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bearing
11-09-2012, 05:53 AM
My SB9 does not have a QC gearbox and one cannot set one up the this model SB9 so I need to manually change gears to accomplish any threading.
This is a pic of the gears, are they correct for threading.
http://i478.photobucket.com/albums/rr144/bluearc5/lathe/faceplate0072.jpg

I attempted a few times, unsuccessfully, and would be grateful for any help with this. I thought I followed the sequence to properly make threads but it didn't work although it looked like a few threads did appear momentarily and then back to just turning.
thanks,

winchman
11-09-2012, 06:44 AM
The most likely cause it not using the thread dial correctly. If the dial slips or you miss the mark on a subsequent pass, the result is a coarsely turned surface instead of threads.

As far as the gears go, if you selected the correct set and they stayed engaged, there's not much that can go wrong there.

big job
11-09-2012, 07:42 AM
Good question "are they correct for threading"? They are as shown in the photo BUT
for what TPI? Nobody knows unless you count the gears the stud gear and the lead
screw gear so a gear chart is a must they are online. In short take a light cut and
measure that if the pitch gauge says 10, thats the gears in there. If you have a thread
dial with lathe off Manually turn it by pulley or belt engauge 1/2 nut (stop) now mesh
the thread dial just pick a number your choice and lock the dial. start machine and try
it using the same mark every time. If you do not have a dial put a piece of tape some
where on the lead screw and count it. Oh there are those who leave half nut on and
reverse machine, personally I dont like that. That just puts more wear on the 1/2 nut.
best I can explain. If you have a pitch gauge and complete set of change gears-good
ta go.

bearing
11-09-2012, 07:55 AM
Good question "are they correct for threading"? They are as shown in the photo BUT
for what TPI? Nobody knows unless you count the gears the stud gear and the lead
screw gear so a gear chart is a must they are online. In short take a light cut and
measure that if the pitch gauge says 10, thats the gears in there. If you have a thread
dial with lathe off Manually turn it by pulley or belt engauge 1/2 nut (stop) now mesh
the thread dial just pick a number your choice and lock the dial. start machine and try
it using the same mark every time. If you do not have a dial put a piece of tape some
where on the lead screw and count it. Oh there are those who leave half nut on and
reverse machine, personally I dont like that. That just puts more wear on the 1/2 nut.
best I can explain. If you have a pitch gauge and complete set of change gears-good
ta go.

Yes, the thread dial is set on "1" as it is engaged when the threading is started, but still not working correctly.
http://i478.photobucket.com/albums/rr144/bluearc5/lathe/2053_zps022a42d2.jpg

kitno455
11-09-2012, 09:28 AM
You are currently setup with the dual compounds for fine feed. That cuts something like 480 TPI. You need the gear change chart:

http://www.lathes.co.uk/southbend9-inch/img19.gif

allan

gvasale
11-09-2012, 09:30 AM
I think what the others are trying to tell you is this: there isn't any quick way to tell you what the lathe is set for now, wrt to tpi (other than doing a dry run.) Using the threading dial is relatively simple and the markings (number to watch) will change with different tpi. Normally, the dial will rotate until you engage the lever on the apron. Your job is to engage that lever when the right number lines up with the index mark. You also need the chart for selecting change gear combinations.

kitno455
11-09-2012, 09:50 AM
I think what the others are trying to tell you is this: there isn't any quick way to tell you what the lathe is set for now, wrt to tpi...

Actually, there is: 8 TPI / (16/54*18/72*18/80) = 480 TPI. See how easy that was? (sarcasm) :)

allan

firbikrhd1
11-09-2012, 10:29 AM
If you don't have a set of change gears and the appropriate chart you are unable to set up for the pitch of the thread you are attempting to cut. You either need to know how to do the math to set up the gears (the hard way) or use a chart. I suggest you obtain a copy of South Bends, How to Run a Lathe. It's a great little reference and inexpensive. Available on Ebay usually.

