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Posted: **Sat Oct 26, 2019 10:29 am**

LatakiaLover wrote: ↑Thu Oct 24, 2019 3:25 pm If so, yes, just a hardware store tap. Starting taps dead-straight can be tricky, though, I strongly recommend making or buying a jig designed for the purpose.

Like the thing that was used to drill the hole, perhaps?

Posted: **Sat Oct 26, 2019 11:05 am**

Easy with a lathe, but most of the entry-level guys around here are using a drill press.

Posted: **Sat Oct 26, 2019 12:13 pm**

I don't use any kind of tapping guide.

Posted: **Sat Oct 26, 2019 6:51 pm**

You drive on the wrong side of the road, too. And eat baked beans for breakfast.

Posted: **Sat Oct 26, 2019 6:53 pm**

Pfft, we know what we are doing, we have been doing it long enough. I use teaspoons that are older than your country

Posted: **Sat Oct 26, 2019 10:03 pm**

Triumph TR7 (1975–81)

The Triumph TR7 was one of the last models produced by Triumph before the brand was axed by British Leyland 1984. The TR7 was widely criticized and ridiculed for its styling, especially the strange curve in the side. A popular urban legend states that upon its debut, legendary Italian auto designer Giorgetto Giugiaro examined a TR7 at an auto show, walked around to the other side of the car and exclaimed, "Oh my god – they did it to the other side, too!"

Quality problems tended to undermine the car's image in the market place. In its Frankfurt Motor Show preview edition of September 1977, the German magazine Auto, Motor und Sport reported that the engine of a TR7 press car had broken down and "started to boil" while undergoing a maximum speed measurement exercise over a 4 km (2.5 miles) stretch of track as part of a road test.

It was included on Time magazine's list of the 50 worst cars of all time; automotive journalist Dan Neil wrote that the main issue with the TR7 was that "The cars were so horribly made. The thing had more short-circuits than a mixing board with a bong spilled on it." Jeremy Clarkson criticized the TR7 and destroyed one in his DVD special Heaven and Hell. Edmunds.com ranked the TR7 as the 47th worst car of all time.

British Leyland stopped production of the TR7 in 1981.

Posted: **Sat Oct 26, 2019 10:43 pm**

Sasquatch wrote: ↑Thu Oct 24, 2019 9:20 pm If only we could just somehow cut the tenon from the same material as the stem....

My thoughts exactly! I sure hope one of you guys figures it out and shares it with the rest of us. All this glueing and threading and drying and cross-hatching just so George can repair your shitty Delrin tenon. There must be a way that could be done in roughly the same amount of time with the right skill.

Posted: **Sat Oct 26, 2019 10:48 pm**

I wanted a TR7 when I was a teenager.

Posted: **Mon Oct 28, 2019 6:31 am**

wdteipen wrote:
Sasquatch wrote: ↑Thu Oct 24, 2019 9:20 pm If only we could just somehow cut the tenon from the same material as the stem....
My thoughts exactly! I sure hope one of you guys figures it out and shares it with the rest of us. All this glueing and threading and drying and cross-hatching just so George can repair your shitty Delrin tenon. There must be a way that could be done in roughly the same amount of time with the right skill. [emoji38]

That's why I gave up on pipe making. All this glue is making me dizzy.

Sent from my MI 8 Lite using Tapatalk

Posted: **Mon Oct 28, 2019 5:43 pm**

The British were not the only ones making crappy cars in the late 70's. Almost everyone was.

George

Posted: **Tue Oct 29, 2019 12:04 am**

Chris and I have been at this for years. It's a running gag.

Posted: **Tue Oct 29, 2019 11:19 am**

Another solution: thread'em (when working from scratch). Cut diagonal grooves in the threads internally and externally with a rotary tool to lock everything in place once the glue has cured. G-Flex is best in my opinion. There MUST be some sort of mechanical lock unless you have access to plasma treating or chemical etching or flame treating. Delrin (acetal) falls into a family of LSE (Low Surface Energy) plastics and that makes glue bonding problematic. Polyethylene, polypropylene are other examples of LSE plastics.

Posted: **Tue Oct 29, 2019 11:24 am**

oklahoma red wrote: ↑Tue Oct 29, 2019 11:19 am Another solution: thread'em (when working from scratch). Cut diagonal grooves in the threads internally and externally with a rotary tool to lock everything in place once the glue has cured. G-Flex is best in my opinion. There MUST be some sort of mechanical lock unless you have access to plasma treating or chemical etching or flame treating. Delrin (acetal) falls into a family of LSE (Low Surface Energy) plastics and that makes glue bonding problematic. Polyethylene, polypropylene are other examples of LSE plastics.

Well DUH! I guess I should have read all the posts. Threading was already discussed. Oh well, back to my cave.

Posted: **Wed Mar 04, 2020 10:49 pm**

Reviving an old thread: Just to experiment I got out my Harbor Freight tap and die set. Clamped the delrin in a vice and cut the threads by hand. Very easy. Very straight. Then I drilled a mortise hole and tapped it, also by hand. Just a tiny bit crooked though. But, the fit was perfect. Threaded in snug as can be. Tomorrow I will try tapping the mortise with it all in the lathe with the tap fixed in the tail stock and turning the chuck by hand. If that comes out straight this will be my standard delrin tenon procedure.

Posted: **Wed Mar 04, 2020 11:27 pm**

LatakiaLover wrote: ↑Sat Oct 26, 2019 11:05 am Easy with a lathe, but most of the entry-level guys around here are using a drill press.

How did I not see this earlier?

Honestly though, a drill press can be done similarly to a lathe. Just like a lathe, don't move anything but the quill between drilling and tapping. A drill bit and a tap of the same rough length ought to be able to be swapped out between operations. But even if you do move something, you can get stuff lined up just fine anyway - as long as you don't remove the vulcanite from the vise you're using.

Posted: **Thu Mar 05, 2020 2:04 pm**

caskwith wrote: ↑Thu Oct 24, 2019 5:24 am Of course the best method is to thread your tenons

What happens when a “lefty” habitually turns his tenons the wrong way?
DocAitch

Posted: **Thu Mar 05, 2020 3:07 pm**

You get an Australian tap and dye set.

Posted: **Thu Mar 05, 2020 4:23 pm**

...or end up with a conservative tenon...

Posted: **Thu Mar 05, 2020 7:30 pm**

So I tried this again, chucking things up in the lathe. Worked great. Everything lines up straight and true. Takes a minute or two longer than doing it the regular way. Will try it on a pipe sometime this week.

Posted: **Fri Mar 06, 2020 2:38 am**

DocAitch wrote: ↑Thu Mar 05, 2020 2:04 pm
caskwith wrote: ↑Thu Oct 24, 2019 5:24 am Of course the best method is to thread your tenons
What happens when a “lefty” habitually turns his tenons the wrong way?
DocAitch

You slap them and tell them to do it properly. Seriously though, the glue should still hold for turning both ways, the difference being if the glue does fail the tenon is still perfectly functional and much easier to repair/remove.

Do left handed people turn then counter clockwise? I am left handed and turn them clockwise, but I may have a sub conscious bias of course.

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Delrin tenon failure avoidance

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