router bit speed

Re: router bit speed

Eliot......if you were going to spin a large hunky piece of wood on a lathe.......would you turn it slowly or as fast as the lathe could spin it??

Re: router bit speed

Everything you need to know about router bits.  https://www.abcsignproducts.com/Media/Default/files/multicam/Onsrud-Routing-Guide.pdf

Re: router bit speed, Impressive Mr. Coers

Elliot, The thing Dick posted is impressive and literally everything you want to know.  I may print it out and read it myself.

Generally, smaller bits need to run faster and bigger ones slower.  One thing to keep in mind is rim speed, just like on the lathe.  The cutting edge on a 1/4" bit does not travel as far around the circle as one on a 2" bit.  So run tiny bits near full speed and slow the big ones way down.  I did not read Dick's post but one idea is the chips carry away much of the heat.  Pretty sure that's a major factor when machining metal but it may not be so much when cutting wood.  But that has to do with Feeds and Speeds (page 17).  The feed rate is important and may explain why we get burning in corners where we pause for a split second and at other pauses along the way.

RPM's got noticed when variable speed routers came along.  Apparently we got along for years without the ability to slow down the shaft.  

One "problem" I have is I have made a slab flattening table.  Got a huge old single speed router in it.  Would like to use one of the 2 or 3" bits that use replaceable carbide cutters.  Have not been able to find one rated for 23,000 RPM.  Saw one in a video and messaged the company (China) and asked if it would be safe to run at that speed.  The answer came back that I could run it that fast but would not be safe. The wording was sketchy. So I am sticking with my 1" solid carbide bit.

So pick a speed that works, take light passes, keep moving.

That comes from my years running a big CNC router.

Re: router bit speed, Impressive Mr. Coers

Barry, what about a PC 7518 or a Triton router for your slab flattener?

Ellis

Re: router bit speed

 Yeah, that part is fairly obvious. but there is apparently a lot more to it. I am going to have to read through Dicks link to get at what I am after-- like speed depending on the type of wood, for example, or what speed for this or that type of router cut.

Planing Router

Just finished thicknessing some 11/4 walnut slab crotch cuts.  My DW 621 did a fine job running a 2" spoilboard bit.  Had to move the operation out side given the amount of dust generated.  Cut both sides (double pass) and then used the sander.  Got three tables (2 bookmatched) of 8/4.  Router didn't miss a beat at 14K.Rough

Finished:with Britannia inlay

Now Ellis...you know I am too cheap to buy new router...

Especially when I have an ancient single speed one I got at an estate sale for $20.

But now that you mention it, I will give it some thought. 

Re: router bit speed

Trust can be very dangerous to your heath.

Tooling has a maximum "safe" operating speed.

Router manufacturers promise variable speed control, so that you can match the speed to the tooling and application.

The fact is that the speed control on routers can fail!   Unfortunately if you are using a tool at 8000 rpm and is suddenly runs up to 24,000 rpm you may get hurt.  The sudden and unpredictable speed increase can torque the router out  of your hand, catch the bit into the wood and send it flying ruining your work or your body. 

Or in my case where I had a small grinding wheel in the router, and going to use it to finish hone some metal parts on the lathe, This is incredibly delicate controlled work. the rapid increase in speed, far in excess of the grinding wheel maximum rpm, caused the grinding wheel to explode sending a chunk of grinding wheel like a bullet through my face, taking out a chunk of bone and three teeth. I wasn't even using the tool at the  time, I had just turned it on to warm up for a few minutes, when it went crazy, and I was just in the wrong place at the wrong time. Your results may vary. 

Variable speed, for sure!  control....eh... sometimes.

Man I hated those 7518s

The feedback to the speed control could be measured with a sand timer. I had one in an ancient old shaper table. You could start an end grain cut with a panel raising bit, the speed dropped and about an inch into the cut the rpm came back up. When you went out of the cut, the speed went way up and you waited for it to come down. And if you did mount them upside down, the elevation grooves would fill up with sawdust and pretty soon it felt like you needed a pipe wrench to break it free. They didn't improve that router from the very first design. EVERYONE passed them by with speed controls that actually worked.

