How to Cut a Fine Thread on a Lathe (Training Film)
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- เผยแพร่เมื่อ 9 ก.ย. 2013
- A detailed guide to cutting a fine thread using a lathe, from a U.S. World War 2 training film. For more about the open source machine tools project, please go to www.opensourcemachinetools.com
- วิทยาศาสตร์และเทคโนโลยี
What a nice looking machine. The old machines seem to have a charisma about them.
I love the modern world. This shows up in my TH-cam feed and I find out about how they did the cross slide stop. Thought that hole was for lubrication. I've got an almost identical lathe (LeBlonde 13") that was originally from Camp Lejeune. Random connections after 75 or so years are awesome.
Ah a reminder of my youth. I've sat thru every one of these training films. I can still hear the metal shop teacher saying ya see that guy he's a dumb ass ya know why he's not wearing safety glasses. Then pointing to the paddle on the wall if I catch you with out your safety glasses I'm going to bust your ass got it. A few didn't believe it. They found out they were wrong. Yea that was a long time ago before they made pussies out male children.
old films always do it better!
eriktorres
Thanks just got my first lathe I’m a woodworker. However I just got my first 13 inch Logan Lathe circa 1945 or before. These-old training films built this country and ended WWII. If it worked then to teach master machinists, it does so today! As always, thanks’ for taking the time to show this video! ~M~
+Mike A Drover very nice, Have fun! I have a 1949 Logan 820. Awesome little machine, with the turret as well, original paint and all!
Look out for "Winky's Workshop" - he runs a Logan.
@@RubSomefastOnIt Look out for "Winky's Workshop" - he runs a Logan.
when I moved from indonesie to holland these movies were magical to me
They did make one mistake. One, generally, never takes the part out before the threads are done. In a perfect situation one may get away with it, to spin the nut on, but they didn't mention making sure the drive dog was placed against the same side(the driving side) of the face plate slot, it could make quite a timing difference. In real life, a steady rest is used in production with the end hanging free to test with the nut.
I checked, it was replaced correctly - and it was only a skim pass that had been done - all the proper threading was done without removing the work.
A nut made in New England will fit an axle thread in Michigan, wow thats a long nut!
They used a 13" LaBlond! I used to have that same lathe. Cool!
theme called old nuts
Kevin, This is obviously false: they're at different latitudes, so they'll be turning at different speeds.
-dlj.
Maybe Michigan'ers have loooong axles :)
@@jeffworrell2339 and not long nuts😅
Really enjoy the training firms from the early years. Always short and to the point. Would of liked living in those days did you notice that guy never stopped to post on Facebook. Lol. Just kidding you. I know that there was no Facebook then. You actually had face to face conversations with your friends
Great video!
Clear explanations!
10:35 The extra thou cut was not caused by the spring and give in the tool and work. It was caused by moving the compound 3 thou AT 30° - which is less than 3 thou on the cross slide.
3x cos(30°)= ~2.6. So that'd leave 0.4 left to take off.. so another 0.5 thou cut should do it (IMMIC)
I love❤ this work🙋♂️👍
fantastic!
nice video, very detailed, BUT there was a missed step, the faceplate, which drives the work has 4 slots, as the work is removed to clean/inspect the thread one MUST mark the slot in which the drive dog went in!!- this keeps the angular position of the start of the thread in the same spot, and allows use of the same index line on the chasing dial.
great vid. i want to start cutting threads on my lathe
What stops you?
Un video de lujo
lol I love these old videos from back when they measured things in inches.
Most machining work is still in inches, modern lathes come in inches as default
+Nick B Yeah, here in North America you basically have to be able to work with both interchangeably.. All our machines run in inches, and "inch" tooling is more prevalent.. 3/8 endmill of any flavour? In stock and in your hands that day.. 10mm? special order. lol. I actually hate getting drawings in mm.. if not because I have to convert every detail and mess with things like a .01568 +/- .00393 rads
If you work on modern caterpillar machines you’ll find imperial (AF) next to metric depending on which parts were made where. I prefer imperial fasteners as it is easier to guess the sizes in order to get the right socket or spanner as there is a bigger difference in size between each standard size.
