View Full Version : Help finding a piece of hardware

03-03-2012, 05:13 AM
There's a lot of people on here. I guess I'm hoping someone will recognize this as a $10 part on their...... bicycle or something. I've looked for hours, Misumi, McMaster, Grainger, a thousand images...... and a hundred web sites.

These look great, except for the price though I'm working with LM76 for quantities.

In a perfect world:
1/2"-13 tapped on both ends (female - female) or 1/2"-13 male - female second choice.
4.5" to 7.5" long, preferably 6" long
The O.D. can be 5/8" to 3/4" or maybe a bit larger but should be fairly tight precision , maybe +0, -0.003"
A wrench flat would be nice but not required.
coated / oxide steel or anodized aluminum

I don't mind paying for the first one, but I needs it less than $20 at small quantities.

A lot to ask for right? I swear this part is off-the-shelf. I just gotta find it. Rod extension seems to be relevant as does extension shaft, tie rod spacer.... and a few others.

Duane Degn
03-03-2012, 06:03 AM
There are some of these type of things near the bottom of this pdf (http://www.microfasteners.com.au/wp-content/uploads/2010/11/AllthreadSteel-41.pdf).

I've also seen them (and purchased them) in hardware stores.

Edit: I missed the "4.5" to 7.5" long, preferably 6" long" requirement. The ones I've seen are usually just an inch or two long.

Phil Pilgrim (PhiPi)
03-03-2012, 06:10 AM
Here's a 4" coupling nut (http://www.grainger.com/Grainger/COUPLING-NUT-Rod-Coupling-Nut-1JE39?cm_mmc=CSE:GoogleBase-_-Fasteners-_-Nuts-_-1JE39). Finding a longer one will be a challenge.

Do both threads have to be right-hand? If not, you might find a turnbuckle that's long enough.


03-03-2012, 06:18 AM
I used to have a machine shop and I've seen those as custom parts.

Long story short, $65 for a pair is too much, more like $40 is what they are worth.

03-03-2012, 09:19 AM

I believe you need a better description. The responders are linking to coupling nuts, but I believe you are in search of precision linear shafting. If you are searching for precision linear shafting, I believe Mismumi would be your best bet, because you will have a very hard time finding +0, -0.003". On the other hand, if you can drill and tap your own holes, this comes pretty darn close, however there is no coating and slightly oversized.



EDIT: My bad, that is 1/2 not 3/4 Try this instead +- 0.001, http://www.fastenal.com/web/products/detail.ex?sku=47782

03-06-2012, 04:03 AM
I can't believe it's already been two days since I posted this.

Duane, Phil. Thank you. I gotta have a round shaft though. I tried turnbuckles of all different types too, but not fit my application.

Pedward, Yea, that's what I was thinking especially if I buy ten of em'. I sure can't find what I want though. It seems so simple, yet....

idbruce, Man I wish I had or had access to a lathe or I'd have a lot more options. Thomson shaft would be inexpensive or I can get precision rotary shaft with the wench flats cheap. Having a machine shop auger out two tapped ends runs the cost back up to $35 apiece so I'm back where I started.

Without going into a long boring explanation this is a locating fixture. The OD needs to be precision for a bored hole of a matching diameter. I have all the components sourced except this stupid shaft and I can't come up with a better / cheaper / off the shelf design. I really have a LOT of time in trying to find parts.... Getting each part machined isn't a problem, but the costs associated with that is. It's all for another one of my brilliant ideas to not have to work any more.

Thomson and others have hollow shafting too. I thought about just running a tap in the end, but alas the ID doesn't match the required tap size.... therefore I'm back to getting it turned on a lathe.

Thank you all for your time. Keep me in mind if you run across something. I haven't received the cost from LM76 yet, though my expectations are low. I'm still looking.

03-06-2012, 04:29 AM
Go to google images and search for...

Female Threaded Standoffs

Rod Extension Female to Female

Baseplate Rods


03-06-2012, 12:33 PM

I found the raw material for you at Grainger. 3/4 Nominal Diameter, Diameter Tolerance +0.000/-0.003 In, Length 36", Cost $17.38.


Of course you will have to cut it to the desired size, drill both ends and then tap them. Without the proper machinery, it is definitely difficult, but it can be done.

To drill the ends, you just need to create a good drilling jig, and have a heavy duty drill on hand. However, to create the wrench flats and to square the ends, you need some type of milling setup.