AndyMark 3/8-16 x 7 Hex Head Bolt bending

Does anyone have any experience with the AndyMark 3/8-16 x 7 Hex Head Bolt used in the kit of parts drivetrain bending or breaking? I was using them to design a drivetrain, but my friend said his bent this year.

[FrankJ]

I am pretty sure they are just a grade 5 bolts. I am are pretty sure they are what we used for our 2010 Break Away chassis axles. If so we have been pretty abusive & they have held up.

[IndySam]

Originally Posted by FrankJ

I am pretty sure they are just a grade 5 bolts. I am are pretty sure they are what we used for our 2010 Break Away chassis axles. If so we have been pretty abusive & they have held up.

I'm pretty sure he meant 7" and not grade 7.

Originally Posted by FrankJ

I am pretty sure they are just a grade 5 bolts. I am are pretty sure they are what we used for our 2010 Break Away chassis axles. If so we have been pretty abusive & they have held up.

This part: http://www.andymark.com/product-p/am-1055.htm

[Mk.32]

We have bent the KOP bolts in the KOP long configuration before [8inch wheels, Logomotion lots hard driving]. After we realized this we got some Grade 8 bolts and didn't have any problems.

Originally Posted by Mk.32

We have bent the KOP bolts in the KOP long configuration before [8inch wheels, Logomotion lots hard driving]. After we realized this we got some Grade 8 blots and didn't have any problems.

Do you have any grade 8 bolts you'd suggest using?

[AdamHeard]

Originally Posted by SuperNerd256

Do you have any grade 8 bolts you'd suggest using?

Grade 8 is a rating, not a brand. So if you find anything marked grade 8, you're fine.

Home Depot might have them, unsure. Any industrial supplier should

Socket Head bolts aren't grade 8, but are similarly strong.

[Phyrxes]

Quick check of Mcmaster shows part #91257A650 is $12.13 for a 5 pack of grade 8 bolts if you don't have a local industrial supplier.

[MrForbes]

We used the kit chassis for logomotion, we bent the long bolts that hold on the wheels. That aspect of that chassis is not a very good design, if your robot is going to do things like drive into a wall with it's arm extended. The load of the robot falling back onto it's wheels will bend the axles.

Using a higher grade bolt might fix the problem, but it's still not a very good design.

Originally Posted by Phyrxes

Quick check of Mcmaster shows part #91257A650 is $12.13 for a 5 pack of grade 8 bolts if you don't have a local industrial supplier.

This is exactly what i needed. Thanks!

[bardd]

Originally Posted by SuperNerd256

This part: http://www.andymark.com/product-p/am-1055.htm

We use these all the time. They're really robust, in 2011 6 of them held the weight of our entire max-weighted robot for nearly a year and never complained, but they do bend. I'm pretty sure we don't have a single one of these that is completely straight.
Don't be too alarmed though, most of these bends are unnoticable to the untrained eye (maybe a degree or two).

[Jenn Feathers]

We had one bend almost immediately, It was a pain to get out.

[MrBasse]

Those bolts are good, but they will bend, our Logomotion bot bent all 6 and then 6 more in one season... and it only weighed 84 pounds.

The biggest issue, is that once they bend they are incredibly difficult to remove for replacement. Ours bent to the point where they caused our wheels to wobble and started throwing chains. We use grade 8 bolts now and have had no problems.

[MrForbes]

Originally Posted by MrBasse

The biggest issue, is that once they bend they are incredibly difficult to remove for replacement.

That's the problem...then you get to call in a back up robot and watch the finals from the sidelines. BTDT

[George C]

Try replacing them with socket head shoulder screws aka stripper bolts.

http://www.mcmaster.com/#shoulder-screws/=jintlq