allthunbs

Ok, this one's for all you experts with perfect pitch and who know all of the tricks ;-)

I've just received a router bit speed chart from Kempston. I have one of their panel sets. I also have a pair of Hitachi M12V routers. The speeds noted on the chart are 8,000, 12,000, 16,000 and 20,000. My router has a variable speed setting from 8,000 to 20,000 rpm. My speed dial has five numbers on it from one to five. When I cycle the router through the various settings, it dutifully slows and speeds but there is nothing to indicate what speed we're running at. Further, the sound difference between 1 and 2 compared to between 3 and 4 is impossible to tell.

I have to assume that the slowest (lowest tone) setting is 8,000 rpm but the optimum operating speed for some bits is 12,000 rpm. Any suggestions on how to reduce guess work?

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bobj3

Hi

Most of the routers have a chart ( sticker ) on the motor,,,that SUGGEST the speed but a good rule of thumb always use the number #1 setting to start with the router as a voice and it will tell you to bump the speed up or down...heat will cook the bit by running it high speed when you don't need to...

Speed kills most things, like router bits...speed = heat...


Router Speeds!
http://www.routerworkshop.com/routerbits.html


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rmaxa

allthunbs, Mathematically it would indicate that each number would increment the speed by 3000 rpm approximately. This would mean that setting 2 should be about 11,000 rpm.

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Rolf

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Hannibal Smith

Router is still my name

Router bit speed chart rules are not written in stone. They are a safe basic starting point
that's why routers don't have exact gradual ruller scale for speed. Most important is your feed rate that will contribute considerably to the end result.
Also how sharp your router bit is, What profile, the bit design as far as anti kickback and balance.

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allthunbs

Ok, let's take a look at feed rate. I have two categories of bits, super cheap and super expensive. For the most part and for the day to day stuff, I use the super cheap. They are sharp enough but their grinds are not consistent and chatter worse than a magpie. Their only advantage are they are guaranteed for life against breakage and chipping.

These bits I push quite hard. As long as the router speed remains constant I keep pushing. If you play a piano, I would say the tone drops by a third, i.e. from C to A. (Hitachi M12V running full tilt.)

The expensive bits are very sharp and the feed rate is entirely different. I feed a bit slower and take a bit less material. I protect these carefully and are only used on prime woods.

Ok, how close am I?

Router is still my name

All things being equal/ new perfect as in router bit “Freud or whiteside “then correct speed( excluding bit size) setting is determined by feed rate and feed rate is determined by the type of material and or type of wood.
Example, if you take 4 , ½ straight router bits ( which going by the book) would require a slightly lower than highest setting and run these at steady speed each through Mahogany, walnut, oak and dreaded mdf , You would get completely different results.
Hence, type of material + feed rate = proper speed setting taking into consideration the bit size.
Everyone knows that you can’t swing a 3 inch router bit at max speed.

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allthunbs

Ok, let's take this from another direction. I'm cutting a ½" rabbit. As I begin the cut, the chips fly out the end of the rabbit and all of a sudden it stops. I finish the cut and look at the results and I have chips jammed tightly in the groove. Is this normal, correct?

Any time I've watched the Rosenthals, this is what I think I saw. My memory is a bit rusty.

Conversely, it is not a good idea to start the cut and back out to clear the chips.

Mike

Watching the Rosendahls work has motivated many of us to begin routing. Bit types determine what happens to the chips. Straight bits will leave a dado groove packed with chips. Up cut spiral bits pull the chips out of the cut towards the router; this is true if hand held or table mounted. Down cut spiral bits push the chips into the cut or away from the router. A rabbit cut is on an edge so chips usually are not an issue.

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Julie

I have found hooking up a vacuum system in just the right spot can help tremendously by removing the chips before they get a chance to build up.

~Julie~

traveler

Hobby shops that sell radio control airplane equipment also sell tachometers. These are for holding near the prop while it's spinning. It is an optical tach. You could probably make one work on a router bit as well.