They still use both in North America. As an engineer it's a hugs pain in the you know what. It results in some complications in the design and manufacturing stages if someone was clear enough. NASA actually wasted a bunch of money cause they built two parts of the same rocket in seperate areas, one in the customary system other one in metric, and they couldn't mate the two parts together because they were different sizes.
@@Basement_crusader I think you'll find modern machines are metric - unless you specify imperial.
I worked in a shop where they still cut threads simular to this. they made parts for old gas compressors. but they would twist sand paper at the end of the job and polish the threads. lathes havd to be kept in good condition for thread work, out of condition lathes hav to much slop in the gears for good threading. they also had a thread roller but that is another story.
You can leave the half nut lever engaged
And now I feel like playing Fallout 4
I wish I could live in this film
What ?All black & white ?
Jam Handy knows best
Carbide inserts make the tooling a lot easier. CNC can definitely spit the parts out faster once you have a written and proven program and all the tooling set up but it's really only conceivable if you're making hundreds or thousands of parts. Manuals are usually faster and easier if it's a single piece or two. I run both and my preference is manuals. I feel more in control.
+Christopher Hill The thought of cutting metric threads on an inch lathe or vice versa (127 tooth gear or not), tipped me over the edge of "I'm not doing all that". I deliberately got a manual lathe with no lead gears, to which I'm fitting a stepper motor on Z, and an encoder on the spindle. It's always good to learn how my Granddad did it too, I guess.
+MattOGormanSmith It is a pain to cut metric threads on a standard lathe. My grandfather did atuff that u wouldn't do like make clock gears using a drill press as a mill with a cutter he ground and filing all the teeth to what he needed. I'll take an EDM any day over that!
+Christopher Hill i started at a gear making shop that was just opening under a grumpy old timer. The gear hobbs were all surplus, second hand missing almost all the change gears. So we had to make them, jumping from machine to machine using this machine to cut one gear for another machine then using that one to cut a gear for another, fun times! My shoulder still hurts from keying all those, haha. Still really fun problem solving.
I did screw cutting today on my 48 year old boxford BUD (this lathe is a British copy of the southbend American lathe) I had to set up centre height I used TCT tooling, and set up change gears to produce thread so there is skill used in both manual and CNC machining
Thanks for that - but you can drive a CNC in manual mode too !
human heritage
Why adjust the compound half way through the cut, that will only cut the one side of the thread, not that it would mess up the thread, just not necessary unless the compounds squared to the thread?!?
Someone please tell me the make of this lathe
hated using wires....short runs one mach ok burt long runs and 3..9 machines to run....real pain
What a pullava, slow old ways, much faster today.
1/4 inch parting tool ????
+manu de hanoi A 1/4 inch HSS blank, if you don't grind it, could be used as a basic parting tool.
3:00 I've never cut an 'undercut' for the simple reason it's made automatically when the leadscrew is disengaged.
Then you are likely disengaging the leadscrew while it transfers high torque, which is not good unless you have special clutch to interrupt torque transfer. If you are disengaging it via split nut disengagement, then your nut will wear sooner than expected.
@@toxanbi The 'research' has dried up ! I've not been able to find anything to back up your valid suggestion and it seems the undercut at the end of the thread seems to be simply a theorhetical place for the tool to go after the thread. Anythreading I've done, I've simply disengaged the leadscrew so that at the end of the thread a circular groove is cut equal depth of the thread. This is also what I did when cutting a thread at school but based on the fact I had to show the teacher how to cut threads on the lathe - doesn't say much for the teacher ! (He knew it was possible but had zero practical expeience of doing it!)
So, let's look at the detail - firstly, the load is only that of the depth of cut of the pass - as the groove at the end gradually increases depth along with the thread itself.
