Screwing into thick Steel Post

RedMF40 · Jul 30, 2020

Need some help with this. I need to attach a small electrical gadget, the VFD inverter that powers up my car lift, preferably to one of the posts of the lift itself.

The gadget only weighs a pound or two, and it has four little tabs to put screws through.

Is there a kind of screw that will work its way into a drilled hole in maybe 3/4" to one inch steel? No need to drill all the way through, due to the light weight of the VFD. I know about self-tapping screws but they are mostly for thin metal if I'm not wrong. I imagine I could get away with little 1/4" screws.

Thanks for any help. The VFD has been strapped to a ladder by the lift and held on with zip ties while doing the final wiring. I'm sure it all works now so it's time to finish up the installation so it's correct and I can use the ladder for other things and just get it out of the way.

Gerrit

rustred · Jul 30, 2020

make it a good job and drill holes three sizes smaller than 1/4 " and tap the hole to 1/4 " and done .bolt it down.

RedMF40 · Jul 30, 2020

(quoted from post at 19:41:28 07/30/20) make it a good job and drill holes three sizes smaller than 1/4 " and tap the hole to 1/4 " and done .bolt it down.

That's a good suggestion, hadn't thought of tapping a hold for a machine screw. Thanks,
Gerrit

kcm.MN · Jul 31, 2020

You could strap it on, fabricate a clamp-on shelf/holder, or use neodymium magnets. Lots of magnet styles to choose from.

And lastly, could have it hang from magnetic hooks. I have some rated for 90lbs and they are pretty darn strong. Check these out:
https://www.amazon.com/GREATMAG-Mag...+magnetic+hooks&qid=1596171433&sr=8-3

Charles in Aus. · Jul 31, 2020

This is a bit off the wall but have you considered double sided tape ?
The foam type is almost 3mm thick and can hold immense weights , especially on smooth painted steel surfaces . It might sound like a half @r$ed job but believe me it is so difficult to remove something stuck on with this that it becomes a job in itself .

RedMF40 · Jul 31, 2020

(quoted from post at 22:00:13 07/30/20) You could strap it on, fabricate a clamp-on shelf/holder, or use neodymium magnets. Lots of magnet styles to choose from.

And lastly, could have it hang from magnetic hooks. I have some rated for 90lbs and they are pretty darn strong. Check these out:
https://www.amazon.com/GREATMAG-Mag...+magnetic+hooks&qid=1596171433&sr=8-3

Thanks, I like those magnets but probably won't use them for this. The little VFD is pretty delicate and I do all I can to make it happy. Letting it hang with multiple wires connected might present problems farther down the road. And I tend to knock into things.

Charles, thanks. I'd actually thought of something like that, wasn't sure I wanted to risk it. The tape would probably work, but I'll likely use some other fastener to attach the VFD. I appreciate the suggestion.
Gerrit

derwen1959 · Jul 31, 2020

How about welding bracket to post

jniolon · Jul 31, 2020

if not welding... glue a bracket to the post. Epoxy or 3m panel bond adhesive will hold the bracket and smaller screws hold the device to the bracket

john

grizz02 · Jul 31, 2020

drill and tap it

Russ from MN · Jul 31, 2020

Drill and tap 1/4, drill all the way through, you're less apt to break the tap, and use oil.

dr sportster · Jul 31, 2020

An electrician would mount it on Versabar from tapped 1/4-20 holes in the unit then use spring nuts to mount the VFD

Dusty MI · Jul 31, 2020

(quoted from post at 06:55:16 07/31/20) An electrician would mount it on Versabar from tapped 1/4-20 holes in the unit then use spring nuts to mount the VFD

We always called what your calling Versabar, Unistrut. It's amassing all the fittings and parts that are available for use with it.

Dusty

dr sportster · Jul 31, 2020

The guys telling you to use glue and two sided tape have no idea about the spirit of the elctrical code .Must be done in a workman like manner . Not glue!

RedMF40 · Jul 31, 2020

(quoted from post at 11:04:04 07/31/20) The guys telling you to use glue and two sided tape have no idea about the spirit of the elctrical code .Must be done in a workman like manner . Not glue!

I'll attach the VFD directly to the post with screws. But from reading the replies I got the idea to put thick rubber washers between the unit and the post to help dampen any vibration. Probably not necessary, just something I want to do.

Thanks for all the info, will check back when I have it secured the way it's supposed to be.

Gerrit

DoubleO7 · Aug 1, 2020

The thru bolts will still transfer vibration rendering the rubber washers ineffective.
You could use actual vibration dampeners tho that are a rubber disc with unconnected but opposing studs sticking out.

Not yet mentioned, you could also use drive rivets in blind drilled holes.

Screwing into thick Steel Post

RedMF40

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rustred

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RedMF40

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kcm.MN

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Charles in Aus.

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RedMF40

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derwen1959

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jniolon

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grizz02

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Russ from MN

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dr sportster

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Dusty MI

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dr sportster

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RedMF40

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DoubleO7

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