Jaakko Fagerlund
11-09-2012, 11:51 AM
Oh there are those who leave half nut on and
reverse machine, personally I dont like that. That just puts more wear on the 1/2 nut.
best I can explain. If you have a pitch gauge and complete set of change gears-good
ta go.
You can thread day and night like that and I'm sure that either Darwin or pension comes first before the nuts fail.

gvasale
11-09-2012, 03:29 PM
Allen I wasn't planning on counting teeth on all those gears to figure it out. When I deal with change gears, I do it only because its necessary. I don't even remember what I have the feed set for on my Atlas 10F.

kitno455
11-09-2012, 05:55 PM
Apparently you missed the 'sarcasm' part :)

I happen to have the SB 9" change gear choices memorized. Strange, considering I don't even own one. But it comes in handy on the SB forum over at PM.

allan

rohart
11-09-2012, 06:33 PM
I don't run a Southbend, but it's pretty obvious to me that every gear meshing here is a reduction, so I see no reason to disagree with Allan - you're cutting a thread that's so fine you'll need to use a sewing needle for your tool to realise you're not just turning.

There's something about the gearchange charts that's not clicking with you.

Start from here: if the lead screw turns at the same rpm as the spindle - ie the gearing is one to one - you'll cut a thread that has the same TPI as the leadscrew. If the leadscrew turns at half spindle speed, you'll get a thread that's twice as fine.

oldtiffie
11-09-2012, 07:43 PM
You are currently setup with the dual compounds for fine feed. That cuts something like 480 TPI. You need the gear change chart:

http://www.lathes.co.uk/southbend9-inch/img19.gif

allan

http://www.lathes.co.uk/southbend9-inch/img19.gif

Dead right Allan.

Unless or until the OP comes to grips with and tries and masters your posted gear change chart he will continue to have a problem.

Once he has it right and has the correct gears correctly set up he should be set to go screw threading.

Perhaps someone can post a list of the gears for that lathe so that he can see what if any gears are missing - and do someting about getting new "missing" ones.

gvasale
11-09-2012, 09:18 PM
Allan: I didn't miss the sarcasm. I like sarcasm. Sometimes is the best thing. I didn't grow up as a machinist, and I still have a lot to learn and always have time to read the book. But I still couldn't make a stab at that photo and come up with any more than a guess. So, you may be a couple of steps ahead of me and it doesn't bother me a bit.

bearing
11-10-2012, 06:14 AM
http://www.lathes.co.uk/southbend9-inch/img19.gif

Dead right Allan.

Unless or until the OP comes to grips with and tries and masters your posted gear change chart he will continue to have a problem.

Once he has it right and has the correct gears correctly set up he should be set to go screw threading.

Perhaps someone can post a list of the gears for that lathe so that he can see what if any gears are missing - and do someting about getting new "missing" ones.

The extra gears that came with the lathe are;60T-56T-54T-52T-43T **the others are 46-44-40-32-24.
How many constitute a whole set for this lathe?
thanks for helping with this.

big job
11-10-2012, 07:12 AM
Ah, reading this real quick the most "common threads" are 8-10-11&1/2-13-20-24 that
you usually will be dealing with, quickly what i see is you cant do 8-20 or 24 with what
you have so you need another 32T and a 16T .Now with what you have you can do
10 11 1/2 & a 13. example to do 8 you need two 32T gears you have one. Other
than my quick change SBs I do have a large lathe with change gears so I color coded
these change gears like 32T is green. Also the right side on the chart which is your
friction feed gearing your probably ok there. Dont give up there are plenty of gears
around get the common ones. sam

ljchipmaker
11-10-2012, 09:18 AM
It seems to me that if you were attempting to cut a thread with your compound set at the position shown in the picture, that could be one reason why you couldn't get a thread cut, regardless of what pitch your gears are set at.

Lj

Jaakko Fagerlund
11-10-2012, 12:18 PM
It seems to me that if you were attempting to cut a thread with your compound set at the position shown in the picture, that could be one reason why you couldn't get a thread cut, regardless of what pitch your gears are set at.

