Replies

1. 
   Tao | Jan 14, 2004 03:41am | #1

   Full speed, 25,000 RPM or so, is just fine.  The ones you want to slow down a little for are large panel raising bits and the like, and they should come clearly labeled with their maximum RPM.

   I think the reason small bits like the one in question are not labeled is that they are safe in any known router.  The fastest one I have runs 30,000, but my larger ones run in the 25,000 range.

   Skene

2. 
   eddiefromAustralia | Jan 14, 2004 04:00am | #2

   Here's some advice from Charles Mc, who works at Freud.

   http://forums.taunton.com/tp-knots/messages?msg=8157.6

   Cheers,

   eddie

   edit - I needed to convert this info to a table for work anyway, so here 'tis

   Router bit diameter     (inches     mm)	rpm to give 100mph rim speed
   .25             6	135000
   .5              12	67000
   .75            19	45000
   1               25	33000
   1.25          32	27000
   1.5            38	22000
   2               51	16500
   2.5            63	13400
   3               76	9500
   4             102	8500

   I'd ignore the ridiculous numbers like 135000 rpm - trimmers run at 30000rpm and I'd say that's the maximum speed that router bits are designed for.

   
   

   ---

   edit - see post #5

   My words in the post above could be misconstrued - 30000rpm is the max speed that small bits can be run at, don't use a bit larger than 3/4" in a trimmer (30000rpm), use them in a router (22000rpm).  For the larger bits, run them at slower speeds as indicated.

   Edited 1/13/2004 8:51:11 PM ET by eddie (aust)

   
   

   Edit (following a helpful nudge - I'm having a shocker this week)

   And, for the largest bits (Greater than 1.5") use the only in a table, not in freehand routing. 

   In all cases where a large amount of stock is being removed, remove it in stages, raising the router about 1/8" at a time

   
   

   ---

   Edited 1/15/2004 4:26:00 AM ET by eddie (aust)

   
   

   ---

   Edited 1/15/2004 6:05:38 AM ET by eddie (aust)

3. 
   forestgirl | Jan 14, 2004 08:26pm | #3

   I have a speed chart around somewhere, but use Pat Warner's advice to guide my actions with routers ( http://www.patwarner.com/faq.html )

   "Small cutters (~1-1/2" in length or diameter) can run up to [emph. added] 25K if they don't vibrate. If they do, they should run at a speed below which the vibration occurs or not at all. Bigger cutters should be tested for their best speed starting at the minimum speed and on scrap. Begin the cut at the desired fence or cutter projection positions. The best speed for efficiency and safety will have to be determined experimentally. Experience is your best ally; the answer is not trivial. Don't expect to run before you walk. Routing with big cutters and no experience is risky business; approach it cautiously and stepwise."

   forestgirl Another proud member of the  "I Rocked With ToolDoc Club" .... :>)  you can take the girl out of the forest, but you can't take the forest out of the girl ;-)

1. 
   eddiefromAustralia | Jan 14, 2004 09:43pm | #4

   Firewood,

   After reading f_g's post, I had a blinding flash of the obvious.

   My words in the post above could be misconstrued - 30000rpm is the max speed that small bits can be run at, don't use a bit larger than 3/4" in a trimmer (30000rpm), use them in a router (22000rpm).  For the larger bits, run them at slower speeds as indicated.

   Cheers,

   eddie

   (who was once forced to use a 2 1/2" bit at 22000rpm and had the entire collet assembly come adrift from the motor spindle.  Last time I worked for the guy.)

1. 
   forestgirl | Jan 15, 2004 01:43am | #8

   "For the larger bits, run them at slower speeds as indicated."  And, for the largest bits (maybe you can suggest a dimension) use the only in a table, not in freehand routing.forestgirl Another proud member of the  "I Rocked With ToolDoc Club" .... :>)  you can take the girl out of the forest, but you can't take the forest out of the girl ;-)

1. 
   eddiefromAustralia | Jan 15, 2004 12:26pm | #9

   Thanks f_g

   I'm having a shocker at the moment.

   1.5" is about the rule of thumb.  Above that, use a router table

   Cheers,

   eddie

2. 
   tcbaldmtn | Jan 14, 2004 10:02pm | #5

   Wish I would have read your post earlier.  Used my router table with a PC 7518 at max. 21,000.  I've never used a pattern bit or the table.  Yes, it vibrated, thought that was normal.  Next time I'll start lower and work up.  I spent the morning making zero clearance TS inserts.  I'm going downstairs and put a note with the bit so I remember next time.  Thanks

1. 
   Tao | Jan 15, 2004 12:14am | #6

   RE: vibration.  A router shouldn't vibrate perceptibly more with a bit in it that it does with no bit.  That's when running free.  You can often feel a larger bit "working" when actually cutting with it.

   If you have perceptibly more vibration, you either have a dirty or worn collet (most likely), and unbalanced bit (usually chipped), or a bent shaft on the bit or the router itself (uncommon).  In any case, it's not too smart to keep using it until you have found and corrected the cause.

   Collets can wear out surprisingly fast, especially when they are used dirty, and the bit shaft is allowed to vibrate in the collet because the dirt keeps it from gripping properly.

   Michael R.

1. 
   tcbaldmtn | Jan 15, 2004 12:45am | #7

   It was a brand new bit and brand new router.  It was the first time I used both.

4. 
   GHR | Jan 15, 2004 05:45pm | #10

   There are a lot of different factors in setting the cutting speed.

   I always use the lowest speed I can tolerate.