Truck bearing out?

[dehrlich]

I am getting some noise when the bit spins up that sounds like a bad bearing in the truck, but the truck doesn't get hot like you would expect. I can feel a intermittent vibration in the flex cable, it doesn't get warm either. Truck has probably 120 hours of cut time on it. How often do the bearings need changed? I'm running a rock chuck and the bit is tight. Any ideas?

[bergerud]

The two bearings in the truck are supposed to have a preload on them. There is a wave washer under the top bearing which pushes the outside race up . If you have lost this preload, the bearings could get noisy. There should be no play in the spindle bearings.

There is also tolerance rings around the bearings. Sometimes the bottom one falls out. Have you seen any corrugated strips of metal in to bottom of the machine?

There have also been cases where the top bearing has gone because of overzealous flex lubing (the solvent probably) washing out the grease.

[dehrlich]

no, haven't seen any metal in the machine. I checked the spindle and there didn't seem to be any play. I believe I'm going to order a new set of bearings just because... I need a couple other parts anyway.

[Digitalwoodshop]

Top hat Dry? Remove the 2 screws and look. Any excess lube will cause this due to the high speed.

Remove the Flex and inspect the core and damper spring. I have seen the spring snap and inter wind. Remove Spring and run a .22 Cal cleaning rod through the outer flex.

This picture shows what the damper looks like when it falls out.

Any chance you have a Brush problem in the motor?

And lastly... ARE the Roller Rail Bearings tight and proper adjusted?

AL

[dehrlich]

Well, I just tore the second traction belt in a week, both in the same place. It's the front assembly, on the tracking roller side. Is there something that would cause this? I can't see that they are catching on anything, more like they roll over and bind up. Now i'm shut down because i already used my back up belt... grr!!

[lynnfrwd]

What is your head pressure?

[mtylerfl]

Well, I just tore the second traction belt in a week, both in the same place. It's the front assembly, on the tracking roller side. Is there something that would cause this? I can't see that they are catching on anything, more like they roll over and bind up. Now i'm shut down because i already used my back up belt... grr!!

Sorry to hear about the belt tear. Is there anything 'unusual' about the project you were running when the traction belt got torn? i.e., a board longer than 4 feet, a heavy board, a jig being used, etc.?

Tearing a traction belt is caused from a feed-through problem...head pressure out of whack and/or head unlevel (causes belt/board to track at an angle leading to tearing and rolled under belt), board tipping from lack of level support, a defect on the bottom of the board (like a splinter), a heavy board putting excess strain on the x-feed gears, sliding plate too tightly placed against the edge of the board (causes binding and a torn belt - maybe even broken gears). So many possibilities - all of which can be avoided and/or corrected. More specific info may help us narrow down the cause.

[Digitalwoodshop]

A un level head can cause this too along with cutting many narrow boards...

[dehrlich]

Well, it happened with the same board actually, an 11"x47" stick of hard maple. It does have a slight cup, very slight. I have not checked my head pressure recently. I will look to see how to check the head for level and check that. I patched one of them temporarily with some duct tape on the tear... not a good idea I know but it will get me by till new ones show up hopefully. I tend to cut wider stuff, 5" is about the smallest I do. Thanks for the advise, I will check it out.

By the way, back to the original problem, I pulled the flex cable, removed the top hat, wiped some gunk off the top bearing and put it back together. No noise after that. Who knows!

[mtylerfl]

Ok - glad the flexshaft has gotten quieter now.

Maple is heavy...but a board that size is still well within the machine weight limit of 20lbs. The first thing is to check the head pressure and make sure the head is level. You need to also provide additional outfeed support for that board. I just use a couple of the standard roller stands at each side of the machine when cutting boards close to four feet long. I have actually cut longer boards with no extra outfeed support in the past, but those were pine (much lighter than your hard maple board) and I think I got "lucky".

I know you will need to provide the extra support for sure. It's a little tricky to place the roller stands at a height that is "perfect" - - gravity can pull a longer/heavier board down by quite a bit (1/8" or more) when one end is sticking far out of the machine. The board can "bump" the stand instead of roll over the top if they are placed incorrectly. Extra careful time spent on placing the stands at the "just right" position at each side of the machine is well worth it and can help maintain accurate tracking.

The cup of the board...if it is indeed very, very slight, then you 'should' be able to use it. Place the board with the bow/arch "up" so the edges will "turn down" and remain in constant contact with the traction belts. I have tried slightly cupped boards too...sometimes they work...sometimes they don't.

Keep us posted on how you are making out. Hopefully, you'll get some carving done soon!