Warning about routers

Re: Warning about routers

Barry Irby

Wow! That's awful. Sorry you got hurt. Hope the recovery goes well. Thanks for posting.

One thing you left out was you should have been wearing a face shield. Not sure the cheap one I have would have completely protected you, but it would have helped. Mine has saved me twice. And on one occasion I was going to put it on after starting the lathe and the piece flew off and hit me between the eyes. About fifty stitches later I was back home.

Thanks again for posting. The speed control should be designed to fail the other way and reduce the speed to Zero.

Re: Warning about routers

BrianFromMonumentCO

Sorry to hear that you got hurt. Hope you recover soon and completely.

But you left out one of my MOST important rules.

NEVER turn your back on a running machine. All running machines MUST be monitored completely.

And a full face shield is a great idea. Mine have saved me many times.

Re: Warning about routers

Jesse Cloud

Wow! Best wishes for a speedy full recovery!

Re: Warning about routers

GolfSteve in Calgary

Glad you survived! I was always taught to be very careful with grinding wheels. Before they are mounted they may be dropped or bumped and have invisible damage or weakness. When installed and used the first few times the wheel may disintegrate without warning.

Cutting discs in hand-held grinders are very dangerous as they shatter when slightly twisted.

This may not be the cause of your accident, but any portable grinding wheel should be used with care as bumps and falls during storage could cause invisible damage to the wheel. Spinning a 4" grinding wheel at 8000 rpm gives me the Willies!

Re: Warning about routers

Bruce, a MN Galoot

Glad to hear your situation isn’t worse. Although a face shield might have helped, I’m not sure it would have done anything besides slow that fragment a bit.

Best wishes on your upcoming reconstructive surgeries, and thanks for the graphic reminder.

Re: Warning about routers

John McGaw

Oh, a good face shield would have helped. Even it it only slowed the shrapnel to half speed that would have reduced the energy to one quarter and that could make all the difference in the world in the severity of the injuries. It should be a lesson to all of us, especially those (like me) who decide "I'll just do this quick job without protection."

Re: Warning about routers

Bill Howatt

Very sorry to hear of your mishap but thank you very much for posting it. It seems your eyes were spared which in spite of the other injuries is a good thing.

Wishing you a speedy recovery, Mark.

Bill

Re: Warning about routers

William Duffield

Thank you for warning us about your tragic accident. I hope you recover soon. I have forwarded the link to your post to the leaders of some local woodworking groups to which I belong, hoping they will pass it on to all their members to heed the warning and always be much more careful with their use of grinding wheels.

Re: Warning about routers

John in NM

Man, as bad as that was it could have been worse! I'm glad it wasn't!

Get well soon Mark, thanks for the cautionary tale.

A teachable moment

Ellis Walentine

... and thanks so much for sharing it with us, Mark. Geez, I'm so sorry to hear about your episode and wish you a quick and full recovery. Routers aside, this says a lot about the dangers of grinding wheels. In PA, there was an incident with a grinding wheel where a guy was killed. Protective gear is a must.

Get well soon.

Ellis

thank you for warning

Video of router malfuntion *LINK*

Mark Hennebury

I have tried the router probable 100 times since the accident on June 4th; On the day after the accident it went crazy again when i tried it, so i set camera up to catch it,the following week it worked fine with the exception of two little twitches. The last time i tried it today it went wild a few times while i had the camera rolling.

Please forgive my speech in the video, I have a hard time speaking at the moment, and as you can see i am more than a little nervous when it ramps up, i am actually quite nervous around the blender right now.

So the issues of course are that there is no warning of when it will fail, no apparent reason for it to fail, there is the problem of it going from 8000 rpm to 24,000 rpm plus the torque caused be the acceleration. Either way this is a dangerous situation that can happen in an instant.


Router Malfunction

i assume you’ve shown that to a lawyer?

Dick Coers

Might be time to do so to get compensation for your medical bills.

I suspect that it will do no good...

John in NM

But I'm not a lawyer of course - any lawyers are welcome to contradict me an I'll not argue with their expertise.

The router was being used well outside the application that the manufacturer expected when designing it, so they would have a very easy out.

Speculating wildly, I would guess that the speed control failed in an unexpected way as the result of running a large grinding wheel (second picture in OP) rather than a router bit (relatively small). These kinds of speed controls typically have a soft start where the power delivered ramps up - the inertia of getting a big wheel up to speed could screw with that as it would require a slower ramp up.

There are a lot of lessons in this accident, and I admire Mark's willingness to put it up there for discussion and perhaps save someone else the pain he's had to go through.

Re: Video of router malfuntion

John in NM

I have several small induction motors that would make excellent drivers for a conventional tool post grinder. I would be happy to send you one if you want to go that way for lathe grinding, its much safer than using a router.

Our machinist at work made one using an HVAC motor, but that is a bit big for most applications. I think his runs around 4k rpm, but I'm not sure, I'll have to look at his set up. His rig would fit fine on that big lathe you have, he mostly uses it on a Monarch we have. I think he made it so it would fit on the much smaller Hardinge too, but it's size is inconvenient for such a small machine.