Lj
You can thread easily with the compund in any angle - just plunge cut the thread.

kitno455
11-10-2012, 02:58 PM
Ah, reading this real quick the most "common threads" are 8-10-11&1/2-13-20-24 that
you usually will be dealing with, quickly what i see is you cant do 8-20 or 24 with what
you have so you need another 32T and a 16T .Now with what you have you can do
10 11 1/2 & a 13. example to do 8 you need two 32T gears you have one. Other
than my quick change SBs I do have a large lathe with change gears so I color coded
these change gears like 32T is green. Also the right side on the chart which is your
friction feed gearing your probably ok there. Dont give up there are plenty of gears
around get the common ones. sam

Don't forget the ones that are currently on it (16,80 and two compounds)- You should have 16,24,32,32,36,40,44,46,48,52,56,60,80, plus an 80 tooth idler and 18/54 and 18/72 compounds. Sometimes there will be additional gears like 18 and 64 and 72. Also, the long and cross feed columns on that chart don't apply to the model C in question.

Also, with a minor amount of additional work, you can rearrange these gears to make nearly perfect metric threads:

http://www.practicalmachinist.com/vb/south-bend-lathes/cutting-metric-threads-change-gears-220447/

allan

tyrone shewlaces
11-10-2012, 03:16 PM
If you're trying to cut threads using the engagement dial, but your gear combination is not a compatible one, then you will not be able to use the threading dial and will have to leave everything engaged and reverse your way out for successive passes. (There are a couple tricks that still allow for using the thread dial in these cases, but leaving things engaged is easiest until you feel more adventurous). This is what you have to do when you're set up for metric pitches as well as other odd pitches. The thread dial only works with a standard set of feed rates, which is most if not all on the chart - you probably have to look at the book for specific instructions. For "custom" pitches, you'll be stuck with leaving it engaged and manually reversing for successive cuts. Even with the threads on the chart, for some pitches you can engage at any mark, some only on numbered marks, some only even or odd numbered marks, etc. It depends on your change gear combination. The SB Lathe book is a fun read anyway so since you have the lathe, you might as well get one or find one to download.

You could try here:
http://bbssystem.com/viewtopic.php?t=68

edit to add:
Meh. Doesn't look like that link has what you want. Searching the web might net better results though.

winchman
11-10-2012, 11:01 PM
I'm really curious about this statement in the first post:

"... although it looked like a few threads did appear momentarily and then back to just turning."

How would it ever appear like it was threading if the gearing was so far off?

oldtiffie
11-11-2012, 01:22 AM
If you're trying to cut threads using the engagement dial, but your gear combination is not a compatible one, then you will not be able to use the threading dial and will have to leave everything engaged and reverse your way out for successive passes. (There are a couple tricks that still allow for using the thread dial in these cases, but leaving things engaged is easiest until you feel more adventurous). This is what you have to do when you're set up for metric pitches as well as other odd pitches. The thread dial only works with a standard set of feed rates, which is most if not all on the chart - you probably have to look at the book for specific instructions. For "custom" pitches, you'll be stuck with leaving it engaged and manually reversing for successive cuts. Even with the threads on the chart, for some pitches you can engage at any mark, some only on numbered marks, some only even or odd numbered marks, etc. It depends on your change gear combination. The SB Lathe book is a fun read anyway so since you have the lathe, you might as well get one or find one to download.

You could try here:
http://bbssystem.com/viewtopic.php?t=68

edit to add:
Meh. Doesn't look like that link has what you want. Searching the web might net better results though.

Not necessarily (so).

Assuming the OP's lead-screw is 8 tpi (pitch = 1/8") he can "drop in" anywhere with or without a threading dial or "forward and reverse" if the tpi he is cutting is a sub-multiple of the lead-screw tpi (8 tpi) - ie 8, 16, 24, 32, 40 tpi but other than that without a threading dial he will have to use the "forward and reverse (keep half-nuts engaged)" method.

Just get the change gears right and all should be OK.

tyrone shewlaces
11-11-2012, 03:18 AM
Hmmm. OK.
I thought that's what I was saying... with less specifics. Some threads can drop in anywhere, some on various multiples and some need to stay engaged unless you use tricks.
Best recommendation for a newcomer is to get the book, then go by that book until the concept "drops in" inside the cranium.

darryl
11-11-2012, 04:12 AM
"... although it looked like a few threads did appear momentarily and then back to just turning."

