Routing - What Did I Do Wrong?

[SparkyGoBlue]

I was going to route the T-Molding slot into the edges of my cabinet today.  I was using a 1/16" slot cutter I got from MLCS.   Anyway, I was practicing using the router (my first time) and fine tuning the location of the slot with some scrap MDF.  The first few cuts went okay, but the slot was just a hair off both times, so I made some adjustments and tried again.  About the fourth try or so, the router seemed to be burning the wood rather than cutting it, and I couldn't get a clean slot.  Now, the arbor looks ---fouled up beyond all recognition--- and useless.  I can't figure out what I did wrong!?!

[ChadTower]

Did you cut with the bit going the wrong direction?

[SparkyGoBlue]

The fact that I didn't know there was a right direction probably answers your question.

[ChadTower]

You really want to read the user guide before operating something that can kill you.

[SparkyGoBlue]

Borrowed the router.  No user guide.  Now I know why I've never used power tools or built anything in my 32 years on this earth.  Unfortunately, this isn't even close to the stupidest thing I've done since starting to build this cabinet.  I'll save that story for another time though.

[ChadTower]

Shouldn't matter if you didn't have a user guide... they are pretty much all available on the manufacturer's websites.  Go read it before you power that thing up again or get a book on routers for beginners.  Seriously.  That bit is spinning at the speed of a bullet.

[SparkyGoBlue]

Will do.  Thanks.

[Orclord]

*Shakes Head*


This post has just scared the ---steaming pile of meadow muffin--- out of me.....

[Pops]

Could have been the speed setting too, sounds like the bearings in the guide rollers on the arbour are gone. try some wd40 or similar lubricant if that doesn't help then the bearings are shot, if it dose then you just got some dust from the particle board stuck in their.

Their will be an arrow on the router indicating the direction of cutting, follow it.
Try to get the speed to mach your cutting travel speed ,if it's too fast your just spinning the cutter in the grove and heating it up. Ditto too slow, you re straining the cutter and heating it up again. Cutters can shatter you know!
Safety goggles are not just for learners.

[ChadTower]

wd40 is a terrible lubricant.  Attracts dirt like crazy and gums up fast.  It would do far more harm than good in a router.  It's a solvent and a moisture repellant - never a lubricant.

[Orclord]

Yep......

Use a PTFE dry lubricant......

If the cutter is gunked up with resin (as I suspect it might be) clean it with some resin cleaner or cellulose thinners

[ChadTower]

Ironically, wd40 might make a good cleaner for that stuff... just don't expect it to be a lubricant. 

[northerngames]

  Now, the arbor looks ---fouled up beyond all recognition--- and useless.  I can't figure out what I did wrong!?!

dont re-use any of it again if there is apparent damage replace them if your going to attempt it again.

[javeryh]

It's not that you were cutting in the wrong direction it's that your slot cutter (the disc with the three blades) is upside down.  Take out the bit, disassemble it, flip the blade and put it all back together.  This should give you no trouble with the cut - it is supposed to be effortless and cut through the material like butter.

Also, before we use any power tools, let's take a moment to talk about shop safety. Be sure to read, understand, and follow all the safety rules that come with your power tools. Knowing how to use your power tools properly will greatly reduce the risk of personal injury. And remember this: there is no more important safety rule than to wear these — safety glasses.  

[ChadTower]

That struck me as odd.  How can you possibly eff up the arbor with a 1/16" slot cutter and something as soft as MDF?  I could see damaging the cutter if you burned it badly enough but the arbor itself?

[ChadTower]

Also, before we use any power tools, let's take a moment to talk about shop safety. Be sure to read, understand, and follow all the safety rules that come with your power tools. Knowing how to use your power tools properly will greatly reduce the risk of personal injury. And remember this: there is no more important safety rule than to wear these — safety glasses.   

He always says that right before leaning over his tablesaw and manually pushing narrow stock without any blade guards in place.   

[Dustin Mustangs]

You can also burn things up by moving the router too slow.  I have personally put burn marks in wood on account of this before, but I am not sure if you could heat things up enough to damage a cutter or not.

[fixedpigs]

And remember this: there is no more important safety rule than to wear these — safety glasses.   

He always says that right before leaning over his tablesaw and manually pushing narrow stock without any blade guards in place.   

yeah...safety glasses don't trump common sense...

i guess they would keep any blood out of your eyes though...

[Daniel B.]

Just to add a little about safety glasses....

I used to work in a plastic injection molding plant.

One day, a jig was stuck together, and being a complete dumbass, I stuck my eye up the the hole to see if something was jammed in between it. Just as that occured, the pressure was too much (what pressure that is, I really don't know, I was 18 and probably stoned at the time....) anyway, hot ass molten plastic came SHOOTING out of the hole and had I not been wearing safety glasses, I would have definitely lost my eye. They saved the glasses for future trainees to see.

