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Slick1
04-16-2011, 10:42 AM
Hello, I have a new lathe and trying to learn how to use it. I have used one in the past but with assistance. I have never done any lathe threading though. My lathe has a quick change gear box and a chart on the left. Can someone explain how to read the charts to set the quick change gear box for the respective thread. The lathe is a precision matthews 12x36.

Thanks David

Dr Stan
04-16-2011, 10:54 AM
A pic of the QC gear box would be helpful.

Slick1
04-16-2011, 01:04 PM
I have pics but cannot get them on this reply. The photo bucket thing is too far above my computer level. I can email them to you if you would be kind enough to look them over for me.
Thanks David

RussZHC
04-16-2011, 01:05 PM
http://www.lathes.co.uk/standardmodern/page2.html

That's Standard Modern (two photos about half way down page) version but many are similar.
Most often a table/chart where the columns and rows cross is what thread or feed rate it will be.

In the case of this SM there are two movements with letters that match part of the table and holes which align with a table column. If what you want was in row "A" move applicable handle there and then a choice of the column matching the thread and move that handle there.


http://www.machinetoolonline.com/images/PM1236headstock.jpg

is a typical PM series of tables, adjust levers and dials to what the chart/table calls for for a given thread. More details I am sure in the manual and as its a relatively current machine, finding one of those should be little hassle.

Slick1
04-16-2011, 01:35 PM
That is it, the PM one. I am just not connecting with the charts and how the chart works. There about 5 different charts on it. I don't understand which chart is for what. I wish I could get the pics on here but that isn't going to work for me. I tried to copy and paste but that don't work either.
Thanks David

Slick1
04-16-2011, 01:49 PM
This is one chart.

Indicator table
T TPI Scale TPI Scale
4 8
0 16 24
32 40
48 56


T TPI SCALE T TPI SCALE
4 1/2 8 14 2-4-6-8
16 5 4.8 16 15 4.8
5 1/2 8 18 2.4.6.8

Slick1
04-16-2011, 01:55 PM
Well that didn't paste correct. Sorry I do have a manual but it does not cover the charts. I don't guess there is a way to tell you guys the charts. To me there should be a chart that tells you where to set each knob. There are four knobs and if I wanted to make a 16 tpi thread my thinking is that there should be something on this chart that says set knob 1 at say 2, knob 2 at B, knob 3 at I or II and knob 4 and M or S. Is that thinking correct on this?

aboard_epsilon
04-16-2011, 02:25 PM
think you're trying to take too much in at once

leave the machine how it is ..and just practise some threading with it set up as it is ...once you've mastered that ..then you will be able to make some sense of the charts easier...without other stuff dwelling on your mind

PS don't worry about the dial indicator ..thats advanced threading ..get the hang of basic threading first ...trhat is leaving it in threading mode ..and reversing .

all the best.markj

The Artful Bodger
04-16-2011, 04:00 PM
Hi David, your lathe is probably the imperial version of my metric lathe and those charts can be very confusing until you learn the 'code'.

The knobs, the 'M'/'S' knob selects either feed or threading, I think 'M' is threading, but you should try each way. When set for feed the slotted shaft will turn when threading the feed screw will turn.

The ABC etc knob and the 123 etc knob set ratios in the quick change gear box. The other knob is the I/II knob which you might think of as coarse and fine, II is twice the speed of I.

To find 16 TPI, for example, locate 16 on the table. Look at the top of that column and you will see a letter and a number, these are the setting of the ABC and the 123 knob, look to the left and you will see the setting for the M/S and the I/II knob, for threading this will always be M something, so MI for finer threads and MII for coarser threads.

There is one other thing to check and that is the setting of the change gears. Look at the very left of the table and you will see a slightly cryptic diagram of the three gears that make up the change wheel train on our lathes. You need to take the cover off the end of the machine to see these. On mine I usually have a 24 tooth gear on the top shaft and a 48 tooth gear on the lower. There is one big gear in between these two. Now for inch threads on an inch machine this gear can be any size as it plays no part in the gear ratio. However, just to confuse things somewhat this is likely to be a 'compound gear', that is two gears in one, for inch threads on an inch lathe both the top gear and the lower gear must engage with the same set of teeth on the compound gear.

