Dave Anderson replies: I personally wouldn’t bother using an acid bath to resharpen a file or rasp. First, it is a process which requires a chemical (the acid) which is dangerous and more importantly, difficult to dispose of safely and legally. The second difficulty is that of choosing the proper strength of acid and picking the correct length of time to submerge the file in the bath. You may not get the results you desire without a few trial runs and are quite likely to get either no results or alternately ruin the file by etching away too much material. A file which is not rusty will not benefit from using electrolysis, so this is a non-starter.
My recommendation is to go to the premier file sharpener in the country, Boggs Tool Processing & File Sharpening Company. The contact information is below. Boggs uses a process called liquid honing and can turn a dull file into one which is sharper than most of those purchased new.
I have friends in the woodworking tool making business who will send a rasp like a Nicholson #49 or #50 to Boggs before they use it for the first time. Their prices are reasonable and are based per inch of length. Most files can be sharpened for under $2 – $3 each. In over 10 years of knowing about this company, I have never heard of an unsatisfied customer. They have done several files for me including a couple of 100+ year old antiques and the results have been spectacular. As a new customer, they will often do two files for free.
Boggs Tool Processing
and Tool Sharpening Co.
14100 Orange Ave.
Paramound, CA 90723
800-547-5244 • www.boggstool.com