Cutting RH Threads Reverse Spindle; Upside Down LH TH- On-edge Check my logic, Pls

[UptownSport]

Hello folks,

Could you give my logic a quick lookover, please?

LH Stand-up triangle toolholder- STVOL or similar- mounted upside down
Spindle in reverse
Feed to left (actual, effective will be to right)

Results in Right hand threads?

Reason is, I no longer have a machine with a clutch and wish to not guestimate spindown time.

 

[NRDock]

Joe Pieczynski has a good you tube video on this.

YouTube

 

[Booze Daily]

If I understand correctly, yep.

 

[FredC]

My rule of thumb for threads assuming you have right hand threads on the lead screw is:
If the spindle and lead screw turn in the same direction you get right hand threads, if they turn in the opposite direction you get left hand threads.
I have seen many lists trying to cover all the possibilities of upside down holders feed direction and people still get unexpected results.
I think my rule applies in every case, if so the OP gets right hand threads as described.

 

[Joe Gwinn]

Yes, I do this, and it does work quite well. Try the combination with the carriage away from anything, doing a scratch cut, and verify that the carriage moves the correct direction and generates the desired thread.

 

[awander]

Just make believe the tool is a nut, and the spindle is a bolt.

As you turn the spindle and the tool moves, is the "nut" threading on or off the "bolt" like a regular nut/bolt would? If so, it's a RH thread. If not, it's LH.

 

[carlherrnstein]

Fred is right, if the spindle and lead screw are turning the same way, you get right hand threads.

My favorite way to cut left hand threads is to run the spindle in reverse and the tool upside down. Of course the lead screw direction has to be reversed. Then the compound is away from the chuck and there is no need to cut a relief groove at the end of the thread. I won a 12 pack of Yuengling on that bet.

 

[UptownSport]

Ok, thanks!

Leadscrew = Spindle rotation results in RH Threads- Check
awander- Good way to explain it.

Joe P Vid had LH toolholder- Nice and cheap- Check

That Joe P dispensed with the 29 1/2°-
My brother was a machinist and he never saw the need for moving the compound while threading-
So I always just used the cross feed. My guess is it minimizes chatter as only one edge of
the single point is cutting.

It's shiny wood, and I'm not starting a thread well just 'plunging'- I doubt that's a problem.

I'll just do a surface verification cut Joe G, got it.

That Joe C reminds me of an Army NCO

Thanks again, all!

 

[thermite]

My brother was a machinist and he never saw the need for moving the compound while threading-
So I always just used the cross feed. My guess is it minimizes chatter as only one edge of
the single point is cutting.

Actually... for rather a LOT of us ...we didn't use the compound because it was a pain in the anatomy to go find it ... and put it back on the lathe!

Seriously stout 4-Ways mounted directly to the cross topslide were right common, so we just learned to thread "straight in". It works. Most any CNC does the same. Tool shape is less forgiving, but one learns, grows, JF deals with that. It becomes our "normal" we no longer WANT the compound annoying us ...unless doing short tapers.

I'll just do a surface verification cut

"Cut" can be "mark" instead. Chuck up white PVC pipe, pen, pencil, sharpie, white-board marker - wotever does NOT "cut"... where the tool-tip WILL go... and make yer pass. Wipe if off and try again until right.

Cheap "insurance", and no metal harmed in the making of.. etc.

 

[UptownSport]

Thanks, Thermite.

In hindsight, SHOULD have learned up, then bought a thread roller years ago. I really didn't understand the specifics of how, or if they would've worked on a Sheldon or Clausing 5914 type machine, and then, the price stopped me.

I don't think it's an exaggeration; Ford would STILL be making threads for the model T, if they had to cut each one.

Thanks again, all. Hopefully it all comes together.

 

[thermite]

Thanks, Thermite.

In hindsight, SHOULD have learned up, then bought a thread roller years ago. I really didn't understand the specifics of how, or if they would've worked on a Sheldon or Clausing 5914 type machine, and then, the price stopped me.

I don't think it's an exaggeration; Ford would STILL be making threads for the model T, if they had to cut each one.

Thanks again, all. Hopefully it all comes together.

Geometric dies? Herr Pelz had a design of his own devising. One side. Only!

Damndest of things. Made under binocular microscopes. They been cranking out brass or Alpaca metal screws by the multiple tens of thousands a year for the better part of 40 years.. on tuned-up Iron-bearing South Bend nines!

Chief Engineer ups and dictates human-sweat-resistant stainless to cut the cost of Gold plating the brass and such? Pelz finally bit the bullet, preid the moeny out of the skinflnts, and ordered-up that 8,000 RPM-capable "Hardinge Brothers" as the Old Timers always called them!

There I sat. 88 cents an hour and 5500 RPM, minding my hand-levers right sharply to crank-out #000-124 thread stainless screws!

Earliest lesson in common sense over craftsmanship came with it. Pelz was in his mid 70's, retiring.

"FNG" - from a larger consumer electronics production background looks at that rig, moseys into his office, gets on the phone. Hardinge goes idle.

