Quick-acting nut or screw clamps 4

[briggha]

I'm looking for a screw clamp or a bolt/nut assembly that can quickly be pushed in to place and then tightened (preferably in stainless steel). I found a screw clamp that does this at Carr Lane (BAR-LOK™ Quick-Acting Screw Clamps on carrlane.com), but they don't have anything in stainless, and then I found a quick-threading nut at McMaster-Carr (P/N 98150A710), but they don't have it in stainless either, and I don't know how reliable these are (I'm not even sure exactly how they work). Does anyone know of something that would work? Also, does anyone know how the quick-threading nuts work, and how reliable they are?

Thanks a million!

 

[handleman]

Misumi has something similar in knurled round or hex versions, plain steel or 303 stainless, with metric threads from M6 to M12. Part number designation is QCNS (round stainless) or QHNS (hex stainless)

 

[bruiser]

Stainless is problematic because of its susceptibility to galling. It will just be a matter of time before the fastening system galls fast and you will have one hell of a time getting the nuts off. I does not take much torque at all for stainless nuts to gall on a stainless bolt. It is probably why you are having a hard time finding what you are looking for in stainless. You may want to find an alternate material for this application.

 

[MikeHalloran]

The ones I've seen and used work as follows:

The nut is extra deep. The threads are relieved as if you ran a 1xOD milling cutter right through the center of the nut at ~45 degrees to the axis. Which would be a decent way to make a few on short notice.

When the nut is seated, it engages the stud threads like two grooved 'hands' or half-nuts facing in opposite directions and displaced from each other along the stud axis by half the nut depth.

To disengage, back the nut off a couple turns, and then tilt it around an axis normal to the stud axis, and the nut can be freely withdrawn straight along the stud axis.

They're strong enough to use for tooling, and work great, with high strength studs. I don't think they can develop quite as much tension as a regular nut, because the radial force from the axially displaced thread halves applies a bending moment to the stud. If you're going to cinch 'em real tight, you need to check your studs for bending under that loading condition, which would not be present with regular nuts.



Mike Halloran
Pembroke Pines, FL, USA

 

[bluesman0007]

I agree with bruiser on the material choice. You might want to search quick acting vise manufacturers as to how they work. I used to work for a company that made them but a little hard to explain here. I remember the shaft was threaded and was hex shaped, in essence the shaft would slip by the flats section and engage the nut when turned. I know about a clear as mud. Good Luck.

Dennis

SolidWorks 2007 SP2.0
Windows XP Pro, Pentium4 3.00GHz
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Logitech Marble Mouse, CadMan

 

[briggha]

Thanks a lot for your help!

 

[BillV39]

These nuts are commonly used on drill presses to limit the drilling depth. Try Sears if you want to see one. They're also offered as quill nuts for lathes (there they have micrometer graduations for precise adjustment). I don't believe that they're suitable for true tightening as with a standard nut; just as a temporary stop.

In my experience, antiseize compounds do a good job of stopping galling. However the stainless grade and whether it's heat treated or not is important. 316 easily galls whereas a heat treated 400 series doesn't.