threading the wrong way

JT.

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dit some testing a few days ago for threading the rong way from the headstock away
having a lathe with metric feedscrew i need to cut TPI thread on a barrel
so for threading i can not diengage the half nut and need to revers the rotation ore feed direction (i prefere lathe rotation change but got no idea if thise is the best way )
still in the proces of learning to cut a desent HSS threadcutting tool to cut at a slow speed
i wanted to make it easyer for me to cut with the carbide inserts i got but a low speed the thread looks like crap .
i got nice threads at 500+ rpm but 18 tpi at 500 rpm i am not quick enuff to do al the neaded stuff to stop the machine on time before it runs in to the sholder ore
the headstock .
so i came up with thise from the headstock cutting i now that some cut with a tool upside down and from the back .
i got me a LH holder LH carbide insert full profile and a neg .1.5dg underplate
mounted the tool upside down and run the lathe in reverse speed at 520 rpm
i dit 3-4 0.01" deep passes (no angle straith in feed ) and then 3-4 clean up passes (seems to do nothing on the apearence the threads looked the same as before the cleanup passes)
it seems to work rather good that way and no stress for me


adraad.jpg



some reflection ideas etc are very welcome

adraad.jpg
 
Last edited by a moderator:
I would say you did it just right. Looks good.:thumbsup2:
 
dit some testing a few days ago for threading the rong way from the headstock away
having a lathe with metric feedscrew i need to cut TPI thread on a barrel
so for threading i can not diengage the half nut and need to revers the rotation ore feed direction (i prefere lathe rotation change but got no idea if thise is the best way )
still in the proces of learning to cut a desent HSS threadcutting tool to cut at a slow speed
i wanted to make it easyer for me to cut with the carbide inserts i got but a low speed the thread looks like crap .
i got nice threads at 500+ rpm but 18 tpi at 500 rpm i am not quick enuff to do al the neaded stuff to stop the machine on time before it runs in to the sholder ore
the headstock .
so i came up with thise from the headstock cutting i now that some cut with a tool upside down and from the back .
i got me a LH holder LH carbide insert full profile and a neg .1.5dg underplate
mounted the tool upside down and run the lathe in reverse speed at 520 rpm
i dit 3-4 0.01" deep passes (no angle straith in feed ) and then 3-4 clean up passes (seems to do nothing on the apearence the threads looked the same as before the cleanup passes)
it seems to work rather good that way and no stress for me


adraad.jpg



some reflection ideas etc are very welcome


They look good. We used a hand held wire brush to clean the threads after the final cut. Nice job.

adraad.jpg
 
Last edited by a moderator:
just cleaned it up with an old T-shirt .threading up side down another advantage is that the debris are falling down
 
easier , simpler & cheaper to grind a H S threading bit .......cutting w/reverse spindle ususally done for cutting away from a shoulder when a full thread needed up to the shoulder . if for any reason you need to "set back" & rechamber , you will be short on thrds now ......been there .
best wishes
doc
 
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