Dick bought those tiny-to-us, great stove-bolts to THEM #000 screws from Vallorbs in Switzerland - whole year's supply about a peanut-butter jar size - for about the same net cost, finished and PERFECT .. as we had been wasting in Stainless SCRAP off the back of our imperfections!

Howard Hughes to Noah Dietrich:

"Find the experts, Noah. Find the EXPERTS!"

Ford, ya say? Can't tell that lot there's a rumour going around that shit is suspected of stinking.

Henry was a plumber as thought Weird-Adolf was a b***dy genius.

See "strength of STEEL" mechanical brakes long after saner folk had gone hydraulic! Pissed him off Ford had to cut royalty deals with BOTH of GM and Chrysler for bits of patent when finally they did go to catch up!

ISTR Ford traded 'em for faster-drying shinier-initially paint chemistry? Then EVERYBODY could rust faster when it failed?



Got theyselves in the same YEARS behind the R&D / developmnent curve mess, automatic transmission, had to kiss GM and Chrysler patented ass. Yet, again, another time.

 

[Mikel Levy]

Hello folks,


LH Stand-up triangle toolholder- STVOL or similar- mounted upside down
Spindle in reverse
Feed to left (actual, effective will be to right)

Results in Right hand threads?

On a manual lathe, if the cutter is upside down with spindle in reverse and feed towards the chuck, the result is a left-hand thread.

 

[FredC]

On a manual lathe, if the cutter is upside down with spindle in reverse and feed towards the chuck, the result is a left-hand thread.

So many variables that could be listed. Tool on the back side, front side, upside down, or right side up. How about inside or outside tools. Making a list of all possibilities makes your life complicated and makes room for mistakes.

Simple rule: if the lead screw and spindle turn the same direction you get right hand threads, opposite directions you get left hand threads. Maybe there is an odd lathe out there with a left hand lead screw, but I have not seen it.

If you find one with a left hand lead screw the rule is then reversed: same gets you left hand, opposite gets you right hand threads.

Why make life more difficult and more prone to mistakes?

 

[michiganbuck]

Good to have a good size left hand bolt and throw it in to look at the set-up, rather than chance the set-up..With a theard in place set-up will be easy.

 

[eaglemike]

On a manual lathe, if the cutter is upside down with spindle in reverse and feed towards the chuck, the result is a left-hand thread.

Just feed away from the chuck. Easy peasy for not running into a shoulder.

 

[UptownSport]

Thanks!!

Worked just fine, easy as pie- and quick.
How many years did I time just where I'd need to disengage the clutch?

Couldn't find an STVOL 8 or 10 reasonable, so used an AR Warner internal threader-
externally.

The only foreseeable issue would be selecting 'F' instead of 'R'

Thanks again!

 

[thermite]

Thanks!!

Worked just fine, easy as pie- and quick.
How many years did I time just where I'd need to disengage the clutch?

LOL!

"Good on yah!"

Dunno about YOU .....but I was taught the trick, 1959!

ALL the "Old Timers" had learnt the value of it on the damndest of clumsy-as-Hell and usually wore-TF-OUT old "company" lathes that didn't leave much OPTION!

Got OEM "ELSR" on one of my 10EE.

Prolly wisest to sell the parts to get them TF out of the way of progress and hep' someone less educated who actually thinks it is a good idea!

Basic advice?

- A) "single-point" thread AT ALL only when you MUST.

If nuthin' else taps and dies have a habit of repeatable delivering standard sizes. So it cuts down waste of time a-measuring at it all.

- B) THEN.. thread AWAY FROM any shoulder.. or other "limiting feature".

Why "volunteer" yerself to take-on extra stress? Got plenty of it arredy in a life.

- C) The above makes Joe Average come out lookin' like a f**kin' GENIUS!

Which WAS the purpose of the exercise! Git 'er done. Not braggin' how HARD it were!

Lots of nicer ways to amuse yerself than playin' wit' yerself at single-pointing threads!

"Single pointing" a lovely lady for one example.. if the thread is meant to be about the finer points of screwing!

Upside-down, backwards, and "in reverse?"

Dammit. Now I have to go and ask them uncooperative grownups.... again.

 

[dian]

threading away from spindle sounds easier than it is. first you might need a left hand tool and second you will often have problems with tool height.

 

[thermite]

threading away from spindle sounds easier than it is. first you might need a left hand tool and second you will often have problems with tool height.

Yah but.. You are Swiss.

You are SUPPOSED TO BE expert at... making a problem out of any possible solution.

That's how y'all have f**ked up the Germans, French, Italians, and Austrians ever since Rome first tried to invade and eventually ended up misplacing a whole damn Auxilliary Combat Legion....of Brit mercs, of all things.. as gave rise to Romansch. Nothing ever said Swiss weren't allowed to PRACTICE brain-fuckery of enemies by confusing other Swiss was there?

 

[UptownSport]

Don't want to be party to an international incident.

I did see a STVOL -10 on eBay, but the definitely nicht Schweiz threader cobble is working.

There's a personal lesson in deviating from habit/convention - before necessity dictates.

Thanks again to all who commented.