You may make jokes like "it will keep the blood out of your eyes", etc. (not to pick on the poster that wrote that), but alot of "macho men" will not wear glasses. Put them on when you walk in the garage, and take them off when you leave. They are too important to skip.

Please, wear your safety glasses!!!

[fixedpigs]

i'm not poking fun at wearing safety glasses at all...they are certainly a very crucial element in protecting your eyes...

my contention was that there are definitely more important factors than putting on a pair of safety glasses...

like common sense...common sense would say 'put on some damn glasses...!'

 

[ChadTower]

And if you look like me... tie your damn hair back.  With multiple elastics if necessary.

[aszurom]

I did the 1/16 route for my T molding today.  I was absolutely certain that my slot cutter was turning the right direction too - double thanks to reading this post.

However - even though I went fairly quickly with it, I got some "mmmm... what's on fire?" smells, some nice blue smoke, and the cutter got hot enough to bubble the paint off of it.  The reason?  Cheapass slot cutter bit.  I got it at Harbor Freight.  Molding fit perfectly first try though!

So, it might be possible that the O.P. did have it going the right way after all.

One interesting side note - one of the three carbide tips de-bonded at the end of my second side panel.  About a foot from being done with the project.  I wasn't sure what happened but I heard something go "plap!" into the wall behind me and I looked but didn't want to stop cutting so close to the end.  I didn't feel any difference in router performance, but when I pulled it out it was immediately obvious that one of the tooth-tips was gone.  Whoops.  Now I know what zinged off the wall.  Given that my sawhorses are about the height of my inseam, I'm pretty glad that little bullet didn't embed itself in my leg or the holy of holies.

I'm going to wear a lexan codpiece from now on when slot cutting 

[sstorkel]

Here are a few handy little tips for people who don't know how to use a router. Which appears to be just about everyone in this thread 

1) While you may get some burning during a cut, you shouldn't be getting much. If you can see smoke you're doing something very wrong! When running a bit at very high speed, it is  important to keep the cutter moving through the workpiece. If you stay in one spot too long, you'll generate a lot of friction, a lot of heat, and eventually end up burning the wood or the bit.

If you're getting burning you need to either move the router along the wood faster or reduce the speed at which the router turns the bit! I've noticed that newbies tend to be a bit hesitant with the router. I guess they're afraid of it getting out of control or something, so they lock it in a death grip and move it along the wood at a snail's pace. If you have this tendency, dial back the RPMs!

Of course, this assumes that you've installed the slot cutter so that it's spinning in the right direction 

2) Don't buy cheap carbide bits. Especially don't buy cheap carbide bits if you're the type that has a problem with burning wood, bits, etc. while using your router. There are two problems with cheap carbide bits: A) the cutters tend not to be as sharp as on more expensive bits so they generate more heat, and B) the way the carbide cutter is bonded to the bit isn't as strong. As aszurom found out, when you overheat a cheap carbide bit, the bonds holding the carbide to the bit tend to fail. I can't imagine it's fun to get hit by a sharp piece of carbide... especially in the face!

[ChadTower]

That piece could easily have hit you in the torso... at that point it's a red hot piece of shrapnel that will ---fudgesicle--- up your day in a hurry.

[Neverending Project]

Here are a few handy little tips for people who don't know how to use a router. Which appears to be just about everyone in this thread 
[snip]

Also (with the exception of slot cutting), don't try to do it all in one pass. If you are routing out a recess or rabbeting out on edge (notice the spelling?  ) you may need to do 1/2 or 1/3 the depth, then adjust the router depth, rinse and repeat. Trying to take off too much material in one pass will surely overheat your bit and burn your wood.

[aszurom]

Wasn't getting hit in the torso I was worried about.  It was my power pills.

I think yeah my problem was router RPM then, because I was going around the piece as fast as I felt comfortable walking while holding a death shredder.

Anyway, it didn't burn in a charcoal sort of way, just a little toasty.  Cheap bit sure sucked though.

[ChadTower]

That's foolish, bro... getting shot in the gonads isn't going to kill you.  A shot in the torso might.

[sstorkel]

That's foolish, bro... getting shot in the gonads isn't going to kill you.  A shot in the torso might.

The carbide cutters are typically pretty small and have very little mass. No matter where you get hit, you're not likely to die. If you get hit in the face, you might end up disfigured for life, but that's a small price to pay right?

[ChadTower]

Not likely, no, but a perforated liver or kidney can do that. 

[pacmandude]

Look at the direction the router spins the bit. Look at the bit and imagine it spinning that direction. Are the teeth making contact first? Speed can also have a dramatic effect on woodburning if you have a variable speed router. I actually saw a guy create a large orange-hot smoking/burning ember when cutting at the wrong speed with a slightly dull bit. He thought it was normal 'friction.' Take the time to purchase good quality bits and keep them razor sharp.

