Need assistance in changing the chuck on a battery drill

Trying to put a new chuck on a Makita 8391D 18 V combi drill and cannot get the locking screw in the middle undone. Supposed to be a left hand thread. I've tried normal screwdriver, T-handle driver, hex bit in a small ratchet wrench and the 18 V Makita impact driver that came with the drill. Contemplating cutting the chuck apart for better access and, if necessary drilling the screw head off. Making a replacement screw won't be hard.

Before I get destructively drastic has anyone any suggestions. Be unsurprised to discover I've missed something blindingly obvious.

Power Tool Centre ltd of Liverpool **LINK** did me an excellent deal. Change from £90 for two 18V batteries and a chuck including delivery, all genuine Makita factory parts.

Thanks.

Clive

You sure it's a left hand thread, is it in the manual?, mains and battery ones, though not Makita, I've done in the past have always been normal right hand. Stands to reason they should be right hand as the majority of time the drill is being used forward not reverse.

Not taken a Makita chuck off in years but all the cheap ones I have removed lately the locking screw has been left hand and the chuck right hand thread so they lock together.

Might have some thread locking compound on it perhaps?

Paul

There are several videos showing how to do it on youtube.

My old 18v nicd Makita is left hand thread BUT I could not remove the chuck even when it was out.

I know that sound daft and several people told me so and took it off me to try. No one can remove the chuck!

I'd love to know if there's a trick I've missed of if anyone else has had this problem.

Maybe this will help?

**LINK**

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Edited By herbert punter on 02/12/2014 07:05:46

I and others tried all this but to no avail. It's history now as I car-booted it, with the new chuck, and told the buyer the problem which he was confident he'd crack. I wished him luck

Edited By Roger Provins 2 on 02/12/2014 08:53:50

I have always changed the chucks on Makita drills, the locking screw inside the chuck has always been a left-hand thread. Have had no particular difficulty removing them, but they did have traces of a thread locking compound on them.

It is very easy, once the screwdriver blade is in the screw, to forget to turn it clockwise.

Suggest penetrating oil and some heat - I have a pencil flame burner ideal for such small spaces - and give the end of the screwdriver a clout with a mallet once it is in the slot, to break any seal.

Thanks for all the assistance gentlemen with a special mention for herbert for a very useful link now downloaded and copied into my manuals folder.

In the end nothing worked so I cut the offending beast off! Having done the deed and figured out the quickest approach I figure the brutalistic approach can be done in 1/2 an hour or less so it will now my preferred method if the chuck doesn't succumb immediately to the book method. I went all round Robin Hoods barn and took around 2 hours due to being not sure where to cut but if anyone else wishes to try here's how. The body is quite soft so an ordinary hacksaw and file will do fine.

1) Dig out the little spring ring on the end, slide off chrome cone, plastic sleeve and ball bearing thrust ring.

2) Ferret out the jaws and knock the thin toothed ring off, it only pressed on and gets in the way of holding when cutting.

3) Hold the chuck body in a vice and carefully cut round at the base of the jaw slots. Have to go round rather than straight across as the cut will be pretty much level with the bottom of the screw head. My screw spun straight out with the impact driver.  Only Lawyer Murphy and the Gremlin Squad know why it wouldn't shift with the chuck in one piece.  If yours still won't move consider a bit of heat or my favourite of welding a nut on so you can really lean on it. Power Tool Centre linked to in my first post sell the screws at £3.45 so its not the end of the world if you have to destroy it.

4) With the screw out of the way cut straight across at the base of the front flange. This cut was about a mm clear of the threaded spindle end on mine. Probably wise to check it will be clear on yours and adjust cut position if need be.

5) File the remaining cylindrical part of the body down flat until you just reach the thread. With care you will be able to see that you have reached the thread before actually breaking through onto the spindle. Filing into the flange next to the drill doesn't matter but if you go right through it would be easy to damage the drill body. Flip 180° and do the same.

6) Carefully saw through the remaining flange and plastic ring in line with the two flats. The hoop strength is now destroyed and things will unscrew quite easily. I lightly gripped it by the flats in a self grip "Mole" style wrench and ran the drill in reverse to spin it off. Bit of a jolt to start so hold tight.

I imagine that all the cordless drill keyless chucks are pretty similar in design to the 13 mm Rhom brand one on my Makita so a similar approach should be possible for other breeds and sizes but it would be wise to check that the cut positions are safe and make adjustments to prevent damaging the drill shaft if need be.

Clive

Edited By Clive Foster on 02/12/2014 16:03:33

Sounds Brutal, but obviously effective, Clive.

One to remember; for when the day comes.

MichaelG.

Maybe not so brutal in practice.

On reflection I suspect that I, and many others no doubt, are illogically reluctant to use surgical methods of removal on stubborn components which will be scrapped anyway. After all the bin doesn't care if it comes off in one or ten pieces. Realistically you are much more likely to cause collateral damage by getting aggressive in attempting to make the book method work on something which is clearly much to tight to remove in the approved manner than you are by careful and thoughtful dismemberment. In this case its mostly the gearbox that holds things steady against unscrewing forces. A potentially expensive component to damage.

My main worry when resorting to surgery was that the chuck components would be either hardened or a semi tool steel requiring angle grinder or diamond files to dismember. An angle grinder in particular being much harder to control closely than a files and hacksaw.

Clive

.

Well said, Clive.

MichaelG.

Good job Clive. I had same problem, but used an angle grinder, with a narrow wheel it was no problem. I am pretty sure it was glued on with something.

1) Open the jaws of Keyless drill chuck fully, and remove M6x22 - Flat head

screw (left-handed and threadlocker coated) by turning clockwise using

cordless impact driver in Forward rotation mode with slotted bit.

the correct way to remove the chuck is to remove the screw that retains the chuck then put the largest allen key you can fit in the chuck small end of allen key first then holding the drill with one hand knock the allen key and the chuck should come loose

.

Geoff,

Very true; but if you look back to the original post, you will see that the problem was; "cannot get the locking screw in the middle undone."

MichaelG.

re removing the left handed screw usually found inside the chuck if it wont come out like this one then spray down the chuck with wd 40 and leave it chuck upright for a while to allow the wd 40 to soak in or immerse the chuck in to a tin containing enough paraffin to cover the chuck and leave this for a while

I have had some chuck screws that would not come out and have had to cut the chuck off carefully with a disc cutter until it could be removed

hope this will be of help but please no smart comments

It's a long time since I took a chuck off, but I seem to remember I had similar troubles, so I tried putting a soldering iron on the head of the screw. Whether that did it or not I don't know, but I got the chuck off.

Ian S C