Warning about Routers

[Larry Edgerton]

Sorry about your injury buddy! I have had the same thing happen to a PC 3 1/4 VS running a 4 1/2" cove bit, speed control burnt out and defaulted to 21,000. Had hands on and shut it off but it scared the daylights out of me. I got rid of the internal speed control and went with a separate for the rest of that job. In my case I feel that it was probably overloaded as the bit is a very heavy Nordic Tool custom bit, but in your out of cut blowout ???.

Been doing this and construction my whole life and injuries happen, as you have said it is dangerous work and sometimes things beyond our control line up against us. All we can do is look at what happened and change our procedure. I think the guys that do this for a living and make it through their whole life without a mishap are the exception rather than the rule. Hope you heal well.

[peter gagliardi]

Mark, sorry to hear about your injury. That is a pretty serious amount of damage to you, and I hope the healing goes well without the onset of infection.
Tiny bits of the wheel not seen and removed can really hamper recovery and lead to infection. I wish you the best with it.

Sadly, the 1/2 dozen or so VS routers I have had over the years have all exhibited lack of ability to keep a set speed. As such, I was aware early on about that issue and bit size and what I used the router for.
Now, I only run bits sized to take full speed.
The only routers I have that have not exhibited this phenomena YET are the mid sized Festools. I am NOT endorsing or saying they are better, just that they have thus far proven to be more reliable on the speed issue. I fully expect it is a case of “when”, and not just “if” the speed control goes haywire.
Most of my new routers are the old Stanley and Porter Cable single speed types from the 70’s or before.

[Jim Becker]

I was thinking about this and unrelated to a different way of spinning the grinding wheel, a machine operation like this would benefit from a heavy, clear Lexan shield mounted to the machine, itself. This is in addition to eye and face protection. Grinding wheels are what they are and by their nature they can shatter for any number of reasons, even on a "traditional grinder". A machine mounted shield can be the "first line of protection" during an automated process like shown. This is yet another reason I'm working myself up to replace my wheels with CBN.

[Larry Edgerton]

I was thinking about this and unrelated to a different way of spinning the grinding wheel, a machine operation like this would benefit from a heavy, clear Lexan shield mounted to the machine, itself. This is in addition to eye and face protection. Grinding wheels are what they are and by their nature they can shatter for any number of reasons, even on a "traditional grinder". A machine mounted shield can be the "first line of protection" during an automated process like shown. This is yet another reason I'm working myself up to replace my wheels with CBN.

Or maybe a solid shield [metal] on the working side and do the work from a mirror on the side away from you? May take some practice, and this is just a random thought so don't shoot me.

[Ole Anderson]

Sorry to hear of your accident, hope the healing goes swiftly and well.

It comes at quite a price, but reading of accidents tends to keep us all on our toes, at least for a while. As far as not putting on a tool not rated for full router speed, that becomes problematic for anyone using full size raised panel bits on a router table. Typically they are limited to 8000 rpm in a router capable of 24,000. And even good face shields don't always protect us in our shop, remembering a lady wood turner that lost her life when a (bowl?) she was turning exploded in her face. I believe she was wearing the same face shield I trust. One of the few lessons I remember from my school shop days was to always stand to the side of a grinder until it comes up to full speed. Your experience will remind me to start doing that again. Interesting setup on that metalworking lathe BTW.

I would be concerned with that long shaft on that id grinder. It reminds me of a situation that happened to the guy that used to turn my 72" long barefoot booms. He was turning down the end of a 1.75" diameter solid aluminum rod and had the end stuck out the rear of the lathe, unsupported. It was a rather large lathe able to accommodate the size of the stock. Apparently he had the rpm set too high and the free end started to wobble and became totally unbalanced, bending the rod while rotating at high rpm. It started walking the multi-thousand pound machine across the floor while slowly pulling the rod through the chuck as the free end spun closer and closer to the floor, bent at about a 60 degree angle. He finally got it turned off and then was able to leave to change his shorts.

[Mark Hennebury]

HI Ole, and thanks.

The big lathe is an awesome beast, 7.5hp 6000LB sleeping monster that can turn you into mincemeat without slowing down. Lots of horror stories and some nasty videos. The lathe has lots of evil tricks to get you. When you have to get things done, you make judgement calls, you learn what you can about the machine and operation, weigh the risks and make your decisions on what you think is doable, and what is most likely to happen, where you need to be for a "reasonable" degree of safety and get on with it. Hopefully you have made a sound judgement and if anything goes wrong you have considered that and accounted for it by putting yourself, body parts out of harms way. 100% safety is not to do anything. Driving on the road back and forth to work entails far more risk than anything that i have ever done in the shop.

Sorry to hear of your accident, hope the healing goes swiftly and well.

