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Plomb 4751 Restoration - Pawl Replacement

Electron2002

Well-known member
Joined
Aug 21, 2012
Messages
77
I recently came up with a Plomb 4751, which has a been a quest tool for me for a while now. When I got it, it only worked in one direction and the throw out lever wouldn't stay in position and would creep back to a center position. When I tried to select the opposite direction, the gear would just freewheel.

I had my suspicion about the cause, but couldn't open it up there to inspect. Instead I just used it to my advantage and got it for a whole $2.

When I finally got to open it up, My thoughts were confirmed and I found that one of the two pawls was flat out missing. The spring however was still there, bouncing freely in the case.

No service parts exist for the 4751 and considering that it is marked a "No Replacement" tool, I kinda doubt they ever offered them.

Since the 4751 is a fairly rare tool in the Plomb universe, it seems unlikely that I'll find another one that still has the pawl in it that I would need, unless I pay considerable more money when one pops up for auction. Even then, you never know if the right one is in there, or if its even usable.

So, I decided to make my own pawl. Since the remaining pawl was actually in very good shape, I was able to measure and pattern the opposite side part. I picked up a 6" piece of D2 tool steel from McMaster (1/16" x 1/4") and went to work.

First, I shaped the rounded "pivot end". One of the ends of the tool steel had a slightly rounded end from when it was originally cut, so continued rounding that end off.

Second, I began filing in a V notch just inside of the pivot point. On the original part, this notch is there to help it clear a corner on the body of the ratchet.

Third, I ground the width of the steel down to .200"

Fourth, I ground the inside body of the pawl down to .1615". The pivot point of the pawl has an extended tab that indexes into the body of the ratchet to keep it in place.

Fifth, I filed the index tab round, so that it would fit to the hole in the body.

Sixth, I cut the pawl from the length of stock, slightly long.

Seventh, I ground and flat filed the square end of the pawl down to an exact 0.335"

After a bit of cleanup and a tiny bit of lubrication, I reassembled and it sprung back to life. All in all, I spent about 45 minutes doing the work. Totally worth it.

I don't ever plan to use this ratchet for any purpose than to have in my collection, so I'm not that worried about the pawl not being correct.

Here are some photos that I took while working on it.


End rounded and v-notch cut


While cutting the steel down to width (sorry couldn't get focus)


Index tab profile cut in and pawl cut from stock.



Final product before final cleanup


Final product installed in ratchet during test assembly


The finished product. Works smooth as butter.
 
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bonneyman

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Joined
Apr 22, 2010
Messages
8,836
Location
Desert SW
Excellent work!

You know, with all the vintage rats being found not working, if you could set up your jig to do 2 dozen or so at a time....I'd bet you'd have a line of customers buying those pieces!

Especially those tic-toc style of pawls. They are a very common style of ratchet system, and alot of ratchets are out there with worn/missing parts.
 

Steven67fr

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Joined
Sep 7, 2010
Messages
438
Location
Gilbert
I've got 4 of these - two were non op when I got them... both were fixed by new pawls and one needed the lobed cam that shifts the pawls. Whenever I can pick up one of these ratchets for $20 or less I'm on it.:thumbup: Two have been ebay, and two have been from the local swap meet.

You did a darned nice job fixing up that ratchet. Glad you didn't let it go to waste over a lack of parts availability!!!:beer:
 

mattmus4357

Well-known member
Joined
Dec 21, 2012
Messages
122
Location
Land of Oz
Awesome job! It's cool to see someone taking the time to restore something rather than throw it out. I've started slowly collecting old tools as I visit a lot of auctions. It's fun to get a good deal on something that others think is just junk.
 

Bruce Lancaster

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Joined
Apr 3, 2006
Messages
1,642
Inspirational, and a reminder that you can accomplish a lot without a computerized Bridgeport!
The other big common problem with old Plombs: Center cam installed backwards! The correct way just looks wrong...and when assembled backwards, they are just wonky and erratic rather than completely kaput.
 
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OP
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Electron2002

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Joined
Aug 21, 2012
Messages
77
Very nice work!

Those 4751s are so tiny, I think they often were used beyond their limitations.

You've probably seen this one with two broken pawls currently on ebay;
http://www.ebay.com/itm/Rare-Vintag...308?pt=LH_DefaultDomain_0&hash=item35ce07a584

I recently had both of mine apart for cleaning... tweezers and mini screwdriver required.

Yeah I've seen that auction. It's too bad the throw out lever is actually broken as well. After making a pawl for this ratchet, I'm confident I can make another pair, but I think it would be even more difficult to repair the broken lever.

Thanks for the feedback guys. It was fun to make it and bring this little guy back to life
 
OP
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Electron2002

Well-known member
Joined
Aug 21, 2012
Messages
77
I've got 4 of these - two were non op when I got them... both were fixed by new pawls and one needed the lobed cam that shifts the pawls. Whenever I can pick up one of these ratchets for $20 or less I'm on it.:thumbup: Two have been ebay, and two have been from the local swap meet.

You did a darned nice job fixing up that ratchet. Glad you didn't let it go to waste over a lack of parts availability!!!:beer:

Thanks Steven. When you fixed the ratchets you have, how did you come up with parts to do it?
 

drivesitfar

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Joined
Oct 23, 2013
Messages
36,038
Location
Pacific Northwest
Electron: WELL DONE. did you happen to check Proto and ask if they sell the parts because I think they still have some inventory for old Plvmb tools?

in any case it looks like you did a fantastic job. if you have time can you post up the fix on the Show your Plvmb thread over in the vintage tool section?

thanks and here's the link

http://www.garagejournal.com/forum/showthread.php?t=135342
 

48548

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Joined
May 14, 2008
Messages
4,030
Location
Phoenix
I don't think proto has parts for these as I have never seen a proto labled one. I think these are just rare. I have 3 and they all work, but they do not seem to the be the strongest design.
 

ganymede

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Joined
Nov 29, 2012
Messages
2,332
Location
New England
. .... I think these are just rare. I have 3 and they all work, but they do not seem to the be the strongest design.

Agreed. I've got one and it was bent and had a broken pawl.
I had to fab a pawl like the op.
The ratchets are just too tiny to take the place of a regular 1/4" drive ratchet.
Mine is a supplement to my 1/4" drive set. For really cramped low torque stuff.
 

Plombob

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Joined
Oct 19, 2008
Messages
4,136
Location
Tennessee
Great job, Electron! I have one that is missing a pawl and would like to fix it. This thread inspires me to make one, even though I don't have machining tools. What kind of steel did you use?
 
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