MIMF

You know what I'm talking about. The set screw in the little collar that holds the bearing in place always comes loose and it all come apart and gets lost in the bottom of your bit box.

Never had that happen. I have had good luck with the Freud pattern bits and with MLCS bits. I drilled a matrix of 1/4" and 1/2" holes in a block of wood that I attached to the wall and store my bits (shank first) in that.

Try a drop of Lok-tite thread locker on the threads.
Freud and Whiteside are the ones I use the most, I've never had a problem with either. You can buy replacement bearings from VXB now

oh. so I guess it's only me. Seems to happen every time though. I'll try a freud next time. I think we usually get Bosch. Or I could just get a new set screw and put lok-tite on it.

I've never seen that happen either. Does your router shake, rattle, and roll more than normal? I think most of my bits are Amana or Bosch, for whatever that's worth.

My very earliest roundovers are Bosch (about 20 years old). The bearings are mostly shot but none have fallen off yet.
It had never occurred to me to oil them but now I clean the cutting edges daily and oil the bearings with boelube every week or so. I use some of them almost every day.

I had the bearing on a binding bit (Grizzly) go flying mid-operation. I had changed bearings for a different depth of cut, but didn't secure the screw well enough . It went "nnnnnnnggggggddddddd-TIK" and flew across the room, leaving a nice dent in the side of the instrument. Never had a bearing on a larger bit fail, though.

Never had that problem with pattern bits, which are Freud or from LeeValley. A good bit might cost $10-20 more, but it's always worth it.

Brad Heinzen wrote:I've never seen that happen either. Does your router shake, rattle, and roll more than normal?

It must. Or I'm not holding my mouth right or something. I must admit that I am blown away to find out that no one else is having this problem. It must be hereditary because my dad has the same problem. He's complained about this for years and they always do the same thing to me. Different routers, different bits, same results. And it usually doesn't take that long for them to come loose.
Just to be absolutely clear: when I say pattern bit, I'm talking about the bit with the bearing at the top (mounted on the shank held in place with a little collar) not the flush cutting trim bit with the bearing at the bottom (at the end of the bit held on by a little washer and screw.)

Tighten the allen screw after your first or second use of the bit. I may have done that once or twice on mine. But, I've never had it fall off.

Ah ha! I never use that type. I knew there was an explanation. Sorry if I derailed everyone else with my inability to read the op.

I use that type of bit for the vast majority of my pattern stuff, and again, never had one come apart. perhaps checking on the allen screw as Bob suggests, from time to time, will help?

Mario Proulx wrote:I use that type of bit for the vast majority of my pattern stuff, and again, never had one come apart. perhaps checking on the allen screw as Bob suggests, from time to time, will help?

You guys are probably right. you usually are.

I don't have exactly the same problem but have had the top mounted bearings come apart when using thin Plexiglas templates as sold by some of the major suppliers. That could have been due to the retainer slipping but the bearing fell apart from what apparently was due to the Plexiglas wedging between bearing and retainer. I managed to notice it before ruining the guitar but it's always scary to watch the router go out of whack. To keep things in place, I like the idea StewMac uses for their bit. They supply you with some plastic tubing so you can customize where the bearing rides by sliding the tubing onto the shaft. That way, if the retaining screw slips, it can't move much. I do usually add an extra bearing and the retainer if necessary.

I've had it vibrate loose while using it and then it moves up and you lose registration on the pattern. It carves a lovely gouge into the side of the instrument when that happens. I would like to say that I learned from my mistakes, but I forgot to check one just this weekend and 'chukka chukka gronk' a new customization.

Chuck Raudonis wrote:I've had it vibrate loose while using it and then it moves up and you lose registration on the pattern. It carves a lovely gouge into the side of the instrument when that happens. I would like to say that I learned from my mistakes, but I forgot to check one just this weekend and 'chukka chukka gronk' a new customization.

It's also hard not to slip on the wet floor after that happens too.

You got that right.

Here is the section of the build blog with the details of the disaster and the resulting surgical fix.

http://thewaywardluthier.wordpress.com/ ... to-a-bass/

Let this be a warning, CHECK THE LOCK SCREW!!!

As an additional safety to guard against this happening, I use a short length of plastic tube just large enough to slip over the shank, and just long enough to stop against the router collet, and the bearing.