• Spring 2024 meetup in Calgary - date Saturday, April 20/2024. discussion Please RSVP Here to confirm and get your invitation and the location details. RSVP NOW so organizers can plan to get sufficient food etc. It's Tomorrow Saturday! you can still RSVP until I stop checking my phone tomorrow More info and agenda
  • We are having email/registration problems again. Diagnosis is underway. New users sorry if you are having trouble getting registered. We are exploring different options to get registered. Contact the forum via another member or on facebook if you're stuck. Update -> we think it is fixed. Let us know if not.
  • Spring meet up in Ontario, April 6/2024. NEW LOCATION See Post #31 Discussion AND THE NEW LOCATION

SB9 reverse threading

Precisely. And I'm sure there's plenty of volunteers here ready & willing to hold the camera. From the side. At a safe distance...
If I am holding the camera, it's gunna be stuntman style...... Gotta get the "holy SH!T" shot of the look on your face as the spinning chuck decides to chase you across the room.... However, at 40 rpm it's going to be as much the chase scene as a certain white Bronco ambling along the streets of L.A. all those years ago......:rolleyes:
 

JustaDB

Ultra Member
KMS= VERY poor management, understaffed store, poor customer service ..both in person and on the phone.
Good! Then they won't be long for this world. When there's fewer hassles buying online and better customer service from overseas, the brick & mortars w/ crappy service will go the way of the dodo.

I work for a brick & mortar that rec'd recently the Western Canada award for best store in over 400 stores. A big piece of that decision is based upon customer service. If any of us had treated either a phone customer or a live body like that, our ass would have been rightfully sent down the road.
 

trevj

Ultra Member
Looking down the road...

I have a project or two in mind (both internal & external threading) which appear to be easier to single point thread in reverse. That, & it just seems fun to try.

The shortcoming is that the SB9 chuck is threaded on. Can this be overcome? MT3 head spindle to ER collet adapter with a drawbar? Something else?

TIA
Try it on something disposable and see what plays out. Might be much ado about not much...

Not really seeing a need for reverse threading, anyways, myself. Seems like a lot of extra dicking about, for not much in the way of advantage, and reminds me of the amount of time some of the apprentices would put in, trying to avoid actually having to muckle on to a HSS blank and grind a simple tool!
They also usually got a knot in their face, when it was pointed out that if they had spent the time they did looking for a way around, just doing what they were supposed to, they would be done already, instead of still worrying about how to start the projects!
 

YotaBota

Mike
Premium Member
Try it on something disposable
iu
 

Garyt

Active Member
Someone asks a valid question and the tread becomes something unrelated.
So does anyone have a solution to locking a threaded chuck on the spindle? It's not just threading that running in reverse seems to be indicated.
 

YYCHM

(Craig)
Premium Member
Someone asks a valid question and the tread becomes something unrelated.
So does anyone have a solution to locking a threaded chuck on the spindle? It's not just threading that running in reverse seems to be indicated.
 

VicHobbyGuy

Ultra Member
I read through that thread and my 'take away' was that there wasn't anything workable (or safe) for my Logan. But food for thought, for sure. And a SouthBend spindle and chuck may be different from a Logan; the Myfords certainly are.

Some folks leave the same chuck on the lathe for long periods (months? hundreds of hours of turning? ). Those chucks are probably so solidly screwed on that they aren't coming off at all easily. The old 3-jaw on my Logan only came off after a fight; I'm lucky I didn't damage the bull gear or back gears in my ignorance. Nowadays, I seem to be changing from 3-jaw to 4-jaw and collet chucks pretty often; it doesn't take much to get them unscrewed. So that lathe doesn't get to run in reverse. I can do that stuff on my 7x. :)
 

VicHobbyGuy

Ultra Member
Not really seeing a need for reverse threading, anyways, myself.
It does make threading next to a shoulder, or in a blind recess a lot less nerve-wracking for me. Especially if the lathe tends to 'coast to a stop' rather than stop when commanded! :) One disadvantage of the much favoured 'big lathes' with the 50# chucks?
 

trevj

Ultra Member
It does make threading next to a shoulder, or in a blind recess a lot less nerve-wracking for me. Especially if the lathe tends to 'coast to a stop' rather than stop when commanded! :) One disadvantage of the much favoured 'big lathes' with the 50# chucks?
Yeah, well, about that... Practice a little with the half nuts and the cross feed slide, and you can pretty much do away with putting a relief groove at the bottom of a blind hole. Or worrying about whether the chuck stops spinning (which you reasonably, should not need to have happen, until you have enough of a thread to start needing to gage the thread against a reference...

Put a recognizable mark (eg: a piece of masking tape, etc.) on the body of the chuck, and you can watch that mark swing by, as the lathe turns, so that you have a rhythm, so you can disengage the half nuts at the same time you give the crank for the cross slide a quick whip-around, and you will soon find yourself making very nicely tapered out internal and external threads without need of a relief groove for either. I will typically start nodding my head in time with the mark going by. Doesn't matter where it is when it goes by, just that you get a pretty good handle on the rhythm as it does!. At 40 rpm, you can almost sip coffee between revolutions!
 

