Tools, Sharpening and Power Machinery - drill fix questions

I have an electric Makita drill of which the teeth have worn down on the part as shown here as part #6 in the diagram, the "spindle assembly" and therefore is losing its mesh with the toothed end of the armature (part #10) as it runs, causing it slip badly during operation.
http://www.makita.com/en-us/Assets/Images/Products/_PartsBreakdowns/PB_6407.pdf

Here's a couple of photos of the drill as well as the assembly with the chuck still attached to it.
http://i207.photobucket.com/albums/bb153/sgull1/IMG_1121.jpg
http://i207.photobucket.com/albums/bb153/sgull1/IMG_1123.jpg

If I acquire a new spindle assembly (part #6) for replacement, I would have to be able to remove part #7 (ball bearing) from the shaft there, and then of course put it back onto the new assembly afterwards. (The ball bearing part #7 is pressed on tightly to the end of the shaft behind the toothed gear.) Also of course I would need to remove the chuck and put it back on afterward also. For me to accomplish this does it take a small puller tool to take the ball bearing off? And how does the chuck come off, unscrew somehow? And how do I get the ball bearing pressed back onto the end of the new assembly? Thanks

You can use a puller as long as the gear shaft has a center hole. Problem is that after hard pulling you really should put in a new bearing because the balls can dent the inside of the races. Putting it back on should be easier, just find a hollow driver to fit over the inner race, grease everything, align and hit with a hammer. Good luck.

Ps
An arbor press makes short work of such things and preserves the bearing if pressed out correctly. Look into it, sometimes you can get one for the price of a puller.

I would buy the new bearing also. It looks like a flush fit so a plastic hammer should install it. Be sure you only strike the inner race of the bearing while driving it. Should not be hard to install.
The chuck does look like it screw on or off. Open the chuck all the way open and look inside (where the bit goes) for an allen headed bolt that locks it in place. Remove the bolt then unscrew the chuck. Reverse to install.

Put the spindle assembly in your home freezer for 24 hours before putting the bearing on. Be all set up so you can work quickly before it warms up.

put in a new bearing
An arbor press makes short work of such things.

Thanks, I'll look into an arbor press, and also get a new bearing in addition to the worn/damaged part.

I would buy the new bearing also. It looks like a flush fit so a plastic hammer should install it. Be sure you only strike the inner race of the bearing while driving it. Should not be hard to install.
The chuck does look like it screw on or off. Open the chuck all the way open and look inside (where the bit goes) for an allen headed bolt that locks it in place. Remove the bolt then unscrew the chuck. Reverse to install.

Okay will get new bearing too. And I see now how to get that chuck off/on like you said. Thanks:thumbup:

Put the spindle assembly in your home freezer for 24 hours before putting the bearing on. Be all set up so you can work quickly before it warms up.

Thanks for the tip. Will do. What does freezing the spindle assembly do, make the shaft shrink a little or something?

The chuck does look like it screw on or off. Open the chuck all the way open and look inside (where the bit goes) for an allen headed bolt that locks it in place. Remove the bolt then unscrew the chuck. Reverse to install.

Durnit, it looks after all that the chuck must screw off some other way. There seems to be no allen headed bolt down in there, all I can see is a small 1/8" or so round hole, but no allen headed bolt or place to stick an allen wrench. How else do these chucks come off, what the heck is the trick?

It is possible there is no screw holding the chuck on. Since you are replacing the gear assembly and bearing we need not worry about messing the old one up. Put the gare in a vise to hold it tight. Chuck the largest allen wrench you have into the drill using the short side of the allen. Hammer on the long arm of the allen trying to turn the chuck in a clockwise direction. Hit it hard as you can. This should break it loose then you can continue turning it until it is off.
Note if after 3 or 4 good hits it does not come loose try the other direction. I am not sure it is a right hand thread.
Also look again to be sure there is no bolt of any kind inside the chuck.
To put it back on after you assemble the drill with the new parts you screw it on as far as you can by hand. Then chuck the allen wrench as before and hit the handle of the allen a few times to seat the chuck in place.
Now some chucks have a flat area where you can put a wrench to hold it as you remove the chuck. Some chucks are left handed thread so you would hit it in the opposite direction as before to loosen. Some chucks have regular screwdriver slotted bolts instead of allens to hold the chuck tight (usually the reversiable drills). Some do not have a bolt to hold the chuck.
It is the hard sharp rap of the wrench chucked into the drill that pops loose the locktite compound put there by the factory. You may use locktite when you re-install the chuck or not. Your choice.

Thanks for the tip. Will do. What does freezing the spindle assembly do, make the shaft shrink a little or something Yes. Use to do it when I was in the Navy on pimp shafts an 1-1/2 " in diameter because we didn't have the proper tools. The other way is to heat the bearing either in an oil bath or use an induction heater.. Simplest in this case is as I suggested, freeze the shaft.