Vintage B&D Drill broken

Discussion in 'Tool Talk' started by paulhs, Jan 21, 2020.

  1. paulhs

    paulhs New Member

    I inherited a B&D DNJ72V when my dad died in 1988.

    It's a 2 speed (900rpm and 2400rpm) and has a variable speed trigger.

    It stopped working last week, so I dismantled it today assuming that the mains lead was the problem as the outer cable had split. I tested the cable with a multimeter; both Live and Neutral gave a reading on the Ohms scale, so I assume it's not the lead after all.

    I took the cover off the brushes/armature section. Still plenty of length on the brushes, so I cleaned the armature with contact cleaner and a fine pencil type abrasive brush. Put it all back together but no luck.

    Here's some pictures;


    Armature section but not enough light for a clear view

    Shall I forget it?

    I have use of my partner's single speed hammer drill but it's no good for the slower speeds required for drilling metal.

    Also, does anyone know what speed wire brush power tool accessories are best used at? I have some de-rusting to do on my car.
  2. KIAB

    KIAB Super Member

    High speed.

    Try another,just to rule out orginal lead being faulty, might also be switch,easy to bypass that to test it.
    rogerk101 likes this.
  3. sparko69

    sparko69 Active Member

    Please do not attempt to replace the cable and definitely do not bypass the switch. It's scary that someone is advising you to mess around with an electric drill that has got metal that can be touched. It can't be safely used so just keep it as a memento
    masterdiy likes this.
  4. Severntrent

    Severntrent Screwfix Select

    Yes you have been lucky for 30 years plus the years your dad had it
    Astramax likes this.
  5. Astramax

    Astramax Super Member

    Time to move on and purchase an up to date combi drill. :)
    PS, I had exactly the same B&D drill as yours bought it circa 1976, same problem, replaced the mains cable about 20 years ago, still have the drill............................somewhere!
    sparky steve likes this.
  6. sparky steve

    sparky steve Screwfix Select

    5F89D296-4893-4D63-B650-EDB853540027.jpeg Mine not same model, however B&D also purchased in 1976 & it still works:D do not use it tho, just a keepsake:)
    Astramax likes this.
  7. rogerk101

    rogerk101 Screwfix Select

    I'm not a fan of B&D products, but I am a huge fan of repairing and recycling.
    I have had to replace numerous flexible cords on power tools over the years, and I'm still alive, so I don't understand the fear that some are trying to instill in you about simple repairs.
    If you were compromising the earthing or doing something that could risk electrocution in use, I would agree that you shouldn't do it, but come on, how dangerous can it be to change a flexible power cord? Just make sure your connections are nice and secure, i.e. screwed tightly, as there is quite a bit of vibration in most power tools.
    ramseyman and Astramax like this.
  8. Astramax

    Astramax Super Member

    Black and Decker were a huge empire back in the 70s prior to today's go to brands.....alas a different time! :(
  9. ramseyman

    ramseyman Screwfix Select

    Still use mine on a drill stand, put a new bearing in last year that's all.
  10. Bob Rathbone

    Bob Rathbone Screwfix Select

    Ok, this is a bodge and I am going to get flack for suggesting it. The switch is a double pole switch, ie it switches both phase and neutral. If you check the switch for continuity you will find one pole is open circuit. Now, you could dismantle the switch and try to fix the problem, or you could just use the switch as a single pole switch, in the phase conductor. This is not ideal by any means, but the case of the drill is plastic, it's double insulated and I do not recall any where that double pole switching is a requirement on 240v (it is on 110) power tools. I am open to correction on this if others know better. However, you are changing the drill from the makers original spec. Take great care and only do this if you are competent.
    paulhs likes this.
  11. DIYDave.

    DIYDave. Screwfix Select

    It’s a process of elimination and fault finding to determine what exactly has failed

    Sounds like you’ve only tested the lead ? Have you checked continuity along both live and neutral cores ?

    Can do this safely with no mains voltage by using a multi meter

    So check lead

    Check you’ve got continuity running through the switch

    Check at brushes and commutator

    Could be failed motor windings. Insulation usually breaks down, results in lack of power and eventual death !

    What have you checked so far and how

    Understand there’s some sentimentality attached to this drill so I agree, it’s worth investing some time in a possible repair. So what, you loose a couple of hours and drill still doesn’t work ..... don’t matter. It’s your own time so what -

    Work safely by testing with multimeter

    As ever, loads of videos on YouTube so you can check out motor windings/armature

    Good luck
    paulhs likes this.
  12. plumbr1

    plumbr1 New Member

    I'm with you on this , only thing I'd point out is that the op will most likely find that it's the live side of the dp switch that's gone open circuit so it will be necessary to switch over the input wires at the bottom of the switch and likewise output wires at the top of the switch so that the remaining "good half" is now switching the live phase and need to piggy back the neutral into the top rather than simply switch the neutral phase. Although tbh as you say this is a double insulated device and youd have to start poking small screwdrivers through the ventilation slots with it plugged in to give yourself a jolt.
    Last edited: Jul 14, 2021
  13. quasar9

    quasar9 Screwfix Select

    Still around , only now, their main tool brand is DeWalt ! Black and Decker bought Dewalt out in 1960 and bought out Stanley too. In 1980, the CE lead by Honda’s example of creating an upmarket brand Accura, resurrected Dewalt. By 2000, B&D brand was getting increasingly shoddy but I believe they are still around in some markets !

    Had they played it properly, last years Dewalts would be given a new orange and black shell, smaller battery and an electronically throttled down motor but at a lower price aimed at the DIY market !

    I still have my 1978 all metal two speed drill in blue ! No soft start or speed control it’s still good for rough work, but my 1998 battery model is a non working museum piece !
    Last edited: Jul 15, 2021
  14. FlyByNight

    FlyByNight Well-Known Member

    Don't forget that B&D also purchased ELU in around 1984. ELU being one of the premier brands of high quality woodworking machinery.
  15. BillyBobToo

    BillyBobToo Active Member

    Still got an ELU circular saw somewhere.....
  16. Mick Tilson

    Mick Tilson New Member

    Reminds me of the time I used my father in law's antique drill with a sticky switch, drill jammed and I almost spun around like gromit!

    Bin it or frame it.

    Attached Files:

  17. CGN

    CGN Screwfix Select

    They’re like using a blunt saw until someone hands you a new one. Did the job back in the day and still have my grandads one somewhere, but even a cheapy sds will pee over them.
    pppmacca43 likes this.
  18. spirits are real 2016

    spirits are real 2016 Screwfix Select

    Have you changed the plug had someone say their old drill wasn't working so i put a new plug on and it jumped back into life..
  19. spirits are real 2016

    spirits are real 2016 Screwfix Select

    If you dont get any luck send it to the army.

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