Two suprises

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DozerMite

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Jun 26, 2007
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First one...

Thanks to the advice from here, I was successful in cutting threads. It is a 1/4-20 thread in steel. The first attempt was in aluminum and it didn't go so well.
After spending a long time with this, I have a great appreciation for those guys that cut threads with a die. I now have a strong desire to learn the threading capabilities of the lathe.

Second one...

Even though not the best pic, I actually got a good pic and you are able to see the subject.
Now to the pic...
















postthreads.jpg


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The aluminum seems to strip the threads off. The steel held the threads after the first couple. I faced the bad threads off, that's why there isn't a chamfer on the end. The nut threads on fine without it, but one could be put on.
It didn't thread easy by any means. I will play with cutting the threads on the lathe and see if the aluminum threads any better. I'm sure someone on here has done it and can answer that.
 
DozerMite said:
The aluminum seems to strip the threads off. The steel held the threads after the first couple. I faced the bad threads off, that's why there isn't a chamfer on the end. The nut threads on fine without it, but one could be put on.
It didn't thread easy by any means. I will play with cutting the threads on the lathe and see if the aluminum threads any better. I'm sure someone on here has done it and can answer that.
Click to expand...

Not quite sure I understand what you're doing. Are you trying to turn male threads (cut threads) by hand on a wood lathe? (Hats off to you! That's pre-1800 methods!). Are you trying to cut threads on a relatively modern metal lathe, but using a tool, and not a die? That's slightly tricky, but once you figure it out, fairly easy.

Aluminum is a bit tricky to machine. It's easy to machine if you have the right geometry for the tool (much greater rake angle than steel). It tends to build up debris on the cutting edge, so you need to deal with that. Difficult to hand-grind the rake on a 60 deg. V tool used to cut threads.

If you're cutting the threads using a die, starting the die is the trickiest part. After that, just be sure to use plenty of lubrication (especially for aluminum!). Even plain old machine oil or mineral oil, if you don't have anything else, and reverse the die & clean the chips out as you go.
 
Dozer,
I haven't threaded with the lathe yet, still using a die assembly on the tail stock. I did however thread a piece of stainless steel with it and it came out ok. The skin on my hands did grow back and the blistering is but a painfull memory... It's about time I got used to the easy way. PS here is a printable version of the 60" thread article that Andrew linked to.
 

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Andrew,
It is listed in the thread you posted along with a search I did a while back. It's an excerpt from the Frank Marlowe book "Machine Shop Essentials". I haven't had a lot of time to try it step by step, but it it well written and looks easy to follow.
 
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