Making a sqaure hole for a carriage bolt

[ryans69chevy]

Has anyone done this before? I took apart my wood bed and a lot of the carriage bolts were too rusted that they started turning the bolt head causing the sqaure hole to become rounded.

I've researched a little and found they make rotary broaches which are a bit expensive. Does anyone know of any other methods for use on out pickups? I think I'm gonna have a bunch to do...

[LockDoc]

Originally Posted by ryans69chevy

Has anyone done this before? I took apart my wood bed and a lot of the carriage bolts were too rusted that they started turning the bolt head causing the sqaure hole to become rounded.

I've researched a little and found they make rotary broaches which are a bit expensive. Does anyone know of any other methods for use on out pickups? I think I'm gonna have a bunch to do...

Probably not good for a bunch but you can go to Ace hardware and buy a square file.....That's what I use.

LockDoc

[MusicMan70]

Check post #113; for a different application, but it may help.

http://www.67-72chevytrucks.com/vboa...e+cable&page=5

[ryans69chevy]

Thanks for the reply lockdoc. I might have to try that. I should have one of those in my arsenal anyway! I've heard of ppl making their own broaches, but since I have to do so many of them maybe the cost of just buying one would make more sense since all sides would be factory milled to make for a nice square hole. I found out getting all sides perfect is harder than it looks. Found that out when I had to cut down a drill extension and make the end that goes into the drill into a hexagonal arbor to fit back into the drill. It didn't turn out as square as I wanted, but it served it's purpose on the job site.

I've read on another site of ppl just drilling a round hole to fit the bolt into and then tightening the nut onto it and the square on the bolt would cut through the metal forming a square hole. Not sure if this would work for my application or not or if a better method would serve me better.

These trucks have a good number of carriage bolt holes all over not just in the bed if I remember right. Not sure if all are the same size though.

[ryans69chevy]

I checked out that thread musicman. I'm still processing that one... I get the concept, but wouldn't that stone shatter when hammering since it's a round hole you are starting with? Unless they are stronger than I thought!

[cdowns]

it is much better to grind the heads off while disassembly

[B. W.]

I welded scrap stock across several at a time, this prevents them from turning. Doesn't take much time, & all the holes stay square.

[Iamtdg]

Originally Posted by cdowns

it is much better to grind the heads off while disassembly

Or drill them out.

[Jrainman]

you know guys they do make a washer with square holes in them for carrage bolts ,

But the size you need and weld them in Presto all fixed like New

I used them they work great they are called SQUARE HOLE WASHERs

[franken]

Tighten the bolts til they sheer off.

[ryans69chevy]

Yea I went around with my impact wrench to try and bust them loose, but I guess I didn't explain it to the person good enough. I then went around and grinded them off. I never thought of welding a piece of metal to a bunch of them. Like you said that would have saved me on this one.

My header panel is pretty rusted out where the carriage bolt holes are so I'm pretty sure I'll have to cut all that out and weld in a new piece of sheet metal anyway. So I still need to figure out how to get some square holes. I still will look into the square washers!

[Overdriven]

I wouldn't think you'd need a rotary broach for sheetmetal or slightly thicker supports. Rotary broach would be for thicker materials which would require much greater forces applied without the rotary motion.

I'd try drilling a hole and use a vice to basically punch out the corners with a broach. With a deepwell socket just big enough for the broach to slide into behind the sheetmetal you shouldn't distort the sheetmetal. Maybe use this method to make your own "washers" to weld onto your panels.

I hear ya on making your own Hex, that would be tough to get even. But for a broach start out with square stock a little bigger than the hole you need as you won't be pushing it all the way through. Do a little measuring and mark the sides indicating the taper you want and grind down to those marks. Since it's already square and you're just adding the taper it's much easier.

[ryans69chevy]

Overdriven, good idea. That would be pretty cheap just a lot of labor. Could prob file a taper into it on my hour car rides everyday to and from the jobsite. Give me something to do!

[BILT4ME]

I have made a square hole in steel as thick as 3/16" with a hammer and small straight cold chisel. Find a chisel that is the same size or smaller than the square hole you need. Then drill a hole in the center of where you want the hole to be. Then use the chisel to cut out the corners. Straight down on an anvil or the side of a sledgehammer head.

You can also drill out the center hole slightly oversized to the shank and then smack the head of the carriage bolt to use it to make the square hole. This only works on thin gauge steel or aluminum. You can also tighten the bolt and have it pull itself into the hole.

[rpmgroup]

I use a piece of square key stock the size hole that is needed and taper down the edges on the grinder. Makes a great punch for squaring out a drilled hole.

[67ChevyRedneck]

Originally Posted by franken

Tighten the bolts til they sheer off.

I've actually done this on two beds, it works great, especially if they're rusted. The heads snap right off.

As far as the hole going "round", if you use brand new bolts, the nuts spin right on and *usually* tighten down without the head spinning. Removal will once again suck...

[cg285]

you can't rotary broach or press broach sheet metal.
i am assuming you are talking about the bed side panels.
those holes need to be punched OR you can buy weld in patch panels already punched. or you could shear a narrow strip, punch the holes and insert under the old panel.
or you could weld square hole washers over the old hole but won't look as good imo