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Old Sep 23, 2012, 12:34 PM
Anything that gives me a High
super kupfer's Avatar
Canada, BC, Richmond
Joined Jan 2010
1,585 Posts
Question
Cutting down rotors.

What methods are you guys using to cut down EDF rotors?

I want go cut down a 90mm to a 80mm.
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Old Sep 23, 2012, 01:43 PM
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frank40's Avatar
Denmark
Joined Sep 2005
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Maby this can help. http://www.rcgroups.com/forums/showp...&postcount=140
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Old Sep 23, 2012, 01:58 PM
Anything that gives me a High
super kupfer's Avatar
Canada, BC, Richmond
Joined Jan 2010
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Any other options out there?
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Old Sep 23, 2012, 05:41 PM
Closed Account
Joined Jun 2002
921 Posts
Cut down rotors

Quote:
Originally Posted by super kupfer View Post
What methods are you guys using to cut down EDF rotors?

I want go cut down a 90mm to a 80mm.
I cut rotor blades down on my Bridgeport Mill. I mount the rotor on a turntable, and turn it anginst an endmill. If you want, send it to me, and I'll cut it down for you. just send me the funds to send it back.

Larry E.
SouthEast Model Products Inc.
Orlando, Fl.
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Old Sep 23, 2012, 05:55 PM
Big gov never Works
St. Martin's Avatar
Skunk Water, Rhode Island
Joined Jul 2002
12,496 Posts
This may help a little. Just hand tools and a modified TF balancer.
Fuzz

http://www.rcgroups.com/forums/showthread.php?t=1364095
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Old Sep 23, 2012, 09:49 PM
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imyohero's Avatar
Joined Mar 2007
1,057 Posts
I just trim until it barely fits with a hobby knife or even scissors on smaller fans then i mount the motor and fan and turn it with a piece of sand paper between the rotor and housing!

simple effective just a little elbow grease!
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Old Sep 23, 2012, 10:46 PM
Anything that gives me a High
super kupfer's Avatar
Canada, BC, Richmond
Joined Jan 2010
1,585 Posts
Quote:
Originally Posted by LJE4357 View Post
I cut rotor blades down on my Bridgeport Mill. I mount the rotor on a turntable, and turn it anginst an endmill. If you want, send it to me, and I'll cut it down for you. just send me the funds to send it back.

Larry E.
SouthEast Model Products Inc.
Orlando, Fl.
Thanks for the offer but I would like to learn how to do it myself
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Old Sep 24, 2012, 07:20 AM
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Arngeir Blakseth's Avatar
Molde, Norway
Joined Jan 2001
2,470 Posts
I do it like this; cut off each blade with a Dremel so the rotor barely fits in the shroud, then attach a piece of course sandpaper (like 80 grit) on the inside wall of the shroud, mount the rotor onto the adapter and rotate by hand sanding it down. The thickness of the 80 grit sandpape will give you approximately 1mm blade gap and should be ok on most units. The crucial step to this method is measuring and marking each blade correctly before hitting them with the Dremel cut off wheel, what has been cut off is hard to add back on again
So, measure twice, and cut once, the aim is to get close enough so you actually are able to get the rotor into the shroud before the final sanding to fit.

If you have a drill press, you can add a step in between these two where you have a drill bit chucked up in the drill press with the same diameter as the motor shaft, then after getting the rotor blades cut down roughly to the right size, mount the rotor/adapter onto this and spin it up while using a sanding block to slowly work the rotor diameter down. Slow and steady is the way to go.
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Old Sep 24, 2012, 07:39 AM
OUCH!!!
Jayray123's Avatar
United States, PA, Erie
Joined Sep 2008
580 Posts
Lathe works like a charm, and you can even cut a matching motor housing with stators down as well. Must be careful tho and not try to take too much too fast

Jay
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Old Sep 24, 2012, 08:19 AM
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Arngeir Blakseth's Avatar
Molde, Norway
Joined Jan 2001
2,470 Posts
Of course, having access to a lathe would be very nice but for those of us that does not the process can be done pretty easily with tools most modellers have.
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Old Sep 24, 2012, 10:30 AM
Registered User
United States, CA, Mission Viejo
Joined Jan 2005
2,298 Posts
Here is how I plan to do it

Your going to need a disk sander.

I have a Turbax rotor I plan to trim down today.

I have a board -3/4 plywood and I drill a hole in it the size of the hole of the rotor this happens to be 3/8"- the hole is positioned so that the end of the rotor overhangs the edge of the board. I insert a rod ( Cut down bolt - the unthreaded smooth end ( body area).

This rod is a pivot point. Now I simply C-clamp the board to the sander table and can rotate the rotor and adjust the position with the C-clamp.

If you don't have the sander then you may be able to do a makeshift lathe. If you can secure the rotor to a shaft that you can chuck in a drill or drill press then you can spin the rotor and use a sanding board and run the rotor against this while its spinning.

I don't have a milling machine or lathe so I need to come up with another solution.

Good luck - let us know what you come up with

Rick
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Last edited by Air Head; Sep 24, 2012 at 11:20 AM.
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Old Sep 24, 2012, 11:30 AM
My project: FAIREY DELTA 1
Erik v. Schaik's Avatar
Uden Volkel, Netherlands
Joined Dec 2003
4,976 Posts
safest option is to use an outrunner shaft, mount the rotoradapter on and the rotor. place this in a dremel tool and press this against a belt sander until the rotor fits snug in the shroud. Did this last week myself.

An other option is to clamp a file on the workbench and gently press the rotor to is. For this session you need safety glasses.

Both methods work very smooth.

Using a lathe and single cutter will be very hard. The file is a multicutter
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Old Sep 24, 2012, 12:16 PM
Registered User
Canada
Joined Nov 2000
7,270 Posts
Venerable Prather hand held prop balancers . I have 2 of the rascals and sadly Both are mfg'd 'off centre' .
Unless your examples are proven accurate ? These require rework on a decently accurate Lathe. Do not trust to them for impellors at least.
Annoyingly or perhaps not surprisingly ; HK 'clones' are even less accurate
Also a pair of Quarter sized Neo mags stuck onto Vise jaws makes for a Fine balancer widget, superior to the plastic low powered Tower Toy.
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Old Sep 24, 2012, 02:56 PM
Anything that gives me a High
super kupfer's Avatar
Canada, BC, Richmond
Joined Jan 2010
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All great ideas, thanks guys.
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Old Sep 24, 2012, 04:02 PM
Big gov never Works
St. Martin's Avatar
Skunk Water, Rhode Island
Joined Jul 2002
12,496 Posts
Quote:
Venerable Prather hand held prop balancers . I have 2 of the rascals and sadly Both are mfg'd 'off centre' .
Unless your examples are proven accurate ?
No issues here. One in pic is about 30yrs old.
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