For some threads they will also show a 'Z' value. Look at the little gear diagram and one of the gear positions will be shown as 'Z' indicating that that size gear is required in that position.

The purpose of the compound gear is to get the necessary complex ratios required for cutting metric gears on an inch lathe, and vice versa.

John

Slick1
04-16-2011, 04:06 PM
I have been running a few threads on the lathe but there about 6 charts for threading. The knob with a I or II seems to make a coarser pitch on II. But I don't know what that means. I would think there would be more pitches than two on it. If someone would send me an email address I could send the pics to you for some help.
Thanks David

Slick1
04-16-2011, 04:12 PM
John, that makes some sense to what I am seeing. I will go out to the shop with your print out and see if I can make it work. There are some other symbols on the charts that are squigglie lines if that makes any sense. Some of them are vertical and some horizontal. Does that ring any bells with you?
Thanks David

Slick1
04-16-2011, 06:00 PM
I am seeing some signs of life. Threading is just one table? I'm still not understaning the Z thing. There is a Z in the chart and there is also a Z1. I think the Z is a row of the gears that you would use on the bottom gear? What could Z1 mean? This is way too hard for the average guy. There should have been instructions with this thing. There are other tables too. Thanks for helping me out.

aboard_epsilon
04-16-2011, 06:06 PM
maybe this will help

http://groups.yahoo.com/group/pm1027lathe/

aboard_epsilon
04-16-2011, 06:08 PM
is yours like the one in the picture on the yahoo group

if it is

then it is also

Busy Bee b2227

and there will be a manual for that on the busy bee site me thinks

or in the files section of the group

all the best.markj

aboard_epsilon
04-16-2011, 06:13 PM
here's another

http://groups.yahoo.com/group/bluemachining/

all the best.markj

Slick1
04-16-2011, 06:17 PM
It is the one in an earlier post in this thread, the PM12x36. I bought it new and it has a very hard to read manual. But it has nothing about the charts in it. There are some pics on the Precision Matthews site but I don't know if the charts are readable in the pics. I will try to get someone to comeover to teach me how to do the pics on this site but that will be a day or two.

aboard_epsilon
04-16-2011, 06:23 PM
well the blue machining yahoo group mentions the 1236 in its decription message

all the best.markj

aboard_epsilon
04-16-2011, 06:37 PM
how's this ..if the same ..the manual in the link maybe better written

you have to have adobe acrobat reader on your computer to read it

http://www.busybeetools.com/product_manuals/CT043N.pdf

all the best.markj

Slick1
04-16-2011, 06:43 PM
http://www.machinetoolonline.com/PM1236.html

This is where you could see the lathe.
By the way thanks for taking time for this ignorant lathe owner. I will catch on one day.

Thanks David

aboard_epsilon
04-16-2011, 06:48 PM
http://www.machinetoolonline.com/PM1236.html

This is where you could see the lathe.
By the way thanks for taking time for this ignorant lathe owner. I will catch on one day.

Thanks David

yup ..same lathe that the buzy bee sell ..download the manual in that link ..it may be a better manual ..

a lot of these lathes all come out of the same asian factory ..they are just rebranded and painted different

all the best.markj

Slick1
04-16-2011, 06:54 PM
OK yes it is the same as the busybee one. Same manual too. I will keep this manual too it may be written different and have something about the charts in it.

aboard_epsilon
04-16-2011, 07:18 PM
Yes, just had a read of it

You wont be doing any thread cutting with those instructions

They are bad ..!!!!

Bet there is on the net somewhere ..another set of easy to follow instructions for that lathe ..

try grizzly

Grizzly is run by the brother of the guy thats runs Buzy Bee though

sorry dont know any other American dealers

here's some uk ones that probably sell the same lathe

try Chester.co.uk

try Warco

try Axminster

all the best.markj

RussZHC
04-16-2011, 08:22 PM
Try this:

https://www.machinetoolswarehouse.com/.../D240x500_D280x700_GB.pdf

and if the link does not work, google "Optimum lathe manual", that pdf file is on page 2, a little way down

The manual, IMO, is much better written than average but keep in mind it is not identical to your tables (or very unlikely) BUT, starting about page 94 of 120 or so, there is a somewhat lengthy discussion to add to the briefer ones earlier in the pdf file.
The "key" to finding this type of information can sometimes be, as already stated, many of these lathes come from the same or relatively near factories. So once you find a similar manual that is better quality, it can often work for other brands (lathes and small mills).
As example, early in that file they actually define the illustrations of the half nuts being engaged, longitudinal feed engaged etc.

