Indexing the spindle

Does anyone out there have a practical way to index the headstock spindle. I have this hair-brained idea that with the nifty CL hole drilling jig (that I'm about to plagerize from this site) and a way to lock the spindle in every 12 or 18 or 22-1/2 degrees (or whatever's clever) I'll be able to cross drill brake rotors!

I'm actually looking just to spot the holes so I can drill them on a drill press but I think you get the idea.

Ideas?

Some lathes actually came with indexing holes
built in:



Lots of folks also attach an indexing plate
or a suitably-toothed gear to the outboard
side of the spindle to accomplish the same thing.

Jim

Mikey-

Count the teeth on your two spindle gears (which engage the backgear) and on the outboard gear that drives the reversing mechanism. On a heavy 10 for example I believe the bull gear has 75 teeth and the pinion has 36 teeth. You can index integer divisors of those numbers (e.g., 2,3,4,5,6,12,18,25,36 and 75) by locking the spindle on selected gear teeth.

For light work you can bend up an L-shaped sheet brass spring pawl and bolt it in place of the gear cover so the tip slips between gear teeth. For heavier machining you can rig a beefier spring plunger (like the one on an indexer) with a tip ground to enter the gear profile.

There might be something clever you can do with the back gears to get other ratios, have to think about that a little. Adapting a real indexing plate as suggested above would be much more versatile and accurate, though.

mike

Jim,
Thanks for getting my hopes up! Ran out to see if I missed the holes bus alas and alak, no holes.

Ahhh well, the indexing plate is a great idea. Time to hit up ebay I guess.

Any leads on an inexpensive one?

Also...

I'm guessing boring the plate for a locking colar (set screw maybe?) to attach it to the outboard side of the headstock?

Yuup, I'm a noob but willing to learn!

Mike,
Another great idea with the spindle gears, and nothing to buy!

(remember folks, just a poor school teacher)

I won't know what division I'll need until I purchase momma's (read wifey) rotors for her car.

Thanks for the ideas peeps and keep em coming!

Mikey

Jim!

Ya got me thinking!

My old Rockwell wood lathe has an indexing pully on the spindle! Too bad it dosen't have the cool wazoo cross slides...


... hmmmm ...

http://www.mcmaster.com has alum 360 degree marked wheels in about 5 different diameters. I am going to buy a 3 or 4" and add it to a hub to fit the left side of my spindle with a needle pointer. As far as a locking device i was going to make a cone shape part to fit also in the left side of the spindle, in the bore with some spring pressure to keep the spindle from moving. I think. Thats my next project...Bob

South Bend sold an accessory kit to index the spindle on their lathes. I have a catalog from late 40's and one from the early 60's that have it listed. Sorry, I don't have a scanner so I can't post it.

Mark

Have several big cast iron discs with hubs left over from the P&W plant auction in the nineties. These are about 10/11" OD with 2" hub bore. Hub is thick, disc portion about 3/8 thick. Some have partial or full indexing notches, but unlikely to be what is wanted. Good for making useful stuff as per this thread. If interested in one or more, e-mail me at [email protected]

John