Sunday, November 24, 2013

A Cummins Fixmaster 1/4" Drill Teardown

[NOTE: This post got truncated by a Blogger mishap, and I didn't have it in me to try to recreate the lost material. The information here is sound as far as it goes.]

I brought this over from the garage. I thought I'd tear it down and clean it up and pack the gearbox with fresh grease. When I'm done, I'll make a place for it in the workshop where it can be at-the-ready. If nothing else, I'll have a very nice drill handy for light work. Here goes.

1) The Brushes

A neat feature of this drill is the externally accessible brushes. And they don't look too far gone at all.

2) The Handle Left Side Cover

- Remove the two small screws that secure the slide switch. NOTE that these screws are an uncommon size; I think they're 3-48 -- not a likely hardware store item. Should they ever be lost, you'd probably have to drill and tap the switch frame to accept 4-40 screws.
- Two 8-32 x 5/8" oval head threading screws.
- There's a little triangular projection near the top front of the handle cover that makes removing the cover a bit of a 'wiggle-and-jiggle' exercise.

3) Gearbox

- Two 10-24 x 3" plain slot filister head screws.
- NOTE the thrust washer that's loose on the motor's output shaft at this point.
- NOTE that the circular I.D. plate can come away now.

This is a drill gearbox architecture I've not seen before -- there's a plate enclosing the reduction gearing chamber that carries the front motor bearing

4) The Chuck

The chuck is a wonder. It's tightened by means of a cam that you turn with a 5/32" hex key. Here's a view of the chuck taken apart.

The cam is that shouldered pin affair at the lower left of the photo. Note the barely visible dot on its end, and the red dot on the base of the chuck. On the base of the chuck it says, "ALIGN DOTS. ADJUST SLEEVE. LOCK WITH KEY."

Aligning the dots sets the cam to where it least extends that round plunger to the right of the chuck's base. At that point, you  snug up the chuck's sleeve by hand, then you turn the key in the cam to force the plunger up against the ends of the chuck's jaws. That's the action that securely tightens the chuck.

* * *


 I'm not even going to try to re-create it. 'Sorry, but I'm going to truncate this post and call it a loss.

- - -

Anyway, I did carry on and complete the cleanup and re-lubrication of the drill, plus I replaced its shabby power plug. It runs beautifully.

I also modified the chuck key for better comfort and leverage, and added a chuck key leash per my usual method. Here's a view of the drill with its chuck key leash.

Now I have a portable drill that's about the same age as I am. (From what I can find, these date from the early 1950s; I was born in '51.)

# # #


# # #