Cylindrical Grinder with Ball Screw

[RC Mech]

Mid-1970’s Kondo Gloss 450 cylindrical grinder, machine is in relatively good shape but the previous owner (plastics co in US) put a ball screw on the X axis.

Why on earth would that be necessary? The ball screw may have zero back lash, but it’s not self-locking. Bad idea for a grinder no?

Haven’t checked if the screw is the appropriate pitch for the dial reading to be accurate, but it may be moot if I have to make a new acme lead screw and nut.

Thanks for any insight.

 

[eKretz]

Bad idea? Yes and no I guess. For one, not really necessary on a machine that's not computer controlled. On a CNC it's important that the machine know where the tool (or wheel, in this case) is at all times whether feeding in the in or out direction. On a manual machine, not really; you're not going to be feeding multiple axes at a time doing complex contours.

Much more important is that the wheel can hold its X position whilst the machine is traversing down the length of the part. That could be accomplished in your case as simply as by adding some form of braking mechanism to the screw or handwheel rather than making or purchasing a whole new screw and nut. And the pitch problem is moot if you have a DRO or if you use a dial indicator on the slide as many do when they don't have a DRO.

But no, I can't think of a single reason why someone would have thought it necessary to switch to a ballscrew

 

[Robert R]

This 1985 Kondo 450 also has a ball screw + hydraulic rapid feed on the X axis. The ball screw installation appears to be original .

9.8 Swing 18 Centers Kondo Hi-Gloss-450-H-TS OD GRINDER, I.D., HYD TBL, A for sale Kondo Hi-Gloss-450-H-TS #18756 in category Universal Cylindrical Grinders

Specification of Kondo Hi-Gloss-450-H-TS #18756 9.8 Swing 18 Centers Kondo Hi-Gloss-450-H-TS OD GRINDER, I.D., HYD TBL, A listed for sale at MachineKs.com

www.machineks.com

 

[RC Mech]

Its possible then that this screw is original. Interesting- I've never had a universal grinder with ballscrews. We'll see how it holds position once I get it cleaned up.

There is a thrust bearing arrangement on a plate at the rear bottom of the wheel head. This plate is not anchored, but should be, as it moves outward as the screw is moved. Couple of house keeping details...

 

[Garwood]

Dumb question- Which axis is "X" on a cylindrical grinder?

 

[RC Mech]

I assume(d) it's the one perpendicular to the spindle axis Z, in the sense of a lathe.

But a surface grinder has Z being "toward/away" from the operator, X being the traverse and Y being plunge. I didn't even know the ball screw was standard-issue, so I'm not an authority on grin-ders.

 

[eKretz]

Yep, same as a lathe. X is toward or away from the OD of the wheel. Z is longitudinal. In most cases Z is always toward or away from the face of the spindle. Very few manufacturers deviate from that.

 

[michiganbuck]

Dumb question- Which axis is "X" on a cylindrical grinder?

*That's not a dumb question at all.
Here you find advice saying X is usually the long travel. And other advice that may the exchange Y and Z...

It is a good practice here on PM along with the X, Y or Z to include/add down, long, and cross when talking about XYZ on manual machines.
I have run 5-axis CNC machines but still, find the XYZ to be odd on various machine types that I don't have extensive experience on.

Consider vertical mill, horizontal mill, Blanchard, SG, OD grinders, once you get used to the axis it is easy for a particular machine type.. and then you may run into an odd manufactured machine that has it differently.

Oh, IMHO (to save arguments)

 

[eKretz]

I agree with Buck that if you're unfamiliar with the axis designation on your grinder, it's always safe to just use longitudinal, cross or down.

 

[EmGo]

Here you find advice saying X is usually the long travel.

Actually, that's not what he said, you didn't watch or listen. It's all determined by the Z axis and always has been. There's standards (which the japs often ignore.) Length of travel has nothing to do with it.

It is a good practice here on PM along with the X, Y or Z to include/add down, long, and cross when talking about XYZ on manual machines.

It's even better to ditch the stupid x,y, and z when talking manual machines and stick with traditional terms. Much less confusing.

 

[michiganbuck]

QT EG: (Actually, that's not what he said, you didn't watch or listen.)
It sure looks and sounds like at about 1:20 he said the x axis follows/is parallel to the floor and is usually the longest axis.

Re: QT EG...It's even better to ditch the stupid x,y, and z when talking about manual machines and stick with traditional terms. Much less confusing
* I agree with that 100%..

There are standards.. that bases #1 is axial to the spindle, but different references to XYZ are seeming to ignore that when it comes to grinders.
A world standard should be agreed upon for XYZ for each type of machine..
IMHO

 

[EmGo]

QT EG: (Actually, that's not what he said, you didn't watch or listen.)
It sure looks and sounds like at about 1:20 he said the x axis follows/is parallel to the floor and is usually the longest axis.

He did it correctly, describing the right hand rule and how the axes are described from the spindle, then used a milling machine in an example and unfortunately said "usually it will be parallel to the floor and the longest axis."

In the drawing he uses he's correct, it's a mill -- but even with a lathe he's totally wrong, the z axis is almost always the long one parallel to the ground in a conventional lathe. But he did say usually and described the correct way first before he screwed up.

He probably should have shut up after his initial presentation. In fact I left before he fucked up because it was boring and had to go back again to see what you were talking about

A world standard should be agreed upon for XYZ for each type of machine..
IMHO

There is a world standard, which was supposedly agreed to. It's just that certain people, predominantly japan, don't follow them. The way Fanuc butchered RS274 aka g-code, is a crime.

Totally agree that long and cross and down or traverse and infeed make a lot more sense for manual machines.

 

[michiganbuck]

QT: (unfortunately said "usually)
usually is the word/ issue that makes XYZ confusing.
How would we like
On a lathe, the cross feed is usually traveling the tool towards the OD of the part.

 

[EmGo]

QT: (unfortunately said "usually)
usually is the word/ issue that makes XYZ confusing.
How would we like
On a lathe, the cross feed is usually traveling the tool towards the OD of the part.

Yeah, he shoulda shut up while he was ahead. In machine tools there is no "usually", there's too many different kinds.

If you stick with the standards, they are explicit. Too bad some companies don't bother