How to restore rusty tap and die (also, what are those other tools?)


Old 10-18-16, 05:39 PM
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How to restore rusty tap and die (also, what are those other tools?)


I inherited the following tools, which unfortunately haven't been maintained to my standard.

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I have the following questions:

1- How can I restore those rusty taps so that they are usable again?

2- On WHICH metal can I use those tap and dies? Al? SS?

3- Can I use them to create NEW threads in a metal piece, or they should only be used to "repair" damaged threads?

4- My understanding is that the 3rd picture represent a bunch of taps with the accompanying handle to use them. They are used to make new threaded holes after I pre-drilled a metal piece. Correct?

5- On the 2nd picture, I know the left tools are dies, that can be used to restore (make?) threads on a rod.. Correct?

6- On the second picture, what are the 4 tools on the right? The top 2 look like taps, but they are double headed...? The bottom 2, I have no idea what they are used for.

7- On the 1st picture, there is a tool that says "Thread restorer". How do I use it? Is it to restore thread on my taps or die?

Thanks all for your input.
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Old 10-18-16, 05:58 PM
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1. They are pretty badly rusted, and proper function of a tap or die depends on it being sharp and being the proper size. Not sure they are worth trying to restore as they are inexpensive to replace. If you want to try, I'd start by wire brushing off loose rust and soaking them in oil. Then try tapping a hole and see how they work. Once they are dull, there is not much that can be done.

2. Taps of that style could be used to tap aluminum, steel, and stainless, copper, brass, some plastics....

3. They are intended to create new threads but can also be used to clean up damaged threads. You start by drilling the correct size hole, which you can find by searching for tap drill size chart.

4. Yes.

5. Correct. You appear to be missing the die stock that holds the dies. Again, you can use it to thread a bare rod of proper size or restore damaged threads.

6.The double ended taps are likely thread restorers, intended solely to clean up damaged threads. Not sure about the bottom two.

7. That is a thread restorer file used to restore external threads, such as on a bolt. They are size specific. You hold it against the threads and rotate the threaded item against the restorer to clean up dirty and clogged threads.
Old 10-19-16, 03:26 AM
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I see you have 2 different types of dies; round and octagon. Obviously they take 2 different die holders. I prefer the latter if you end up replacing them. I've had issues with the rounds ones not tightening up good enough and spinning on me. There are various products that you can soak rusty metal in but they normally turn the rust black. Not sure how that would affect the threads but it should wear off and clean the rust of when used.
Old 10-19-16, 04:01 AM
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I have had limited success with electrolysis for large, expensive taps and dies. It converts rust into hard black oxide, so not so much metal is lost. Look into it. But I honestly agree with CarbideTipped - for a small set like this it is not worth it. Most likely you'll end up with dull taps, which will break when you go to use them in SS. Something I don't wish on anybody.
Old 10-19-16, 05:19 AM
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I would give the taps & dies a coating of rust preventing oil or with WD-40 and use them when needed. I would try to limit their use to softer metals and when using them keep them lubricated well. You may notice galling especially with un-heat treated aluminum especially if you don't lubricate well enough. But other than that there is no way to bring them back. Just try to get as much use out of them as you can. The taps & dies may not be able to do 4-40 in stainless anymore but they should be fine for cleaning up buggered threads.
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