Orbital Sander: Losing power with pressure.

I’ve got a Bosch corded orbital sander. It’s always been pretty bombproof, but have just been using it and it’s started to lose power when you put downwards pressure on it. Is it on its way out? Or just clogged with gunk? Fixable? Or new sander time?

Ta!

how much downward pressure … it shouldnt be anything more than light pressure.

leaning on it wont get the job done any quicker.

Could be clogged or possibly the brushes on the motor are on the way out. They might be accessible and replaceable. Outside chance its a damaged cable. I’ve had that on bigger motored devices before with similar effects, not sure it would do it in this case but you never know.

Trail Rat, not loads of pressure, but enough to get it stuck in and not spinning over the surface.

Nickjb, thanks. Might just pop it open and see what there is to be seen.

I’ve got one doing exactly the same thing , spins away perfectly normally until you put it down on the workpiece when it seems to just lose its momentum. Metabo rather than Bosch, have bought new brushes for it but haven’t tried them out yet

There is a speed controller in there that should be upping the power as the
load increases – it may be failing/failed – definitely worth a big cleanout
in case its heat related – bit of a pain as parts usually expensive apart from brushes.

I have a Bosch one that does exactly the same. It all works fine then randomly the power drops. It usually comes back up to full power if I just keep using it. I’m not sure what the problem is but I was going to try some new bushes if they are available. Might just buy a new sander though if it’s likely to get expensive trying to fix this one as it’s old and doesn’t owe me anything.

is the bearing spinning free?

I would look at brushes and the bearings.

My (admittedly cheap) one would turn into a palm held angle grinder when the bearing jammed which would make it interesting to use.

Might well be the switch full of crap. My Makita palm sander was doing similar after a mammoth (and filthy) ceiling sanding session. It worked better if I prodded the switch in the right way. Full strip & clean sorted it.

Our Bosch G150 kept doing that. Changed the bushes etc which helped for a bit but ultimately, we got another…

If it’s an induction motor, might be the capacitor has degraded? I had a router with this problem – fine under no load, but couldn’t develop any torque.

Not sure if this is likely as most small motors are brushed single phase.

Well, I’ve had her splayed-open on the worktop.

And she was absolutely choc-a-block in fine white dust. So I’ve cleaned it up as best I can using the hoover, an old paintbrush, compressed air, bit of contact cleaner etc. So gonna leave her to dry out then attempt to put her back together then I’ll report back.

Brushes looked good.

Hey, she’s fixed!

I nearly gave up and binned it out of frustration trying to put it back together. You need three hands and the patience of a saint. It’s hard to say whether it was the dirt that was the problem, or something knocked out of alignment that’s been rectified by my fettling. A clean can’t have hurt though so all good.

WIN

I’d say you’ve earned a beer

I’d say you’re right.