RussZHC
04-16-2011, 08:24 PM
previous link does not work (too many ...), the manual I refer to is the second one on the second page of "optimum lathe manual" search (at 10 hits per page)

aboard_epsilon
04-16-2011, 08:36 PM
previous link does not work (too many ...), the manual I refer to is the second one on the second page of "optimum lathe manual" search (at 10 hits per page)

is this the one , looks a lot better

https://www.machinetoolswarehouse.com/xcart/files/CZ1440G-1_manual.pdf

all the best.markj

Dr Stan
04-16-2011, 08:39 PM
Slick1,

Sorry I haven't gotten back to you, but I've been out in the shop pulling wire and figuring out how to wire the drum switch and reversible single phase motor I put on my Fray. Not something I do everyday so it took a while.

One of the best books on the lathe is "How to Run a lathe" published by the original South Bend Lathe Works. Look for it on EBay and other sites. Lindsay Technical Books http://www.lindsaybks.com/ also has several good publications on basic machining as does Audel's http://www.contractor-books.com/How-To/Audel_Technical_Books.htm.

Have you looked on YouTube for threading videos?

Stan

Just remembered, the site www.metalillness.com has a PDF of the Navy's Machinery Repairman book. I know it has an excellent section on threading as it is what was used when I went to the Navy's machinist school.

RussZHC
04-16-2011, 08:41 PM
Nope;
quite good though and in some details "better" than the one I found which seemed to have quite a few more pictures (the file size as nearly double the one you posted)...the lathes in the file I found are the Optimum colors of grey/pink/white (and are a simpler version with fewer knobs and handles)

aboard_epsilon
04-16-2011, 08:43 PM
Slick1,

Sorry I haven't gotten back to you, but I've been out in the shop pulling wire and figuring out how to wire the drum switch and reversible single phase motor I put on my Fray. Not something I do everyday so it took a while.

One of the best books on the lathe is "How to Run a lathe" published by the original South Bend Lathe Works. Look for it on EBay and other sites. Lindsay Technical Books http://www.lindsaybks.com/ also has several good publications on basic machining as does Audel's http://www.contractor-books.com/How-To/Audel_Technical_Books.htm.

Have you looked on YouTube for threading videos?

Stan

Just remembered, the site www.metalillness.com (http://www.metalillness.com) has a PDF of the Navy's Machinery Repairman book. I know it has an excellent section on threading as it is what was used when I went to the Navy's machinist school.

the trouble he's having is understanding how to set the machines levers up for threading ..his instructions are crap ..

he can move onto "know your lathe" once he's understould how his lathe actually works .

all the best.markj

The Artful Bodger
04-16-2011, 11:51 PM
David, to answer some of your question you asked while I was out today.

The 'Z' thing, they use Z to represent the small gears that you can change in the gear train. Where the table shows, for example, Z20, that means you should mount a 20 tooth gear in the position shown by 'Z' in the diagram.

Just revising what we have talked about so far....

When threading find the thread pitch you require, look to the diagram to the left and check that the gears shown there are what are presently loaded on your lathe. If one of them is labelled 'Z' then look upwards from your selected thread pitch until you get to the second row, which will be the 'Z' values for the different pitches in that table. Look at the first row of the table for a letter and numeral pair which you use to set too knobs on the gear box, look to the left of the thread pitch to the first colum where you will see "M" and "I" or "II" and that tells you how to set the other two knobs.


Those squiggly lines, the vertial squiggle represents cross feed pitchs and the horizontal squiggles represent carriage feeds. You read the charts the same way as for thread pitches but off course the MS knob is set to "S" for feeds.


