped, dont have any monitoring of the pressure but there are limits, or will be, that look at the clamped and unclamped positions so if though necessary these could be used to throw an error.
People have made their own couplings up but on a small machine the dowel would be good enough I think, as Dan says tapered pins are the way to go and you can readily get tapered dowel pins and tapered reamers to suit. If going that route it may be a good idea to actually have the pin move via air/hyd/motor so that the turret plate itself  doesnt need to unclamp.
Hood

BTW curvics are very nice, they are ground with a convex on the edge of the teeth on one half and a concave on the other so as they wear in they get more accurate. Think Gleason are the ones that are big in them, they make the grinding machines to make them.
Hood

Russ heres some plans etc for a turret someone else did
http://www.dumpstercnc.com/projects/gallery2/main.php?g2_itemId=544
http://www.youtube.com/watch?v=o-9J4KsXYwU&feature=related
http://www.cnczone.com/forums/967389-post12.html

Coupling wont be anywhere as accurate as the curvic and curvics seem to hold themselves together where this wont, but think it would still work well enough.
Hood

Hood,

Nice turret. Wonder if he made the coupling as well.

Any good reason you'd want a curvic coupling dead accurate? Most probably you'll still need to adjust each tool's height so even if it weren't indexing accurately you'd still have all tools aligned in the end. Repeatability will still be there and I think that is what maters in the end.

Dan

I think he did make the coupling as its really a simple one, think there is a taper there on the edges but no convex/concave and teeth also at 90 degrees to the face rather than angled like a curvic.
Reason you would want accuracy is you really want the angle of the insert to be correct as well as just the height of the cutting edge, probably wouldnt make too much difference in the end but the more accurate things are to begin with the better your chance of having accuracy in your work.
 There is a guy I talk to from Iran that has made his own turret up and it seems its on a similar line to that one, he definitely made his own coupling up.
Hod

Have the rear turret removed, have placed the new one on and measured how much I need to take off (I hope ) have dismantled it and am now machining that amount off.
If I screw up the worst case is I need to cut the slots a bit wider and shim but I am hoping I dont have to, time will tell
To give an idea of scale the live centre in the tailstock is a Morse 5 taper.
Hood

Got the base machined to size, cut the keyway and fitted the keys and bored the holes for mounting and got it placed onto the lathe cross slide. It seems to be within 0.05mm on height which should be good enough but may be spot on once I tighten down the bolts and get the hydraulics hooked up and clamping properly.
I still have to make up brackets for the limit switches and make up pipes for the hydraulics and then should be able to test things out, hopefully will get that done tomorrow. Then I will have to make a cover for the turret, a guard ring to keep muck out of the curvic and also will need to finish off altering the ladder. I can use the ladder I have at the moment but it will just index 2 slots at a time until I get that sorted.
 Once all that is done then I will make up blocks for the drills/boring bars and drill them in place on the turret with a drill in the chuck, that way they will be spot on in line and height.
Oh also need to mount the coolant plunger and pipe up the coolant.
Hood

Have the turret bolted down now and have the hydraulics hooked up and amazingly there are no leaks
I put a 3ft long crowbar in behind the turret plate and tried as hard as I could to unseat it and couldnt even move it. Previously when I had done this on the front turret it had uncoupled. Its the same cylinder and shaft but I have replaced the "O" Rings in the cylinder so I can only assume they had been worn enough to have some leakage.
Well better go see about making up a bracket to mount the limits, once thats done I should be able to test it.
Hood

Well its raining today so I have a good excuse not to be outside welding Alu so can get on with some of the turret

I now have the limits fitted and set correctly and have it indexing away. As mentioned earlier it only indexes to six positions at the moment as I have not altered the ladder, macro or wired the extra input, which is required,  to the drive yet.

Heres a vid of it working and so far its looking good

http://www.youtube.com/watch?v=hRTfxuXf6yk&feature=youtu.be
Hood