Almost sounds to me like the half nuts aren't engaging properly.

bearing
11-11-2012, 07:26 AM
Ah, reading this real quick the most "common threads" are 8-10-11&1/2-13-20-24 that
you usually will be dealing with, quickly what i see is you cant do 8-20 or 24 with what
you have so you need another 32T and a 16T .Now with what you have you can do
10 11 1/2 & a 13. example to do 8 you need two 32T gears you have one. Other
than my quick change SBs I do have a large lathe with change gears so I color coded
these change gears like 32T is green. Also the right side on the chart which is your
friction feed gearing your probably ok there. Dont give up there are plenty of gears
around get the common ones. sam

This is a pic of what I have, and what is the significance of the or difference of the {T} following the numbers.
http://i478.photobucket.com/albums/rr144/bluearc5/lathe/changegears11-11-12008.jpg

This is a pic of the chart on the machine, however I am skeptical as to its validity to this machine because it was not hinged correctly, also the some of the tooling that was included do not fit this machine.
http://i478.photobucket.com/albums/rr144/bluearc5/lathe/changegears11-11-12001.jpg

John Stevenson
11-11-2012, 07:41 AM
Al,
The T stands for teeth, so 45 T means 45 teeth, rather obvious but probably not to a raw beginner.

Now this is said with the greatest of respect as at some point we were all there but you need to do a lot of homework first before you can use this machine correctly.

A very good place to start is the South Bend book "How to run a lathe "

Download is here.

http://www.wewilliams.net/docs/How%20to%20Run%20a%20Lathe%20-%203rd%20ed.pdf

The South Bend book is an early copy and it doesn't look like it was ever updated.
However Boxfords in the UK which made a clone of the South Bend with a lot of improvements produced their own later book, a copy which is available here.

http://www.pulse-jets.com/boxford/boxford_know_your_lathe.pdf

Similar on line help is this file but it's not specific for the South Bend.


http://team358.org/files/mechanical/HowToUseALathe.pdf

Best to read these books as grounding for using your machine.

RussZHC
11-11-2012, 12:01 PM
however I am skeptical as to its validity to this machine because it was not hinged correctly, also the some of the tooling that was included do not fit this machine

as a noobie with some experience, your statement is a bit of a concern to me...I would expect some tooling involved in a used machinery purchase to not fit the machine (strictly based on the passage of time and how most of us, I think, accumulated stuff). I am a bit confused as to why the conclusion would be reached that the threading chart is not for that machine...of course there is a chance it is not but...sorry, to me a bit of a leap (it is not something, compared to tooling and other parts such as change wheel gears, that really goes walkies...you would have to have a gear cover from another machine that fit the same way...)
The flip side is if you just got a box full of parts, there may need to be a lot more sleuthing done...if, for example, the change gears are really not for that machine...

I would fall into the group of previous posters who suggest gaining some more knowledge or, at the least , approach the problem a bit more systematically. The list of gears kitno455 lists total 16 plus another possible 3, counting the ones from the OP on the machine and the ones in the photo in your post # 25, I get to a total of 14 gears...they may not prove to be immediately of need but those 2 "missing gears" could play a role.
Threading esp for someone with little experience is not the easiest of things, to me not one of the first things that would be attempted when learning to use a lathe. I have never cut threads, its on the never ending list so hopefully next season. I would suggest playing around more with just "simple" cutting operations including changing the gears (first task there will likely be getting them, the new one(s), to mesh well with their mates) and just observing what happens. Among other acts, you should figure out how to stop carriage movement quickly (will likely come in very handy when you begin threading)...all I know is when I first attempt to single point a thread it will not be on a vital part, it will not be to a shoulder and it will not be internal. Some have had great success at threading right away, not trying to scare you off of that operation, but I prefer slow and methodical at least when learning.

bearing
11-11-2012, 07:04 PM
Al,
The T stands for teeth, so 45 T means 45 teeth, rather obvious but probably not to a raw beginner.

Now this is said with the greatest of respect as at some point we were all there but you need to do a lot of homework first before you can use this machine correctly.

