How to Restore Small Cordless Screwdriver? - Page 1
Forum section: electronics / repair

author: Boris_yo
author_rank: Frequent Contributor
timestamp: November 21, 2021, 02:22:22 pm
content: Hello,Wanted to use my Black & Decker that I haven't used for many years.It has been collecting dust in my toolbox majority of last decade and when I took it out, pressing buttons didn't start it. I noticed liquid leaking out of screwdriver's head. Disassembled and saw everything inside is in that liquid. Upon closer inspection and based on smell it reminds grease. I saw gunk in some spots seemed to have formed (as a result of grease drying out?).I don't think grease should be leaking but if it does, it means time to clean it and replace with a new grease? Everything is in grease inside screwdriver's head with 6 cogs. I only have sewing machine oil so would that do and how should I clean out old grease? Alcohol or hand soap?

author: coromonadalix
author_rank: Super Contributor
timestamp: November 21, 2021, 02:32:03 pm
content: Just clean the grease an re-apply a more recent one, the grease components have separated over time, happened to me in the past ... if the batteries haven't leaked (photo seems fine)Just redo lubrification in the gear sectionsJust wipe a maximum of it with a cloth and or Q-tips/ connton swabs, a solvent (break cleaner or else) may break the triangle shaped plastic holder, hoping it did not get brittle over the years...

author: Boris_yo
author_rank: Frequent Contributor
timestamp: November 21, 2021, 02:43:03 pm
content: Quote from: coromonadalix on November 21, 2021, 02:32:03 pmI don't have grease. I have sewing machine oil... Good/bad?Do you know what is this disc for?

author: Runco990
author_rank: Frequent Contributor
timestamp: November 21, 2021, 04:35:52 pm
content: NO! Get a small tube of grease!Sewing machine oil is much too thin and would just run out.Next time you change the oil in your car and have none, just use sewing machine oil and post back the results.

author: Nusa
author_rank: Super Contributor
timestamp: November 21, 2021, 06:57:21 pm
content: The metal washer is a smooth sturdy wear surface as the gears turn, with a secondary function of helping keep the grease in. If you left it out, the red plastic would soon get destroyed as you operated the screwdriver.Oil separating from grease is normal over time and gets mixed back in when the tool gets used. Normally it isn't a leaky problem unless you don't use the tool for many years or you keep it in a very hot place (e.g. toolbox in desert sun). Your options here are to replace the grease, or to put it back together and just wipe up what's leaked. What's left is probably good enough for a lightly used tool. That exact model is still sold for about $11 USD at my local hardware store.That's assuming you fix the electrical side of the screwdriver. If you don't do that, greasing the gearhead doesn't matter.

author: GLouie
author_rank: Regular Contributor
timestamp: November 21, 2021, 07:11:25 pm
content: Describe the failure please:Did it make a noise, but not move? Forward and reverse? Does the motor turn when the gear head is removed?As mentioned in your other thread, these are electrically simple and easy to test. If the grease is at all pasty, it is unlikely to be any problem.If your screwdrive has a collet lock (to prevent the bit from turning when used without power), they can mechanically jam. Sometimes a little force to the bit back and forth will release the lock. You might have to look inside the gear head, usually very near the front.

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 22, 2021, 01:48:37 am
content: Before going any further, check if the motor runs with the gearbox removed. Make sure that works before cleaning it out. Wipe off the old grease with paper towels and use lithium grease as the replacement.A common failure mode is the contacts oxidizing. Use contact cleaner to clean them, then apply a thin layer of dielectric grease to prevent them from oxidizing again.

author: Boris_yo
author_rank: Frequent Contributor
timestamp: November 22, 2021, 12:40:44 pm
content: Quote from: GLouie on November 21, 2021, 07:11:25 pmIt has function that you described when I turn gearhead on manual. It locks in place so I can apply manual force to release stuck screws or tighten screws. Is this like collet?

author: Boris_yo
author_rank: Frequent Contributor
timestamp: November 22, 2021, 12:44:20 pm
content: Quote from: NiHaoMike on November 22, 2021, 01:48:37 amI have managed to start the motor. I shook screwdriver a little and moved gearhead back and forth.Is there home-made equivalent to dielectric grease or close to it?Can I use that for cleaning corroded battery contacts? I used to use finest grit sandpaper on contacts...

author: Zero999
author_rank: Super Contributor
timestamp: November 22, 2021, 12:54:17 pm
content: Note: do not get grease anywhere near the motor's brushes and commutator. It will burn and cause them to wear out very quickly. The brushes and commutator will be designed to be self-lubricating.

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 23, 2021, 02:26:00 am
content: Quote from: Boris_yo on November 22, 2021, 12:44:20 pmIt should be readily available at a local auto parts store. Basically a special kind of silicone grease designed specifically to protect electrical contacts from moisture and oxidation while not interfering with the electrical connection. Might be sold as "spark plug grease" or "bulb grease". There's also "battery terminal grease" but I think that's designed to neutralize leaked acid and isn't the best choice for general electrical connections.While you're there, they should also have the lithium grease.

author: GLouie
author_rank: Regular Contributor
timestamp: November 24, 2021, 05:55:48 am
content: Quote from: Boris_yo on November 22, 2021, 12:40:44 pmYes, this is a collet lock. As NiHaoMike says, make sure the motor runs without the gearbox, and gearbox moves freely. Then there is nothing more to check, it is a simple mechanism, although I am always amazed at the planetary gearing.

author: Boris_yo
author_rank: Frequent Contributor
timestamp: November 28, 2021, 08:09:07 am
content: The screwdriver works now except I have problem with reverse button:https://streamable.com/gd7qoc

author: AndyC_772
author_rank: Super Contributor
timestamp: November 28, 2021, 09:10:57 am
content: Normally I'd be 100% in favour of repairing and restoring an old tool, but in this case I think I'd make an exception.I used to have a very similar B&D, but it too lived unused in a tool box for many years because it was - frankly - rubbish. It would strain and then stop with any screw that needed reasonable force to set it fully, and then the bit would cam out and damage the screw as I tried to apply the last few turns by hand.If you have a job that uses more than a few screws, do yourself a big favour and treat yourself to a proper impact driver. It'll absolutely transform your idea about how hard it is to take screws in and out; it'll be way faster and more powerful than a little B&D, and greatly reduces cam-out during those last few turns when the torque really increases.It does take a little time to get used to the power, but you can control it with the variable speed trigger. Practice for a while and you'll have a superbly versatile tool that makes you wonder why you put up with a toy screwdriver for so long.Mine is a DeWalt DCF887, other cordless tools are available.

author: Aqualuv
author_rank: Newbie
timestamp: April 25, 2023, 04:32:31 pm
content: My cordless screwdriver gearhead had dried grease inside. It looks similar to the images displayed in this post. Mine has 3 wafers with 3 gears on each and 6 pins or bearings. I did not see how the pins or bearings fit in the gearhead. How to assemble the pins?

author: coppercone2
author_rank: Super Contributor
timestamp: April 26, 2023, 12:57:55 am
content: that screw driver has a clever arrangement of metal plates inside for the switching logic, there is probobly a bad contact perhaps full of drained grease

author: Boris_yo
author_rank: Frequent Contributor
timestamp: April 28, 2023, 07:42:09 am
content: Quote from: coppercone2 on April 26, 2023, 12:57:55 amDoes mine on the photo have 1 wafer with 3 gears?