Ray-CA
Well-known member
I have some tubing with a wall thickness of 0.120-inch. Is this thick enough to tap? Or should I use a nut-sert/rivet-nut type of fitting?
Thanks,
Ray
Thanks,
Ray
Too thin to tap???
- Thread starter Ray-CA
- Start date
spooler41
Well-known member
Go with the nutserts, you don't want a pullout when you need it most. I'd also use 5/16 or 3/8 bolts with the nutserts, .120 is to thin to get much thread into.
..........jACK
..........jACK
bluesman2a
Well-known member
Can you get us a picture of what you are trying to do? I understand what you are saying, but trying to visualize where you are tapping it.
For most things I would say that .120 wall is OK to tap and will be fine. I do a lot of cage work and work almost exclusively with .120 wall, so I know what I'm talking about here. But it will NOT be structural. It certainly will not be enough to contain a flailing driveshaft. One thing I have done in cases like this is to drill through the tube, with a hole-saw and weld in a bung, say like .75" round, .120 wall tube, then you can thread the entire bung for more engagment.
More simply you can drill it and weld a nut on the opposite side. This doesn't keep you from crushing the tube or the bolt from tearing it in the hole, but you most likely wouldn't need to worry about either of those in your application.
For most things I would say that .120 wall is OK to tap and will be fine. I do a lot of cage work and work almost exclusively with .120 wall, so I know what I'm talking about here. But it will NOT be structural. It certainly will not be enough to contain a flailing driveshaft. One thing I have done in cases like this is to drill through the tube, with a hole-saw and weld in a bung, say like .75" round, .120 wall tube, then you can thread the entire bung for more engagment.
More simply you can drill it and weld a nut on the opposite side. This doesn't keep you from crushing the tube or the bolt from tearing it in the hole, but you most likely wouldn't need to worry about either of those in your application.
Defender Chassis
Well-known member
Rule of thumb: You need at least as much thickness as the fastener is wide.
Therefore you would only be able to use about a #10 machine screw.
Another thought, make a sleeved and pinned loop like many of the chassis builders sell.
I will see if I can find a pic............
Therefore you would only be able to use about a #10 machine screw.
Another thought, make a sleeved and pinned loop like many of the chassis builders sell.
I will see if I can find a pic............
Defender Chassis
Well-known member
-B-
Well-known member
It depends on size of fasteners and load they will have to take. Off the top of my head I say use nutserts not rivnuts , in the long run the threads will be stronger.
bluesman2a
Well-known member
I think that's the best "removable" approach. It's not going anywhere.
Take a look here (http://www.ffcobra.com/forums/showthread.php?t=221688) There are nut-serts included with the part so that's taken care of. Just thought I could tap the hole instead. Looks like I'll go the nut-sert route.
Thanks,
Ray
Thanks,
Ray
-B-
Well-known member
These are the nutserts i prefer the most they have better strength to grab in thin wall situations.
I use them to replace rivnuts in bicycle frames for water bottle bosses. I do have to tap them out to m-5 it is no big deal as they are so close in size that the threads are actually better than OE.
I use them to replace rivnuts in bicycle frames for water bottle bosses. I do have to tap them out to m-5 it is no big deal as they are so close in size that the threads are actually better than OE.
rsanter
Well-known member
you can get (or make) a bracket that goes around the tube and clamps on. then you bolt the loop to that
otherwise just weld on a tab (thin plate) that you can bolt the loop to
bob
otherwise just weld on a tab (thin plate) that you can bolt the loop to
bob
nate379
Banned
Never heard that rule before.
One I have always heard and been told is 3-5 threads. Pretty much look at a nut for the bolt you want to run in the hole you are tapping and that is the # of threads you want.
One I have always heard and been told is 3-5 threads. Pretty much look at a nut for the bolt you want to run in the hole you are tapping and that is the # of threads you want.
nissan_crawler
Well-known member
http://www.ballisticfabrication.com/OD-Tube-Clamp_p_1474.html
I would rather go this route than drill that many holes in a row in a piece of tube frame, IMHO.
I would rather go this route than drill that many holes in a row in a piece of tube frame, IMHO.
Last edited:
[curious]
Didn't the bus? come with a driveline catcher to begin with? Does the manufacturer have a bracket you can buy or copy? I certainly don't think .120 of engagement will keep a flailing commerical truck driveline in place.
[/curious]
Didn't the bus? come with a driveline catcher to begin with? Does the manufacturer have a bracket you can buy or copy? I certainly don't think .120 of engagement will keep a flailing commerical truck driveline in place.
