Threading with Grizzly G0516 lathe?

[vascon2196]

Howdy folks,

Does anyone know how to thread with a Grizzly G0516 lathe?

I can't figure it out.

There is no threading dial on this thing???

I kept trying to add a thread but the damn thing kept cross threading.

The gears are set up correctly...the compound is set to 29.5 degrees...I kept starting from the same position...not sure what I'm doing wrong.

Thanks

 

[johnl]

I have the Grizzly G4015 lathe/mill and have wondered the same thing. I got acceptable threading by never disengaging the half nuts. I stop the spindle at the end of the threads, retract the tool and reverse the spindle back to my starting point. I would be interested to know if there is a better way.

John

 

[Philjoe5]

Chris,
If you're cutting a metric thread on the machine it's usual practice to stop the feed at the end, don't disengage the half nuts, retract the tool, reverse the carriage to the start, advance the tool to make the next cut and keep repeating.

If you're cutting a Unified thread, you can also follow the same procedure, though it's tedious.

Depending upon the pitch of the Unified thread you can engage the half nuts only at certain marks on the threading dial. Your manual should tell you what they are.

Cheers,
Phil

 

[rythmnbls]

I have a G0516, Phil and John are correct, you must leave the carriage half nuts engaged and reverse the spindle at the end of each cut.

There are threading dial kits available for this lathe, the littlemachine shop has them.

Regards.

Steve.

 

[vascon2196]

Great...thanks guys...I was not sure of reversing it would break something.

But it does not have a threading dial so it kind of makes sense now.

I'm gonna go try it now!

 

[Tin Falcon]

IIRC in theory you can thread without a dial but it is very limited. the thread being cut must be a multiple of the lead screw.
Tin

 

[OrangeAlpine]

Way back in 1958, while in high school, we were shown a training film by the South Bend Lathe Company. The subject of the film was single point thread cutting. They never disengaged the half nut. It made for a pretty busy operator but the thread was cut in very short order. I never followed the practice.

So the practice is not only okay, it was the preferred way. I must add that the conventional 110/220 motors will not reverse unless allowed to coast to a stop. They will simply continue in the same direction as the starting circuit does not energize at high speed.

Bill

 

[vascon2196]

So I was able to cut the thread by never dis-engaging the half nut. I added a relief groove at the end of the thread so when I shut off the power (at the right time) it coasted to a stop in the groove. Then reversed the direction and let the tool go back to the beginning. Now I know how to do it!

This was only the third time I have ever threaded but I have a much better understanding of what is going on now.

I was going to use a die, but I got yelled at by the machine shop instructor here at the high school (yelled in a good way). He pushed me to use the lathe for threading for practice...I'm glad I did.