It comes at quite a price, but reading of accidents tends to keep us all on our toes, at least for a while. As far as not putting on a tool not rated for full router speed, that becomes problematic for anyone using full size raised panel bits on a router table. Typically they are limited to 8000 rpm in a router capable of 24,000. And even good face shields don't always protect us in our shop, remembering a lady wood turner that lost her life when a (bowl?) she was turning exploded in her face. I believe she was wearing the same face shield I trust. One of the few lessons I remember from my school shop days was to always stand to the side of a grinder until it comes up to full speed. Your experience will remind me to start doing that again. Interesting setup on that metalworking lathe BTW.

I would be concerned with that long shaft on that id grinder. It reminds me of a situation that happened to the guy that used to turn my 72" long barefoot booms. He was turning down the end of a 1.75" diameter solid aluminum rod and had the end stuck out the rear of the lathe, unsupported. It was a rather large lathe able to accommodate the size of the stock. Apparently he had the rpm set too high and the free end started to wobble and became totally unbalanced, bending the rod while rotating at high rpm. It started walking the multi-thousand pound machine across the floor while slowly pulling the rod through the chuck as the free end spun closer and closer to the floor, bent at about a 60 degree angle. He finally got it turned off and then was able to leave to change his shorts.

[Mark Gibney]

Mark your story made me wince. I know how these things can come out of the blue.
Hope your recovery is complete.

And thanks for making us all the wiser.

[Bill Space]

Mark,

I hope your recovery is a speedy one.

I was was thinking about your unfortunate experience as I was cutting several acres of grass this afternoon. For me this is a reminder of the importance of matching ratings of components in a system. Especially because, in a case like yours, I am likely at some point to forget to set the speed to the proper level, and could experience a wheel explosion without having router failure.

Ole Anderson brings up a good point. How about raised panel cutters? I use them in my router table. Never considered the speed rating and what might happen if I forgot to turn the speed down before installing one. And NEVER thought about a router speed control failure like you experienced.

I am am going to have to rethink their use in my router now...

Bill

[Eric Danstrom]

Thank you for sharing this. I'm sorry for you injury and hope you heal well.

[David Buchhauser]

I was thinking about this and unrelated to a different way of spinning the grinding wheel, a machine operation like this would benefit from a heavy, clear Lexan shield mounted to the machine, itself. This is in addition to eye and face protection. Grinding wheels are what they are and by their nature they can shatter for any number of reasons, even on a "traditional grinder". A machine mounted shield can be the "first line of protection" during an automated process like shown. This is yet another reason I'm working myself up to replace my wheels with CBN.

Hi Jim,
This is exactly what I have on my larger conventional lathe. I made this up when I bought the lathe back in 2007. The top guard utilizes a 1/2" thick Lexan widow, which is hinged to swing up out of the way when not in use. In addition to the safety factor, it keeps cutting oil (for certain operations) from being slung up into my face. I also made some sheet metal pieces that fit below the top cover for additional protection. Of course - I also wear safety glasses while running the machine. I would most definitely have the guard in place for any tool post grinding operations.

I've also added some photos of my larger cnc machines. In an industrial environment - these safety protective covers are mandatory. The cnc lathe includes metal bars embedded into the clear cover to protect against high speed explosion of the part being machined. The redline for this lathe is 4500 rpm.
David

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[Rick Potter]

Just curious, does my PC 7518 with the 5 speed switch have this speed up problem? Only problem I have had is once when it wouldn't turn on, and I opened up the switch and blew the sawdust out. Then it worked fine.

[Bill Dufour]

I often use a loggers helmet when using power tools. It has a face screen, not shield, so it does not fog up and earmuffs. Great for mowing the lawn and planer, shaper, tablesaw use.

[Frederick Skelly]

I often use a loggers helmet when using power tools. It has a face screen, not shield, so it does not fog up and earmuffs. Great for mowing the lawn and planer, shaper, tablesaw use.

Bill, I would be interested in seeing the helmet that works for you. Looks like there are a few different types - can you post a picture or link to yours?

Thank you.
Fred

[Mark Hennebury]

A general guideline for safe maximum operating speed from an article from the Rockler website Printed on January 17 2019

https://www.rockler.com/learn/router-bit-speed/

Manufacturers don't always agree on top speeds for router bits of a given diameter, and as mentioned above, there are other factors to consider. For a rough guide, here's a typical maximum router bit speed chart:

Router Bit Diameter....Maximum Speed

Up to 1"........................22,000 - 24,000 rpm
1" to 2".........................18,000 - 22,000 rpm
2" to 2-1/2"..................12,000 - 16,000 rpm
2-1/2" to 3-1/2"............8,000 - 12,000 rpm

Remember, that's just a reference; Always follow manufacturers recommendations and the sage advice that if something doesn't feel like it's working right, there's a good chance that it isn't. Better yet, pick up a Router Book and get to know your router inside and out.

[Brian Holcombe]

I usually err on the slower side since my router is loud and slowing it down really helps in that regard and seems to do very little to reduce the quality of cut. I run router bits in a knee mill at 3000 rpms and never get chip outs, poor cut, burning or poor chip evacuation. Come to find out, after speaking with Whiteside they actually test their bits using knee mills.