Imperial threads from a all metric lathe

Bernard Reilly · Post by **Bernard Reilly** » Sat 21 Apr , 2007 21:03 pm

Hi all I am new to this groupe. Can anyone tell me if there is a chart to cut imperal threads on a metric gearbox of a TDS1/1GB Viceroy lathe.
Thank you bernard25@tiscali.co.uk

Triac whizz · Post by **Triac whizz** » Sat 21 Apr , 2007 21:10 pm

hmm, I don't have a chart, but googling would probably do it.

Do you have a 127/100 gear? I'm assuming you'll need this as I do to cut metric threads on an imperial lathe

25.4 TPI should be easy

(not sure what you'll use it for though)

Post by **Denford Admin** » Mon 23 Apr , 2007 9:25 am

Sorry I can't help, but I'm sure Dazz could help you, and maybe you can help him ? - he wanted to cut Metric threads on his TDS:

viewtopic.php?t=897

Andy B · Post by **Andy B** » Wed 25 Apr , 2007 11:06 am

For cutting Imperial threads on a Metric machine, you probably need a 127/135 tooth gear pair.

Admin has kindly posted the 280VS charts on the downloads section for Imp to Met and Met to Imp.

So if you have the same size intermediate gears (48T), you just need to know what metric threads the various lever positions give (on the 280) and then you should be able to work it back from the lever positions on your gearbox. Did that make sense...?

I'll try to remember to make a note of the threads / lever positions on mine this evening.

Andy

sweep · Post by **sweep** » Wed 25 Apr , 2007 12:50 pm

At long last I thought I had the opportunity to give something back to this forum ...but unfortunatley, and probably quite wisely, you cannot upload programs with .exe file extensions.

If anyone wants it mailed direct, I have a simple program that will allow you to input your available change wheels and it will spew out the metric threads along with pitch errors etc.
If Denford Admin want to vet it first I can let you have it.

Regards ...Richard

Post by **Denford Admin** » Wed 25 Apr , 2007 13:04 pm

Just send it along to technical [at] denford[.]co[dot] uk and I'll check it and attach it as a link or a ZIP file

Post by **Denford Admin** » Wed 25 Apr , 2007 14:22 pm

Ok - its in the downloads section now:

viewtopic.php?p=2997

Cheers

dazz · Post by **dazz** » Mon 30 Apr , 2007 12:05 pm

Hello

Attached is an Excel spreadsheet I wrote to produce thread tables for an imperial TDS 1/1 lathe. It includes a macro that helps search for the best combination of gears to convert the lathe to cut metric pitches.

The first spreadsheet just lists metric pitches. Nothing fancy.

The second spreadsheet calculates thread cutting pitches for the standard imperial setup or a metric conversion. I figured there is enough space under the gear cover to insert two compound gear pairs into the existing gear train by making a new quadrant arm.

The third spreadsheet explores the capability of the Denford metric conversion gears/quadrant to produce metric pitches. Note that the in/out gear change was not included in this conversion.

The third spreadsheet demonstrates how the second can be modified to suit the application. In your case, you just need to change the gears and gearbox ratios to suit your metric lathe. Make a copy first (4th spreadsheet) and experiment on the copy.

This is posted as-is, where-is. I made it for me, so it is not well documented or sophisticated. If you have problems with it, buy a book on Excel and VBA programming. Please don't ask me for explanations.

Enjoy.

Denford Software & Machines

Denford Software & Machines

Imperial threads from a all metric lathe

Imperial threads from a all metric lathe

Charts