Unwanted taper when cutting tenons

[MonsieurLabo]

I am experiencing unwanted taper when cutting tenons. I am cutting tenons with my Taig lathe. the thicker part of the taper is on the end of the tenon where the draft hole starts. What is going on? Any ideas?

I was thinking, ok, maybe it is deflection so I put a live center up to the tenon. Still have the same result. The piece of vulcanite I am using is not very long, maybe 4 inches. It is from AAP.

Cutting tool is sharp and the stem I cut on the pipe has no taper.

The material does seem to not cut as clean the closer I get to the center of the rod stock. Is it a quality issue? These are the first stems I have ever tried to cut and the only material I have tried so far. Being a beginner and all...

I appreciate any input.

[caskwith]

Sounds like an alignment issue, is the carriage properly aligned with the headstock, is the tailstock centred?

[DMI]

If you are cutting delrin it may be that you are putting too much pressure on the material and it is bending slightly, this happens to me if I have more than a half inch or so of rod sticking out the chuck.

If you are cutting acrylic or ebonite it may mey getting too warm and softening slightly which will allow it to bend.

David.

[Tyler]

Sounds like an alignment issue, is the carriage properly aligned with the headstock, is the tailstock centred?

+1

Sounds like the headstock is turned away from the carriage.

The poor finish is probably because it is cutting deeper as it goes.

[MonsieurLabo]

All alignment checks good. Just cut an even tenon last night not sure what the helk happened.

Thanks for the input. My guess was heating or inconsistency in the material. Not gonna worry too much.

[andrew]

This sounds like you are using the movement on the turret rather than the carriage. Which movement are you using to cut the tenon?

[MonsieurLabo]

Using a Taig which is carriage driven I suppose...