THREADING TUTORIAL TURNS NIGHTMARE!

[@joergengeerds360]

I have the same machine... I have adopted the Joe Pie method, putting the tool upside down, and threading away from the head stock.... waaaaaayyyyy less stressful. (I also have a solid tool post, so I just do simple straight in threading)

[@kathytaylor3521]

Awesome work Andy ! This was a learning experience for us all !! Great filming , you do know your trade !

[@Lappemountainliving]

Many thanks!

[@matter9]

I’d be interested to see data related to thread/fastener strength with and without relief grooves. The older, more skilled folks I’ve worked with have preferred no relief but imo it’s asking for trouble-> with cnc it’s a non issue as retract motion in X will always be identical and synchronized, but manually seems to be asking for trouble. Some passes you’ll retract a tad early, some passes a tad late. Those irregular loads on what are usually the more delicate tools (smallest tnr) just seem to tempt fate for a broken tool on a penultimate finish pass. Case in point @28:45, albeit with extenuating circumstances. Question: on I.D. threads do you go no relief? Ive never seen anyone not cut a relief on a bore thread, but there’s a first time for everything. Incidentally, as others have suggested, inside out threading, from headstock to tailstock, run at much faster rpm means higher surface speed which means lower loads, as higher surface speeds have a greater plasticising effect on workpiece material, and carbide is not as tough as HSS, so more likely to fracture at low rpm / bottom of machine useability envelope conditions which is when things tend to go sideways, at least for me. Consider giving it a shot and trying the reverse method and see if an old dog can learn a new trick, you might like the results.

[@Lappemountainliving]

Thanks for the well thought out comment You could go with no relief on an internal thread but you would have to be very careful to not crash the back side of your boring bar into the threads on the far side as you're pulling out of the cut. assuming there's plenty of room back there it wouldn't be any more difficult than threading with no relief on the OD. There's a few things I don't like about threading from left to right. First off if everything else remains the same and you're threading from left to right then you're cutting a left hand thread. To cut a right hand thread from left to right you would have to run the lathe in reverse with the threading tool upside down. While this is possible it would make inspecting the condition of the threading tool very difficult. The compound rest, cross slide and carriage are all designed to work with a downwards load on them. They will work with a upwards load on them but they won't be as happy. Here's the single biggest reason I wouldn't try threading left to right. When I'm pulling out at the end of a pass (quite close to the chuck) It doesn't matter how much I crank it out or what setting I end up at as long as I bring it out far enough. In the case of 8tpi .094" is enough. To come swooping in a the beginning of the cut and landing at an exact graduation on my cross feed handwheel, I think would be impossible. Also, consider that I was threading at 80 RPM. My whole pull out happens within approximately 1/4 of a revolution so 60seconds/80 revolutions/4 1/4 of a revolution = .187 so I would only have .187 of a second to advance my tool inward and land on a exact graduation. I am confident that I could not do that. The reason it works for me going the other way is I am simply cranking it out as fast as I can when I get to the zero on my dial and it makes no difference what graduation I end up on. This normally works pretty well for me. Lastly there would be no forgiveness in the engaging of the split nut. In a fraction of a second you would have to engage your split nut and set your depth of cut. Again impossible at least for me. Threading right to left you can start as far away as you like, Your depth of cut can be set in advance of engaging the split nut and you have plenty of time to get your wits about you before the actual cutting begins. Hope this helps Cheers!

[@stringmanipulator]

good thing you share when things goes wrong, because there's quite a bit to be learned from recovering from those. I have a small lathe and have had the same (weakness on low rpm) problem. I could not finish the thread at all, no matter how small of a cut I was trying.

[@Lappemountainliving]

Thanks for the comment. Thanks for watching!

[@aCiraify]

From an absolute nobody, I've never touched a machine my whole life, and it's probably hundreds of reasons to not do it or even not possible. But is it not possible to have the threading ending outside the stock? What I mean is, start the threading on the tricky part where you "swoop out" and let the thread end in empty air outside the stock. That would remove most of the muscle memory magic. I also guess this means flipping the insert upside down and running in reverse. Maybe that is a reason to not do it that way? "Swooping in" at a known zero mark might not be a thing.. I'm just thinking out loud at this point. Thanks for the great video!👍🏼 Sorry in advance!

[@Lappemountainliving]

Not a thing but I appreciate your comment. Thanks for watching!

[@matter9]

No thread relief, sure not a thing, but cut a relief, add a radius, and get to it, shouldn’t be a problem. Thinking about it for a couple more seconds, the acceleration rate required to start in the relief groove may overwhelm the clutch. Alternatively you could do what most mags have done and swap out the excessive clutch with a shear pin arrangement. The clutch *seems* like a good idea but it’s probably better suited for the feed shaft, not the lead screw.

[@peterfitzpatrick7032]

Actually ... it IS a thing, tool inverted and reversed spindle... I've done it myself... 👏😏

[@Lappemountainliving]

Right you are, I've done it myself but not 1/4" from the chuck and I was also able to set my depth of cut before engaging my split nut when I did it. I fail to see how I could engage the split nut and advance to tool to it's cutting depth all in 1/4 revolution. Under the circumstances in my example I would argue it's not a thing

[@Lappemountainliving]

I agree. I think I will disable the clutch for threading and re-enable it for turning.

[@DK-vx1zc]

You sure know what you are doing, but that machine doesn't want to do what it should be doing. Perhaps with that machine you need to thread from left to right at those settings, or take lighter cuts.. Thanks for sharing, I enjoy your videos, and I learn!

[@Lappemountainliving]

Thanks for commenting!

[@joergengeerds360]

Smithy has a couple of options for motors, maybe you got unlucky and got a weak version. I would contact smithy support and see which motor you have, and if there is an easy upgrade. As I have the same machine, I never really managed to stall the motor, other than I.e. cutoff blade getting stuck

[@Lappemountainliving]

Thanks for the idea. Well worth a try!

[@sawz5]

I think that machine is not heavy enough to cut an 8 thread.

[@matter9]

Modified infeed perhaps. Straight infeed taps out machines earliest, then a 29°/30°, then modified infeed, also known as alternating infeed. As in setting compound to 0° and using alternating passes of compound at 0.000”, then say +/-.005” to widen the thread, then reset compound back to 0.000”, infeed cross slide, etc until wires or thread mic reads ok. Surface finish might leave something to be desired though.

[@Lappemountainliving]

That's new one for me. Kinda stuck in my ways but thanks for the comment and thanks for watching.

[@Lappemountainliving]

Haven't heard of that before. I'm kinda set in my ways but thanks for watching and commenting