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  1. #21
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    Speedy Metals. Choose alloy, 4140, hot rolled, heat treated. Then choose your size. 1 3/4 x 12 shows up as $46.14.

    Other sites may be cheaper, surf until you are content.

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    Maybe it's time for clarification - you don't want to make a fastener, you want the stock to have the same relative strength as a Grade 8 bolt, right? It's correct that large -8 bolts are lower strenght, and may not be uniform in hardness from outside to center, so you are likely better off not using bolt stock for your part, but a dedicated material like the EDT or pre-hard.

    And I guess I'll play "Mom" here too, and say that if this thing has a stress requirement that involves safety or durability you need to either give full details and/or get a proper engineer or materials guy involved.

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    Quote Originally Posted by memphisjed View Post
    grades are not given an alloy restriction (type 1 or 3 is the alloy call out). Grade 8 is heat treated after threading with tensile of 150k psi. Grade 490 which is what your 2 inch bolt would be is 120k - sometimes tempered after threading. a490, a325, b7 are twins from another mother, and slightly better than grade 5- way better to use.
    I am for doing work yourself; when spec is grade 8 there is no room for error. St Louis bolt and screw or Portland bolt would be the ones to call.
    can grade 8 be thread rolled after heat treat? like 12.9?

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    Quote Originally Posted by Milland View Post
    Maybe it's time for clarification - you don't want to make a fastener, you want the stock to have the same relative strength as a Grade 8 bolt, right? It's correct that large -8 bolts are lower strenght, and may not be uniform in hardness from outside to center, so you are likely better off not using bolt stock for your part, but a dedicated material like the EDT or pre-hard.

    And I guess I'll play "Mom" here too, and say that if this thing has a stress requirement that involves safety or durability you need to either give full details and/or get a proper engineer or materials guy involved.
    Customer is a logger, hasn't provided the full context yet but from what I gather they're modifying some attachments on the logging skid steers which were originally secured with grade 8 bolts. I just wanted to collect some preliminary metallurgical advice so I am better prepared to look into it. May seem like I am unreceptive to the safety advice, but that's not really the case.

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    Grade 8 bolts take a beating in logging equipment just like it does in oilfield equipment. I'm sure construction equipment is the same. Just tell your customer there is no guarantee your new bolts will hold up but give them a try and go from there. I would suggest going to a 4330v with a 140-160K ys steel and not mess with ETD-150 or 41xx Q&T material.
    Ken

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    To OP.
    Calibrate Your expectations.

    Exotic steel alloys are fantastic - but very much more expensive than std bolts of 12.9 as premium stock, to modify.

    You are probably NOT going to make better fasteners, cheaper, than std 12.9 bolts, of a given size, nor anywhere near.
    They have already paid off the process, docs, testing and heat treat stuff and deal with metric tons of the stuff day in.

    You are doing well if You can make a custom 1.5" bolt, 12" long, for 300% of the cost of a similar one from a good industrial supplier (wholesale price, not retail).

    And for such large bolts, at a high grade, it is likely someone will have to sign off on strength/elongation/etc.

    In small quantities, work hours are usually much more than material costs, as are tooling and setup costs.
    You cannot work for free, and the tooling and testing kit is expensive.

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    cricket, we still don't know what shape this part would look like, except that it's a foot long and will be under tensile stress. If it is "stud-like" or "bolt-like", I'd second the recommendation you contact Portland Bolt. They will do custom parts, and might even be able to do "standoff-like" female threaded parts if that's what you need. External threads will be rolled, heads can be formed (so you don't need to buy max diameter blank stock), etc.
    Last edited by sfriedberg; 12-04-2021 at 04:07 PM. Reason: feex tipoo

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    Quote Originally Posted by hanermo View Post
    To OP.
    Calibrate Your expectations.

    Exotic steel alloys are fantastic - but very much more expensive than std bolts of 12.9 as premium stock, to modify.

    You are probably NOT going to make better fasteners, cheaper, than std 12.9 bolts, of a given size, nor anywhere near.
    They have already paid off the process, docs, testing and heat treat stuff and deal with metric tons of the stuff day in.

    You are doing well if You can make a custom 1.5" bolt, 12" long, for 300% of the cost of a similar one from a good industrial supplier (wholesale price, not retail).

    And for such large bolts, at a high grade, it is likely someone will have to sign off on strength/elongation/etc.

    In small quantities, work hours are usually much more than material costs, as are tooling and setup costs.
    You cannot work for free, and the tooling and testing kit is expensive.
    If I'm not mistaken, DIN class 12.9 significantly exceeds SAE grade 8 in terms of tensile strength.

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    Quote Originally Posted by 4GSR View Post
    I would suggest going to a 4330v with a 140-160K ys steel and not mess with ETD-150 or 41xx Q&T material.
    I keep wondering why people recommend 4140. It only quenches an inch deep and not as hard that deep as at the surface. I'd go 4340 or 300M. Make the part then have it heat treated. Straighten. Nice radiusses everywhere and maybe shot peen if you want to go crazy.

    Can't do much better than that without going exotic.

