PM-1440GT Change Gear Thread Pitch Calculator

Bob, Attached is a comprehensive thread chart with TPI, decimal TPI and decimal MM. Doesn't fit on one sheet. LOL

It's a bit cumbersome and only really useful using the search function.

FYI the the data driving cells are hidden but the visible cells are not protected.
Wow! Thanks yet again, Jay. Great and useful stuff!
 
Once again friends. We are blessed here with a wealth of knowledgeable members willing to help when the occasion arises. I personally will/have abuse(d) Jay and Mark myself. I am glad Jay and I have the same lathe. LOL
 
Once again friends. We are blessed here with a wealth of knowledgeable members willing to help when the occasion arises. I personally will/have abuse(d) Jay and Mark myself. I am glad Jay and I have the same lathe. LOL
Wait until you get my bill......:cautious:
 
Hi Ron,

If I understand what your saying is you would prefer if the published table was just reorganized in ascending order?

In Bob's example he was looking to cut a 27 TPI thread which is not published for his lathe. Based on his description of wanting the raw data represented in decimal form was to be able to find the decimal equivalent or near equivalent that could be used, 1.e. 27/1 = .03707. As far as I know the only way to find if that exists within the available gears/settings is to calculate all the available combinations.

Maybe I've misunderstood?

Hi Jay
I have had a look at your latest table and it is quite impressive. You must have put an enormous amount of work to produce it. It will clearly be very useful to some members.

From my point of view it is really overkill. There would only be a very few times if any in my lifetime where it would be used. I really only use a limited # of feed rates and thread pitches. These are actually presented in the tables attached to the headstock of my lathe- but in a form that is not so easy to use.

How do we actually use thread and lead lathe tables?

Take a typical scenario trying to cut a std pitch thread.
We first decide on the thread pitch required then,
Choose the appropriate change gears
Then set each to the Gearbox levers /dials in logical sequence to achieve the desired result.

From my point of view this is the complete reverse of what is presented on the headstock tables.
When I looked at your spreadsheet with its myriad of options I was immediately confused by how I would find the option that was closest to the pitch /lead that I required. (There are many many options presented on many rows)

For my needs I am merely going to translate what is on my headstock into two tables sorted initially on increasing pitch and lead then listing in logical order as to how it would be achieved. Clearly this is not what everyone wants but I think the logic behind the suggestion would improve the presentation in your table. Perhaps just eliminating options that are not the closest option would improve the usability.
Cheers
Ron
 
Hi Ron,

As I pointed out to Bob. That kind of table is only useful by using a search function but it does provide all the raw data which could in turn be further manipulated if one wanted to take on that task. . The KLS-1340A table is only good for that model or equivalent so only useful for a few.The table itself not all that complicated to do once you know all the gears and gear ratios.

My purpose of going down this road in the first place was to figure out all of the combinations that could be used on my lathe that are not published on the factory tables. Can I cut "X" thread on my lathe even tough it is not on the factory table? Even if the pitch does not come up as a whole number there may be a combination that is close enough.

The kind of table you're looking for I think is what I have seen on some lathes with universal gear boxes where the first column lists the pitch in ascending order and the second column list the lever positions. These lathes usually don't have change gears so it simplifies things.
 
Thanks Jay
I will photograph my lathe labels for pitch & feed and reorganise the existing data. I don't think I even need a spreadsheet. I think a simple table will provide all the organisation I require.
My lathe is metric, these days I only cut metric threads and my lathe only has two change gears, 30 teeth and 60 teeth. Quite simple I hope. Hopefully each table will fit on A4 sheet at font size that I can read. Will laminate them and stick them to the outside of the change gear cover.

Thanks to all who have contributed to this thread as it has got me motivated to fix a problem that has been bugging me for a while.
Ron
 
Hi Jay, did you come up with a full set of possibilities for the PM1440GT? I can't open the attachment in the first post.

My purpose of going down this road in the first place was to figure out all of the combinations that could be used on my lathe that are not published on the factory tables. Can I cut "X" thread on my lathe even tough it is not on the factory table? Even if the pitch does not come up as a whole number there may be a combination that is close enough.

TIA
 
Hi Jay
I have had a look at your latest table and it is quite impressive. You must have put an enormous amount of work to produce it. It will clearly be very useful to some members.

From my point of view it is really overkill. There would only be a very few times if any in my lifetime where it would be used. I really only use a limited # of feed rates and thread pitches. These are actually presented in the tables attached to the headstock of my lathe- but in a form that is not so easy to use.

How do we actually use thread and lead lathe tables?

Take a typical scenario trying to cut a std pitch thread.
We first decide on the thread pitch required then,
Choose the appropriate change gears
Then set each to the Gearbox levers /dials in logical sequence to achieve the desired result.

From my point of view this is the complete reverse of what is presented on the headstock tables.
When I looked at your spreadsheet with its myriad of options I was immediately confused by how I would find the option that was closest to the pitch /lead that I required. (There are many many options presented on many rows)

For my needs I am merely going to translate what is on my headstock into two tables sorted initially on increasing pitch and lead then listing in logical order as to how it would be achieved. Clearly this is not what everyone wants but I think the logic behind the suggestion would improve the presentation in your table. Perhaps just eliminating options that are not the closest option would improve the usability.
Cheers
Ron
The charts on the lathe panels only cover the common threads that people use, otherwise the tables would be as huge as the spreadsheet is. When you need a thread and it is not on the chart, what do you do? Go buy a different lathe? Consider yourself limited and give up? The great help Jay gave me opened up MANY more possibilities for other threads, using only the change gears that came with the lathe. On a lathe with simple change gears only, no quick change box, it is not too difficult to check for the possibility of a given ratio with pencil and paper, but it still takes a lot of time. Before there were computers everywhere, what Jay did in an hour or so would be more like a life's work. I cannot thank Jay enough for what he did for me. He made sense out of FM (f'ing magic.) The aha! moment was when Jay found the tooth counts of the change gears, which are not in my manual, and figured out the actual ratios of each thread/feed box position (the feed/thread box is fully enclosed and in an oil bath, and has no cover like the headstock does so you cannot easily count teeth.) He then added way more computer skills than I have, and shazam, a chart with all the possibilities. The sum of those skills is beyond f'ing magic, it is brains, knowledge, and willingness to take on the task. Wow, just wow!
 
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Hi Jay, did you come up with a full set of possibilities for the PM1440GT? I can't open the attachment in the first post.



TIA
I have not done a full chart for the PM-1440GT like I did for Bob. The calculator I posted above works enough for what I need. If you don't have Excel I can convert it to another open source format. I will eventually get around to making a full chart. It won't be nearly as large as Bob's since we have less gears. Not high on my list right now.
 
Not a problem, I was just curious. Thanks.
 
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