Spindle collets

[stockbub]

OK, total brain freeze but. for a 3/8" Bit, do I need a 3/8" collet for my spindle. From shopbot, I got 1/2" and 1/4" collet. If so, where do you get them? And where would I get them anyway for spares?

[harryball]

I believe Shopbot sells 3/8" collets, I happened to purchase mine from Onsrud when I completed my first order with them. They are not expensive... the collet nut, on the otherhand, must contains some gold content.

Robert

[stockbub]

When seating the collet in the nut, do you just place it in the spindle, then tighten the nut?I just briefly looked at it while ago, still having problems hooking up my PRS. So have not been able to cut anything . Just turned o the spindle and let it run to kind of burn it in.

ALso, have you heard of a quick change spindle collet. Fast like a manual tool changer.

[harryball]

You make sure things are clean and screw the nut with the collet installed (clicked in place) into the spindle. With it loose slide the bit up so it is at least 80% engaged but none of the flute or gaps enter the collet. Then tighten. You get more comfortable with it over time.

As I understand it, the quick change mechanism is married to the spindle. You can't easily convert a standard spindle to a tool changer type spindle. As for other methods of quick changes, I've not seen or heard of one that wins approval by anyone on the forum.

Take your time, enjoy the process and understand the tool. It's worth the effort, when something makes an odd sound you have a better idea about where to look and what to do.

Robert

[olecrafty]

check ebay. you can grab them from ebay for a reasonable price.

[fleinbach]

Martin,

As Robert says make sure you snap the collet into the nut. When I got my first spindle there where no directions and not being familiar with the collet nut design put mine in without snapping in place. Well the first job was to flaten my table with the 1 1/4 inch bit so that's the one I inserted. I was seated when I turned on the spindle for the first time. Everything seemed fine as it spun up to 12,000 rpm. But next I recieved a big surprise when the bit flew out and landed in my lap. Luckly without injury.

[elcruisr]

Another point, don't buy cheap collets! Make sure you get precision collets. The cheap ones will just introduce more runout, increase tool wear and make a poor cut.

Collets also have a definite life span. 400 hours is about max, sometimes less. Drop one on a concrete floor? Best replace it (Don't ask ow I know). Major crash? Replace it. I always keep a few spares around.

[olecrafty]

Eric is correct. Always buy precision close tollerance collets. Longer bearing life for the spindle, better cuts, longer tool life, and safer.

[conceptmachine]

yes do buy good quality collets,but as far as life span,in my experience i have some collets on my vmc's at work that have 4 or 5 thousand hours on them and they work as well as the new ones.we hold tolerances of +/- .0002 with these collets.our machines are very rigid compared to a shopbot so it might not be a good comparison.

[elcruisr]

My experience is based on production cutting 3/4" ply, single pass as fast as the ol' Bot can go for years! That's been our average. The manufacturers are currently rating 500 to 700 hours production time but I see a difference on the cut at about 400.