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    Quote Originally Posted by crickets View Post
    Two inch grade 8 bolts are a bit on the pricey side My target diameter is 1.5"
    Do you need a lot of these? Also: is the service potentially lethal or otherwise critical? Large crane, walkway, etc? For a few fasteners, probably would feel better myself to use good quality grade 8 that's been properly heat-treated and has the yield and fatigue strength, and the ductility needed for service.

    If you have a lot of these it may be worth perfecting the process to thread bar stock. 1.5 inch grade 8 bolts are around 50 bucks each. But 1.5 inch 17-4 PH rod is about ~$80/ foot and ETD is about $50/ft so it would take a lot for the view to be worth the climb. For me at least.

    It may be that you have to up the size of the fabricated threaded area as cut threads will be weaker than rolled Grade 8.

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    Quote Originally Posted by bosleyjr View Post
    grade 8 that's been properly heat-treated and has the yield and fatigue strength, and the ductility needed for service.
    Not so sure on the ductility part. On the midget we'd never use grade 8's. They'd snap where grade 5 would bend until the load was distributed over more attachments.

    And I'd much rather make the part myself than hack something out of a cots bolt. 300M or 4340 and a good heat treater and you know what you've got. You can even adjust hardness to whatever is most suitable for the service it will see.

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    Quote Originally Posted by crickets View Post
    I gather they're modifying some attachments on the logging skid steers which were originally secured with grade 8 bolts.
    It reads like he will be making the attachments that are secured with grade 8 bolts. Beyond that all that is known is than the attachment can be machined from a rod 1.5” x 12”.

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    20 some odd years ago the steering cylinders on my JD544B blew out, in the process I found the bolts that secured each end of cylinder were fubar. JD wanted something like 500 bucks a pop for those bolts, I bought some spec hex stock, forget what it was, and turned the bolts out of that, cylinders were rebuilt again about 5 years ago, those bolts are still good. So if he is making custom bolts for some type of logging skidder, it just might be cheaper than the dealer.

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    It doesn't look like the OP is wanting to make bolts, it looks like he is fabricating something that will be bolted using Gr8. If he is making bolts, use the ETD 150 and roll the threads. Where I worked before retirement we used it for tierod bolts on hydraulic cylinders. We rolled the threads and it is tough stuff. If he is looking for a material to fabricate an attachment and he could use a flame cut plate I would consider Weldox.

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    I make lots of parts for forestry.

    Typically-

    If it's less than 3/4" thick A36 they will break it.

    Loggers love T1

    If it has 400 HP and runs at 4000 PSI they want it to run at 600HP and 5500 PSI.

    Most things are not expected to last decades. If you can make it fast and it's better than it was they are stoked.

    When I'm figuring out what material I should use I want an understanding of what the hell the part I'm making does. I sometimes ask for pictures or a phone call with the operator. I've had parts dropped off that I thought were a no big deal, simple repair, but decided to call and double check what it does because the old part was pretty mangled. When they tell me it's the main drive for a tweaked out 3406B running through an Allison in OD to a winch hauling 80K lbs over the heads of people it can have an effect on materials and approach. Sometimes they want shit bulletproof, but that makes the failure fuse something else. If they're OK with that go for it, but sometimes they didn't think that far ahead.

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    Quote Originally Posted by dalmatiangirl61 View Post
    20 some odd years ago the steering cylinders on my JD544B blew out, in the process I found the bolts that secured each end of cylinder were fubar. JD wanted something like 500 bucks a pop for those bolts, I bought some spec hex stock, forget what it was, and turned the bolts out of that, cylinders were rebuilt again about 5 years ago, those bolts are still good. So if he is making custom bolts for some type of logging skidder, it just might be cheaper than the dealer.
    Generally they seem to run their equipment without reservations and under assumption things will eventually break. Thus the difference between say a grade 8 fastener versus a custom one may be not that one will break and the other won't, but rather when one breaks it may be a week of downtime for the special order to come in, versus a local shop making a replacement in a few hours. That's even before going into the "custom" element of it all

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    Quote Originally Posted by crickets View Post
    Customer is a logger, hasn't provided the full context yet but from what I gather they're modifying some attachments .....
    !!Alarm!!

    ....

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    Quote Originally Posted by jim rozen View Post
    !!Alarm!!

    ....
    Just say "NO"

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    Quote Originally Posted by crickets View Post
    Customer is a logger, hasn't provided the full context yet but from what I gather they're modifying some attachments on the logging skid steers which were originally secured with grade 8 bolts. I just wanted to collect some preliminary metallurgical advice so I am better prepared to look into it. May seem like I am unreceptive to the safety advice, but that's not really the case.
    Loggers as customers
    Looking for material advice on the internet

    What could possibly go wrong?

    (If you have to ask here you don't know what your doing)

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    Quote Originally Posted by dian View Post
    can grade 8 be thread rolled after heat treat? like 12.9?
    not according to specs. Grade 8 is pushing limits of material so stress releiving is necessary I guess. Limits are why grade 8's are rarely called out, grade 5 and 325 bend and dont break. I do not think I have ever used grade 8 on critical jobs (bridge cranes or monster gantries).


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