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07-04-2011, 10:57 AM #1
OT:Need H Duty square tube threaded inserts
3/4 and 1" 303 ss tubing. 16 ga wall
Need an insert that will take some torque, won't loosen over time.
The simple one leaf "star" type that pops on the end will not work, need something that can be "driven"-"placed" down into the tubing that will hold.
Searching here, Google, have only found the single star type.
Looking for proper naming of item, or other suggestions.
Application is tubing butted to part fastened with bolt. (1/4thru 3/8 hardware)
Looking to have system that will allow breakdown of assembly to permit UPS shipping rather than LTL carriers.
07-04-2011, 11:53 AM #2
07-04-2011, 11:58 AM #3
07-04-2011, 12:33 PM #4
Perhaps a square nut, brazed or crimped or swaged into place?
07-04-2011, 02:56 PM #5
Perhaps something like this... (name unknown)
Make two wedge-shaped parts out of square material that
nests well inside your tube.
Top has threaded hole.
Bottom has clearance hole.
(Probably start with solid stock, drill for tap, tap half-way, drill for clearance, then saw at angle...)
Stack two parts as above, with bolt passing thru mounting surface, thru clearance-drilled part, and threaded into top part.
Slide tube over two wedges, tighten bolt. Wedge assembly will expand inside tube, and draw it down to mounting surface. To remove loosen bolt part-way, then tap to disengage wedges.
Design loads will dictate material...
07-04-2011, 04:10 PM #6
07-04-2011, 11:05 PM #7
Thinking about this again, I'm wondering if Andy is looking for some sort of insert to push into the end of the tube rather than into a hole drilled thru the tube wall? If so, I can understand why he's having problems finding something as I've never seen anything that looked like it'd resist the pullout force a 2 yr old kid could muster.
07-05-2011, 08:05 AM #8
Yes, the insert goes down inside the tube, not thru the wall, hence rivit nuts will not work.
your idea is right-on except the insert must maintain its lock inside the tube to resist shipping shocks and the assembler "pushing" the unit apart.
thinking your idea with locking parts ,lips that lock when tightened the first time?
square nut possible, trying not to deform tube if possible, tubing will be polished and be visible once assembled. Welding, here again trying to keep away from refinishing the weld location, forced to keep manufacturing time to a minimum.
07-05-2011, 09:15 AM #9
Anything that goes in without welding or drilling will come right back out again with minimal force.
aint no free lunch.
I have used this style-
SUPPORTS, RESTS AND FEET, LEVELING FEET, Threaded Tube Ends (Square) :: Carr Lane Manufacturing Co.
Facility Hardware - Square Tube Glides/Tips
these look more promising-
But I think if you really need strength, tigging in a threaded end plate or a nut on the end is going to be your best bet.
A good tig weldor can put them on with only the barest minimum of sanding needed, then maybe a quick touchup with a scotchbrite pad on a 4 1/2" grinder, and they are done.
07-05-2011, 09:28 AM #10
try these guys Tube Connectors for Round and Square Tubing I know they have the double inserts.
I had a project where I was trying to make a strong insert into 1 1/4 inch tube. These worked good, One of the things I tried was to tap a very light thread in the inner wall and then thread a custom insert into it. I would work with some refindment. but for your application you would have to figure out how to tap a square hole.
07-05-2011, 10:01 AM #11
One could have a tap made to fit the square tubes id plus thread depth.
Chuck in turret lathe and tap, would give "teeth" but maybe not enough area?
07-05-2011, 10:30 AM #12
I have ran across a two piece cast iron nut for tube ends. The mating faces were cut on a taper, and the outer one had a through hole. When you tightened the bolt they wedged tight. I was just a user, no idea where they came from.
07-05-2011, 11:34 AM #13
Well, you could add a secondary fastener to keep the pair clamped in the tube... so the primary could be removed and replaced without disturbing the "set" of the wedges.
BTW, gbent described it better than I did....
Do you have a dozen of these to do, or thousands?
07-05-2011, 04:43 PM #14
You can always make your own press fit inserts with a .001 press fit. Possibly serrate the OD of the Insert as well so it has "teeth" about .2 apart (only .015 deep) to bite the tube.
07-05-2011, 05:23 PM #15
07-05-2011, 05:50 PM #16
I imagined it was seamless extruded tube. But it could be friction welded as well I hadn't thought of that. I have never worked with tubing before so I guess I stand corrected.
07-05-2011, 09:57 PM #17
IF there was a reliable insert then quanity would hit thousands.
1 forced to weld joint resulting in more time to finish tube connection
2 unit then must ship LTL increasing cost to end user, especially for small
3 would require fixtures to align parts for welding, another expense
4 Or as they say .........back to the drawing board and start over
Will be breaking into a market where the competition is making cheap but really low quality units.
I have an open checkbook from a customer to provide quality units with a reasonable cost.
07-05-2011, 11:12 PM #18
Here's a link to a photo of an actual product, for use in street sign mounting...
Liddell Brothers - Our Products
(Scroll down a little...)
Since the "real thing" isn't popping up quickly under "square tubing wedge anchor" searches, my mind wandered...
How about a standard round wedge anchor (as used in concrete, round tube, etc.) fitted with a square expanding collet-style jacket? Square stock, largeish hole in the middle, a couple bandsaw slits parallel to hole, 90-deg apart from opposite ends. Maybe tack weld to the wedge anchor, so it doesn't get fiddly on assembly. If it needs to stay in tube when things are disassembled, then drill and tap the wedge-tightening bolt, so that the assembly bolt threads into it.
The square profile would minimize distortion, you could texture the outside of the collet for gripping power, it's forgiving of tube size variance, and it's darn easy to make.
07-06-2011, 03:03 AM #19
This sounds like a project somebody needs to invent.
07-06-2011, 03:38 AM #20
Put the threaded insert in the tube and stake the tubing in front of, and behind the insert. Quick, dirty,cheap and can be high volume. And it works.