Sanders gone bust

[Dokkodo]

My metabo orbital has become feeble, runs fine with no load but loses all power when you place it down onto any work piece, unless you put it into 'turbo' and then it runs intermittently.

I read around a bit and replaced the electronic control unit, the bit with the power dial. No better, bit annoying as it took ages to come and wasnt cheap.

Any other electronic whizzes around with another suggestion? You can get all the spare parts and im handy enough with a soldering iron, I just dont know what else might be faulty and whether its worth it to keep trying.

heres a parts list to entice anyone interested... https://www.mtmc.co.uk/product.aspx?ProductID=102590&source=googlebase&gclid=EAIaIQobChMI3LDoyfiK2gIV75XtCh3fqAPNEAQYASABEgLG8vD_BwE

 

[novocaine]

I assume what you mean is it spins like billio when not on the surface then slows right down but is still running when it hits the surface.

if so, the bearing in the plate is dead, most likely full of sawdust and locked solid.

replace the bearing.

 

[Ram64]

I had the very same problem with a Bosch orbital sander, and as was said by Novocaine it was indeed the bearing behind the sanding plate. Replacement was easy to find and install and good as new after.

 

[Dokkodo]

ok thanks guys i will take a look at said plate.

(

I assume what you mean is it spins like billio when not on the surface then slows right down but is still running when it hits the surface.

i had already taken it apart and blown the insides clean but I may have missed this bit. when it hits the surface the pad has barely more than a feeble wobble to give, dont know if id call it 'still running', but you can hear the motor straining.)

 

[novocaine]

I stand by it then. dead bearing. it's an off centre cam that the bearing rides on, when it gets stuck (it doesn't have to be seized solid, mine has been freed off a few times now and needs replacing as it's not quite right anymore) the motor starts trying to spin the entire pad rather than spinning inside it to make it wobble.

 

[Dokkodo]

Novocaine, you were right, thanks

A frustrating half an hour to find it out though. Put an awl about half an inch into the ball of my thumb trying to get one of the sprung washers out, ouch (hammer)

and the replacement is 50 quid, double ouch

 

[novocaine]

50 quid for a thumb, feck me.
measure the bearing, go to bearing supplier (I like simplybearings online, but they are local to me too), be about a tenner. it's a jelly bean part. if your having trouble getting what you need, take some pictures so we can tell you what it is but it should have a number on the seal that will help.

 

[Dokkodo]

Aha, I have bought bearings before and wondered whether these would be standard, but its some sort of doubled up arrangement that looks special, tried to get them apart but I had lost the will by this point and went for surrender instead. Ill take some pictures, be great if you could let me know. thanks again!

 

[Dokkodo]

Sorry to dredge this back up by ive finally got around to getting a couple of pictures of the offending bearing(s), and it looks to me like bad news... they appear to be stamped onto a sort of arbor arrangement, so the only ways to go would be release them and replace but im not sure how to re-fix them, or pay through the nose for an original metabo part.

Any words of encouragement either way would be gratefully received

 

[sunnybob]

The numbers are the bearing description. You can get them any where. The arbor is a press fit into the bearing.
You can whack it out with a drift, supporting the sides of the bearing on the sides of a vice, opened up just enough for the arbor to fall through.

When replacing, put the arbor into a deep freeze overnight, and get evrything prepared before you tke the shrunken piece out of the freezer.

 

[Mike Jordan]

My 450 duo went all wimpish and produced a lot of sparks at the commutator. A new pair of brushes returned it to health.

 

[Dokkodo]

Brilliant thanks sunnybob!

And also you Mike, i'd already tried the brush es though, and the electronic control unit, at great expense...

 

[Dokkodo]

I been beat :|

To put this to bed for anyone researching in the future: At the time of posting, the required 32x12x7 sealed bearings can only be ordered in especially from european wholesalers (CWbearings) at a cost that is ≥ the cost of the Metabo spare part.

The alternative is to investigate cleaning out the existing bearings.

 

[sunnybob]

https://simplybearings.co.uk/shop/advan ... rrency=EUR

 

[AES]

Agree with BOTH sunnybob's posts. Makita (or whoever it is) do NOT make their own bearings!

Using those numbers stamped on the "lid" of the bearing (it's a dust cover BTW) search the websites of BB manufacturers like SKF ("Skefco") who will list distributors near you. It's 99 quid to a pinch of "nothing very nice" that this is a standard bearing and NOT something made specially by the BB manufacturer to a spec issued by whoever made your sander.

See the posts about "costs of spares in the UK" here in this Forum - naturally the sander manufacturer will direct you to his own stocks, or to a BB manufacturer who's holding stocks on the sander manufacturer's behalf.

 

[Dokkodo]

https://simplybearings.co.uk/shop/advanced_search_result.php?search_in_description=0&sort=2a&search_3fields=1&keywords1=12&keywords2=32&keywords3=7&keywords=12x32x7%2012x7x32%2032x12x7%2032x7x12%207x32x12%207x12x32%20&currency=EUR

I found that page as well, but as far as i can tell that's just an oil seal.

i appreciate your advice AES but I have searched fairly thoroughly through the main online retailers revealed by google and the only sources I got to were two international industrial distributors for around 20 pounds a piece with shipping

perhaps more interestingly i have had temporary success cleaning and re-lubing my existing bearings anyway, will just have to see how temporary...

 

[sunnybob]

scroll down the page. the bearings are something like 7 quid.

Dont expect your relubed bearings to last very long. if the bearing is full of dust all youve done is make that dust slippery. With the heat of the shaft running the oil will dry out pretty quick and then the dust will clog even harder because the dust is now sticky.

 

[ED65]

if the bearing is full of dust all youve done is make that dust slippery. With the heat of the shaft running the oil will dry out pretty quick and then the dust will clog even harder because the dust is now sticky.

That's the voice of experience I expect Bob, out of curiosity can you clean out a bearing like this with some degree of success? For example I wonder if you soak in spirits, petrol, kerosene or whatever for a while, brush or blow out, rinse and repeat a couple of times whether you'd get the thing reasonably clean eventually, enough that it would run all right once relubed?

 

[sunnybob]

All things are possible, it just depends whether its viable.
The oil seals have to be removed, and they will almost certainly be damaged, so straight away youre into new seals (which can be as much as a third of the total cost of new). then using strong dissolving stuff like white spirit or even acetone you could do repeated soakings, compressed air drying, bearing rotating to shift all the crud actually stuck under each and every ball. That might take you a half day per bearing.

And even then, the heat friction of the bearing being forced to turn at high speeds right up till you finally decide there is a problem could have heated the balls up to annealed temps.

How much is your time worth when a new bearing costs a so little? The new good quality Japanese bearings for my bandsaw wheel cost 3 euros each and a 20 minute each way drive to the shop.

Recovering old bearings to usable condition is the kind of job for when youre the last person on the planet and you cant actually obtain any more. Of course I'm excepting the person who just WILL NOT be beat and WILL spend a year rebuilding a machine that has 3 weeks wages value (G)

 

[ED65]

Invaluable details Bob, those are the kinds of things I wanted to know about to see if it was potentially worth it. TVM.