My Pattern Bit EXPLODED!!!

[javeryh]

Last night I was cutting out some openings in an MDF panel and I had some clean up to do on the edges.  I typically use my pattern bit and a straight edge to do these types of cuts.  Anyway, there were a total of 6 edges to clean up and right in the middle of cut #4 my router bit basically exploded.  Check it out:



I am lucky that I didn't get hurt and also that the router did not cut into the panel and ruin it which could have easily happened. I only found one ball bearing (I have no idea how many were actually in there). The ball bearing casing just gave out - the bit is a few years old but it was still cutting well. I learned a valuable lesson without getting injured - ALWAYS wear safety glasses.  I swear this was the first time ever I didn't have them on because I was trying to make a very precise cut and I can't see as well when I am wearing them.  Never again!

 

[ChadTower]

That's two recently... the bearing fell off of mine cutting laminate and I did gouge it all up.   

[shardian]

Note to self: When I buy my pattern bit in the next few weeks, only buy a quality bit.

[ChadTower]

Mine is from Holbren - used once prior to that.

[javeryh]

This was a Porter Cable bit from Home Depot.  I had another one I ordered from MLCS but I lost it.     I will be ordering from them from now on - I never have trouble with any of their stuff.

[Chadwick]

Buy Amana or FS Tool if you want quality carbide tipped bits.  If you can't find them, let me know and I can hook you up with a high quality bit.  I distribute both brands.

MDF dust wreaks havoc on bearings.

[ratzz]

Nasty  ...

It really knocks the stuffing out of you, that doesn't it?

I did my apprenticeship in joinery (carpentry), and had a few close shaves with high-speed equipment, including getting part of my thigh ripped in a belt sander (still have the scar to prove it!) and this kind of thing doesn't do your confidence any favours.

Really pleased that it did no nasty damage was done.

[Axe]

Ensuring to clean out the bearing races, or at least make sure the bear ing is smooth running before any cutting should cut down on this...

I've got some nice ones i've got from Stew-mac guitar shop supply (i repair guitars professionally) But i did catch one of them with some grit in the bearing race, I blew the grit out and then lubed the bearings. it has been fine for months since then... But small steel balls dropping onto a metal bit spinning at high speed would be unpleasant.
:

[facesmiths]

WOW very glad you did not get hurt. I have had eerything imaginable in my eyes usually due to the item going through my protective lenses. I now wear two pair the big nasty things that have the wrap around seal and a pair of the more like sunglasses but clear type as I had a peice of tungsten carbide embedded in my eye (white thankfully) that I had to litterally dig out with my finger nail since the stuff is not magnetic at all.

everyone please be safe.

[shmokes]

That's super scary.  I would never leave my safety wear off while using the router.  In addition to the extra danger because the motor spins so much faster than most tools, I just can't.  The thing creates too much dust.  If I'm not wearing safety goggles it takes approximately five seconds before I've got crap in both eyes and I can't keep them open.  I typically wear my safety goggles and dust mask and ear plugs regardless of what power tool I'm using.  Every now and then I make an exception if I'm standing above a workpiece and just drilling wood, but even then I usually wear safety equipment.  I never wear cloves, though, which I've often thought is probably a bad idea.  I think my wife secretly thinks I'm kind of a dork cos her dad and grandpa have always done a lot of woodworking, and they're the types to not use any safety equipment at all.  But that doesn't bother me.  Her grandpa is missing half of one finger and a quarter of another.  I'll take looking like a dork while I work over that any day of the week.

Actually, I have to admit that I took my eyewear off the other day while I was making a cut with a jigsaw in black melamine because I couldn't see the cut line (didn't show up well on the shiny black surface).  I was super paranoid the entire time, especially since the jigsaw cuts on the upstroke.  Speaking of which, why does the jigsaw cut on the upstroke?  It's a pain in the ass.  It throws sawdust all over the surface, obscuring the cut line.

[ChadTower]

Isn't cutting on the upstroke just a function of the direction of the blade's teeth? 

The only equipment I generally use is goggles.  Sometimes if I'm stripping something really old I'll wrap a cloth around my mouth and nose in case it is lead paint.  That's pretty much it.  Always wear goggles, though, which can be a pain because my kids like to grab them and not put them back.  I think I have about 15 pairs now because if I have work to do and can't find one I just go buy 3 more.

[shmokes]

I'm really careful about what goes into my lungs.  My dad was always super susceptible to chest colds.  He died of pneumonia last year (well, Acute Respiratory Distress Syndrome brought on by pneumonia).  It was totally unexpected.  He was only 68 and still strong.  He had just finished building a block wall around his back yard all by himself less than two weeks earlier.  While he was in the hospital they did a biopsy of his lungs and they looked like someone's who had smoked two packs a day for twenty years.  He never smoked.  I'm not sure I got his lungs, but I don't want to find out the hard way.  So I've always been inclined to wear dust masks ever since I started woodworking cos my dad has always seemed to have weak lungs. 

And when I breath in dust after using the router on MDF I feel like the stuff is just going to settle down into the nooks and crannies in my lungs and just make itself at home in there. 

