Cutting Metric Threads

[EdK]

It's been a while since I've cut a metric thread and have never cut one on my current lathe. I need to cut a M5x0.5 thread and I have all of the change gears set and the tool bit ready to go. I remember one has to not disengage the half nuts for metric threads but what I don't remember is if you have to synchronize the thread dial to a certain number for metric threads. I'm guessing not but don't want to ruin my workpiece by "assuming". Am I correct in that one does not need to synchronize the thread dial with a certain number for metric threads? The lead-screw is imperial.

Thanks,
Ed

[doubleboost]

Just leave the nut engaged and reverse the lathe
http://www.youtube.com/watch?v=1sDps7TdgoU
John

[TomG]

Or engage the same number on the thread dial for each pass.

Tom

[EdK]

I was successful in cutting the thread with no mishaps. That's one fine thread.

Thanks for the advice John and Tom.

Ed

[PixMan]

(03-03-2013, 05:25 PM)TomG Wrote: Or engage the same number on the thread dial for each pass.

Tom

That doesn't always work out when the lead screw is an inch lead. You can get lucky with some lathes (as it appears Ed did), but it's best to engage it ONCE and leave it there until the thread is completely done.

[EdK]

(03-03-2013, 07:30 PM)PixMan Wrote:

(03-03-2013, 05:25 PM)TomG Wrote: Or engage the same number on the thread dial for each pass.

Tom

That doesn't always work out when the lead screw is an inch lead. You can get lucky with some lathes (as it appears Ed did), but it's best to engage it ONCE and leave it there until the thread is completely done.

I didn't disengage the half nuts. I did it the way I'm use to cutting metric threads and the way John's video shows.

Ed

[TomG]

I'm glad Ed didn't screw up his threads based on my bad advice. Thanks for calling me on it Ken.



Tom

[EdK]

(03-03-2013, 08:15 PM)TomG Wrote: I'm glad Ed didn't screw up his threads based on my bad advice. Thanks for calling me on it Ken.



Tom

No problem Tom. I already knew that the half nuts needed to stay engaged. It was the use of the threading dial that I was unclear on. I was finished by the time I saw your post.

Ed