Metric thread with Quick Change

[JPMacG]

I just realized that the Atlas/Craftsman Quick Change gear box does not provide a means of cutting metric threads. According to Tubal Cain, I would need to convert the lathe to a manual change gear configuration in order to do metric. This would be too costly for me.

Anyone know of another method? I can imagine changing the ratio between the spindle and the Quick Change gearbox by just changing two gears.

 

[Bob Korves]

Change gears to do metric threading can be used with a quick change gear box. You just need the chart of which gears it takes for the threads you want. starting with the metric transposing gears.

 

[Dave Paine]

I agree with Bob. I have an imperial thread lead screw and QCGB. I recently needed to single point an M16 x 1.5 pitch thread since the thread was LH and I have no LH dies or taps.

My Grizzly lathe has a few gears to change to enable machining many, but not all, metric threads or some special imperial threads.

I looked at the chart in my manual, changed one gear out and engaged with a second gear in another and I was able to machine the thread.

What is the pitch you need to machine?

 

[JPMacG]

I need to do a metric 1.5 pitch thread. I will have to go through the arithmetic and see if I can work it out with a single gear change.

 

[Dave Paine]

This is the metric chart from my Grizzly G9249 lathe in case your gears match.



I may be able to machine this for you if you do not have the correct set of gears. I am up the NE Extension, NW of Allentown.

 

[Rob]

All you will need is an additional 52T gear to cut 1.5 pitch thread. It is not perfect but close enough you shouldn't have any problems. That is what I used to make my collet chuck for ER32 collets on my Atlas lathe.

 

[JPMacG]

Thank you Rob. LOL That is exactly what I want to do.... cut the threads for the nut on an ER32 chuck.

And thanks for the offer Dave. Ideally, I want to make the chuck on my lathe so that it is aligned on the spindle the way it will be used. I work in Souderton, about 45 minutes south of Allentown. I live near Newtown, a bit farther.

 

[rzbill]

I'd say that 52T gear would work fine per the Atlas chart. Assuming the claimed 0.05906" pitch is exact (IE 0.0590600) vs a rounded number, it would take a 300mm long screw thread to show a 0.001" deviation in thread location from the 1.5mm perfection (0.05905512......")

 

[T Bredehoft]

17 pitch will be close enough if you make it a scosh undersized.

 

[JPMacG]

And I only need it to work over about 1/2 inch of thread. I plan to get a 52T gear and give it a try. There are a bunch listed on eBay. That same gear fits the indexing center on my mill, so it may find a second use some day.