[ChadTower]

Ah.  Can't say I've ever even coughed from the MDF dust.  Sometimes it comes out when I blow my nose.     It helps that I do everything outside and my area usually has a breeze going.

[Portnoy]

This is the exact thing that happened to mine.  Porter Cable, from HD.  It was my fault for not keeping up with the oiling in between cuts.  I have to say the one tool that keeps me on edge is when using my table saw, especially for smaller pieces. 

P

[Jdurg]

I ALWAYS wear my safety goggles when woodworking.  As a former chemist, I learned pretty quickly that there is no better piece of equipment than good safety goggles.  My first day of chemistry in high school, the teacher did a demonstration that stuck with me forever.  She took some egg whites which are basically full of the same proteins that make up your eyeball.  She then dropped a few drops of some quite dilute NaOH on the eggwhites.  They almost immediately turned white and "cooked" from the addition of the strong base.  From that point forward, I never touched a single chemical without safety glasses.  On two occassions, they saved my eyesight.

1):  In a biology class we were disecting a giant clam.  My biology teacher was an old school teacher who still used Formaldehyde to preserve the specimens.  (Didn't like the new Formalin stuff).  I had my goggles on and my buddy just happened to squeeze the stomach.  I was standing right near the mouth.  A jet of formaldehyde came flowing out of the clam right onto my goggles and face.  Where it touched my skin, the skin immediately started to slough off and left my face quite raw.  If I didn't have goggles on, I'd be blind.

2):  College Advanced Analytical Lab.  I was doing an analysis of a metal mixture and I needed to use 70% fuming nitric acid in the analysis.  For some reason that I still can't understand, the concentrated HNO3 came spraying out of an opening in the flask right onto my goggles and my left cheek.  I washed it off immediately, but my skin still turned yellow/brown and was kind of sore for a while.  Amazingly, there were no scars.  Still, without the goggles I'd probably be blind.   

[patrickl]

Speaking of which, why does the jigsaw cut on the upstroke?  It's a pain in the ass.  It throws sawdust all over the surface, obscuring the cut line.

Like Chad said, it's a function of the blade. If you want to cut on the downstroke, just buy a different blade (with the teeth the other way around). I have different blades so I can choose on which side I make the cut. Either upstroke or downstroke for bad looking edge up or down.

Besides, just hook up your vacuum cleaner to the jigsaw and the sawdust won't be an issue.

[paulscade]

OK... so I suppose that this is bad timing...

I just now returned from Home Depot... where I purchased a Porter Cable pattern bit.  I hope that this isn't the norm for this brand... 

[Chadwick]

I'm not sure who makes the Porter Cable bits.  I'm fairly certain they're just private labeled though.

His carbide was fine (correct me if I'm wrong), it was his bearing that crashed.  MDF dust is BRUTAL on bearings.  I have customers that cut MDF every day with flush trim bits and they change the bearings once a week.  They'll buy one bit and a 10 pack of bearings.

[javeryh]

I'm not sure who makes the Porter Cable bits.  I'm fairly certain they're just private labeled though.

His carbide was fine (correct me if I'm wrong), it was his bearing that crashed.  MDF dust is BRUTAL on bearings.  I have customers that cut MDF every day with flush trim bits and they change the bearings once a week.  They'll buy one bit and a 10 pack of bearings.

So is my bit salvagable?  You are right - only the bearing broke - the bit is fine.   

[Chadwick]

If only the bearing was damaged then your bit just needs a new bearing.  I would carefully inspect your carbide for chips though just to be sure.

What you need to know is the I.D. (inside diameter -- probably the same diameter as the shank) and O.D. (outside diameter -- should be the same as the diameter of the cutting edge portion of the bit).  The bearing goes on the shank and then a stop collar goes on top of the bearing.  The stop collar should have a set screw in it.  Loosen the set screw in the stop collar, put a new bearing on, put stop collar back on and tighten.

From your picture, it looks like you have a 3/4" Cutting Edge Diameter x 1" Cutting Edge Length x 1/4" Shank.  You can see that bit here: http://www.amanatool.com/routerbits/pattern-template-routerbits-45481.html

If my guess at your dimensions are correct, take a look at tool # 45464.  Just for reference (no idea what you paid for your bit), we quote that bit at $27.60.  Replacement bearings at $4.35, and replacement stop collars at $3.75 each.  Keep in mind the Amana bits are some of the highest quality carbide-tipped bits you can buy.  They are made for heavy industrial use and their price reflects that.  Also, those are wholesale prices as we are a distributor not a retailer.  That bit would probably be near $40.00 off the shelf at a hardware store.  FS Tool (made in Canada) and Whiteside Machine (made in North Carolina) are also high quality bits.  We distribute both of those brands as well.

[NiteWalker]

This was a Porter Cable bit from Home Depot.  I had another one I ordered from MLCS but I lost it.     I will be ordering from them from now on - I never have trouble with any of their stuff.

The best bits money can buy.  Whitesides tested tops in 2 issues of fine woodworking. Once recently and once back in 99 I think. Very cheap at holbren. Just make sure to get the whitesides and not holbren's house brand. Around the same price as MLCS. The only bits I use. Never had an issue.

[ChadTower]

The one that crapped out on me is I think Holbren's house brand.