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Speeds on routers

Posted: Fri Aug 01, 2014 7:35 am
by kjetilhansen
I use an Bosch router on my shapeoko, but I was wondering;

The speed wheel on the router goes from 1-6. Is it possible so easy to just divide 23000 RPM by the 6 steps and I have the speed per step?

Other tips to know how fast your spindle turns?

Re: Speeds on routers

Posted: Fri Aug 01, 2014 10:34 am
by WillAdams
I was able to find actual measured numbers for the 6 speed settings on a Makita RT-070x and linked them to the wiki --- can't recall how linear the change was, but it should provide you w/ some indication of the change.

Re: Speeds on routers

Posted: Fri Aug 01, 2014 12:11 pm
by Woodworker
Is there an inexpensive non contact RPM meter? Even of I had to build it, something like this would help most of us know what speed we are running.

Re: Speeds on routers

Posted: Wed Dec 17, 2014 5:26 am
by Mnlth
kjetilhansen wrote: The speed wheel on the router goes from 1-6. Is it possible so easy to just divide 23000 RPM by the 6 steps and I have the speed per step?
I've been wondering this too now that I am taking more care in getting feedrates etc. optimised for production. We use the Bosch Colt PR20EVSK that shows a specification of 16,000 to 35,000 RPM, and has a scroll wheel from 1 to 6 for the variable speed.

I have really not looked too much further into it than dividing it up as you've suggested above - if it works well I'll report back with results.
  • 1 = 16,000 RPM
    2 ~ 19,800 = 18,000 RPM
    3 ~ 23,600 = 20,000 RPM
    4 ~ 27,400 = 22,500 RPM
    5 ~ 31,200 = 26,500 RPM
    6 = 35,000 RPM
    Based on a 3,800 RPM step between each setting.
EDIT: Just spotted the below in the manual and have updated the above listings to suit. The relationship is not linear with the step from 1 - 2 - 3 being 2,000 RPM each, 3 - 4 is 2,500 RPM, 4 - 5 is 4,000 RPM and 5 - 6 is 8,500 RPM. So it looks like simply dividing the range is not a good way to do it. I also made a spreadsheet and graph to help with interpolating speeds between settings that you can access on Google Drive.

Image

Re: Speeds on routers

Posted: Wed Dec 17, 2014 6:47 am
by AlBorland
My guess is that those speeds are not accurate, but can serve as a starting point for own experiments. I did some measurements on my Kress 1050 FME-1. It has a speed dial with numbers from 1-6, I measured the actual (no-load) speed when the digit appears on the upper side of the window, is in the center of the window, and is on the low side of the window (printed as high/center/low). The expected speed comes from the speed dial table that is printed on the back of the Kress.

1 measured - / - / 4998, expected 5000
2 measured 4998 / 7332 / 8502, expected 7700
3 measured 10170 / 12000 / 13176, expected 12500
4 measured 14514 / 15678 / 17340, expected 16500
5 measured 18516 / 20028 / 21510, expected 21000
6 measured 23670 / 24840 / - expected 25000

Re: Speeds on routers

Posted: Wed Dec 17, 2014 1:38 pm
by Gadgetman!
Woodworker wrote:Is there an inexpensive non contact RPM meter? Even of I had to build it, something like this would help most of us know what speed we are running.
Maybe this one?

http://www.ebay.com/itm/LCD-Digital-Las ... 1c4ae59e7b

Re: Speeds on routers

Posted: Wed Jan 14, 2015 2:20 am
by Mnlth
I did some RPM measurements on the Bosch Colt PR20EVSK over the weekend using a non-contact RPM measuring tool, and had the following results:
  • Setting 1 - Specified 16,000 RPM - Measured 12,500 RPM
    Setting 2 - Specified 18,000 RPM - Measured 14,000 RPM
    Setting 3 - Specified 20,000 RPM - Measured 16,350 RPM
    Setting 4 - Specified 22,500 RPM - Measured 19,150 RPM
    Setting 5 - Specified 26,500 RPM - Measured 23,700 RPM
    Setting 6 - Specified 35,000 RPM - Measured 29,600 RPM
Hopefully these will be of use to someone. If anyone else can measure theirs it would be good to verify the accuracy of the measurements.

Re: Speeds on routers

Posted: Wed Jan 14, 2015 3:54 am
by Schruminator
I just measured my Dewalt 611 and I recorded the following numbers:

1 = 15820 RPM
2 = 16960 RPM
3 = 18950 RPM
4 = 21280 RPM
5 = 24270 RPM
6 = 27080 RPM

It's advertised as a 16,000 - 27,000 RPM router and my measurements seem to support that fairly closely.

Re: Speeds on routers

Posted: Wed Jan 14, 2015 12:29 pm
by WillAdams
Thanks!

I added both of those to the wiki: http://www.shapeoko.com/wiki/index.php/ ... _999_Watts

so we now have that data for the 3 main name brand contenders --- it'd be great to get some of the European models as well.

I'd still like to fill in the weight column though, as well as noise.

I'm trying to convince myself that it would be worth doing this w/ a 1/4" HF Trim Router, but given the availability of the others on sale fairly regularly, am not succeeding.

Re: Speeds on routers

Posted: Wed Jan 14, 2015 2:20 pm
by Hans
If we know the no-load speeds, what makes closed-loop control like SuperPID worthwhile for us? A 50W cut is pretty aggressive on a SO and that should only drop the RPM by 500 RPM or so from no-load on a 900W motor, without getting too deep into the numbers. Is that just inaccurate?