Possibly the world's worst setscrew...

[rjlittlefield]

"Dear Manufacturer, here is an example of what not to let out of your factory."

On the left, the example: a 3 x 0.5mm slotted setscrew. On the right: a properly formed 3 x 0.5mm thread.


There's a story behind this, of course.

I finally decided it was time to buy a fiber optic illuminator. After giving the marketplace due study, I decided to go for an eBay unit that looked pretty reasonable. It came yesterday. The unit is quite nice -- better than I expected, to tell the truth.

But there was this one aspect that just didn't make sense. The fiber tubes have focusable output lenses, and the focus was locked with a slotted setscrew. How silly, I thought, for something that's gonna get adjusted frequently. Besides, they didn't even seem to work very well. When I investigated, I found what is shown above -- possibly the world's most badly manufactured setscrews, which had already destroyed their mating threaded holes.

It's all fixed now. A simple matter to drill and tap new holes for some new capscrews -- things I can lock and unlock with my fingers instead of tools.

Why would a manufacturer mess up an expensive assembly to save a couple of pennies on a setscrew?

--Rik

Canon 300D, 50mm El-Nikkor reversed on bellows, f/8, mild stacking. Fiber optic illumination with ping-pong ball diffuser.

[MikeBinOKlahoma]

Why would a manufacturer mess up an expensive assembly to save a couple of pennies on a setscrew?

I'm not a mechanic myself, but a buddy who is tells me that many auto manufacturers do this as a matter of deliberate policy, notably with the little lube points in the chasis (I may not have expressed that right). They use greatly inferior nozzles<?> to save a couple of bucks off each car.

[Ken Ramos]

Mike said:

I'm not a mechanic myself, but a buddy who is tells me that many auto manufacturers do this as a matter of deliberate policy, notably with the little lube points in the chasis (I may not have expressed that right). They use greatly inferior nozzles<?> to save a couple of bucks off each car.

I used to work on aircraft quite a bit (fighters and attack) and back then we called those lube points, "zerk fittings," and they are very easy to strip out and require replacement from time to time. Some call them "alamites" too.

In response to Riks post and gripe, I can sympathise with him. I have in the past ran across the same thing. You lay down good money and get shoddy workmanship. Have to agree, that is one sorry looking set screw. Wonder how they got it in there in the first place!

Just outta curiosity Rik, do you often use leaves as background surfaces quite a bit?

[georgedingwall]

Mike said:
Wonder how they got it in there in the first place!

Hi there,

I might be able to help there.

Around 30 years ago I used to moonlight as a lathe operator in an electrical manufacturing plant. One of the jobs I had to do was to cut threads on a high speed lathe.

Occassionally things go wrong and and you end up with a bucket of scrap.

Here is a link to an image of a thread roller that quit on me back then. The machine was so fast that hundreds of threads had been destroyed before I stopped the machine. This was the damage caused to the thread roller.

http://freespace.virgin.net/george.gdin ... Roller.jpg

I promise that I disposed of all of the scrap in a proper manner, and swear I didn't send any of it to the USA.

Bye for now.

[rjlittlefield]

Ken, I think you've seen every leaf I ever used as a studio background. Two maples, one raspberry. Who knows what will appear next? Scrambled eggs with fresh pepper, maybe.

George, that's a nice shot of your damaged threads. Of course I would have been pleased to have such a nicely formed part in my illuminator!

I'm sure you must be right -- some piece of high speed automatic equipment started cranking out junk, and nobody noticed, or cared, or had authority to do anything about it.

Of course there were two steps in the process. First, make a junk setscrew. Second, insert it.

I don't know modern manufacturing processes. I suppose there must be automatic setscrew inserters. But it's interesting (what a useful word!) to think that some human maybe put that screw in place by hand, and kinda didn't notice (or care, or...) that he/she was having to torque it harder than usual. This presumes, of course, that the human had any idea what "usual" should be. Could always have been their first day on the job, and they thought that setscrews always felt like that.

In fairness to the manufacturer, the rest of the device seems quite good.

--Rik