Making a workhead spindle

JohnnyJohnsoninWI · Nov 30, 2006

Let's say I wanted to make a new spindle for something like the workhead on a cincinnati #2 tool and cutter grinder or a cincinnati monoset grinder. Obviously, I would obtain the appropriate raw materials, rough it out on a lathe, then send it out for heat treat. Once it comes back, how would I grind the bearing journals and internal taper on one or both ends?

Assuming you had a cylindrical grinder capable of such an operation. I think it would be best to grind the journals and the taper all in one set-up (ie. one chucking) on the machine. That way you'd be concentric within the accuracy limits of the cylindrical grinder. However, I don't know how you could hold the workpiece so that grinding all those surfaces are possible without rechucking.

Possibly, the journals are ground and the spindle is assembled into a workhead, then the internal tapers are ground while the spindle turns on it's own bearings?

It seams to me that any other approach would be a struggle to minimize concentricity and parallelism on the rotational axis?

How do the manufactures do it and how do the rebuilders do it?

Thanks,
John

Gary E · Nov 30, 2006

If you had a Cincinnati Universal grinder the bearing journals would be ground first then located on one of them and steadyrest on the other so the internal taper can be ground. Every milling machine spindle was made that way and the workhead spindle of the No 2 Tool and Cutter grinder as well. Both are 50 taper. and yes the 40 and the 45 Cat tapers all made the same way.

dsergison · Nov 30, 2006

I'm told some manufactures grind the tapers as assemblen in their bearings....

and Spindle Grinding Service deffinately re-grinds them in-situ. others do as well.

I'm sure it comes down to contamination vs concentricity.

Gary E · Nov 30, 2006

I'm told some manufactures grind the tapers as assemblen in their bearings....

No new machine was ever made that way at Cincinnati...

Maybe the regrind in the field guys do that.

JohnnyJohnsoninWI · Nov 30, 2006

Hi Guys,
Thanks for your fast replies. Gary, I was hoping you'd chime in here, as I know you worked at Cincinnati for many years.

Actually, I just hauled a Cincinnati 10x24 Universal cylindrical grinder home. It was made in 1962 and has 385 hours on it and is very well tooled. However, there are a bundle of wires the size of my wrist which need to be reconnected before I can try it out. This might take a while.

The specific project I'm thinking of is the workhead on a Monoset. I just bought one of these also, but the workhead spindle has been "worked on". I'm thinking of making a new spindle which would use TG100 (or ER) collets rather than monoset collets which are hard to come by.

dsergison, I searched this forum for comments from Walt@SGS. I wonder how he would do it if he was making one from scratch?

Thanks,
John

Gary E · Nov 30, 2006

After all of that grinding is finished, the threads are ground on the spindle for the bearing adjusting nut.

JohnnyJohnsoninWI · Nov 30, 2006

Grinding threads, hmmm. That could be tricky.

John

Gary E · Nov 30, 2006

The 10 x 24 is a very accurate grinder...
Do you have the internall attachment and the steady rests?

You should be able to makea spindle for the Monoset on that machine

Trying to think of where that many wires would be... rigth now I'm stumped.

This machine only has a several motors as I remember..
Work head
OD Grinding wheel
Internal wheel spindle
Hydraulic pump
Coolant pump

what else??

Gary E · Nov 30, 2006

Find someone that specializes in Thread Grinding, you do not want to skip that operation or try to get by with chased threads.

JohnnyJohnsoninWI · Nov 30, 2006

Yes, the internall attachment, steady and follow rests are there; some other tooling, too, all of which I haven't completely identified. Looks like a radius dresser, but might be missing a piece or two.

The seperate power control panel, 480V, is almost 6' tall, 36" wide, and 12" deep. Fabricated out of 1/8" thick steel, I estimate it weighs nearly 500 pounds. Inside, there is the bundle of wires which have been disconnected from the machine. Fortunately, they all appear to be color-coded, to it shouldn't be too hard to figure it out, if I can just find the time.

John

Gary E · Nov 30, 2006

All the wires will be numberd and the terminals in the pannel are marked also... Unless a butcher took it apart you will have no problem re connecting it.

Gary E · Nov 30, 2006

Grinding the OD is simple...

Grinding the ID Taper, notso simple
Unless you have the master tapered plug gage..

If you dont, you get to make one first.
Do you have a sine plate and a good set of blocks to check the taper? Then some redlead or maybe bluestuff, to check the internal taper?
Lotza steps, but followed correctly you will have a spindle every bit as good as a factory made one.

Spin Doctor · Nov 30, 2006

One trick we used for internal work was after grinding the ODs we installed two studs in the grinder face plate. A drive plate was passed over the work and 2 springs installed on the studs with washers and nuts. With the front ground diameter supported in the steady rest the drive plate was used to compress the springs and then locked to the work piece. The springs held the work against the dead center and the steady held the front end. The internal wheel never puts enough pressure on the work to pull it off of the center.

Gary E · Nov 30, 2006

Good idea Spin Doc

Spin Doctor · Nov 30, 2006

As to grinding the ID while holding the OD in a bearing set up. One problem is of course contamination of the bearing. Another is unless you have some sort of fixture plate the bearing could be mounted to placing it in a steady rest is going to raise the possibility of squeezing the outer race out of round. The only time I used the bearings of a part to grind it is with rotary bushings when the ID has a mandral passed through it and the work head is used to turn the bearing housing of the Rotary Bushing on its bearings while the mandral is held stationary (a hose clamp with a short section of allen wrench works well). Even in this case care must be taken to prevent swarf and coolant from entering the assembly

dsergison · Nov 30, 2006

"some manufactures" is not equal to "Cincinati"

Gary E · Nov 30, 2006

Who told you?
comon spill the name

Someone who worked at Bubbas grinding and part time lawn mower repair??

dsergison · Nov 30, 2006

I've read it in somebodies sales lit. not somebody small and insignificant.

something to the effect of "our spindle tapers are finish ground in their bearings to ensure....."

some VMC maker dont know who.

Rich Carlstedt · Nov 30, 2006

The rest of the quote
" our spindle tapers are finish ground in their bearings to ensure.....That you have to do it again whenever you replace the bearings "

Like a Government plan..sounds good at first, but the devil is in the details.

To do the grind while in the bearings, the manufactiurer would HAVE to MARK the spindle for the matching bearing "High Spot" marks that all precision bearings have. Then the instructions would always have to mention location of bearings to spindle, or any rebuild could produce DOUBLE the error of the original spec...bad idea for a machine tool buider UNLESS the item is a throw-away piece of tooling !
Rich

Mud · Nov 30, 2006

On a VMC, If it's old enough that the bearings need replaced, wouldn't it be time to grind the spindle taper also? Walt are you there?

Making a workhead spindle

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