About safety glasses...WEAR THEM. I used to wear them 'sometimes' until a little over two years ago I was ripping a piece on my tablesaw. There was actually a piece of buckshot in the wood which hit the blade and launched out...at my face. The piece of metal stuck into and cracked my safety glasses. It really rattled me. I always examine my stock before cutting now as well.

[ChadTower]

It doesn't have to be debris, either.  Plain ol' sawdust can get in your eyes and cause an accident too.

[sstorkel]

Not likely, no, but a perforated liver or kidney can do that.

A carbide cutter from a slot cutter doesn't have enough momentum, due to its low mass, to penetrate to the liver or kidneys. In fact, I've never heard of anyone needing more than a pair of tweezers to remove a piece of carbide from a wound...

[ChadTower]

Going that fast and from only a foot away?  I'd really have to see some sort of documentation on that one.  We're talking about a little blade going at 5 figures RPM.

[shardian]

It doesn't have to be debris, either.  Plain ol' sawdust can get in your eyes and cause an accident too.

I pulled a ceiling box out and wasn't wearing my safety glasses. I got dust and tiny particles of drywall in my eyes. I was completely miserable for almost a week. I couldn't sleep, my eyes watered like crazy, it felt like I had BB's under my eyelids and I couldn't wash them out. I will NEVER go without safety glasses again after that miserable experience.

[Jdurg]

Safety glasses are the norm for me.  I took a lot of chemistry and chem lab courses and when working with chemicals it is a MUST to wear full wrap around goggles and safety glasses.  I've spent so much time in a lab that I don't even notice the goggles anymore.  In fact, I feel a bit "naked" without them on.  With some of the stuff I've worked with in my lifetime, I can't even imagine having an "accident" with some of that stuff.

[sstorkel]

Going that fast and from only a foot away?  I'd really have to see some sort of documentation on that one.  We're talking about a little blade going at 5 figures RPM.

Let's think about this...

I can't imagine that the carbide cutter weighs more than 2 grams (= 0.0044lbs). The diameter of a slot cutter is 1.875in. The recommended spindle speed for a bit like this is probably 2000-3000rpm but most people are probably running their routers at 20,000rpm anyway. For one revolution, the cutter travels 5.89in. Round this to 6in just to simplify the math. Multiply that by 20,000rpm and the cutter is traveling at 120,000in/minute or 167 ft/s or (according to Google) 114mph or 50.8 meters per second.

So, we know the weight of the cutter and we know how fast it's moving. We can use this to compute the momentum of the carbide chip (p=mv). So 50.8 times .002 kilograms gives us a momentum of 0.1016 Kg-m/s. Or 0.7304 ft-lb/sec.

Of course, it's been 20 years since I've taken a physics class and I wasn't very good at it even then so it's entirely possible that the numbers are completely wrong. The conversion from rotational momentum to linear is probably the most likely place for an error. In any event, these miniscule numbers don't scare me. They're the equivalent of a nasty cut, not major organ damage. Hell, if you run your router while wearing a shirt, you might not even get cut...

[ChadTower]

It's true, the tiny mass makes for low momentum, but this is a blade, not a pebble.

[sstorkel]

It's true, the tiny mass makes for low momentum, but this is a blade, not a pebble.

It's a six-sided object with 2 or 3 sharp edges. Your chances of getting hit with a cutting edge are less than 50%. Probably much less, since the edges will only cut at certain angles...

FYI, even blades are subject to the laws of physics. You may get cut, but the chip has so little momentum it will quickly be stopped. I frequently get hit with metal chips when cutting steel beams with my multi-cut saw. It has a 14" blade that spins at 5000rpm. So the cutter is spinning at 220,000 inches/min, or 208mph, or 305 ft/sec, or 93 meters/second. Most of the chips are as large or larger than a carbide cutter and they have sharp ragged edges. Notice any similarities here? I haven't been cut once! Well, at least not enough that I started to bleed...

[Orclord]

Well I masturbate at approx 200 strokes  a minute.....

Average time 5 mins...So that's 1000 strokes.....Moving approx 3 inches/750mm of skin...

So that's 250 feet/76.2M of skin being battered....

Not one friction burn......

Not to say it can't happen though......

I'm just careful....

[shardian]

Well I masturbate at approx 200 strokes  a minute.....

Average time 5 mins...So that's 1000 strokes.....Moving approx 3 inches/750mm of skin...

So that's 250 feet/76.2M of skin being battered....

Not one friction burn......

Not to say it can't happen though......

I'm just careful....

I can't remember if my dynamics book had a friction coefficient for skin. If you had that, you could calc some really cool numbers.