[The Raglan lathe, early versions, were noted for being difficult to disengage carriage drive - although as I'm typing, this possibly rlates to the feed drive, not the leadscrew drive.]
Late disengagements will lead to the DOC being deeper than the thread DOC.
I've looked in FIVE books I have at home spanning at least 50 years of machining/lathework and thread information - one of the books being of a particularly professional nature as it comes in three volumes. Not one book details the ending of the thread cutting other than being specifically careful when threading either to a shoulder or in a blind hole.
Several YT videos show creating the undercut at the end before starting threading but none have explained specifically why it's done. I'm therefore stuck on whether it is 'officially' the way to do it or not.
I totally take your point and hence why I agree it's a valid one. When setting up the lathe for screwcutting, the process should end by specifying the leadscrew bearings should be oiled/lubricated and a greater portion of the screw itself should be brushed clean of debris, well oiled and a 120% length test drive to ensure clean and full engagement of the half nut(s) to correctly effect saddle travel. A well oiled leadscrew should minimise wear upon it.
One final point to note is the leadscrew thread form. I have not come across a leadscrew that is not an Acme thread. It is not a square thread but slightly tapered. This means, in typical use of opening the half nut(s) as soon as the nut(s) start to leave the thread, drive is lost and pressure & therefore wear on the nut is removed pretty much instantaneously.
Have you any info from 'reliable sources' (i.e. books) that raise this issue ?
@@toxanbi My final comment on this is from someone with more experience than me: "Most people will let the cutter cut a ring around on the last pass when threading. I have done it both ways but started pulling out some time back and seem to have stuck with that method. Honestly, it really does not matter that much one way or the other."
The ring at the end will make space for any dirt pushed along the thread by the mating part too which should ensure the whole length of the thread is available for its intended purpose.
1:50 Looked it up on a table to discover that a 1"-14 thread (as stated on the drawing) is 14 T.P.I.
I wouldn't even ask this guy where the toilets are !
2:00 Brilliant, they can't count - that thread is 15 TPI !
On any thread, you agree that there are as many grooves as there are threads. So count the grooves - the first one is at 0" and the last one is at 1" - so that's 2 - and there's 13 more between those.
When you count threads, you count spaces not the peaks. As an example , take a look at your hand you count 5 fingers and only have 4 spaces.......Have à good day..
Anybody in the world know when 1”-14 UNF turned into 1”-12 UNF?
My machinist handbook says “formally NF”
Presumably at the time of Unification.
You are right, this is very confusing. If I have to machine a part from a drawing that ask for ( 1"-NF ) I'll phone the drafter to be sure. You'll find (1"-14 UNS ) in the UNIFIED SPECIAL THREAD CHART . And (1"-12 NF ) in the NATIONAL FINE CHART. Anyway still confusing, even for an experienced machinist.....Many times simple things have to be complicated.!!?(&*;":%.)
Why is this video titled 'How to cut a fine thread' ? I was expecting over 100 T.P.I.
Maybe it's 14 TPI, 12-start ;)
Something that took minutes and required much attention to detail on a manual lathe, now takes ~10 seconds on a CNC lathe
Yes, but most operators doing that work on a CNC lathe wouldn't know what do if you said "Here's a South Bend 9A lathe, cut that thread on this." I know that nearly every CNC operator that I work with has no idea how to cut a thread on a manual lathe or even what "between centers" means.
Viktor dulal
Yes -- and how many people do you know that have a CNC lathe in their basement or garage?
r3drebel A CNC machine can do things fast, After it has a program to run, the setup and tooling for a job can take allot of time too. The skill of the programmer and machine operator determine how fast it can make things. There are still plenty of times where a manual machine can out perform a CNC machine, such as in allot of cases if you're only making one or a few of something.
@@crookedriver2079 That number is growing !
@@tonytiger75 Nothing stopping you driving a CNC manually. Buy a couple more encoder wheels and plug them in.
He sounds like he is wearing a tin mop bucket over his head
hated using wires....short runs one mach ok burt long runs and 3..9 machines to run....real pain