Facets in my 16 TPI Threads - Need some help!

[rwm]

Wait...what...you figured it out???? You have us all on the seats of our collective chairs with this drama!
What is the answer?
Robert

Edit: You forgot to lock the lever on the QCTP?! (ask me how I know)

 

[TX COWDOC]

Bamban travelled 2 hours south to help me sort through this today! What a guy. Looked over the machine. Checked the gibs. Watched me thread with the same results. New HSS tool. We disassembled the compound and discovered the compound did not seat squarely on the cross-slide. See video below.

 

[TX COWDOC]

We spent 2 hours honing the surfaces of the cross-slide and the compound until the movement was gone.

 

[davidpbest]

Bamban travelled 2 hours south to help me sort through this today! What a guy. Looked over the machine. Checked the gibs. Watched me thread with the same results. New HSS tool. We disassembled the compound and discovered the compound did not seat squarely on the cross-slide. See video below.

Yep, that would sure make threading a challenge. Once that is rectified, my guess is you'll be able to go back to using carbide.

 

[Weldingrod1]

What will we DO without mystery!!!

Congratulation on your solution!!!

Sent from my SM-G892A using Tapatalk

 

[TX COWDOC]

65 RPM. Carbide. Compound feeds as follows: 0.001" scratch; 0.009", 0.008", 0.006" times 2; 0.003" times 2, 0.002", 0.001 with spring passes until finished. beautiful 16tpi threads. I could tell on the 1st and 2nd pass that the problem was solved.

 

[davidpbest]

 

[rwm]

That makes sense. Glad you figured it out. I'm surprised it didn't show up in turning and facing? Why only threading?
Robert

 

[TX COWDOC]

That makes sense. Glad you figured it out. I'm surprised it didn't show up in turning and facing? Why only threading?
Robert

The interesting aspect of the play in the compound was that it was absent when the compound was oriented at 0 and 90 degrees relative to the spindle axis. When the compound was moved to the correct setting for threading it rocked. I've got more videos of the DTI moving across these surfaces. Suffice it to say that there was considerable movement with the DTI at the 1-3 o'clock and the 7-9 o'clock areas of the compound seat.

With the threading issue addressed, I made a practice run on a Rem 700 tenon. Mated up nicely.

Thanks to all for the feedback. I learned a lot about the machine during the process. I lost a lot of time but made some good friends along the way.

 

[Aukai]

Skol....