Toolbag Tales-Homemade and improvised tools

[NewcastleFalcon]

I think my black and decker of many years standing has finally thrown in the towel. Maybe not maybe just needs new brushes, but new brushes from B&D may well be more expensive than a new drill from LIDL. The brushes area is certainly where the popping and the lights show is coming from.

For the time being this has made a return to use after laying unloved and unused for some time.

Neil

[MattBLancs]

If it's been in use a long time, have you had the brushes out and see if they are just down to stumps?

I'd put the drill number in to eBay, being a household name I wouldn't be surprised if someone is knocking out equivalents

[NewcastleFalcon]

If it's been in use a long time, have you had the brushes out and see if they are just down to stumps?

I'd put the drill number in to eBay, being a household name I wouldn't be surprised if someone is knocking out equivalents

Here's the brushes....bit lopsided in their wear, but will new ones revive the drill? Not much money if equivalents can be found.

Neil

[myglaren]

We had a washing machine, a Hotpoint I think, that used to eat brushes. I went to the local washing machine repair shop and the bloke there said to buy Fiat alternator (I think) brushes that were far cheaper, just needed cutting down a bit.

[MattBLancs]

Well they do look pretty worn! Normal seems like the spring is near coil bound with new brushes so would think they are 2/3 to 3/4 gone.

I'd measure the dimensions - cross section easy, length is obviously a best guess - as as myglaren says, can cut down over long replacements if needed. If can find some say less £5 then worth a gamble. Obviously a good clean up of the commutator as is very tarnished at present. Wet and dry, pretty fine grade for that.


It is worth noting that the fireworks could be one set of windings has gone short circuit though, it is likely game over if so.

Might be able to test this with a multimeter on resistance setting, put quite laborious given so many windings to check.

If it were me (and bear in mind am a cheapskate/keen in recycling!) I'd try the following in order:
Measure brush dimensions.

Check brushes slide freely up and down their guides (can be jammed with carbon muck - need to slide freely to make good contact)
Clean up the commutator with wet and dry

Try that and see if any better. If massive improvement then keep using the drill (and research brushes as lower priority task / forget about it until it conked out again)

If no better either price up brushes of suitable dimensions - if nothing cheap available then days are numbered for that drill as the brushes are pretty much gone.
If cheap then either first try the multimeter check of windings or else cross fingers and just try a new set of brushes and see what happens.


Or more sensible option is probably head down to Aldi or Lidl and £10-£20 on a brand one with a 3 year warranty

[NewcastleFalcon]

Well they do look pretty worn! Normal seems like the spring is near coil bound with new brushes so would think they are 2/3 to 3/4 gone.

I'd measure the dimensions - cross section easy, length is obviously a best guess - as as myglaren says, can cut down over long replacements if needed. If can find some say less £5 then worth a gamble. Obviously a good clean up of the commutator as is very tarnished at present. Wet and dry, pretty fine grade for that.


It is worth noting that the fireworks could be one set of windings has gone short circuit though, it is likely game over if so.

Might be able to test this with a multimeter on resistance setting, put quite laborious given so many windings to check.

If it were me (and bear in mind am a cheapskate/keen in recycling!) I'd try the following in order:
Measure brush dimensions.

Check brushes slide freely up and down their guides (can be jammed with carbon muck - need to slide freely to make good contact)
Clean up the commutator with wet and dry

Try that and see if any better. If massive improvement then keep using the drill (and research brushes as lower priority task / forget about it until it conked out again)

If no better either price up brushes of suitable dimensions - if nothing cheap available then days are numbered for that drill as the brushes are pretty much gone.
If cheap then either first try the multimeter check of windings or else cross fingers and just try a new set of brushes and see what happens.


Or more sensible option is probably head down to Aldi or Lidl and £10-£20 on a brand one with a 3 year warranty

Thanks Matt, a comprehensive and totally spot on strategy The shorter of the brushes is probably at the virtually useless stage.

Neil

[NewcastleFalcon]

The clean up and rebuild using the same brushes had no effect specific fireworks at the brushes and a rapidly depositing layer of carbon on the commutator. Motor span to start with.

Did check the commutator with the multimeter, every "finger" showed continuity with every other finger without exception.

Wasn't as thorough as this didn't measure just put the meter on "beep" continuity test.



I think the problem is the brushes, the Drill ref is KR550RE dimensions 6.3x6.3x11mm

As expected the B&D branded price for such a pathetic little item is £12.99 Each! If this UK seller is representative.

https://www.ebay.co.uk/itm/132984245277 ... R67uu9LnYg

Neil

[MattBLancs]

A quick trawl:

https://www.ebay.co.uk/itm/125364741626
£3.99 free p&p

[NewcastleFalcon]

A quick trawl:

https://www.ebay.co.uk/itm/125364741626
£3.99 free p&p

Thanks Matt...closest from that seller 12mmx6.3x6 more expensive than the landing page selection.

Neil

[Rp0thejester]

I love brushes, they used to give me an early work day especially on a Friday!! They make excellent markers and if you heat the spring up enough they contract so no contact with the armature, sorry bud, I'll be back Monday!

[MattBLancs]

Too big one dimension (file them down) but bit under the other:
https://www.ebay.co.uk/itm/382850335176?
20x7x6mm £4.10/pair, £4.96 for 4.

Exact width and height:
https://tdspares.co.uk/product/black-de ... m-x-63mm-x
6.3x6.3x13mm £4.99/pair + £2.99 p&p

Another size match:
https://www.ebay.co.uk/itm/142595199519?
£6.95 free p&p

Winner so far, size match:
https://www.ebay.co.uk/itm/182084079682?
£4.99 / pair free p&p

[MattBLancs]

https://www.ezee-fix.co.uk/shop/carbon- ... blck-deck/
£1.88 / pair, £2.48 delivery

A late entry takes the "cheapest size match spot" there!

[NewcastleFalcon]

https://www.ezee-fix.co.uk/shop/carbon- ... blck-deck/
£1.88 / pair, £2.48 delivery

A late entry takes the "cheapest size match spot" there!

Many thanks for all the the searches Matt. I will have to give one of them a go at those prices, and see if I can resurrect the old Black and Decker. It has been getting quite a lot of use recently so it would be nice to have it back working.

Neil

[NewcastleFalcon]

Winner so far, size match:
https://www.ebay.co.uk/itm/182084079682?
£4.99 / pair free p&p

and they are the ones I have sent for today. Thanks again Matt.

Neil

[thorter]

Regarding multimeter testing on commutators, with the usual armature winding system, the windings go from segment to segment. So across any diameter, there are two current paths, round one side and round the other, each through a series chain of half the windings. Obviously they get switched around as the motor rotates, but the pattern stays the same unless there is a fault.

What you need to test is the resistance between adjacent commutator segments, going round all the way in turn. When you come to a much higher value, you have found where there is a break. Occasionally this can be fixed if due to a bad crimp or other dry joint. The meter needs to be on a low range showing some resistance value (ie not zero). The segment to segment values will vary a bit, but should be within 20% of each other. A very low or zero value indicates shorted turns, or rarely, a shorted commutator which there may be a chance of fixing providing it is not due to disintegration. Forget fixing shorted turns though.

Field windings are in series, and in a universal motor also in series with the armature. Shorted turns in a field winding lead to overheating because the back EMFs in the two sides of the armature do not balance, and there is thus a large parasitic circulating current.