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-   -   Probably dumb question about carriage bolts (http://www.diychatroom.com/f19/probably-dumb-question-about-carriage-bolts-174084/)

nikeman 03-10-2013 01:27 PM

Probably dumb question about carriage bolts
 
I bought some 1/2" carriage bolts for my deck and they of course have the squared off portion near the circular head of the bolt. I tried putting a 1/2" washer on it and it of course will not go over that squared part. Am I supposed to get a larger washer for these types of bolts or is that how it's supposed to be?

Larryh86GT 03-10-2013 02:06 PM

I've used them without a washer at the head end and just sucked the square portion into the wood and put the washer at the nut end.

joecaption 03-10-2013 02:11 PM

No washer needed.
The whole idea or the square part is to hold the bolt in place so you can tighten up the nut without the bolt turning.

woodworkbykirk 03-10-2013 02:58 PM

what joe said.. if the carriage bolt is exposed not having the washer gives a cleaner look.. you need the washer on the opposite end though where the nut is

Daniel Holzman 03-10-2013 04:18 PM

Carriage bolts can be a PITA on for deck applications. If the square head is driven into the wood, and the wood dries out (which is common with PT lumber), the square head may no longer be tight enough to prevent rotation of the carriage head when you tighten the nut. It is very common for bolts to loosen up after one season or so since PT lumber is often quite green when first purchased, and as it dries and shrinks, bolts can become loose, and it may difficult to tighten carriage bolts adequately. I recommend use of standard hex head bolts, they can always be tightened.

tony.g 03-10-2013 05:29 PM

Why are they called carriage bolts in the first place?

joecaption 03-10-2013 05:34 PM

http://www.blacksmithbolt.com/gpage14.html

Dan where are you going to find hot dipped hex bolts.
The nuts only need to be snug to do there job.
There mostly for shear loads.

jagans 03-10-2013 06:05 PM

They are called carriage bolts because the frame of carriages were punched with square holes to hold the square portion under the head so you dont need a wrench on one end. You can still find square holes punched in the frames of automobiles today for the same purpose.

The multiple problems with using them on wood are for one thing the fact that the square portion reams out the wood which has very little resistance to torque. The cross section of wood is resting on threads which can cut into the wood fiber. Last and worst: You cannot put a washer on the head end to distribute the load over a larger area, like a split ring connector does.

Incredibly, and due to their infinite wisdom, some barney fife local building codes actually require them.

"Forgive them father for they know not what they do" Comes to mind.

nikeman 03-10-2013 06:27 PM

Thanks guys. I'll stick with carriage bolts. If they get lose I know I can get them snug again. I got stainless carriage bolts because they do look a lot better than the galvanized bolts and they will be visible all the time. I figure the large round head will act like a washer anyway.

A Squared 03-10-2013 06:36 PM

Quote:

Originally Posted by jagans (Post 1134056)
The cross section of wood is resting on threads which can cut into the wood fiber.

Well, no. Again, carriage bolts do not necessarily have full length threads, many have shanks. Didn't we just have this conversation a few days ago?


this is a carriage bolt:


http://www.traderscity.com/board/use...933-b108-1.jpg

these are carriage bolts:

http://image.made-in-china.com/2f0j0...Long-Size-.jpg

these are carriage bolts:

http://img.weiku.com/waterpicture/20...45605988_1.jpg

Like I said in the previous thread, what makes a carriage bolt a carriage bolt is the style of head, not whether or not it has a shank.

nikeman 03-10-2013 06:46 PM

I made sure to get bolts with a long threaded area over the ones that were only threaded for the last inch or.

Daniel Holzman 03-10-2013 06:50 PM

You can get hot dipped galvanized or stainless steel bolts, washers and nuts at any decent hardware store, and most big box stores. Ditto for carriage bolts. For me, it is mostly a preference thing, as I said I don't like the issues with tightening carriage bolts.

A Squared 03-10-2013 06:50 PM

Quote:

Originally Posted by nikeman (Post 1134079)
I made sure to get bolts with a long threaded area over the ones that were only threaded for the last inch or.

well in your particular case, jagen's comment is valid then. It's much better to use a bolt with a shank of the proper size for the material fastened then it is to use one with the material bearing on threads.

I'm just saying that jagen is incorrect when he says that carriage bolts don't have shanks.

jagans 03-10-2013 06:57 PM

They are called carriage bolts because the frame of carriages were punched with square holes to hold the square portion under the head so you dont need a wrench on one end. You can still find square holes punched in the frames of automobiles today for the same purpose.

The multiple problems with using them on wood are for one thing the fact that the square portion reams out the wood which has very little resistance to torque. The cross section of wood is resting on threads which can cut into the wood fiber. Last and worst: You cannot put a washer on the head end to distribute the load over a larger area, like a split ring connector does.

Incredibly, and due to their infinite wisdom, some barney fife local building codes actually require them.

"Forgive them father for they know not what they do" Comes to mind.

stadry 03-11-2013 06:28 AM

lag bolts need wshrs - carriage bolts don't,,, something about carriage bldrs trying to keep a more presentable appearance of their work back in the day,,, ' carriage ' bolts are named for just that purpose,,, imagine that - who'd have thunk it ? ? ? ? :whistling2:


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