How to thread an aluminium rod Answered


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I have got some 1 inch aluminium pipes (GI pipes) which I want to thread. I got the threading machine (hand held racheting type) and when I try to thread using that, it goes about 2 threads and after that, its pain - so stiff and even after exerting all my force, the pipe wont thread.

I had read that to thread easier, you should coat the pipe with Wax or threading oil. Is there any other tips or tricks that you have used for threading? Any input is greatly appreciated.



are you sure it's aluminum, not galvanized steel

GI means "galvanized iron" Use a magnet to test. Iron or aluminum

Even with cutting oil, expect it to take a lot of force to thread it. Typically these pipes only thread for the first inch or so. With tapered threads, the further you cut threads, the more "meat" you remove.

I am in a course for Millwriting/Machining and we are currently dealing with taps. You are supposed to use a cutting fluid when tapping and quite frequently. As well indeed like other people have said you have to go back a quarter turn for every half turn you advance to break the chips inside the flutes. Hope I helped.

IIRC, along with using the oil, I "think" the the method involves occasionally backing up a tiny bit to break off the ever increasing piece begin cut off the pipe. This piece tends to bind the threader (at least, this is how I have to do it when putting a thread on a bold with a die).

.  Thanks for mentioning that. It is even more important with Aluminum, as Al tends to gall when threaded. Breaking off the cuttings will help a lot. Lubrication is a must. Sharp tools are a big plus.

YW, I wasn't absolutely sure it applied in this instance, but assumed it would since taps and dies for bolts are smaller and doing (essentially) the same thing on a larger scale would requite it more often.

Sure, emphasize the importance of lube if you are working with parts that are rusty or have been sitting around for a while.

As with Goodhart's suggestion, you do have to back it out every few turns to ensure the cut bits are ejected. Depending on how fine the thread you are cutting or coarse, it may take more force or finesse to cut. Maybe you need a longer handle to give you leverage, place a pipe extender over the handle. Make sure the piece is securely fastened in a vise. Make sure you have the proper cutting end going in. Make sure the hole is correctly sized for the tap you are using. Make sure you have the tap going straight in. Is the tap worn out, chipped and dull? Aluminum should not be too hard to work with. Good luck.