Cat 50 Spindle?

[Konrad]

Hi all!
I can probably find this in the machinist's book, but have it in the shop.
Have to machine 2 new splinded spindle, old one is wrecked, [customer's client]
Taper is chewed up badly,.. would like to find out the inside 50 taper diam. on the very large end.
The cat 50 holders what go inside measure 2 3/4" so the hole should be smaller.. but to what?
I will leave around .015 grinding allowance.
Or you might know how much the holder standoff from spindle should be?

Konrad

[RICHARD ZASTROW]

You're right, it's all in the book. LOL

Dick Z

[mc-motorsports]

It's a 7/24 taper, other than that, you have to have a gauge to set the depth.
Too deep, and the drawbar won't have any clamping force. Not deep enough and you you can run into multiple problems with clamping and drawbar sensors.

I'll take it your machining a new shaft? If your just rough machining the shaft, you could use a known good tool, measure the stand off and leave an additional .025" for the grinder, should leave you .015" on the diameter. But you'll need the gauging tools to grind the taper, atomic air gauges aren't nessessary, but nice. I think we used to use Kelch hand guages.

[Konrad]

Thanks!....
Today is Monday and here we have a holiday, tomorrow it will be back at work and I will look in the book.
I use a new 50 tool holder to check the taper, I don't have a mill with 50 taper to check the stand off.

Konrad

[Konrad]

OK... got the answer out of the machinist book and the size is 2 3/4"
The tool holder also measures 2 3/4" 1/8 away, [undercut] from the flange / shoulder,..this means I will end up 1/8" stand off.

Konrad

[mc-motorsports]

Originally Posted by Konrad OK... got the answer out of the machinist book and the size is 2 3/4" The tool holder also measures 2 3/4" 1/8 away, [undercut] from the flange / shoulder,..this means I will end up 1/8" stand off. Konrad

That's not really the important part. The critical dimensions are from the angles for the gripper fingers to the tool taper depth.

I've never cut a brand new spindle shaft, but I've reworked and reground pleanty of them. In an extreme situation, you can chrome the taper and regrind it. Depends on how beat your old shaft is.

[Konrad]

Not sure by what you mean on angles and gripper fingers.

The book say's 2 3/4" on the very large end, [front] on taper, I.D of spindle, so the gauge will be 2 3/4", when grinding I.D., the gauge should be flush to top of spindle ...tolerance in /out is .015"

I had chromed and ground others too but this one is beyond repair, she is also bent.

Konrad

[mc-motorsports]

Are you using a ATC drawbar system? Or just a threaded drawbar like a dedicated spindle or conventional machine?

Every CAT spindle I've ever rebuilt used the OTT-Jackob style drawbar system. I know Kennametal has thier bearing type which isn't nearly as complicated.

[mc-motorsports]

If you get bored:
http://www.ame.com/line.cfm?id=spin-ott-catalog
It's a link to the OTT catalog in .PDF
I also attached a cut away view from the catalog showing the "gripper fingers" for the ATC drawbar.

[Konrad]

Thank you MC!
I'm copying the old one and I'm not sure what goes inside, it might be a OTT, or manual? This is not a problem, the whole spindle is around 16" long with a hole thru, around 1 5/8" diam. In the middle of the 1 5/8" hole, there is a step, around 1/8" larger in diam. Also 2 internal snapring grooves.
2 areas of the 1 5/8 hole is going to be ground also,... perhaps honed?
On the outside it has a spline, 2 3/4" x 5/8", I machine this on the CNC with endmill, [if I can not find a spline cutter] and stay over about .015" for grinding. The spindle has 2 bearing fits, large front and smaller diam. in back with 2 threads. Front face of spindle has 1" keyway, .52" deep for drive key, drill and tap for mounting key, also 4-16 mm threaded holes, 7/8 deep on 4" bolt cyrcle. This is a filler job for me,...I'm glad... it's slowing down now so I can work on and off.
Konrad

[mc-motorsports]

Ahhh... That is some kind of modular spindle. I used to rebuild them for Hermle machines, very similar description, the front cartrige would bolt to the servo body and the splined shafts would engage.

Good luck with your job!
MC

[Konrad]

Thank you MC...here a picture, ready for heattreating.

http://i25.photobucket.com/albums/c9...3625_1_2_1.jpg