A very good place to start is the South Bend book "How to run a lathe "

Download is here.

http://www.wewilliams.net/docs/How%20to%20Run%20a%20Lathe%20-%203rd%20ed.pdf

The South Bend book is an early copy and it doesn't look like it was ever updated.
However Boxfords in the UK which made a clone of the South Bend with a lot of improvements produced their own later book, a copy which is available here.

http://www.pulse-jets.com/boxford/boxford_know_your_lathe.pdf

Similar on line help is this file but it's not specific for the South Bend.


http://team358.org/files/mechanical/HowToUseALathe.pdf

Best to read these books as grounding for using your machine.

Advice taken; it will probably be a good idea for me to leave the forum until I learn how to use the lathe, when I reach an advanced degree of competence operating the lathe I will rejoin the forum and at that time I hopefully will be able to exchange information on an equal level,
thank you, to all of you that tried to help me,
AL

oldtiffie
11-11-2012, 07:36 PM
DON'T LEAVE THE FORUM.

There is no need to and if you feel that you have been hounded for any reason, I really do hope that is not right and I will be thoroughly pi$$ed off if it is right.

You are a full member here with equal rights to/as everyone and anyone else here, and have been since you joined. There are no "seniors" and "juniors" here irrespective of any who think there is. "Rank" here is alloted automatically at 100 (I think) posts irrespective of merit. "Seniority" is not "earned" either as it is based on "date joined".

"Number of Posts" is just that as it has no relevence to "quality" of posts - just the numbers.

Stay here and use the skills and information that are available and in the vast number of cases freely given.

big job
11-12-2012, 07:08 AM
Not a good idea, stay in here, report your findings, thats what this is for. And the idea
is for someone to be tweeked in the correct direction.

"A problem thoughly understood, usually has a simple solution" Hugo Young

firbikrhd1
11-12-2012, 11:03 AM
Bearing, leaving is a really bad idea. Like you, I started as a complete newcomer to machine work. Unlike you, I didn't have this forum to rely upon for quite a while after I was into it. I relied totally on books and really wished I had a friend I could ask questions of.
Today, I still don't consider myself a machinist. The real machinists here have a lot of formal training and years of experience working in shops. Thanks to my perseverance, reading a lot and the fine people here I do pretty well for myself these days. I am even able to offer advice sometimes, which in itself really amazes me. I visit the Forum often just to read the problems others have and learns the solutions. Who knows, I may come across a similar situation one day, sometimes I post a picture or two of my projects just for the feedback, and I still occasionally ask a question when I'm stuck. This is a good place to be a part of. Don't let the occasional curmudgeon's comments get to you and you'll find this one of your most valuable resources.

Wirecutter
11-12-2012, 01:55 PM
Bearing -
I agree with firbikrhd1 (http://bbs.homeshopmachinist.net/members/114-firbikrhd1) and others that leaving is not what you should do. Hang around. Sure, there are some members here that are a little 'prickly', but there are also a lot of great, helpful people. More than a few are damn funny, to boot.

I have the same lathe, and your setup looks like the slowest feed rate you can get. I use the 2nd slowest feed for turning down stock to a smooth finish. Referring to your photo, see the smallest gear visible? I use the next size up, the 20T, if I recall. The rest of the setup is the same. This is not for threading, though - I use it for turning down stock to smaller diameter. I don't think I have a tool pointy enough to thread that fine.

From your later photo, it appears that you have a complete or nearly-complete set of gears. I'd recommend that you take a little time disassembling the gears and experimenting with the configurations from the gear chart. The chart you have looks correct to me. It's not difficult, but if your machine is anything like mine, you'll get your hands pretty dirty in the process. It's all part of the fun.

When I got my lathe (my first and only, BTW), one of the coolest discoveries and learning experiences was cutting threads. The next coolest was discovering that, after spending some time with it, I inadvertently cut my first threads with a left hand thread. :D Anyway, with a good cutting tool, you can cut nice threads on any diameter stock that you can chuck up in the machine. There's a ton of literature (and a bunch of discussion threads on this forum) about thread cutting.

One of my first "exercises" in thread cutting was making a stainless steel "pill bottle" with 32 TPI on the cap. Thusly I learned how tedious it is to unscrew a fairly fine-thread pill bottle. But it's a neat little piece of work, and when the top is on it, it's hard to see the seam between the bottle and the top. I use it to store little ball bearings and other tiny parts.

Anyway, hang in there (here), and enjoy the machine.

-Mark