"chasing" a thread

[wch]

I have a 3/4" diameter piece of threaded aluminum that I can't get started into a nut; I have a 3/4" die that I can't get to start on the aluminum plug.
The extent of my tools are a hacksaw and several files-is there something that I can do with these to enable the process of threading the plug?
I mean, something like cutting off a minimum of material to "catch" the existing thread or filing some type of notch or edge on the plug?

[Case Stuffer]

Here are a few photos

http://www.google.com/search?q=threa...w=1297&bih=656

I have several of the thread restoring files which work well. You can use a three corner file or even the edge and face of a flat file to file(cut) a led right before and into the thread piece. Said nothch (grove) to be at an aprox. 45 degree angle.

Hope that bvoth pieces are in face the same pitch dia. and length. There are coarse fine US plus metric and English threads and some are close enough to look same but in fact are not.

[Reg]

A standard three corner file matches the standard 60 degree pitch form on all standard US threads. Start with that three corner file back onto where you are sure the threads are not deformed and just lightly at first then increase the depth of the thread as you follow the thread out to the end. Pay attention to the shape and depth and follow as close as you can. You could even go slightly deeper in depth as you reach the end. When you think you are getting close then try to check with a nut or what ever the part is supposest to fit into . Nice thing about aluminum is that it will show with a dark shine where it is still tight. If you pay attention and use care you will not even need that die and in fact can often do even a nicer job than with a die.

[sprinkintime]

I have a 3/4" diameter piece of threaded aluminum that I can't get started into a nut; I have a 3/4" die that I can't get to start on the aluminum plug.
The extent of my tools are a hacksaw and several files-is there something that I can do with these to enable the process of threading the plug?
I mean, something like cutting off a minimum of material to "catch" the existing thread or filing some type of notch or edge on the plug?

I really think you need a thread gage to determine what the thread really is, if it is British it could be 55 degrees instead of our 60 or Metric which would look close but not right. The price of a set is fairly reasonable.
Sprink

[wch]

I had a fella at the local hardware check the thread pitch and length, so I'm in spec with those measurements-I'd like to thank you all for your taking the time to answer.
wch

[bob208]

you shure you are not trying to put a course thread into a fine thread nut or the other way around ?

[wch]

you shure you are not trying to put a course thread into a fine thread nut or the other way around ?

Yes, the pitch gauge(s) showed that the "bolt" is coarse threaded.

[I'll Make Mine]

There are commercially made thread repair sets that are likely to be easier and more reliable than using a 3-corner file to repair that thread (BTW, modern British threads are metric and have the same 60 degree angle as US NC and NF threads; it's only Whitworth, generally found on pre-1960 equipment, that has 55 degree profile). I've used the thread repair sets; select the correct one, and it's literally a matter of a few stroke to rejuvenate the thread even on a steel part; on aluminum, your biggest concern will be to avoid cutting too deep.

Even simpler and first thing to try, though -- just chamfer off the end of the aluminum male part, cutting deep enough to get past the first turn of the existing threads. This will fix up a "won't start" thread almost every time.

[Cap'n Morgan]

Either the threads don't match, or the aluminum threads are screwed - so to speak! Take your hacksaw and cut a nut in half. Hold the "half-nut" against the threaded alu part and check if they match. If the start of the threads are indeed ruined you can use the two half-nuts to fix it: Clamp them lightly together below the start of the thread and unscrew the part. The good threads will act as a guide and straighten the bad ones.