VicHobbyGuy

Ultra Member
Yeah, well, about that... Practice a little with the half nuts and the cross feed slide, and you can pretty much do away with putting a relief groove at the bottom of a blind hole. Or worrying about whether the chuck stops spinning (which you reasonably, should not need to have happen, until you have enough of a thread to start needing to gage the thread against a reference...
I'm just a beginner, so definitely I need more than 'a little' practice!
I'd be interested in seeing a video of single point threading into a deep blind hole, with no clearance groove, with the half-nuts always engaged-which is necessary when cutting metric threads with an 'inch' leadscrew.
With the lathe running in forward, right-hand thread.
When the end of the boring bar isn't really visible, it's a matter of watching the dial indicator (no lathe DRO) to know when the end of the hole is approaching.

Lots to learn, for sure.
 

trevj

Ultra Member
As a more serious aside, I would suggest that rather than ONLY operating the Half-nuts to stop a threading operation, get used to using both the half nuts and the cross slide simultaneously.

I generally set my cross slide with the crank handle at either the top, centered, or the bottom, centered, so it is very natural to crank one full turn away from the work, at the same time as the half-nuts are disengaged. You should only be using the cross slide screw for setting the tool at it's "Zero" point, and returning it to that point for the next cut, with all the actual infeed being taken care of, using the compound. Disengage everything, slide the carriage back to it's starting point, spin the cross slide TWO turns across it's "Zero" then once back in against any backlash so you can set the cross slide ON the Zero, feed in the compound, for the next cut, wait for your index mark to roll around (if the thread is not evenly divisible by the pitch of the lead screw, on inch machines!), and engage the half-nuts when you so desire.

You can use the same rhythm of the chuck, to set the speed that you crank over the handle on the cross slide, and you will very soon find that you stop worrying about things like blind holes and shoulders.

Stuff happens! Fiddling with both the cross and compound feeds, is a skill worth developing too, as you use that for picking up a thread that is already on the part, if doing a repair, or picking up your thread to continue it, should you duff the tip off of your threading tool, and you find yourself doing a regrind. ALL of the apprentices I taught, were thoroughly un-excited about breaking a tool, or having to otherwise pick up and existing thread, once they had a couple goes at it, and it was no longer a 'scary' thing! Especially in Repairs, being able to pick up a thread is a really handy skill, and a bit of practice at it (like thread cutting itself), goes a long ways to taking the fear factor and, well, pretty much destroying that!
 

VicHobbyGuy

Ultra Member
Sounds good; thanks.
But....
I'd be interested in seeing a video of single point threading into a deep blind hole, with no clearance groove, with the half-nuts always engaged-which is necessary when cutting metric threads with an 'inch' leadscrew.
With the lathe running in forward, right-hand thread.
When the end of the boring bar isn't really visible, it's a matter of watching the dial indicator (no lathe DRO) to know when the end of the hole is approaching.
 

trevj

Ultra Member
I'm just a beginner, so definitely I need more than 'a little' practice!
I'd be interested in seeing a video of single point threading into a deep blind hole, with no clearance groove, with the half-nuts always engaged-which is necessary when cutting metric threads with an 'inch' leadscrew.
With the lathe running in forward, right-hand thread.
When the end of the boring bar isn't really visible, it's a matter of watching the dial indicator (no lathe DRO) to know when the end of the hole is approaching.

Lots to learn, for sure.
I have only run one lathe that I would try that on, a Schaublin 150, which had a Ballscrew instead of a lead screw, and was tight enough, that when you reached depth, you simply slapped the forward reverse lever to the opposite direction, and the tool would follow it's last cut out of the thread. Really a spooky thing to do the first few times! Fun as hells, once your confidence in the reproducible result was built up. The Schaublin was also equipped with an auto kick off, that disengaged the feed when it hit the stop pin, too, so when you could afford to put a relief groove in, or were threading through a hole, you could do so at some really scary speeds, and it would all pretty much work out.

Yeah, I would probably be playing a lot more with the idea of a hand crank on the spindle, rather than getting too excited about the methodology above, when working with bisexual threads like that example, Metric threads on an Inch machine, or visey versa!
 

johnnielsen

John (Makonjohn)
Premium Member
If your chuck and your lathe spindle both have a collar/flange, you can make a split collar that clamps across the two of them. That eliminates any chance of the chuck coming off during reverse machining. There is a variation to this if the chuck doesn't have a collar.
 

trevj

Ultra Member
You need to step up to a 7x14 Sieg with a brushless motor! :)
About that... Maybe that's a hard no, thanks! LOL! Unless I need it as a fishing weight! Already got a Myford in the basement, as my 'indoor' lathe. Still trying to find a reason to pull my Colchester Master 2500 inside too!
 

Susquatch

Ultra Member
Administrator
Moderator
Premium Member
I'm just a beginner, so definitely I need more than 'a little' practice!
I'd be interested in seeing a video of single point threading into a deep blind hole, with no clearance groove, with the half-nuts always engaged-which is necessary when cutting metric threads with an 'inch' leadscrew.
With the lathe running in forward, right-hand thread.
When the end of the boring bar isn't really visible, it's a matter of watching the dial indicator (no lathe DRO) to know when the end of the hole is approaching.

"Just a beginner" and "threading a blind hole without a relief" are not compatible statements. Especially not cutting metric threads on an imperial lathe..... A lathe crash or broken tools will be the guaranteed outcome of that setup. When you reach the point where you have the experience to be able to do that, you won't need a video.... ;)

Just sayin......

A hand crank on the spindle would be my advice.

A VFD driven motor is also an improvement cuz they can be reversed on the fly.
 
Top