Threaded rod

Jonathan Allison

Hey

I'm in need of some small, say 1/8th threaded rod. Preferably the thread pitch will be very.... uhmmm, well whatever way it needs to be so it takes a lot of turns to move the rod very far. I guess that would be a steep pitch, but I'm not sure on that. Anyway, basically waht I am looking for is to salvage it out of something, or perhaps pick it up at a hardware store where it would be intended for another application. This is for use with my "wire winder" and would be used for the guide

Anyone have any ideas?

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Johnny

David W.

Jonathan

The rod you are looking for would be around a 5/40 threaded rod this will have 40 threads to the inch which will move a nut

about .025 for each turn of the rod.

David

Beau Schwabe

What you are looking for is called "all-thread" ....You can easily get this at a local hardware store, but be warned, that
this diameter is seldom "straight" due to poor handling at the store. Through careful examination you can usually find
a straight rod that will work for you. Aluminum or Steel will most likely have a pitch of 10 or 20... This translates to how
many complete revolutions you get per inch if you were to turn the rod. If you are not opposed to it you might also
check out what is available in Brass. These, for whatever reason, usually have a finer pitch of 30 or 40 sometimes.

PS. Make sure that you have a couple of Nuts or Collars that will mate with your all-thread,
and be aware of Metric vs. US threading.

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Beau Schwabe - Mask Designer III

National Semiconductor Corporation
(Communication Interface Division)
500 Pinnacle Court, Suite 525
Mail Stop GA1
Norcross,GA 30071

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David W.

Jonathan

·To find how much a nut will move forward per turn of the rod just ddivide 1.00 by the number of threads per inch

·1.00/20 = .050 I hope this helps i don't know if this works with metric but metric thread is not done in threads per mm but the distance from one thread to the next.

·David

Jim McCorison

Johnny,

You might check out Small Parts (www.smallparts.com) if you can't find what you need. Search on "all thread". They got a good selection in smaller and larger sizes than what you are looking for.

Jim

steve_b

I was going to recommend smallparts too.· I've never seen that small of threaded rod at the hardware store.· Smallest is 3/8's...maybe a quarter...

Not sure about hobby shops.

You didn't mention length.

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Steve
http://members.rogers.com/steve.brady
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."

Matthew

Jonathan,

For my current wire winding project, I went with the #4/40 threaded rod. I think I got it from www.sdp-si.com

Matthew

BTW: It's around 1/8" thick

achilles03

The terms you're looking for are "coarse" and "fine" thread. For example, 1/4"-20 is coarse, 1/4"-28 is considered fine. There's not always as much difference as you'd think. 10-32's are a good fine thread I always like, and they don't bend too easily (.188 dia).

You can try mcmaster-carr (mcmaster.com), but most hardware stores, as mentioned, will carry threaded rod. Mcmaster might have a lot more options as far as types and materials, some with might be easier to turn and work with.

Dave

Matthew

Hmm, now that I think about it, I might have the #10-32... I'll have to check tomorrow.

Post Edited (Matthew) : 2/15/2005 6:08:45 AM GMT

SPENCE

Check your local hobby shop for sterling or other brand metal shapes.

Round tubing, square tubing, both that telescope with adjacent size. Brass and stainless both afailable here. Also tee and el beams for frameing and chassis work on robots.

Another name for continuous thread is "readybolt". I have seen up to 36" long and up to 3/4" dia.

Jonathan Allison

Thanks for the feedback, I'm going to take a look at Canadian tire tonight, see if they've got anything.

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Johnny

Boris

How do you go about securing a threaded rod to the axis of the motor?
And how do you attach a rotating threaded rod inside any kind of fixture/enclosure? Ball bearings?

achilles03

Usually most motors have a flat cut on the end of the shaft (like it's been cut in half). If you're putting a threaded rod on top, the best way is to drill a hole (ideally the same diameter as the motor's shaft) up the center of the threaded rod and have another threaded hole in the side of the rod that you put a set screw in. The screw clamps down on the flat surface of the motor's shaft once it's been screwed in.

Another good way is to get a drill bit slightly smaller than the motor's shaft (like .003" to .001" smaller, if you can order one). Drill a hole up the center of the threaded rod with that bit, and then heat the rod. The rod undergoes thermal expansion and the hole diameter increases. Press it onto the motor's shaft and let it cool... as it cools it's going to shrink and "grab" the motor's shaft. The pivot joints on the B-2 bomber's wings are done the same way, only they dip the shaft in liquid N2 instead.

There's other ways, but those are two ways that are good (if done right) and that come to mind.

You might want to consider aluminum for the threaded rod, as it's easier to drill and has a high thermal coefficient. You could probably just get a threaded nylon rod (if it's strong enough for your application) and do a drill and "press-fit" without heating (or just use hot water). Nylon's relatively compliant... just don't press too hard on the shaft while holding the motor or you can damage the bearings in the motor. Ideally, you'd like the shaft (sticking out the other side, if it shows) on a hard surface so that all the force goes through the shaft only.

Hope that helps,
Dave

steve_b

You could also remove the threads on both ends of the threaded rod.· Use a milling machine or some muscle-bound grunt!·
Both diameters would need to be smooth and the same....you could then press some bearings on them and either direct attach a motor or use a gear train that fits the thread pitch.

Instead of attaching the whole piece of rod....cut a small piece and fit this to the end of the motor shaft, then use this to move the other.
Not sure which is more feasible.

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Steve
http://members.rogers.com/steve.brady
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."

Jim McCorison

Another method, depending on how much force you need to apply, and how accurate the rotational alignment needs to be, is rubber tubing. If the motor shaft and the threaded rod are the same diameter, use a short length of rubber tube which is a tight fit over both shafts. The rubber tubing has the advantage of allowing for slight misalignment in the shaft and motor as well as absorbing some shock. The down side is that you won't be able to apply as much torque, and there can be minor rotational positioning variances due to the flexibility of the rubber tube.

Also, browse through the aforementioned Small Parts site. Or better yet, order their free catalog. It makes great bed time reading. Anyway, they have a variety of shaft coupling options including small universal joints.

Jim

steve_b

Certainly a spider coupler would work.

We've one on a motor called 'LoveJoy'.· sounds funny!

We calibrate a wind sensor in the manner Jim describes....we attach a motor to the end of an anemometer shaft via rubber tubing and spin it up.· It's nice for being misaligned...but will definately shudder and slow down if you're misaligned.· And forget torque....you basically have none!



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Steve
http://members.rogers.com/steve.brady
"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."