Nice thing about using induction motors for these applications is that you can find them in just about all sizes. Bill's never going to wear out the HVAC motor in his grinder, and if he wanted speed control we could put a VFD on it, though your accident is making me rethink the idea of solid state speed control for grinders. Two pulleys and a V-belt!

For reference...

Mark Hennebury

Router bits are made up to 3 1/2" diameter. and quite heavy. The larger size bits the max recommended speeds are in the 8000-12,000 rpm

Thanks for the offer...

Mark Hennebury

But i don't think i will be trusting electronic speed control for a while. Belt drive is the next tool post grinder for me.

Thanks

It's less about diameter than mass...

John in NM

And having not weighed bits like that compared to a grinding wheel, I won't claim that the wheels you run are too heavy for the router.

As I said, my theory was speculating wildly. Could also be a fault in design of the speed control that fails over time regardless of application, that is certainly a common problem.

Re: Thanks for the offer...

John in NM

You're welcome, and it stands as long as you like. The motor is from a little diaphragm pump set up, maybe 1/10 hp and 1-2k rpm. Might be a bit small for a tool post grinder actually, since induction motors aren't as torque-y as universal motors I could see this one getting stalled even with the light cuts of this kind of grinding.

The other thing you could do is get a surplus DC motor and run it with a KB controller - those things are really good quality and when I've seen them fail they've failed open. Just a basic SCR controller with a manual control, it shouldn't run away like those router controllers.

Re: Warning about routers

walta

Please understand I am not saying this to add to your pain. But so we all can learn a lesson from your accent?

The designer of this router never considers that it would be expected to operate in a cloud of power fine metal and stone dust. My guess is this is the fault in your unit, it would not take much metal dust inside the speed controls potentiometer to get the symptoms I saw in your video.

Has anyone else experienced, a speed control fail to a full speed?

Walta

here's the deal .....

Mark Hennebury

Hi Walta,

A couple of points;

I have always had sharpening equipment; bench grinders, surface grinders, straight knife grinders, tool and cutter grinders, drill grinders, cut-off saws, sanders, and angle grinders. I have worked in all kinds of dust, solid wood, ply, mdf, plate glass, fibre glass, and composite boards, i have machined aluminum, brass, steel and cast iron, corian and granite, plus all of the abrasive dust. I own probable a dozen or more routers, four of which are Makita RF1101 routers.

I did a quick look online and found a few conversations on this problem dating back to 2006;

CNC Zone 03-10-2006

https://www.cnczone.com/forums/diy-c...18394-cnc.html

I have a home built cnc router with a 2 1/2 hp Makita router. One of those ones thats suppose to be real quiet. The problem it has been devoloping is that the rpm goes up and down instead of remaining constant. Its constantly reving up /down. Has anyone had a problem like this with a router? Am i going to need to buy a new one or is there a fix?

Router Forums 06-21-2009

https://www.routerforums.com/general...d-control.html

Hi.

I have a Makita RF1101 which functioned beautifully for years, until a few weeks ago. Now the speed is erratic, changing at random intervals to random speeds during operation. The brushes are in good shape, and I suspect that the problem is the motor control (part #63139702) but I was looking for at least some confirmation of this before I drop $70.00 plus shipping on the part.

Any help is appreciated.

posted 10-16-2012 10:04 PM

https://www.lumberjocks.com/topics/42433

My router (after 7 years) has decided to speed up and slow down. I checked the brushes and they don’t look that bad. Controller board?? Anyone got a suggestion?

03-11-2016

https://www.cnczone.com/forums/diy-c...394-cnc-2.html

Re: makita router rpm constantly reving up/down any one had this problem?

Originally Posted by tsalaf

This is a defect in some earlier Makita routers and was repaired on both of mine free of charge, even after the warranty had expired.

That is a very interesting observation, tsalaf. My Makita RF1101 has the same problem.

Do you recall how you want about receiving this service? How did you learn that they'd take care of this for you?

It's a shame...

Barry Irby

you did not know this sooner. As you say, some of this dates back more than a decade.

I almost never bother to register my tools. This might be a good reason to do so. If we thought the companies were honorable enough to notify us of such problems.

Also might be a good reason to check in on user groups and such. OTOH such groups might be reluctant to post such information.

Hope you are healing well. Keep us posted.

Reminds me of my youth..

david weaver

...spending hours at the local airport. The mantra there was always "stay out of the arc of the prop".

Nobody that I ever met knew anyone who got hit in the arc of the prop, but it sticks with me with routers. Easy to say and do when you don't use routers often - I'm sure I'd get comfortable over time and get tired of standing out of the arc and leaning in to do work.

A good reminder that things that don't happen often sometimes still happen.

A second thought....

Barry Irby

I know these routers have speed control to allow the use of very large bits/cutters. What I am thinking is maybe it's not a good idea to install anything in a router that can not tolerate the full speed of the motor. I don't think anyone would want to operate those big panel raising bits at full speed, but I don't think they would explode before you could turn the router off.