Advice on breast drill rehab

[Geoff Duke]

I picked up a grimy Millers Falls #12 breast drill at an estate sale a couple weekends ago. Today, I started cleaning it up with WD40 and some brushes and scouring pads. I'm pretty happy with the results so far.

MF12 drill disassembly 1 - sm.jpg

However, I'm stuck on a few things. First, there are two knurled parts that seem to turn just a bit (A), but I'm not sure what they're for and whether they should turn more. Second, there's a set screw hole (B) but I don't know what the screw adjusts.

MF12 drill disassembly 2 - annotated.jpg

Third, the shaft doesn't spin very cleanly yet, and I'm not sure how or if it's possible to remove the shaft from the frame. I wondered if the chuck and shaft unscrew somehow. I gave it a gentle-ish try, but I didn't want to damage anything by cranking on it like well, a Neanderthal.

I'd appreciate any suggestions or pointers to docs I've missed.

--Geoff in VT

[Jim Ritter]

Welcome Geoff. I have that same drill. I'll take a look at it tomorrow. That set screw might be to get oil to the innards. Not sure about the knurled rings but I'll take a look.
Jim

[Joe Bailey]

I would imagine that's how you change gearing/speeds

[Jim Ritter]

Joe you change the speeds by moving the whole crank gear to a different hole thereby changing the gear spacing and ratios.
Jim

[Jim Koepke]

Howdy Geoff,

Welcome to the Creek. Where do you call home? You may live close to another member who is willing to lend a hand with your MF #12.

There was a way to put these things together so there is usually a way to take them apart.

jtk

[Kim Malmberg]

Geoff
I have never taken a MF #12 apart so I can't say. But the description on Randy Roeder's site would indicate that the knurled rings conceal the double ball bearings added to this model after 1917.

http://oldtoolheaven.com/breast_dril...ast_drill1.htm

It might become rather messy to try and remove all the parts and at the same keep track of the bearings. Does the spindle not move well enough? I mean, is it necessary to remove these parts? The screw hole looks a bit too large to be intended for lubrication. I would think that the screw going into the hole would keep the spindle locked.

In my experience spindles are very often held in place by pins going though both the spindle and gear wheels. So if you have to remove the spindle I would look for a pin on the gear wheel, then gently tap it out. That would probably release the spindle, but if there are ball bearings inside the knurled rings I would want to be very careful.

[Geoff Duke]

Jim, thanks; any additional info is appreciated.

Kim, I used that oldtoolheaven link to identify my drill; it's got the Leland jaws, spring-release buttons for switching axle location to change the gear ratio, and it lists Greenfield on the trademark. You make a good point about not making things worse. If I can get it well lubricated, maybe it will spin freely.

That said, I have a difficult time leaving puzzles unsolved.

[Kim Malmberg]

That said, I have a difficult time leaving puzzles unsolved.

I know the feeling, and I might do exactly the same, even though I have lost my bearings a few times. Curiosity can be a great motivator.

[Mark Herdman]

I picked up a grimy Millers Falls #12 breast drill at an estate sale a couple weekends ago. Today, I started cleaning it up with WD40 and some brushes and scouring pads. I'm pretty happy with the results so far.

MF12 drill disassembly 1 - sm.jpg

However, I'm stuck on a few things. First, there are two knurled parts that seem to turn just a bit (A), but I'm not sure what they're for and whether they should turn more. Second, there's a set screw hole (B) but I don't know what the screw adjusts.

MF12 drill disassembly 2 - annotated.jpg

Third, the shaft doesn't spin very cleanly yet, and I'm not sure how or if it's possible to remove the shaft from the frame. I wondered if the chuck and shaft unscrew somehow. I gave it a gentle-ish try, but I didn't want to damage anything by cranking on it like well, a Neanderthal.

I'd appreciate any suggestions or pointers to docs I've missed.

--Geoff in VT

Remove screw B
In the teeth of the drive gear will be a pin, drive out with a long punch. (this pin may be tapered, try both ways, before hitting too hard)
Do this next bit over a washing up bowl or bucket!!
Withdraw the the chuck shaft...slowly..the gear will fall off...many small ball bearings will follow..into the bowl/bucket.
Unscrew the knurled parts A.
These knurled parts are adjusters to take up slack/wear in the main drive shaft.
When rebuilding, hold the ball bearings in with grease..always over the bowl/bucket..adjust for smooth running, replace screw B

The balls are small round and bounce all over the bench...floor..with luck can be found with a magnet....I know...how do I know?

Lets us know how you get on.

Mark

[Scott M Perry]

Geoff -

I'm thinking about picking up one of these as a project, too - how'd your restoration turn out?

Scott