[/curious]
Major Ramifications
Well-known member
I've never met one who was too thin to tap; on the other hand, I have met some who were too fat to tap.
Ahh...
School buses and presumably all buses, have driveline catchers to prevent the drive shaft from falling onto the ground and rolling the bus, should it catch a depression in the pavement. So I'm told, anyway.
I think most of us were under the impression a drive shaft of that type was what you were referring to. Being close to 20 feet long with multiple middle bearings, they have quite a bit of weight behind them should the U-joint blow apart.
Understanding the application would help.
nate379
Banned
I don't see how you figure it's a school bus. He's working with .120 tubing and has a race car in is avatar... not too hard to figure out it's probably some kind of race car.
Pictures would be helpful though.
Pictures would be helpful though.
nissan_crawler
Well-known member
Agreed. I've had driveshaft hoops in several vehicles. Ever see one come up through the bed of a pickup and start flopping around? That'll make your ******** pucker, believe me.
Moose-LandTran
Well-known member
Could you weld a captive nut to the end of the tubing?
Here is the car:
The front of the drive shaft is about even with the driver and passenger hips. There have been a few cases of u-joint failure with some spectactular
damage to the cockpit area. If you follow the link in one of my earlier posts, you can see the area and resulting damage.
Thanks for all the advise. It looks like I'll be using the nut-sert method rather than trying to tap such a thin walled tubing. It's also much to far inside the tube to attempt to weld a nut inside.
Ray
The front of the drive shaft is about even with the driver and passenger hips. There have been a few cases of u-joint failure with some spectactular
damage to the cockpit area. If you follow the link in one of my earlier posts, you can see the area and resulting damage.
Thanks for all the advise. It looks like I'll be using the nut-sert method rather than trying to tap such a thin walled tubing. It's also much to far inside the tube to attempt to weld a nut inside.
Ray
Attachments
nissan_crawler
Well-known member
why not use the tube clamp, rather than drilling holes in the frame
nissan_crawler
Well-known member
Holy ****. Yeah, I would use inserts too, in that case. i figured this was a 1.5/2" tube. I guess that's what I get for ASSuming.
I goofed up by not fully explaining what the application was. I thought I was asking a simple question but apparently kicked over a can of worms.
Thanks for the input. If you want, take a look here (http://www.factoryfive.com/rdsterhome.html) for some good shots of the frame etc.
Ray
Thanks for the input. If you want, take a look here (http://www.factoryfive.com/rdsterhome.html) for some good shots of the frame etc.
Ray
It depends upon both the diameter of the threaded fastener and the thickness of the material. You need to engage at least four (4) full threads for the fastener to have the full strength of the threaded joint. Therefore, if you have a 1/2"-13 bolt then you need a material thickness of 4/13ths of an inch. If you have a 1/4"-20 bolt then you need 4/20ths or 1/5th of an inch thick material to thread.
Also, remember, the size of the hole you drill before you tap the hole matters also. Are you going to have 70% or 60% thread depth? It varies between steel and aluminum and the better tap/hole charts will list both hole sizes for the thread depth. When I say "thread depth" I'm referring to the difference between major and minor thread diameters.
Phil
Also, remember, the size of the hole you drill before you tap the hole matters also. Are you going to have 70% or 60% thread depth? It varies between steel and aluminum and the better tap/hole charts will list both hole sizes for the thread depth. When I say "thread depth" I'm referring to the difference between major and minor thread diameters.
Phil
Falcon67
Well-known member
One more thing - IMHO no nutsert is going to hold a driveshaft loop intact if the front joint fails under power. The size of the tubing might keep it out of the cockpit, now whatcha going to do if the nose digs into the asphalt and vaults the car. It happens. There is a reason NHRA/IHRA spec 1/4" steel, 360 degree, 2" wide not father back than 6" from the front joint. The minimum is probably the tube chassis 1.25" x .083 wall stuff. Also - why not weld it in? We race and I maintain two cars with big, wide driveshaft loops. The Falcon has the pieces trimmed and welded together because it fit the tunnel better than way. I have never had the need to remove it during service work on the cars.
I know a guy with one - I'll ask him what he did for that, if anything.
I know a guy with one - I'll ask him what he did for that, if anything.
Last edited:
Drive shaft is only 11-inches long. It's not going to vault the car, but it can beat the trans tunnel into shrapnel. There are 4 nut-serts per side (total of 8). After checking with the sanctioning race bodies out here, they say that I'll be ok for tech as long as the hoop is 1 to 2 inches to the rear of the front u-joint.
Ray
Ray