Problem- TL-2 Tapered Thread Problem

[dhelms]

I'm cutting a 4.00" x 4 TPI thread with a 5 degree taper on my TL-2. For some reason, when I enter the taper per foot (which should be 1.0499), the tool doesn't follow the 5 degree taper on the part. The tool doesn't touch the piece at the beginning of the thread, and just starts to cut at the end of the thread. I ended up changing the taper per foot to 1.9100 to get it to follow the profile. Any thoughts on what's going on? I'm stumped.

[HuFlungDung]

I don't know if you are using some sort of conversational programming, but since your value obtained through trial and error is about double, then I would guess that there is some confusion between a taper angle as measured relative to the spindle centerline, and taper per foot which is computed across the included angle between each side of the part.

IOW, you have to double your single taper angle to get taper per foot.

Don't forget to allow for the full Z travel of the tool. If the tool begins at Z0.2 in front of the part face, this does not change the taper per foot, but it does change the X start point, which puts it a bit below the corner of your part as verified in CAD.

[dcoupar]

Why not post the code you're using here so we can possibly see what might be the problem?

[CNCRim]

put your program on here we will take a look at this and see.

[cam1]

Hi: In general the Taper per Foot is defined as the difference in diameters of a cone over a 12 inch span. Taper angle can also be expressed as a half angle or included angle. This would explain the difference. I usually make a sketch before doing tapers just to make sure that I've interpreted the info correctly.

regards

[kiemkhach]

Hi
I have'nt runing a taper ,but after calculating 5 degree taper
I think your Tpf could be 2.0997 but you apply only half of your Tpf 1.0499 that why it not work

Originally Posted by dhelms I'm cutting a 4.00" x 4 TPI thread with a 5 degree taper on my TL-2. For some reason, when I enter the taper per foot (which should be 1.0499), the tool doesn't follow the 5 degree taper on the part. The tool doesn't touch the piece at the beginning of the thread, and just starts to cut at the end of the thread. I ended up changing the taper per foot to 1.9100 to get it to follow the profile. Any thoughts on what's going on? I'm stumped.