View Full Version : Metal Rod~ Fastener?

02-18-2009, 02:56 PM
Hello, I am using a .25 inch metal rod for mounting my motors and since they are not threaded rods, I have no idea how/what kind of fasteners to connect to it. I was thinking nuts, bolts and washers, but again, they arent threaded so you mech. guru's I need your help! :) please

02-18-2009, 03:13 PM
duct tape? elmer's glue? chewing gum?

With the description you've given I have no idea how you're trying to attach motors to a piece of wire, my imagination is decreasing linearly with age..

You'll need to give some more info to get good answers :happy:

/edit with an imagination boost: you're attaching the rod on the motor's axle, along its axis? (i.e. as in lengthening the axle?)
In that case, try some vinyl tubing with hose clamps. Used a lot in the homebuilt CNC world and seems to work ok for quite high torques.

02-18-2009, 03:29 PM
Assuming ScuD's assumption is correct (that's a lot of assumptions) then I'll second the tubing and hose clamps. I have used this in the past with great success and the supplies are available at Home Depot or Lowes.

02-18-2009, 04:59 PM
if you have a drill and are doing what is assumed.
you can take a spacer that fits over both the rod and the motor axle and drill through spacer and rod in two places, at 90 degree angles to each other. Then put screws in those holes. repeat for axle on motor. Works extremely well for high torque, even with small screws. I recommend locktite for it to. Also will require small drill bit and a center punch would be helpful or drill a pilot hole.

Had to do this before for a robot.

02-18-2009, 06:20 PM
Here I drew a crude MS Paint blueprint:


As you can see it is static, and so not necessarily an axle. Does this change any of your suggestions?

And thanks Ironman, a very good idea, however, I do not have access to a drill press, or any fabrication tools for that matter so I don't know if that is a very ideal job in my case, as well as the fact that it is round and .5" thick might pose some kind of difficulty.

Also you can spot the mounting holes I am talking about easily in this picture:


02-18-2009, 07:45 PM
How about shaft couplers?

These are smaller, but you can find them up into the 7" range, even. I have some half inch here I swiped off of an old line printer, but I've seen them online larger than these 1/4"...


02-18-2009, 09:54 PM
Since it's not threaded rod, you could always make it so, using a 0.25 die (http://en.wikipedia.org/wiki/Tap_and_die#Die), and stick a nut on the end. There appears to be a threaded bolt hole in the picture, besides that large bushing hole I think you're hoping to use, might get a bolt to use that hole too, in attaching these motors to a frame.

02-19-2009, 05:40 AM
How about shaft couplers?

These are smaller, but you can find them up into the 7" range, even. I have some half inch here I swiped off of an old line printer, but I've seen them online larger than these 1/4"...


They look extremely sturdy, how do I use them?

02-19-2009, 01:21 PM
You can join two rods or shafts together. So if you need to go motorshaft to axle, you put the motor shaft in one side and the axel in the other, then set the set-screws, put a drop of locktite in, and you're set.

And yeah, a tap-and-die set (or two or three) is a requirement, IMHO.

02-19-2009, 07:34 PM
Is there a cheaper way? I mean I like your idea Adrenalynn but it is way too costly (~$8.00 per fastener) I also do like Ironman's idea, except the only drill I have access to is a hand drill and I am working with stainless steel so it might be a #%[email protected]# to do. Anyone have any experience with drilling holes in stainless steel rods? I googled around real quick and found that I should make a quick tiny dent to make sure I don't slip when drilling, and to use a butt load of oil.

Any other suggestions?

PS: they are not hollow

02-19-2009, 11:40 PM
patience, slow speed, cutting oil. That's how you drill stainless steel. A dent would be a necessity too, if i was doing it. Followed by a pilot drill hole, aka something smaller than what your final whole size is. Then your final hole size.

also if you can make a jig (out of wood) to hold the axle in place that will help a ton. And if you can be directly over whatever ur drilling and have a level you can make a pretty straight hole.

I'm not certain on how it would affect the strength if your hole is perfect, i think it'd still be within reason though.

02-19-2009, 11:55 PM
Yeah, a vice is a requirement. Slow even pressure. A cobalt bit.

02-20-2009, 12:05 AM
Are you sure its SS. Check to see if its magnetic. If it is then its not SS. SS rods are expensive and normally not used unless the conditions require it.

Your going to have a hard time drilling a decent hole in any rod with out a press. Even if you center punch it your almost for sure not going to drill it by hand.

You need to find a drill press and use a centering bit to start that hole otherwise its going to walk on you.

But you can try it like Adrenalynn said use a vice and a good drill bit. I would go for the Tungsten Carbide bits but cobalt will work as well. Tungsten Carbide is just a tougher bit,


02-20-2009, 02:27 PM
Well I was going to use stainless steel as it is the strongest/cheapest metal available to me. But I decided I wouldn't, and would experiment, since I am not willing to shell out $10 for each rod without seeing if the lesser would work. The two rods are:

"Alloy Steel 4130 Normalized Cold Finish Round 0.375" Cut to 24""

"Alloy Steel 4130 Normalized Cold Finish Round 0.25" Cut to 24""

Very cheap too, $1.00 and $3.00 , do you think these are capable of supporting a load ~ 150 lbs together?

02-20-2009, 02:55 PM
Rods are not the way for you to go. You need to use a tube/pipe. That much wieght will bend the solid rods for sure.

Plus using a tube will be easier to drill a hole thru it. The tube will give you more strength than the rod.

Check out home dpeot or loews. They have steel tubes in thier sheet metal area. Also AceHardware would have them. There not that expensve either. A couple bucks for 4ft sections.

02-20-2009, 03:45 PM
Wait are you sure? That tubes are stronger than rods? What information can you base that off of? I really don't think I can believe that. Because volume is proportional to density and density is proportional to sturdiness, so as volume (non hollowed rod) increases, as does the sturdiness of said tube.

These are to be able to support 150lbs together.