Re: Man I hated those 7518s

Egad, I must have been one of the lucky ones. I've still got one in a router table and it's working fine after 20-odd years. I guess mileage varies. I'm sure there are better variable speed packages out there -- and more powerful routers -- but mine has spun everything including large panel-raising cutters at acceptable speeds.

I'm wondering if there's a particular router you'd recommend for Barry's purposes?

Ellis

Re: router bit speed

You're lucky you weren't killed, Mark. So sorry to hear about this freak accident. I wonder how many cases of speed-controls-run-amok have been reported? Is this a known issue with your particular model of router? Are any brands reportedly more or less reliable than others?

Ouch! Are you healed up yet?

Ellis

Im still a big fan of what is now the Dewalt 625

The Dewalt 625 is still my go to. Started with those when they were Elu. The Elu was "the best" when it was made in Switzerland, but still acceptable where ever it's made today. Don't get me wrong, the PC 7518 machined miles of work for me. I used it so much in the table, the cord took on this odd look from being twisted so much with that elevation method they used.

Re: router bit speed

I am fine now, thanks.� This happened three years ago. Serious impact when it sends a missile at 24,000 rpm and you are only a couple of feet from it. I got my face stitched up in the emergency that night, but could get the bone and teeth removed until a week later after the swelling had gone down, so that was an uncomfortable� week. Faced swelled up a lot, what surprised me was how much bruising showed up over the following week, all of the way from my eye down to� my chest. The third� photo down is me this morning. The emergency doctor did a good job� sewing my face up considering the mess a chunk of grinding wheel makes on its way into your mouth. I don't have the teeth replaced, as the surgeon has told me that I would need bone graft first and it would take four operations over a year to get inserts. So I am presently going with the toothless grumpy old man look. I severed a nerve, so my speech� has changed a� little, kind of� sounds and feels like� I have just come from the dentist and still have the� lingering effects of anesthesia. I am pretty sure that if the chunk of grinding wheel hit me someplace else it could have been fatal for sure.

That was an issue from the past too

Makita had an issue around 2007 or 08 and scrambled to get them all repaired. Curious how old that router is?

router testing.

I have about a  dozen or more routers, of various makes and models, 4 or 5 of this model. They are all in good condition and  have not been abused.

Re: That was an issue from the past too

My Makita routers  are probably from back then, I haven't bought any for a long time as I mostly have been rebuilding machinery the past twenty years.

You should contact Makita

Send them that injury picture too. I bet you get some quick action!

Re: You should contact Makita

This is  Canada, victims are low priority here. The lawyers have been discussing it for three years, I doubt that I will get anything.

Re: router bit speed

Mark......I'm very sorry that this happened to you........I'm also glad that you have recovered and that it was not worse.......thank you for sharing this with us (I never had any idea that you had been injured) as we all need to be reminded about how dangerous our hobby can be.

Me, too

The shop I worked at 20+ years ago bought a DeWalt 625 and the first time I used it I decided to get one for myself. It's been in my router table for over two decades and still works great. The spindle has less run-out than any other router I've used and it's collet system grips tight and releases easily. The speed control has been reliable and at the lowest speed the router is very quiet (for a router, of course).

Well now I know two I won't be buying...

Mark, sorry you got hurt, quite a wound, If it had hit your eye it might have killed you.

Seems the obvious answer is to make the controller so it will fail into a slower mode or stop.

In my case I want to run a bit that has three or four carbide cutters that mount like the ones on a Shelix Head for a planer. One of those would be a hell of a projectile.  Giving that more thought.  I know a shop that will flatten a slab for one or two hundred dollars. Beginning to sound like a bargain.

Thanks for posting.