Tenon and Mortise help.

[brownleafbeardsman]

So, I'm a very new pipe maker and I'm loving the learning process and the mistakes that come with it.
I am wanting to purchase a tenon turning tool from Steve norse, but he's been out of stock for a month, and I've been looking at the site every day.
I have a Xuanjie 7mm Tenon/Mortise cutter and it works very well. However, I am running into a bit of a problem with the tenon having a slight taper. So when inserting tenon into mortise, the beginning is very loose, and it gradually gets the the perfect tightness about halfway down the tenon.
I have a Jet Wood Lathe, and I've checked the centers, they do not seem to be the issue.

I've thought this could be caused by a few things:
1. The drill chuck being not the best quality, and having a very very slight downwards bend coming out of the tailstock.
2. Cutting the Ebonite rod too fast, so that material builds up and it doesn't cut as accurately.
3. Drilling the mortise too fast, briar getting hot and causing a change in the diameter of the mortise.

I've tried to single these possibilities out, and troubleshoot them to the best of my ability.
I've purchased a better quality drill chuck.
I've tried my best to drill the briar at a proper speed and not let material get built up inside mortise.
I've tried to cut the tenon and get the material out of the way.
The stopping and starting when cutting the tenon actually seemed to make things worse, so then I tried cutting a tenon in one pass, but the material did get hot and seemed to burn the ebonite, and it became very rough, and after smoothing that out it was no longer the proper diameter.

I know most of you guys use metal lathes, and I plan on getting one in the future, in the researching and learning phase now.
Until Steve norse is back in stock with that tenon turning tool, what I have been doing is starting the tenon with tool that I have, making about a 1/4 inch tenon, and then measure out the size it should be on the rod stock. Then cutting that material down using the 1/4 inch tenon as a guide, and then using a parting tool to get the just a hair off of that 7mm, and sanding/checking fit, over and over. This process is tedious, but after trial and error, it is what has provided me the best results so far! I do actually enjoy the process, and don't mind the extra work/time. This is most likely what I will continue to do.

If anyone has had any similar experience and any tips on what I am doing wrong, or what I could do differently, I'd love to hear them. Thank you!

[Sasquatch]

So, first you gotta figure out what's tapered, the tenon or the mortise, and you might need calipers for that. Calipers are super, super handy in pipe making anyway.

My guess knowing the jet is that there's just a bit of run-out, looseness in the tailstock as you move it and it's allowing a bit of wobble and tapering the mortise hole. I keep the spindle lock just a little tight if I am drilling on that lathe, try to eliminate the wobble.

I cut about 100 tenons by hand, just spinning the stem between centers, it's not hard at all.

[brownleafbeardsman]

I'll check on that tomorrow, I do have some digital calipers. Thank you for the advice! I think you might be right about the slight wobble in the lathe, that had crossed my mind but I just didn't want to believe it lol. I guess I'll stick with that process as it is proving to be producing the best quality tenons. Thanks again, Sasquatch!

[seamonster]

Another thing that might taper a mortise is a wobbly drill bit. The longer ones have a little flex, and if you are drilling an uneven surface, they can wobble quite a bit. You might try a shorter bit, with less flex.
https://www.mcmaster.com/drill-bits/sho ... rill-bits/

[brownleafbeardsman]

Thank you, seamonster. I know exactly what you mean and I know that could definitely add some runout, but this is what I am using for this operation:

https://rawkrafted.com/yu-xuanjie-tenon ... utter-set/

I actually was going to be ordering some stub bits soon for my first attempt at using Delrin, as that is what is stated on Kurt Huhn Delrin guide, and for the same reason you had just stated.
Thanks for your input!