Exploding stem... no, really...

hazmat · Post by **hazmat** » Mon Feb 27, 2006 2:59 pm

So.. I'm (attempting to) cut a tenon into a pre-fab vulcanite stem. Have it chucked up in the metal lathe nice and centered, it's spinning beautifully and I've taken one.... two... three swipes out of it.. everything's going well. Swipe number four, I lock in for some auto-swipes.. and !POW! the stem popped!!! 8O

All I could do was stare... and then laugh my arse off. Never saw something like that happen before. Anyway, just a quick anecdote and a lesson in "less is better" when turning a tenon on a lathe. I've heard of things blowing up in people's faces.. figuratively.. never thought I'd have it happen.. literally. oh well... :boohoo:

ScoJo · Post by **ScoJo** » Mon Feb 27, 2006 3:43 pm

Note to self (since I am not good at cutting tenons anyway):

Wear safety glasses next time I cut a tenon (since I'll probably be cutting it instead of using my delrin anyway).

hazmat · Post by **hazmat** » Mon Feb 27, 2006 3:56 pm

I've been reading about your delrin problems.. thought I've not yet used the stuff, my advice would be: keep trying until it works for you. I HATE... I can't stress that enough.. HATE turning tenons unless I absolutely have to. When I started seeing how often delrin is being used and hearing nothing but good feedback about it, I'm willing to suffer with the pain of learning how to work with it if it means no tenon turning unless the design of the pipe practically screams for it.

ScoJo · Post by **ScoJo** » Mon Feb 27, 2006 4:06 pm

I know what you mean about turning tenons. I have tried and tried and wasted a number of premolded stems. It seems I either can't get the cutting tool sharpened well enough or I can't get it at just the right angle to the tenon to get a smooth tenon. It's a painful process for me. That's why I bought the delrin in the first place. Seemed like a way out, but I can't get the mortise drilling down to be able to use it. At the suggestion of someone else I am going (tonight, maybe) to pull out the 2-3 5/16" bits that I have and do some drilling experiments into some 2x4s I have lying around to see what kind of variability I get.

hazmat · Post by **hazmat** » Mon Feb 27, 2006 4:09 pm

I have a trash piece of briar that I do that with and another I use as a "handle" to put stems in after I've turned the tenon. I work on the main part of the stem there if I need to make any aesthetic changes to it prior to plugging it into the mortise to flush it up.

I tried 2x4s for this tool, but over time the pine looses up considerably and the stems start falling out at very inoportune times.. not fun..

Progcat · Post by **Progcat** » Mon Feb 27, 2006 9:05 pm

Hello All,

I use delrin exclusively now which I obtain from www.online metals.com I just purchase the size delrin I want to work with (3/8 for the most part) and then get the same size drill to drill the mortise hole. It has been working very well for me. I get a nice tight fit. It really takes the stres out of cutting a tenon from acrylic. Then if you are making your own stem, you done have to risk breaking the tenon in the process. Hope this helps.

Tim

custom300 · Post by **custom300** » Mon Feb 27, 2006 11:30 pm

Just when I think I begun to understand the tenon and mortise concept, the Delron topic arose. So I understand, you basically replace the tenon with a short piece of Delron...correct? A couple of questions, how long should the piece of Delron be? Should a mortise be cut on the stem as well as the shank? Do you have to face the delron? like put a small angle on it or just cut it square. Thanks for any assistance.

Post by **KurtHuhn** » Tue Feb 28, 2006 12:16 pm

I'll start a new thread with all that info.