Swingup external threading tool

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AdeV:
[deleted due to off-topicness]

bogstandard:
I have now unlocked this topic again, to show you what has happened on the testing.

I could only manage an hour this afternoon so not much to show, but a lot to talk about.

I had set everything up as I would normally set up for threading, using the normal offset method. I set the lathe to cut a 2mm pitch.
A lump of 1" nylon bar was used for the first cuts, if something was going to go drastically wrong, I didn't want my tipped cutting tool damaged.
Everything worked exactly as planned, it cut the thread perfectly and when the lathe was flipped into reverse, the tooltip lifted, wound back to off the job and duly dropped down into the cutting position again. I carried on for a few more cuts, and nothing changed, it behaved perfectly.
This now gave me a little more confidence in what I was doing, so then I thought that it was time to give it a good try out.

Raiding my steel recycle box, I came up with some of the worst crap to thread, a length of 7/8" diameter steel conduit. This stuff is made from the dregs of the steel world. I was expecting major problems.

So after mounting it up, it was threaded the same way as I had done the nylon, with exactly the same results, except that the finished threads were real rough, but I had expected that because of the material, it is no better when you thread it up with a die when fitting it up in a factory.
There was no chatter, jumping or farting, in fact nothing out of the ordinary, except it only took me a fraction of the time it would normally take.

So after a quickie switchover, I swapped it to 5mm pitch, and carried out the same exercise on the other end of the pipe. I couldn't go any deeper otherwise I would have been thru the tube wall.

Results.

This is getting monotonous, exactly the same as before.

Conclusions after this very short trial.

This really wasn't a full trial, but an initial proving run. Until smaller threads are cut then a final conclusion cannot be forecast, but if it goes like these three have gone, it should mean that this concept is definitely a winner, and could be designed to be made much simpler.

I found that when using it, I sat on my stool, with one foot on the brake and one hand on the fwds/rev lever. It was so simple to do, put on cut using topslide, start the machine fwds, stop when at end of cut, flip machine into reverse, run off the end of job then stop, repeat process. In fact it is easier than trying to use the drop in dial, no waiting about or counting. So for me, I will use this method all the time, rather than mucking about with other settings.

I have now to make a camera mount to video the process and to prove the concept on other materials and sizes.

BTW, after seeing how the swarf behaved, I don't think that will be a problem at all.

Now gents, is the time for your criticism, worries and conclusion jumping.

Bogs

Bernd:
Bog's

Well, I was proved wrong in thinking that the backlash of the machine would mess up the threads. I was thinking that with the backlash of my machine that it would take the tops off of the thread going in reverse. I came away with that conclusion because I used the regular way of mounting a cutting tool, or solid mount and ran the machine backwards after having it set up to 8 threads per inch. When reversing it the carriage didn't start moving until I was half way between the threads. Thus the conclusion that the tool needed to be rasied all the way above the part manually.

I now stand corrected on that matter of thinking. Perhaps you have some insight as to why I would have thought this? (yes I know what you'd like to call me, but be kind please)

And thanks for finishing the thread. I really didn't want to build a tool and prove that my thinking was in error. :nrocks:

Regards,
Bernd

Rob.Wilson:
Nice one Bog's :headbang: :headbang: :headbang: :headbang:

Regards Rob

Divided he ad:
Job done!

Awaiting full trial testing..... When ever, I've never even tried threading! This is pure curiosity for me :)

Ralph.

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