[canman77]

Hi everyone,

(Go easy on me here, I'm a rookie)

I bought a Chinese 3040 machine some time last year and have upgraded it to a fairly decent CNC router. I swapped out the drivers for 6460 drivers from James Newton (massmind.org) and ditched the spindle for a Makita RT0701C router (1.25hp). The machine moves quick and cuts accurately. Lately though, I've noticed bizarre noises coming from the router when making cuts. It doesn't happen all the time, which I find odd:

https://www.youtube.com/watch?v=95VR...m-upload_owner

Here are the specs of the job:

Spindle speed: typically between 3-5 on the speed dial, depending on tool chatter
Feed rate: 1500mm/min
Depth of cut: 2mm
Width of cut: variable...the tool path was programmed in Fusion. I believe the max stepover is something like 4mm.
Tool: 6.35mm downcut spiral bit, solid carbide
Stock: Soft maple. But this happens in every wood I've cut lately...poplar, beech, birch, walnut, and soft maple.

I took the router apart to see if the bearing was the issue. I don't notice anything wrong with the bearing at the top or the bottom of the router. Both seem to spin freely. Not super fast, but there does not appear to be any resistance.

I get this noise at all router speed levels...it gets worse when the speed is slower. So I'm wondering if 1.25hp isn't enough to make a 2mm depth of cut? Or am I trying to cut too fast? Everywhere I read says to basically fly through wood, it's the best thing for your tool. Maybe the router speed needs to be on full (6 on the speed dial)(30kRPM) the whole time?

I tested the router itself by running wood through it manually, and setting it at various depths with Mach3. It's definitely not the machine groaning, it's the router, because I get the same noise when I push wood through it. Generally, anything over 1mm passes gives me noise. I'm not really sure what the issue would be here, so any help would be appreciated!

[RCaffin]

You may have worn bushes (bearings) on the motor. They can make funny noises when they are worn. Lubrication is needed, and a wood environment tends to suck all the lube out.
If the motor has ball races rather than bronze bushes, check to see whether the races can rotate in their sockets. Very bad news if they can.
The thing is, these routers were designed to be used for a few minutes at a time, in manual mode. Putting them in a CNC takes them way out of their comfort zone.

Cheers
Roger

[canman77]

Thanks for the reply Roger! I did forget to mention, when I had the router apart I did lubricate the bearings...both the top and bottom. I didn't really know how much to add, so I just added a ring of oil around the inside and outside race of both bearings.

I forgot to mention as well, this router is only a few months old. It's seen some pretty good use, but probably no more than an hour or two a day, a few days a week.

The outer race does not seem to rotate within its socket. It's tough to check because I can only access the bearing from within the housing. But I am realizing these routers weren't meant for long applications as I do more research. I run this router for maybe 40 minutes at a time, which isn't very long, but still maybe too long for this router.

I'll test again today and see if the lubricant helped with the noise during a cut. It would appear my options are to either disassemble the router every month or so and lubricate it, or buy a Harbor Freight router with a lifetime warranty and run it into the ground and have it replaced when it tanks.

[RCaffin]

Mind you, it is also quite possible the noise is coming from somewhere else - something resonating maybe. It can be very hard to tell whether it is the motor or an adjacent bit of framework rattling or ringing.

Um - is there any end-float on the spindle?

Cheers
Roger

[CNCMAN172]

Routers used for long periods can have the bearings go bad. I used a router for years on my cnc machine and lost the bearings at least three times. Then I purchased a spindle and it has been running for more than 10 years. Spindles are designed for running long periods of time and have much larger bearings. A hand router is typically used for 30 minutes at a time and does great at the task it was designed.

Russ

[canman77]

Routers used for long periods can have the bearings go bad. I used a router for years on my cnc machine and lost the bearings at least three times. Then I purchased a spindle and it has been running for more than 10 years. Spindles are designed for running long periods of time and have much larger bearings. A hand router is typically used for 30 minutes at a time and does great at the task it was designed.

Russ

Unfortunately, I don't have the electrical capability to run a spindle and all the proper CNC equipment and won't for the foreseeable future. So I think I'll try to keep my jobs to less than 30 mins. I'd just expect the bearings to last a little longer than a few months on a new router!

Mind you, it is also quite possible the noise is coming from somewhere else - something resonating maybe. It can be very hard to tell whether it is the motor or an adjacent bit of framework rattling or ringing.

Um - is there any end-float on the spindle?

Cheers
Roger

Does end float mean the same thing as runout? If so, the runout is minimal in the router. I've also tested the router sitting stationary on the machine and manually pushed wood through and got the same groaning noise, so I think I've eliminated other options. Maybe..?

[RCaffin]

Does end float mean the same thing as runout?
No.
Runout could be said to be a sloppiness in the XY plane - at right angles to the cutter.
End-float is looseness along the Z axis. This is very different. You can have bad end-float and zero runout.

