Queston on a Proto 1/4" Ratchet

[Indexmill]

Hi,

I am restoring a Proto 1/4" pear head ratchet, # 4749. I would like to replace the two flathead screws with new ones. So, I dissassembled the ratchet. The two screws were hard to start to loosen but came out fine.

However, it looks like the threaded holes in the plate are 2-56 and the actual screws are 4-40. A new 2-56 goes into the plate perfectly and tight; the screws go into a new 4-40 nut fine. The threads on the ends of the two screws that had gone into the plate are clearly deformed.

The head of a new 2-56 flathead screw nearly goes right thru the countersinks in the body of the ratchet so I really don't think a standard 2-56 flathead screw is correct. And a new 4-40 flathead screw will not come close to starting in the plate holes.

I wonder if anybody can look at their 4749 and report what you find. It seems fascinating to me that Proto could have done this by design.

Many thanks for any input on this.

John.

 

[wrenchr]

Sounds like an old ratchet, I bet someone swapped them out before.

 

[WWIIjeep]

I wonder if anybody can look at their 4749 and report what you find. It seems fascinating to me that Proto could have done this by design.

I looked at my '60s-vintage Proto 4749, and an early '40s Plomb 4749 and a late '40s Plomb 4749 pebble finish, and they all use 3-48 flat head machine screws. I confirmed that with a thread pitch gage and a 3-48 tap and die.

The 3-48 screws in the Proto 4749 are 0.350" long (1/64" longer than the screws in the Plomb 4749s, because the Proto head is a little thicker than the old Plombs).

I'd guess the PO of your Proto replaced the original screws with the wrong ones because 3-48 might be a little harder to find at the hardware store than 4-40.

As for your plate appearing to be 2-56, I tried a 2-56 screw in my 3-48 plates and it does act like it threads in, but really, it's only riding on the minor thread diameter, not making full contact with the 3-48 thread. That might be what's happening with yours too.

 

[ganymede]

Are there any size lock washers tiny enough to fit and give the head of the screw a bit more support.?

 

[SMKS]

The only advice I can offer is that my local hardware store has provided screws for several Proto ratchets. I don't know the thread pitch, but I know they had screws that fit several ratchets.

 

[Indexmill]

Thank you Jeep; your response fits all the pieces together. I never thought about 3-48!

I will get a 3-48 screw and check mine out.

Thanks again, John.