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Discussion Starter · #1 ·
metallurgists and builders please share your ideas,i need to make my own bolts for my girder and can't get to grips with what to use,
stainless?? yes that would be nice but is there different qualitys?? steel? ok what to look for,the bolts will have threads in both ends for nuts and the needle bearings will use the bolt as surface so it needs to be good stuff :)

//thanx
Janne
 

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Don't know if you can find anything along the lines of these over there, but they'd be about perfect:
http://www.mcmaster.com/#linear-shafts/=h49wiv

Spendy, but McMaster usually is.

Failing that, any good quality alloy steel should do. Maybe 8620? It'd be a pain to put threads in it, but it should stand up great to the needle bearings. I don't like stainless for brakes or suspension, because it can fail when exposed to vibration for too long, especially if you've cut threads into it (instead of rolling them). I had it happen to a set of bar mount bolts that I deepened the threads on with a tap (fortunately they broke when I was removing them, but it took almost no force to shear them just below the nut).
 

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Discussion Starter · #6 ·
Don't know if you can find anything along the lines of these over there, but they'd be about perfect:
http://www.mcmaster.com/#linear-shafts/=h49wiv

Spendy, but McMaster usually is.

Failing that, any good quality alloy steel should do. Maybe 8620? It'd be a pain to put threads in it, but it should stand up great to the needle bearings. I don't like stainless for brakes or suspension, because it can fail when exposed to vibration for too long, especially if you've cut threads into it (instead of rolling them). I had it happen to a set of bar mount bolts that I deepened the threads on with a tap (fortunately they broke when I was removing them, but it took almost no force to shear them just below the nut).
thanx for the info :)

it was numbers like that i had thoughts about as they can be used here to, will be making all the threads in the lathe but i have no idea what sort of quality to look for but will ask my supplier about that one and see if they can help

//Janne
 

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If you can get hold of a copy, have a read of "Nuts, Bolts, Fasteners and plumbing handbook" By Carroll Smith.

It's the Bible.


Amazon UK still sell it, I think.
 

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I've ordered some 8620 rod for pins, and it seems readily available here, so I'm familiar with that particular one. If you can't get 8620, maybe you can find something similar. There are probably a lot of alloy steels that would work well, and probably no few that would work better.

The 8620 I get is already heat-treated. As with any pre-hardened steel, it'll wear your tooling. The outside hardens thick enough to polish without going through (assuming you're patient), but the core remains ductile. That will give the bearings the nice, hard surface they want to ride on without making the steel brittle, which you don't want in a suspension component. Any steel that has those qualities will work well.
 

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Discussion Starter · #10 ·
You could try 4140, its not to tough on your tooling and you can case harden it with a torch...
thanx for yopur input everyone :)

as there is some language problems from my point of view can you please explain the red part a little more,i th9ink i know but please explain in short what it is :eek:

thanx

//Janne
 

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thanx for yopur input everyone :)

as there is some language problems from my point of view can you please explain the red part a little more,i th9ink i know but please explain in short what it is :eek:

thanx

//Janne
http://en.wikipedia.org/wiki/Case_hardening

Any steel alloy will be relatively soft in its "annealed" state - that is after it's heated to a red-hot state, held there for a while, and cooled slowly. How hot, how long to hold it, and how slowly to cool it differs A LOT from alloy to alloy.

"Case hardening" refers to heating the piece in charcoal and quenching it to make the surface harder. Again, how hot, how long to keep it hot, and how quickly it's quenched varies from alloy to alloy.

I'm an apprentice bladesmith with the equipment to do all that, and if it were me I'd still order a hardened alloy and just plan to cut it slowly & put a lot of wear on my tools. For a few small parts, doing the heat-treating myself just isn't worth the trouble.

Doc
 

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4140 chromoly makes a great axle so I'd think that it would make an equally suitable girder bolt. Keep the full diameter through the legs with threads only long enough for the nut. This will keep it's stressed areas off the shear points.
Hardening will make the part more brittle. I think I'd rather bend a bolt than fracture it. If you are making all the pieces incorporate brass wearable bushings or bearings to stop wear on the bolt and leave the 4140 as is. i think you would have to ride that thing at least 100,000 miles to wear that shaft at all. At that point you can machine a new bolt if you needed to.
 

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Discussion Starter · #13 ·
4140 chromoly makes a great axle so I'd think that it would make an equally suitable girder bolt. Keep the full diameter through the legs with threads only long enough for the nut. This will keep it's stressed areas off the shear points.
Hardening will make the part more brittle. I think I'd rather bend a bolt than fracture it. If you are making all the pieces incorporate brass wearable bushings or bearings to stop wear on the bolt and leave the 4140 as is. i think you would have to ride that thing at least 100,000 miles to wear that shaft at all. At that point you can machine a new bolt if you needed to.
the levers will have needle bearings and lubed via grease nipples through the bolt from each side so not through the entire bolt,and threads will just about cover the nut and schims :)

thanx guys,this is a awesome place to get help,inspiration and smiles

//janne
 

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Discussion Starter · #14 ·
http://en.wikipedia.org/wiki/Case_hardening

Any steel alloy will be relatively soft in its "annealed" state - that is after it's heated to a red-hot state, held there for a while, and cooled slowly. How hot, how long to hold it, and how slowly to cool it differs A LOT from alloy to alloy.

"Case hardening" refers to heating the piece in charcoal and quenching it to make the surface harder. Again, how hot, how long to keep it hot, and how quickly it's quenched varies from alloy to alloy.

I'm an apprentice bladesmith with the equipment to do all that, and if it were me I'd still order a hardened alloy and just plan to cut it slowly & put a lot of wear on my tools. For a few small parts, doing the heat-treating myself just isn't worth the trouble.

Doc
Thanx for the info :)
 

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Don't forget, when you are making the threads, you will need a bit of relief between the last thread and the shoulder to allow the nut to bottom out completely against the shoulder.

It is important on fasteners in a shear condition that this relief is radiused and not sharp corners.

It is also important that the last thread is not cut into the relief area. IE, the relief should be a couple of thousandths smaller than the minor diameter of the thread
 

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Discussion Starter · #16 ·
yes it's easy fix in the lathe later on,need to find the material first,and waiting for the levers to be done,they are to complex and as there are 4 exactly the same i'm not sure i can make them so perfect i would like on my old lathe so i called a friend :D
 
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