Is This a Preventable Spindle Killer?

[gerryv]

I recently bought a low use PRS alpha but when it arrived the spindle sounded terrible and a test cut was bad. On removing the collet from the 4HP HSD spindle I noticed that a few of the slots in the collet were plugged hard with sawdust and one slot had a small chunk of metal jammed tightly in it. Although we did the initial cut with the collet and tool that came already mounted in the spindle, we also ran it with a clean collet and new tool and without the collet and nut. No luck; had to buy another spindle :(

However, getting to the point of this post that might help others:

My guess is that the unevenly closing slots caused the tool to be out of balance and misaligned when the nut was tightened, thereby causing premature failure of the bearings. Any thoughts on this as a probable cause and therefore, something to always watch for?

[mtylerfl]

Hi Grerald,

I guess the obvious answer is to inspect the collet and spindle before use. Make sure both are clean, etc. Also, avoid overtightening - you can easily distort the collet from too much force.

You might also enjoy reading the following regarding Spindle maintenance. It's a guideline written by the folks at PreciseBits (I follow their recommendations and use their collet care product myself).

http://www.precisebits.com/tutorials/coletcareprocedure.htm

[gerryv]

Thanks for the info and the link Michael.

I'm also hoping to find out if I'm correct or not in thinking that the piece of metal jammed in one of the collet slots could indeed cause misalignment/imbalance of the cutting tool and thus likely lead to the spindle bearings failing prematurely.

[Chuck Keysor]

Hello Gerald. I normally don't like to comment when I don't have any facts or experience to base my opinions on, so don't put much value on this. But, it is commonly stated that spindles are not designed to handle vertical thrust loads, such as created by drilling operations. But spindles are supposed to be designed to withstand large lateral loads, such as encountered by plowing a deep groove into a piece of solid oak.

With such a comparison, it doesn't seem like some junk stuck in the collet would create much of a lateral load. And it wouldn't create any type of vertical load on the spindle.

Again, that is simply my guess on your situation. I look forward to the replies of people who know, as you have posed an interesting question. Thanks, Chuck

[zeykr]

Just personal opinion, but I tend to doubt a small piece of metal in a collet slot would cause enough imbalance to be a problem that way. I expect most cutting tools are out of balance more than that.

Junk in the collet grooves is usually thought of as a problem leading to tool slippage.

[bill.young]

This may not be the problem, but not everyone instinctively knows that if you're using a spindle that the collet needs to be snapped into the collet nut BEFORE the bit is inserted and the nut is threaded onto the spindle. Failing to do this can damage the tapered bore in the spindle, cause the collet to jam in the spindle bore, and generally make everything out of balance.

Here's a short animation of the process:

http://www.youtube.com/watch?v=6gMezORPi8M&feature=share&list=UU5ImzwA-Yky3vBLAAlBrLLg

[jTr]

Bill -
I've been running 6+ months without any issue, but now I'll snap them together. Guess I've been lucky thus far that I've not damaged my spindle.

Did I miss reading this somewhere in the manuals???

Thanks for this valuable info!!!

Jeff

[dlcw]

Hi Grerald,

I guess the obvious answer is to inspect the collet and spindle before use. Make sure both are clean, etc. Also, avoid overtightening - you can easily distort the collet from too much force.

You might also enjoy reading the following regarding Spindle maintenance. It's a guideline written by the folks at PreciseBits (I follow their recommendations and use their collet care product myself).

http://www.precisebits.com/tutorials/coletcareprocedure.htm

I would love to get some of the cleaning fluid and try this. To bad they have a $50 minimum order. I don't need that much stuff. :(

[mtylerfl]

I would love to get some of the cleaning fluid and try this. To bad they have a $50 minimum order. I don't need that much stuff. :(

I totally forgot about that...but, it hasn't been a problem for me since I seem to have no trouble making the $50 minumum 'cause I order bits from them too! :)

[GlenP]

Hey Guys. Not to get off original post but I am Canadian distributor for Precise bits and I don't have the min order of $50. I think allot of the USA distributors might not as well. Don I am going to send you a pm.