Reply With Quotewhat's the original made of chum ?Originally Posted by CapitalBee
Boingerati
One for you techie's. I'm thinking of making my own quick release cocking arm pins for HW's. Mild steel and case harden or stainless? Mild steel easier to machine, but then heat treatment or stainless, which is tougher but harder to machine. I'd welcome your thoughts...
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what's the original made of chum ?
Will only use cherry lipbalm
MS *& CH: I'd hate to have an SStl pin stuck in there to try and drill out, the bloody stuff work hardens too quickly!
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Jerry
Boingerati
I'm pretty sure they're m/stl. Possibly case hardened, but as that applies to the top 20 thousandths of a millimetre you can cut / drill through the hardened surface. It's probably the best and the cheaper option for manufacture. Or, straight m/stl?
"Right a bit, left a bit............"
I personally wouldn’t use mild steel. I’d use 304 stainless (which is easy to machine) or silver steel.
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I'm not falling for this again........
I did a few for people last year and was going to case harden mild steel but ended up making them out of 304. They all seem quite happy with them.
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Thanks Steve.
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I thought ordinary free cuttting mild steel included a lead component that made it unhardenable, including case. The moment you had to case harden they gave you the green ended bar that did not cut any where near as sweetly. OTOH my brain is getting old and the less well used memories are starting to fade. I can be safely ignored
"Right a bit, left a bit............"
I’m no expert but I think there is more than one grade of mild steel. You’re quite right though, one of them does have added lead.I thought ordinary free cuttting mild steel included a lead component that made it unhardenable, including case. The moment you had to case harden they gave you the green ended bar that did not cut any where near as sweetly. OTOH my brain is getting old and the less well used memories are starting to fade. I can be safely ignored
We can judge the heart of a man by his treatment of animals.
Rudeness is the weak mans imitation of strength. Eric Hoffer.
If I don’t reply to your comments it’s probably because you’re on my Ignore list.
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En1a is painted blue and is free cutting leaded steel that dose not weld well.I thought ordinary free cuttting mild steel included a lead component that made it unhardenable, including case. The moment you had to case harden they gave you the green ended bar that did not cut any where near as sweetly. OTOH my brain is getting old and the less well used memories are starting to fade. I can be safely ignored
En1b is painted green and has no lead but welds well.
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Personally I wouldn't use stainless as it has a propensity to gall in high friction applications.
Most steels EN8 or better should be more than adequate in their natural state and in a pivot you want the pin to wear out before it starts enlarging the hole which is more difficult rectify as you lose the centre and increase the diameter each time.
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What you need is silver steel rod from an engineers merchant its available in lengths of about a foot. Its precision ground high carbon steel but drillable you can temper it afterwards if you wish and it will then be very hard. I used to use it in the tool room at work regularly. I would also try the bay.
Last edited by keithy; 20-02-2019 at 04:26 PM.
mk2 rapid.22
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ditto silver steel harden in oil , then no need to temper afterwards
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Silver steel comes in oil or water quench types. Oil quenching doesn' t mean it's tempered to the required use specification you still need to temper at the right temperature or colour.
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No only ever come across one type , I may be wrong . Quench in water then very hard (65 rockwell) but very brittle , you can then temper in a flame , from straw colour through to blue, or you can be scientific and do it in an oven , or you can heat to a dull red then quench in oil, to give a hard wearing but tough condition ideal for pins and latch rods , done many this way and it works , but obviously if you can case harden mild steel effectively in your garage then that would be ideal.
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