[lsfoils]

Hey, there is a lot of talent on this site. So I want to challenge (and promote future challenges) to the brain power out there. You guys proly' have 'nough to do already, but like some who've posted recently, sometimes a diversion is a good thing. (Wow, can't believe I jess used a convicted felon's own werds'... oh noooo!) Anywey, here is something that was posed to me a hundred years ago (well, 'm'by not that long ago). My brother-in-law told me about a machinist they had in their Montana shop that had a 2 headed bolt with a nut in between. The nut turned freely on the bolt's threads and the threads faded out at each end. Thats all he knew. 'cept He said the guy mentioned there was a seam. But, that was all. It took me quite a while to figure out a method to figure out a way to produce such an animal (I was a fledgling machinist at the time and still on my way to knowing-it-all; hmmm, might still be trying to get there, seeing what I see on this site.) Without a doubt it may "not" be the same way his machinist did it. But I figured out a way to do it and a lot of guys sat and scratched their heads, trying to figure out how it was done after I finished mine.

This is a great exercise for any machinist who doesn't already know the trick. It requires a lot of forethought, a specific methodology and good lathe practices.

For those who already know this one I ask: please don't respond to this post. Not just yet.

And for those that don't, give it a shot, post an idea! Think about how you might solve this one. I'll give you 2 weeks to post your solutions and then I'll post the one I found. I hope you have fun with this, and, I hope it will promote others to post some of their own devious puzzles. C'mon! You folks love puzzles! Otherwise you wouldn't be doing this problem-solving-stuff you're doin' now, eh??Hey, isn't life a puzzle? Hey Benny, this one's for you, man.

Oh, the original is Vietnam. Had some pics of it but I don't know what happened to them. So this is a rendering of the original idea. I'll post a blow-by-blow when the 2 weeks is up. Good luck y' guys and gals!

[NOCARRIER]

I hope this solution doesn't offend you .

Take two bolts, chuck on in you lathe and the other in the tailstock.

Thread the nut on .

Advance the tailstock towards the chuck.

Align the bolts and threads so the nut can screw smoothly between the two bolts.

Tack weld the bolts togeter.

Remove bolts from lathe and finish welding.

Return to lathe and re-cut threads.

Deliver product.

[lsfoils]

Hi NOCARRIER,

That is a good possible solution! Sounds like it would work if you can keep the bolt straight. I should have mentioned that my brother-in-law said there was no welding involved. Still a good solution, though.

[Rekd]

There's a few ways to do this without welding.. including press-fitting the two together, threading the two together.

'Rekd teh outside the box

[hardmill]

Turn one and bore the other, then press together.

PEACE

[HuFlungDung]

You guys aren't any fun. I want to know how to make that out of one piece, with the threaded nut in the middle... you know, like those wood carvers who make those chains out of one stick of wood

[ynneb]

I will also be no fun and offer a dud solution.

I note in the picture the unthreaded section is cut lower than the thread. If this is the case, It would just be a matter of cutting an ordinary bolt with another small thread......ummmm errrrrrrrrrr...................................... ............... shoot i dunno........................does it require heating the nut so much that it expands over the bolt head and you place it on that way?

This is a very frustrating puzzle. Please dont do this again. Last night I had a terrible sleep because my dreams were dominated by bolts and nuts. I am now going to have to search the net for the answer because I cant wait 2 weeks for the solution. I need my sleep.

[lsfoils]

Hi ynneb,

Sorry, I didn't intend to create frustration!

No heat is used. Sorry for the misleading image. The bolt is clean finished from the edge of each hex to the begining of the threads. And there is no edge at the threads. No seam. As you turn the bolt the threads just fade off of the surface. Just like a store bought bolt that has a shank. Keep the ideas coming!

[ynneb]

Isfolis, I hope you knew my last post was tongue in cheek. ( I think you did but just wanted to make sure)

I have a question.
Is the bolt arrangement made from the one solid block of steel?

[dmgdesigns]

So let me see if I understand you. This started out as a piece of Hex stock. The middle of the hex was turned down and threads were cut with no undercut or thread relief on either end. Now a threaded bolt with an ID the same as the depth of the threads miraculously appeared, moving freely up and down the threaded length. Also the part has 1 seam we just don’t know where.

Assuming the above is just impossible, I would have to say you had two bolts one nut and the seam was where the two bolts meet. It is only a two headed bolt when they are held together with the nut.

Mark

[Gunner]

Here's another stab.
Take two bolts and a nut. Thread the nut on one bolt. Turn the end of the bolt you just threaded the nut on to the a tad below the minor of the thread. Take the other bolt and cut the shank off. Bore the head to accept a press fit from the turned end of the other bolt. Align the hex of the two pieces and press together. Anyway that's what I would do.

[lsfoils]

Sorry guys, a press fit was not used in the solution I found. The seam is all but invisible to the naked eye. I think that would be harder to do with a press fit. And, the nut travels the entire length of the threads.

ynneb, the first one I made was from a stainless steel valve stem I salvaged from an 8" butterfly valve. I turned off all the shoulders to a uniformed diameter and then started machining the parts. So I guess you could say that it was made all from one piece. Just slightly rearranged...

There is no tongue in cheek smilie or I'd have included it with my last post!

[Bloy2004]

How long is the travel of the threads? Does the nut always cover the potential "seam" as it moves from end to end of the threads?

This would give the "illusion" that that the bolt is one piece.

[lsfoils]

Bloy2004,

The travel of the threads on the bolt is approx. 2 1/2 times the length of the nut.

[Bloy2004]

Okay, so can you share with us exactly where that seam is located? You should be able to reveal this info as the "trick" here is to hand this item to somebody and ask how it was made....and you did say the seam is visible.

[Gunner]

OK, Lets forget the press fit. You can put a smaller thread on the end of the turned end and tap the bore on the other. Then thread the two together. I'm giving up and waiting two weeks for the answer unless I have a revelation. This better be good!

[avsfan733]

hmmm....maybe make the center section with the two hex heads and the thread, then make the nut cut it in half on one side...bend it around that shaft and then hammer the halves together until the seam is nearly invisible ?

[Klox]

You can buy such bolts on ebay! Hehehe!

Klox

[ynneb]

I made a post earlier but I think it got lost in the movement from the old forum.
Here is my answer. Sorry about the crappy way I drew the thread.

[ynneb]

Here was an earlier idea, I had