Metric Bolt Question

[Happy]

I want to make a change on my tire carrier need a bolt that is a little longer.
The factory bolt looks like the pic below. It is a M8.

The bolts I find locally look just like a standard hex head bolt NOT like the one in the picture.
If I get a M8 size and the grade (5.8, 8.8, 10.9) is correct or higher & correct thread pitch will it work?

Are there any special attributes in the bolts that are used in auto work....like the ones pictured?
I can not find any that have the bolt end showing past the thread.

factory bolt

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[RagnarKon]

So that is dog point hex flanged bolt.

To answer your question… yes you should use a similar bolt of the same grade. If you are replacing it with a longer bolt you can use a higher grade just to be a bit safer. If you can’t find an equivalent flanged bolt you can just use a washer as a replacement for the flange.

Admittedly the grading may or may not really matter—depends on what type of stresses these bolts will be under and we don’t have all the details of what you’re trying to do.

 

[Rick Astley]

As long as you only use a Saskatchewan all-sixteenths to remove/reinstall the bolts then you will be fine.

You also haven't identified exactly which bolts you're looking to replace. If it's a bolt holding a plastic housing against sheet metal with a plastic thread behind the metal, then going higher in grade is not helping much.

Are these the bolts to hold the tire carrier to the vehicle? The wheel to the carrier? The 3rd brake light?

There's a fair amount of guesswork with what you supplied.

 

[HBTFD]

Ask your dealers part dept to look up the part number/description. Take the description and call or go online with McMaster Carr. They will have an exact replacement that is slightly longer.

 

[Werkedperformance]

is your concern the bolt head shape? or the "pilot point"? the big tip just helps assembly.

the tip is always a guide.

 

[Happy]

Werkedperformance you posted as I was typing.
You have it!! The tip is my concern.

Will any bolt (any head I am willing to work with) matching the grade rating, work in an application where a pilot tip was originally used? Even if the replacement does not have the tip?

RagnorKon thank you
Rick Astley our Saskatchewan all-sixteenths just broke. Can I use my pipe wrench? Hey I did read your October 12, 2020 post.

This bolt holds the steering wheel of my Hoyt-Clagwell tractor.

 

[604Bronco]

@Silver-Bolt is an expert in bolts. Heck, it’s even in his username.

 

[Paul Gagnon]

If you can, take a bolt down to your local nut and bolt store. Show them what you have and tell them how much longer you need it. They will be able to have you sorted out and with one in hand in a couple of minutes.

 

[Silver-Bolt]

I want to make a change on my tire carrier need a bolt that is a little longer.
The factory bolt looks like the pic below. It is a M8.

The bolts I find locally look just like a standard hex head bolt NOT like the one in the picture.
If I get a M8 size and the grade (5.8, 8.8, 10.9) is correct or higher & correct thread pitch will it work?

Are there any special attributes in the bolts that are used in auto work....like the ones pictured?
I can not find any that have the bolt end showing past the thread.

factory bolt

The lead point is to help speed up alignment on the assembly line. It serves no other purpose. In the metric world of "grades" 5.8 roughly equal to a Grade-2, 8.8 = Grade-5, and a 10.9 = Grade-8. In automotive it is 50/50 if the bolts will be stamped with a Grade/strength indicator. If you can't find the part you need with the flange, a standard hex bolt and washer will serve the same function. For your application I wouldn't go below a Grade-8.8. Preferably a 10.9. Where the automotive parts have an advantage is in the coating. The corrosion protection on the automotive hardware is far superior to the commercial equivalent. https://www.mcmaster.com/screws/hex-head-screws/

 

[mtap]

Let me know what you find. Looking as well.

 

[Happy]

Thank you for advice you all have given.
Now that I know more I am heading to John Deere.
Local dealer has the largest selection and best pricing on bolts over hardware stores.
I know they carry 8.8 and 10.9 rated and a few bins with supposed to be better coatings.

Again thank you.

 

[BRBUSTER72]

Thank you for advice you all have given.
Now that I know more I am heading to John Deere.
Local dealer has the largest selection and best pricing on bolts over hardware stores.
I know they carry 8.8 and 10.9 rated and a few bins with supposed to be better coatings.

Again thank you.

Your local Deere dealer can look on PartsExpert and should have no trouble finding what you need. It won't have the guide tip but that should be a non-issue. We do this at our store all the time.

 

[Happy]

Using these. Nothing special once Igained a little knowledge.
No fancy point and no special coating. No extra horsepower.
They fit and are identical grade as the one coming out.
Thanks again for answering my questions.

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