Makita ROS issues?

[graduate_owner]

Hi all,
I have a Makita random orbit sander which takes 150mm sanding disks. I noticed recently that when I apply even very light pressure, the rotation slows almost to a stop. I have not noticed this before and indeed it might have been like that from new. Does anyone have a similar sander, and could tell me if this is 'normal' or is my sander faulty.

Thanks.

K

 

[Bingy man]

I’ve not had this issue but it’s not supposed to stop . Do you have the manual for it . Hopefully it’s just a drive belt rather than a motor issue..maybe post the model number and other members can help you who may have the same model..

 

[ChaiLatte]

What sort (speed, power) of rotation are you expecting?

On a ROS, the disk should be free to rotate in the sense of not being restrained against rotation, but is not actively driven to rotate by the motor. When in use, any rotation you see is passive, a consequence of other active parts of the drivetrain. You could think of it as akin to the front wheel of your bicycle.

The freeness-to-rotate coupled with the oscillation when powered is what produces the random orbital motion. Contrast this with how a traditional orbital (without random) sander works - the traditional 1/3 sheet is constrained against rotation.

If you power it up in mid air, you should see the disk rotate just from vibration but if you grasp it in that position, you can stop it rotating without straining the motor. When switched off, if there is appreciable resistance to rotation, something has gummed up and needs investigating. It is difficult to describe how much resistance is acceptable. The spinning is not free running, like a bike wheel in a bearing. Best thing I can say is go to a shop that has one and feel how a new one rotates.

As above, tell us the model number and go and look at the exploded parts diagram. That wil tell you how the leg bone is connected to the hip bone and show you what part to focus in upon if you determine there is a problem.

 

[graduate_owner]

Hi guys,
the model is BO6030. When I have it running upside down, it spins quite fast. WHen I put some pressure on the disk it slows down and with moderate pressure it stops spinning. (It still vibrates but without actually spinning.)

So I was wondering if it is faulty or behaving as it should.

K

 

[ChaiLatte]

Sounds normal.

Maybe it is just moving really slowly. Put a piece of tape on the pad and the body. Start with the tapes lined up and use it for a bit. See if the tapes are still aligned after a minute's use.

You might be able to understand its motion by putting a 40 grit disk onto it and using on a lightly-painted surface. The shape of the marks on the surface would tell you a lot.

 

[Bumble]

I have the little brother 5030 and there's no way of stopping that, even going over epoxy resin that hasn't fully set (I fell out of the stupid tree and hit the head on *every* branch on the way down).

I just looked at the makita catalogue and see that the 6050 (I guess it will mostly be the same) has two movements; the full orbit and the smaller orbits for full function and the *free* smoother finishing action which has the smaller orbits and the gentle slower full orbit.

Is there a switch other than the variable speed dial on yours (to change between these two modes)? Either way it sounds like malfunction.

 

[ChaiLatte]

I just looked at the Makita catalogue and see that the 6050...

I am not sure you can infer things about the 6030, which the OP actually has, by quoting product specs. from the 6050, which he does not have.

You could download the manual for the 6030 from Makita's site and read it. Then you would not need to do any guessing.

https://www.icmsmakita.eu/CMS/custom/fi/attachments/user_manuals/User_manuals_EU1/BO6030.pdf

 

[donie]

I have the same model, it did have a somewhat similar problem. It was spinning very slow and making a rubbing noise. Normally you should be able to rotate the pad freely with a flick of the finger and it will vibrate in a 3mm circle powered by the motor but you wont be able to do this by hand.

Over the pad there was a black rubber ring which is for dust extraction. It came away from the body of mine and rubbed on the top of the sanding pad. I think it is supposed to be just touching or very close to the sanding pad itself.

What I did was temporarily take out the sanding disc with the allen bolt in the middle and pull out the rubber ring. It spins very freely now and will go very fast if you have it running in mid air. I will get around to putting it back in eventually but found it very tricky to get back in when I did it so I gave up and left it out.

Hope that helps!

 

[graduate_owner]

Hi Donie, and thank you for that. I will certainly try it. I have looked at the online manual but there is no relevant information there. Other online sites suggest a thorough cleaning of caked in sawdust, but I shall try your suggestion first

K

 

[ChaiLatte]

...I have looked at the online manual but there is no relevant information there.

I would respectfully disagree with that assertion.

The parts diagram of the manual will tell you what items are supposed to rotate and what items remain stationary.

See above: if the dust extraction ring is fixed to the non-rotating body, it should therefore not touch the part that rotates or it will impede that function.

The tyre, rim, tube, spokes and hub of your bicycle rotate. If the rim touches the brake blocks, that is undesirable. If the tyre touches the frame, that is also undesirable. If we can understand these things on a bicycle, we can understand them on a sander.

You are not going to find an ABC of 'fix my problem' in the manual, but with some thought, you will narrow down the likely problem. Take a highlighter pen and mark up all those parts which should rotate; in a different colour mark up the parts that should not rotate. Identify the interface on the machine and look at it for clues.

 

[graduate_owner]

The odd thing is, the disk rotates freely by hand when switched off. It rotates rapidly when switched on but with no load. If I put even a small load on the disk then it stops rotating, but continues to vibrate. There does not appear to be a drive belt or similar device that might be slipping under load. Basically I do not understand how the random orbit mechanism works so as to be able to make sense of the problem.

At least I do now know the unit is faulty. The question for me is can I repair it or do I need to replace it. I don't expect a repair by Makits would be an economic option. I bought Makita because I think (used to think anyway) they are a reliable brand, but this has failed after not much DIY use, so I am very disappointed. Had it been a Lidl tool for £20-£30 then I would not have been surprised but this one was about £120, and I was expecting it to have a long life, especially with only DIY use.

K

 

[Jake]

It all depends what you mean by light pressure, it can be pretty easy to stall the full rotation of the pad by pressing down, pad still traces the little orbits but doesn't rotate. But not much pressure is needed, weight of the machine and passive weight of hand/arm should be enough. Would it stall the (full) rotation if operated like that, or do you mean when applying (much?) more pressure than that?

 

[TRITON]

How long have you actually had it for ? as nothing lasts forever.

Faulty is something that happens to new machines, not if youve had it a while and its worked fine before. I would look to the carbon brushes, and maybe look to dismantle it, and give the insides a bit of a hoover. Very fine dust gets everywhere and that includes inside the motor housing.

It's the main reason you shouldnt sand plaster with your good sander, the ultra fine dust gets in and wears out the brushes.