John

The Artful Bodger
04-17-2011, 01:07 AM
David, I even found a picture of your lathe!

http://i799.photobucket.com/albums/yy274/jonathank15/IMG_20110308_234137.jpg

So.... looking at this picture... to cut a 16 TPI thread..

Locate 16, look to the left and it shows MII, so set one knob to 'M' and another to 'II', now look upwards until you find an alpha and numeric entry, in the first row we see 'A2', set alpha knob to 'A' and numeric knob to '2'. Thats all the knobs set. Note the Z line closest above to to where you found 16, in the first colum (which is the one we are interested as that were the 16 is) we see 48. So you need to mount a 48 tooth gear according to the diagram to the left of where you found the '16'.

Slick1
04-17-2011, 09:05 AM
Wow, I wake up to more great info. Thanks guys! Make sure I see this correctly. There are really two different charts on this. The upper chart is for a 48t on top and a row of Z respective gears for the bottom gear. The lower chart is for the 24t on top and a row of Z(1) respective gears for the bottom gear. Does the 1 after the Z mean anything?

The whole Z row was cornfusing me somehow.

My lathe came with a 24t on top and a 48t on the bottom. So if I were to run with that gearing and say, A,4,M,II, then I would do 20tpi? Or A,4,M,I, then I would do 40tpi? I will cut some of these today!

The squiggly lines are cross and carriage feed rates based on cutters and material being turned.

I know I will be asking many more questions on this forum. Hopefully the next ones will show some signs of life.

Thank you all for taking time to help me out. David

big job
04-17-2011, 09:06 AM
In no way im trying to be a wise guy, I read a lot about these kinds of
problems, all I can say Ill stay with my 1942 SB. Any first grader can
understand those charts. This new stuff with turtles and rabbits alladins
lamps I used brother in laws Chry 300 other day I cant figure out how
to put heat on. Why cant it say heat def so far I know a propeller means
a fan. Mine, all you need to know is the TPI chart says set to C then
the other one on the tpi you want. How simple can it get.

Slick1
04-17-2011, 09:44 PM
Well, I am actually in the thyrd grade. But you are correct. It seems the newer, the more complicated things get. That being said. I did cut some threads today. I used the thread indicator too. Not sure I did it right though. I just started on the same number each time a ways out from the thread. I have read that you start on some numbers if you are doing even number of threads and visa versa. I didn't end the threads good though. I need to study up on how to end them. I plan to do more Monday evening. I have a 2" piece of aluminum that I am threading and then cutting off etc. Do you guys change the QCGB with the lathe running? I saw a video showing them being change with it running. I have been turning it off to change them.

Thanks again David

Toolguy
04-17-2011, 09:58 PM
The best way to avoid mistakes and ruined projects is to always use the same number for all threads. Yes, you can use other numbers sometimes, but make it easy and follow the KISS principle. You can also change toolholders with the lathe running, but you have to be very watchful not to drop one on that the tool is longer than the previous tool. The second it drops, it will gouge right into the work and all kinds of exciting things will happen. It's a lot safer to just turn the machine off and back on.

ftl
04-17-2011, 10:07 PM
Look back into the archives from a couple of years ago:

http://bbs.homeshopmachinist.net/showthread.php?t=34932

In this thread I posted a list of all possible thread pitches that can be created by the lathe we share.

There are also some good descriptions of what those confusing thread charts mean.

If you want the info as a spreadsheet, PM me and I will send it.

Slick1
04-18-2011, 09:02 AM
Hey, I found your charts in the other post. My, what a help that will be. I have printed them out already. You guys have been awesome in helping me. I hope that I can be of help to you guys in some way sometime.

Thanks David

Boucher
04-18-2011, 10:06 AM
David If you included your location in your personal data there might be someone near you. The front side of the learning curve is the steepest. I have been where you are and have finally deciphered most of the information on my lathe. To make things even worse there is one graphic on my lathe that is wrong.

Alistair Hosie
04-18-2011, 03:25 PM
Aboard epsilon is offering spot on advice .Threading is not something to worry about when you finally do it you'll say what was all the fuss about, but in the meantime just concentrate on the very basics I.E cutting any thread at all, and seeing how it's done .I warn you though it's good fun. Addictive. Once you've eventually mastered it you'll never look back. Kindest regards Alistair