Cleaning a Brace & Bits using Citric Acid


In my continued attempts to shove further victims down The Slope, and as I've recently been dabbling in using citric acid for cleaning up tools, I though it might be of interest to some members of UK Workshop to see the process. So here 'tis.

 
A 10” sweep J.A.Chapman ratchet brace and some solid centre or Irwin pattern bits were to be cleaned up ready for their new owner. The ratchet was seized, but the rest was not bad, even some plating still intact in places. The bits were largely in good condition, except for the 1” which I failed to spot was bent. Not having a direct replacement spare, I swapped in a very crispy 3/16” instead. The bit roll was part of the deal too. It may be in rough condition, but it's better than nothing and this type seem to withstand the rust better than any other. A dunk or three in hot soapy water and you could at least bear to touch it without going yeuch...
First task is to mix up the brew, and here are the vital ingredients. I went into some detail and chased up some links here, if you're want to try for yourself.
I started on the bits first, knowing I didn't have time to give the brace the necessary bath before waltzing off up country for the Tools '05 show. Here they lurk in the citric-y depths at about 3pm.
9am the following day, and they've gone black and you can see the bubbles as the acid does its work. Time to fish them out.
Here's one having had its shank scrubbed with a 360grit Webrax (non-woven abrasive) pad under the cold tap. Shiny, no? It was at this moment that I noticed the shank was bent and muttered more than somewhat in consequence...
The absolute easiest way to clean up any tool IME, is to use the "shoe-shine" technique whenever possible. Auger bits lend themselves to it brilliantly, as long as you have a suitable way to hold them still. Here you can see where I've already been nearest the tang, while the pointy end is still to be done.
A quick burst with a file to sharpen up the relevant edges, and there's nothing left to be done but see to the lead screws. Mike Dunbar's Restoring, Tuning and Using Classic Woodworking Tools has good info on bit sharpening, btw.
IIRC, it's Galoot Tom Price who can claim credit for drawing this technique to the on-line world's attention. Time and again you find rusty, blunt, unhappy lead screws on auger bits, and it used to be there wasn't much you could do to help them. Here's what you do. Either procure some valve grinding paste or some other abrasive suspended in oil/grease/paste of some sort. I started out using the grit from one of those Japanese lapping kits and some 3-in-1 oil. It occurs to me I could have tried the diamond compound too. Also required is one piece of scrap softwood and a working brace.
Chuck the bit to be cleaned in the brace, and just start the lead screw into the softwood with a turn or two.
One small and rusty hole; note the current state of the lead screw btw. I shall be expecting oohs and ahhs later... and not just 'cos it's in focus...
Apply a small blob of your abrasive substance into the hole as well as you can.
Start the lead screw back into its hole and turn it right into the wood. Backwards and forwards a little too, to really work that abrasive against the screw.
Behold. One clean, sharp, beautiful lead screw. If one pass doesn't do the job well enough, don't hesitate to add more paste or make another hole. I was lucky in this case. To clean off the paste I've found on the large bits you can just keep boring and let the wood do the job. Smaller bits seem to often need a fresh hole though.
Some holes later...
... and 11 bits ready to go. After they've had a coat of wax to inhibit further rust formation, natch. No, they're not “like new”, but they'll work like new.
See? Now rush to the next page to see how to do it all again, but to the brace...

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