looking for some help on mounting onto car frame without welding

[cubangt]

So i recently posted my fabrication business online and started to get alot of custom order for catalytic converter shields for peoples cars and trucks.. which is great, most of the vehicles ive already made templates for have existing holes in the frames that go thru so i can mount using 3" and 4" security bolts. BUT i ran into an installation this weekend that the hole did not go all the way thru and was at a lost for how to secure it with only a partial hole..

I thought about the threaded insert rivets, but i cant find anything large enough, then i thought about jack nuts, but again, couldnt find anything large enough. The holes on this vehicle are between 13/16 and 7/8 round, i had ordered some "L" hook bolts, but those didnt work out..

They are coming back next weekend and i need to figure something out that would work and be secure to hold this in shield in place.

Do they make any "toggle" like nuts that would be worth trying.. im not looking to make it cheesy, i want to do it right

I was able to cut a larger washer to the size of the hole and it fit in perfectly, i could weld a nut to that so that i can secure it. BUT not sure how to keep the nut/washer from moving while tightening the bolt.

The other idea i had was to weld the washer to the "L" bolt up high enough on the neck of the bolt so that i can slide the bolt up into the hole and once tight the pressure would keep things in place..

Just kinda at a loss on what i can make or what is available to use these existing holes that DO NOT go all the way thru the frame.

Keeping in mind that im not looking to make any modifications to the frame in anyway..

[MAC702]

Does the hole have enough thickness to thread it? Or is that still too much modification? Drill and tap smaller holes? Any way to attach a picture of what you are seeing to help us think about it?

[cubangt]

The holes / openings in the frame are thin, dont think there is enough meat there to thread it.. its probably about an 1/8" if even that thick.

this is one of the holes, that is there on the bottom of the frame but does not go all the way through, so need some form of toggle type setup to make it work. I did find some 5/16 toggle style bolts and nuts, but i dont want to use that unless thats the only option.

[MAC702]

A 5/16" molly toggle will need about a 7/8" hole. With some Loc-Tite, I'd probably trust it if it snugged well.

A T-anchor would be a lot stronger with a full-size nut, and only need a hole the same size as the fastener: https://www.grainger.com/product/15W...E&gclsrc=aw.ds

[cubangt]

thanks i ordered some of the tanchors and will pick up some anchors as well from the hardware store to see what option is best for the installation.

[ryanjones2150]

I believe I would make that hole go all the way through. Is there some reason you don’t want to do that other than you don’t want to do that?

[cubangt]

I believe I would make that hole go all the way through. Is there some reason you don’t want to do that other than you don’t want to do that?

Personally dont want to modify the customers vehicle, when they hear you say, i need to drill a few holes in your car/truck, they don't want you to do anything else. AND i def dont want to be held responsible for anything they may say was caused by the hole...

When i do my truck, if i need to, ill consider it, but for now looking for solutions that dont require making or modifying the vehicle

[Sberry]

Some places a guy could drill a hole, I agree a guy wants to be modest here and not have it look like it was attacked with a chain saw. I got a coffee can full of concrete flat wall tie tabs after we bust them off. They have a slotted hole and good for a lot of stuff. Weld to them, weld nuts to them. I have done bunch of customn install and when I did I get the right fasteners and often better. Today use a lot of common 1/4 20 mild steel, cost a nickle vs some of that plastic stuff and holds so well as well as easy to stock and several kinds of self drillers.
Nothing as good sometimes as figuring how to get at it nut and bolt.
I am not working on new cars though, my people trust me, they understand drilling a common hole.
I will say,,, that is a great aftermarket idea though.

[Sberry]

But,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, to solve my problem at the time would have made used a common fender spring clip and drilled a bolt hole next to it. Would have never known it wasnt there forever and give it a shot of penetrating spray when I tighten it down. I might have simply drilled hole next to it and use simple bolt and washer, install nut thru hole.

[ryanjones2150]

I said drill a hole, not cut it with a chainsaw. I’d be pretty pissed too if somebody tore up my frame. But if the OP is that worried about liability then he probably shouldn’t do any of this work at all. If you get paid to do work, that makes you a “professional” and your work should reflect that. Meaning, don’t do something that’s dumb. If you’re going to be in business and work on other people’s stuff, maybe consider some insurance as well to protect your own stuff.

[cubangt]

well im back on this again.. so i have used a combination of threaded inserts to the toggle that work.. But i ran into a problem this past weekend...i have 1/4 inserts and 5/16 inserts and the 1/4 worked on one hole, but not the same hole on the other side of the truck.. so in that case i had to use the toggle, BUT would like to find an insert that would fit and work better.. I have looked and all the inserts i have found jump from 1/4 up to 5/16... does anyone know if there is a 3/16 or something just slightly larger than the 1/4 insert that i can use or find so i can order?

I found some "threaded weld nuts" that look like they may work, but not sure how i can keep the nut from spinning while tightening the bolt down.

I was also looking at maybe switching over to Metric threaded inserts, and picking up some 10mm and 12mm inserts to see if that would work, since those are slightly larger than the 1/4 insert and may grab onto the opening better

other suggestions are greatly appreciated.

[MAC702]

... I have looked and all the inserts i have found jump from 1/4 up to 5/16... does anyone know if there is a 3/16 or something just slightly larger than the 1/4 insert that i can use or find so i can order?

I found some "threaded weld nuts" that look like they may work, but not sure how i can keep the nut from spinning while tightening the bolt down.

I was also looking at maybe switching over to Metric threaded inserts, and picking up some 10mm and 12mm inserts to see if that would work, since those are slightly larger than the 1/4 insert and may grab onto the opening better

Lots of things don't add up here. 3/16 is smaller than 1/4. In between 1/4 and 5/16 would be 9/32.

If you switch to metric, yes, the slightly different sizes will give you some more variety. But 1/4" is on par with 6mm.

If you are discussing bolt sizes or wrench sizes, stay consistent.

[cubangt]

Yea i noticed once i posted what i had said.. ive been working with 3/16 flat bar this week on my orders, so probably thru that into the mix..
So yes the threaded inserts i tried that are just barely big enough to grab hold are 1/4 inserts.. i need something slightly larger than that to better grab the opening.. i was looking at metric and seems that maybe something 7mm or 8mm then?

[ryanjones2150]

What kind of threaded inserts are we talking about here? Are you using rivet nuts?

[cubangt]

thats what im currently using or trying to use, but open to other suggestions.. i ordered an assortment of other threaded rivet inserts and should arrive this week, but if there is something better to consider id love to hear about it so i can try it out.