When a bearing is placed into a housing or 'socket', it can sit there with no sideways rattle. But what keeps the bearing in the socket, or keeps the shaft securely located in the inner race of the bearing? There are two ways of handling this. On a 'real' spindle you find that the bearings are locked in place, with shoulders, nuts and probably with shims. A commercial spindle will have this. But on something like a router you may find that there is a flat spring at one end which has to provide all the security against end-float, or movement along the axis of the cutter. When you are running something like a pump, such a spring is fine. The rotor will probably centre itself anyhow. But when you are plunging a router into timber, it is that poor spring which has to take the load. Sometimes the spring survives, sometimes it does not.

I am not saying your router has end-float. It might have, it might not. But it is worth checking.

Cheers
Roger

[canman77]

Thanks for all this information Roger, as you can tell, I'm very poorly versed in router mechanics.

That said, when I had the router apart, I don't remember seeing any springs. I believe the armature is attached to the piece where the collet threads on. The lower bearing isn't attached to the armature at all. It sits inside the outer casing, and nothing holds it in place except the force of the aluminum seat. I don't know exactly how snug it is, but it doesn't look like the bearing is going anywhere. Similarly, it looks like brute force holds the shaft inside the inner race. I can't say with certainty. Here's the parts diagram of the router:

Makita RT0701C Parts List and Diagram : eReplacementParts.com

I don't see any kind of spring, but I'm not really sure what I'm looking for here. So I suppose I could have some pretty severe end float...but how do I measure it?

[RCaffin]

Hi Canman

I am not saying you HAVE end-float, just that it is ONE possibility.
There are two springs, or rather wave washers, on the spindle: parts 20 and 27.

You can check end-float by pushing the cutter in and pulling it out. If anything moves more than a few thou', explore further.

Cheers
Roger

[canman77]

Ah, OK so the wave washers are what keep the bearings in place. Interesting, didn't know that. I'll test for end float tomorrow morning and see if I can get anything measurable. I suppose the best way to avoid issues with end float is to helix into the pocket cut?

Regardless, I'll report back tomorrow if I have end float. I didn't get a chance to cut anything today because the computer went nuts but we seemed to have resolved the issue so I'll test tomorrow for more noise. I'm hoping the lubricant solved the issue.

[RCaffin]

I'm hoping the lubricant solved the issue.
On the computer????
Lubricate the electrons - makes them go faster.

Cheers
Roger
PS: I make bad jokes.

[canman77]

I'm hoping the lubricant solved the issue.
On the computer????
Lubricate the electrons - makes them go faster.

Cheers
Roger
PS: I make bad jokes.

I thought everyone fixed their computer problems with oil??

Haha. We'll see how the oil does with the router...and maybe the computer. Stay tuned, should have a result in a couple of hours. Still too early here to start cutting things. Neighbors are a little sensitive.

[canman77]

Well, the oil didn't help. Maybe I used the wrong stuff, or maybe this router isn't meant to make passes deeper than 1mm. Either way, I'm at a loss. I'd expect the next suggestion would be "buy a different spindle/router"...

I also noticed, the aluminum casing down by the bearing gets really hot. I touched the tool after it was done cutting, and it was warm but not hot. Something isn't right here...I get the feeling the bearing shouldn't heat up the casing like that.

[RCaffin]

I thought everyone fixed their computer problems with oil??
Don't laugh - I have done that a couple of times!
Dry bearings in the cooling fans ... one time it was clear that no oil had ever been added at the factory. Faulty batch of large fans.

Cheers
Roger

[RCaffin]

I also noticed, the aluminum casing down by the bearing gets really hot. I touched the tool after it was done cutting, and it was warm but not hot. Something isn't right here...I get the feeling the bearing shouldn't heat up the casing like that.

You are not wrong!
That bearing must be getting very damn hot inside if the case is getting hot. Yes, it certainly needs replacing - or you could try claiming on the warranty if there is one still. I would suspect that the bearing was never lubricated. I have seen that before.

If you want to replace the bearing, you can either buy a replacement one from the mfr OR find the bearing number off the bearing itself and buy a replacement unit. It won't be a 'special'.

Cheers
Roger

[canman77]

I'm not really sure what the warranty is on these routers, but I'll be contacting Makita regardless. Especially since I really haven't put that many hours on it, and it has been getting hot at the base of the casing by the bearing almost since the beginning. Others I have talked to said their Makita runs cool to the touch.

So the question now is, continue with Makita and try to get a replacement from them, or go with a different palm router? After seeing the inside of the casing and the nightmare it will be to remove that sucker, I'm not inclined to try that on my own. I don't mind doing a lot of stuff myself, but that just looks miserable.

Thanks for all the help Roger, I'm learning quite a bit here!

[RCaffin]

Makita seems to be a reasonable company. I have some tools by them. Definitely try them first.

Cheers
Roger

[canman77]

Will do. Looks like I may have missed the boat to call them today, maybe tomorrow if they have customer service reps working weekends. Even if they do replace it, I might have to give the Bosch Colt a try...everyone raves about that thing. Might be what I need to cut down of job time. If I could even go from 2mm passes to 4mm passes (people are claiming 60ipm, 1/4" passes with the colt) that would be huge.