Are there ideal speeds for a router such as plung routing mortises or routing mouldings?
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Replies
Willy, the biggest issue with router speed is when using very large bits, ones like horizontal panel raisers. This wasn't widely known several years ago. Some bit manufacturers list a maximum safe speed but many don't. Variable speed routers were not that common, either. You can experiment with different speeds. A slight change can make the router run with less vibration. Lower speeds often mean less noise. I don't know just how the speed setting is effected by contact with the work but I often run fairly slow, much lower than the maximum suggested. If it feels good and I'm getting the results I want, that's what I use. Here is a pretty good article on the subject.
http://www.newwoodworker.com/rtrbitspds.html
Beat it to fit / Paint it to match
t.y. hammer. I was just curious as to what others were doing. Interesting article. I have been using a 1/2" up spiral for mortises on four legs of a table - mortises 3" x 13/16 deep. I ran the router, an Elu, at it slowest speed. I of course made a number of passes before I got to the full depth. I also used the slowest speed for making raised panels, but again taking a number of passes before the final depth.
Safe & effective router bit speeds are related to weight, length and diameter of the cutter.
Skinny cutters for mortices: Run at max.
Moldings and trim are typically large (1.2 - 3.5" diameters): Speed will have to be determined on a case x case. Safe to run cutters 1.5 x 1.5" up to ~25KRPM
See no.5 for more.
Routers
Since we're talking router speed, here's something I've wondered about. How do you know how fast it's going? The speed control on my router says nothing about RPM. Do you have to use a timing light?
Net RPM a bit like driving past an elementary school.
It is a 25MPH speed limit nationwide but I doubt you/me look at the speedo. We drive at the safe speed for the condtions we're facing.
Even if you knew the exact RPM this time, the next encounter may be with a dull cutter, harder material and so on, (requiring a new speed change). So an indicator number is as good as a tack. Max RPM for most routers (110VAC) is 22 - 25KRPM, necessary and safe for small cutters.
No Speed freak.
Over the years I have noticed that many new (and some old) woodworkers tend to run their routers too fast. The most common sign of this is if you get frequent burning in the profile unless you have a rapid feed rate. Simply slowing down enough to shift you body position should not leave a burn mark.What's worse is that router manufacturers are not helping. There is absolutely no reason to run a bit at 25,000 rpm--so why are the router manufacturers making new routers faster and faster? Well, that's so they can claim higher horsepower.Unfortunately, woodworkers see this ever increasing speed limit and assume that they need to keep pace, so they run their bits faster than they should. So before you increase your speed, look at the performance you are getting first, and use this as the gas-gauge. If you are getting good performance at low speed, then stick to the low speed. If the bit is giving you crisp cuts, then the rpm is good. If the only problem you are seeing is chatter marks, then it is more likely that your rpm is OK, but your feed rate is too fast.
You are correct. My router speed control says 1-6.
I know the sped range is 8,000 to 22,000 rpm's. I can assume it is a fairly linear scale.22K-8K=14K range spread out over 5 steps.
14,000 rpm / 5 steps = 2,800 rpm per division. SO for my router, an approximation is:1= 8,000
2=10,800
3=13,600
4=16,400
5=19,200
6=22,000I hope this helps you determine you approximate settings.If I knew a Bit's max speed is 16,000 rpm, I would start at 3.5 and adjust up or down accordingly. It's not so critical as to need to tach the shaft. If you are the engineering type like me, you may want to do it once and create a chart, or curve and formula to go way over the top.Greg
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Exo 35:30-35<!---->
I tend to start slower than I think the bit should run. Make a test cut, bump up the speed, and make a second cut. Then I compare the two cuts and see which looks better. If the second one looks better I bump the speed and try a third test cut. Repeat until the next test cut doesn't look as good, and back off the speed.
Then write the speed on the shank of the bit with a fine magic marker.
What you want is a photo tachometer. I've been wondering when this would come up on a woodworking forum. There are some inexpensive ones out there. We originally bought ours because the manufacturer of one of our import machines transposed rpm numbers on their boilerplate labels. We found very few of our machines actually run at their advertised speed. Here's one I found in a quick search:
http://www.web-tronics.com/digphottac.htmlI don't know why dealers don't carry these things.
Hey, thanks, cool tool! While I agree with all the advise about listening to the tool and looking at the quality of the cut, etc., something like this that will give an actual RPM readout would be really nice to have.
found this in the archives..Charles M worked at Freud:
http://forums.taunton.com/tp-knots/messages?msg=8157.6
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8157.6 in reply to 8157.1
PNut,
The rule of thumb for cutter speed is to start at 100mph rim speed and adjust as necessary to acheive the desired safety level, feed rate and finish. For a 2" diameter slot cutter this would translate to to app. 17000RPM.
The formula to calculate this is:
RPM=MPH/Diameter/pi*1056
So for a 2" bit:
RPM=100/2/3.14*1056
RPM=16815.28662
Charles M
Freud, I
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, wer ist jetzt der Idiot ?
I guess I need a more accurate tachometer or strobe light to get down to the 100,000ths of an RPM ;-)Work Safe, Count to 10 when your done for the day !!
Bruce S.
hahahaha,..think of it as saving energy..
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., wer ist jetzt der Idiot ?
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