[cnckid]

Greetings! I was curious to know if it makes any difference if the spindle key is ground off shorter so that it will not make any difference in which way the tool is loaded in the spindle? Recently took a job at a company that grinds all of the keys so that operators will not accidentally load a tool the wrong way causing a tool loading jam. They have Johnford mills, Yang mills, Cincinnati mills, and Hardinge/Bridgeport. All of the keys have been modified and have been in use for several years. So, just wondering why there would be a difference in the first place?
Thanks,
Mike

[Geof]

Are you referring to the little key that stops the tool holder rotating while you screw in the drawbar on manual mills? Grinding this off does not alter anything except sometimes making it more difficult to screw in the drawbar if the thread is tight. It does not do anything useful in driving the tool.

[cnckid]

Yes, the little (maybe 13mm x 16mm) key that is on the bottom of the spindle, on CNC machining centers. Basically the same as the ones on the manual mills. Grinding them shorter allows the tool to be inserted in the spindle either way. Since the tool holders have a "short" key side, modifying the key makes it so you don't have to be concerned with orientation. Again, just curious since it doesn't seem to affect the operation.

[Geof]

Those are different keys than I thought you meant. It depends what type of tooling you are using whether grinding those keys down to allow the tool to be put in either way is a good idea or not.

If you are using a single point tool in a boring head with a boring cycle that stops the spindle at the bottom of the bore, orients the spindle and then moves the table slightly so the tool does not make contact with the bore on the way out you must have the boring head installed in the correct orientation. If the boring head is 180 degrees out of position it will crash the tool into the bore.

[txcncman]

Are you talking about the drive dogs on the spindle face? Or the tabs on the tool changer? Ever machine I have ever touched, the drive dogs were identical. What makes the difference is the "key" or tab in the tool changer. Some tool holders have an extra detent on one side. This detent must be aligned for holding the tool holders properly. Grinding the tabs off of the tool changer mechanism or carousel is a "cheap" way for the company to avoid paying for skilled machinists. Most of the time this would not be an issue, until as mentioned, you have a tool that needs to be indexed each time it is loaded.