I'm doing some suspension work and need to cut down some grade 8 bolts..was planning on using a cutoff wheel...dont plan on turning the bolt blue or nothing like that from the heat..just want to make sure i dont screw up the strength of the bolt......dave
If your really worried about it just cut them using a hack saw or band saw, then touch up the edges with a small angle grinder. But I dont think you will put enough heat in them using a cut off wheel to change the physical properties.
Just a side note, Cat Equipment (big yellow stuff) is a great source for grade 8 fasteners and they have a pretty decent variety. Theirs have a black coating on them and aren't shiny though.
Be careful where you buy your "Grade 8" bolts. There are tons of counterfeit Chinese and other places grade 8's sold in this country that aren't even grade 2. Buy from a reputable dealer that knows what they are selling. With grade 8's if they are lots cheaper than the usual price, there is a reason! As for cutting them, if they're real, you'll have no problems.
WOW! Now that is scary!! Good point, but scary!! The whole front end of my car is held up by 4-bolts. Note taken... Really sad that it has come down to that...
Does anyone sell grade 8 online that you can trust? I wouldn't know how to tell cheap made from good. Have to say this worries me.
Tip for cutting bolts: Thread two nuts on and adjust them till all of the threaded length you want cut off is sticking out of the end nut, then tighten them against one another (so they won't spin and move) then you can cut against the face of this bolt. It protects the threads and prevents your blade from wondering. Hope this helps.
I can imagine you are wanting to cut the bolts down because of their cost at the big box stores. I have found that you can go to places like Fastenal, and buy a box of 50 for what a small handfull will cost you at Lowes or Home Depot. I would never cut down a bolt on my front suspension to save a few bucks, and for sure would never re-use a bolt on the front suspension that had already been brought up to torque. Life's too short!!
Aircraft Spruce I feel could be trusted. Also would guess that McMaster Carr would also be just fine.
Why? If you bring the bolt to a proper torque and dont over torque it, you should be able to reuse the bolt with no problem at all. The proper torgue should be well with-in the elastic limit of the material. There for when the torque is released the bolt will return to is original size (no stretch). I feel you could cycle a bolt about 5 times before you should replace it. This is, of course, if the bolt isnt damaged in any way. Rememeber stress will concentrate in small nicks or cuts.
Disclaimer: I would go by the 5 on/5 off rule for general purpose fasteners, but not for head bolts as they are designed to be stretched when the proper torque is applied.
I don't use the Hillman crap or other stuff from the hardware store for anything critical, even if it's stamped G8. Most of it's coming from China and there's no way to know if it's up to spec or not. I've been told the only American manufacturer left is Lake Erie, who produce for a number of different brands. Infasco, which is Canadian, is also a good source. For G8/9 if the seller can't provide country of origin info, I don't buy it.
Well every bolt stretches when the proper torque is applied. The required stretch will be with in the elastic limit of the bolt. If you are stretching/torquing the bolt close to its yeild you will destroy the bolt and it should be thrown away.
actually,I cut the first side to save a trip back to the bolt house...Ended up having to go back and get some other things as well...and yes did get shorter ones.......dave
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