Thread: Keyway in shaft

Chrism3,

I would suggest just about any engineering works could re-machine your keyway, however, you would have to remove the shaft first.

Ken

That looks fairly ugly.

Best course as you suggest is to abandon the damaged slot and cut a new one. Once the spindle is out cutting a new keyway is straightforward for anyone with a milling machine. If you were closer I would offer.

Anyone with a milling machine or shaper should be able to do it, not a hard job, takes longer to set up than to do it though. I had a similar thing happen on my car engine, the machinist re machined the crankshaft and cut a new key. Yesterday my metal lathe stripped a plastic gear, pulled it apart and the shaft needs the key way re cut. To make matters worse, my mill, stripped one of the cast metal gears inside the head.
Kryn

Send a PM to Ewan (Ueee) as he's Canberra based and he'd have the gear to do that or probably suggest someone who can.

Michael

Do you know why or how the damage occurred.

It may be possible to still use the existing key way.

It may only require a clean up with a file.

The replacement key could be drilled and the shaft tapped, allowing you to secure the key to the shaft.

Thanks all, much appreciated.
The damage occurred because the nut holding the pulley came loose, in spite of it being a left hand thread. That presumably allowed the pulley to move around a bit, which then allowed the key to move. Upshot was that the belt came off and melted its way through the plastic cover. Very ugly.
On researching I found that this is a known design problem. The shaft nut is a half nut with a coarse thread, only about 3 threads in contact. And no room on the end of the shaft for a locknut.
I intend to Locktite the new key in, plus the nut.

Have now got the cutter head out, and attach a pic of the damaged keyslot. Also a pic of the belt cover after the belt melted it.
IMG_9743.jpgIMG_9745.jpg

An alternative to a sunk key could be to use a roll pin, through a hole drilled right through the pulley and shaft.
That would have an advantage in that it wouldn't rely on a nut alone, to ensure it all stays together.

Jordan

Just curious did the original pulls have a grub screw in it to lock it on to the key?

Originally Posted by pipeclay

Just curious did the original pulls have a grub screw in it to lock it on to the key?

No, the only locking was via the left hand thread nut on the end of the shaft.

Originally Posted by nadroj

An alternative to a sunk key could be to use a roll pin, through a hole drilled right through the pulley and shaft.
That would have an advantage in that it wouldn't rely on a nut alone, to ensure it all stays together.

Jordan

Yes, I guess that would provide support to the whole pulley, not just the side with the key. Do you know of instances where this technique has been manufactured in?

How complicated is the shaft? Is it feasible to remake the shaft with an extended LH thread to allow the fitting of a castellated nut and split pin?

If the pully has enough room I would suggest a grub screw through the pully and onto the key.

You may also consider an alternative to the pin through the pully and shaft and consider putting a pin through the nut and shaft.

Here's a thread that shows that others have been plagued by this problem - the 560 is almost the same as mine.
http://forums.finewoodworking.com/fi...p12quot-planer