rock jaw-crusher, other rock crushers

Should arrive tomorrow. Will see what it will do.

In my dad's stuff is a chain cutter left over from his hardware store. It's lever operated, and I seen have seen it cut through 3/8 grade 70 logging chain (along with other sizes and grades). We used to stock the stuff in bulk. I don't think I could cut the same chain with my biggest bolt cutters. Wouldn't it be nice to know what that chain cutter is made of. It might not be suitable rock crushing, but it might make for a good lead. I'd cut a piece off and let one of you guys send it out to be x-rayed, but I have no idea how I would cut it. LOL. ;^) Well, and someday it might be handy to have a chain cutter in the shop.

P.S. I haven't been ignoring you guys. I've been busy, and I haven't had much to add.

Bob La Londe CNC Molds N Stuff

-------------------------------- Spark test?

The discount store where I bought my Grade 43 and Grade 70 chain didn't want to cut the 3/8" because they said it was wearing out their hydraulic chain shear. I couldn't complain, a Gr70 3/8" x 20' length with hooks cost $2 per foot, the 5/16" Grade 43 $1.50. I suspect they might have been barrels of chain that failed proof test because it wasn't tagged but I won't load it near its rating. My biggest crane scale and chainfall are 4000 Lbs.

Cast "Hadfield Manganese Steel"?

-------------------------

'd never heard of it. From the description it sounds like an excellent facing over a structure of more machinable steel that contains the bearings.

I wonder how well that would work, if you might have issues with dissolution of the manganese into the substrate giving problems if in the range quoted where it has very poor properties.

I may have a decent sized piece of this steel as some years ago while in a scrap metal yard in Bristol UK getting some steel plate I spotted a pile of what I was told were ore crusher knuckles, now I see them as very worn hammer mill hammers. Pics I've seen show them with a rectangular block working end where the one I bought looks like a mushroom from wear, likely why they were in a scrap yard. I bought one as a metal working stake.

I wonder how well that would work, if you might have issues with dissolution of the manganese into the substrate giving problems if in the range quoted where it has very poor properties.

------------------------- This suggests it can be welded (to other steel?) with the proper procedure:

Thanks for that, as with many things the devil is in the detail.

Thanks for that, as with many things the devil is in the detail.

-------------------------------- Your concern shows up when soldering to a gold-plated circuit board, especially tacking a thin wire to an edge connector finger with thicker plating. The solder needs to stay molten long enough to dissolve the gold, otherwise a brittle lead-gold alloy forms and the joint can fall apart.

"Gold alloys with a small percentage of lead is a hard, brittle, pale-yellow substance, which can be crumbled with the fingers."

Hi Jim, David, everyone

Hadfield Manganese Steel is something very unusual. Not sure there is anything similar. It's "out on a limb" - no incremental connection to anything else?

It is apparently very very very work-hardening. It only works up its properties is subject to extreme "attack". eg. crushing *hard* rock (apparently it can wear quickly if used on soft rocks) railway / railroad junctions / points / switches (went from weeks to decades service-life)

I have handled Hadfield Manganese steel at the Hadfield plant, but didn't much find out its properties. I did try that with a very sharp hacksaw blade and deliberate slow forward cutting strokes with no drag on the backstroke that did some cutting (never let it work-harden). If my memory serves me right.

Hi Jim, David, everyone

Hadfield Manganese Steel is something very unusual. Not sure there is anything similar. It's "out on a limb" - no incremental connection to anything else?

It is apparently very very very work-hardening. It only works up its properties is subject to extreme "attack". eg. crushing *hard* rock (apparently it can wear quickly if used on soft rocks) railway / railroad junctions / points / switches (went from weeks to decades service-life)

I have handled Hadfield Manganese steel at the Hadfield plant, but didn't much find out its properties. I did try that with a very sharp hacksaw blade and deliberate slow forward cutting strokes with no drag on the backstroke that did some cutting (never let it work-harden). If my memory serves me right.

--------------------------------

I assume that with minimal equipment you could torch out rectangles and weld drilled attachment lugs to the edges or back. Or copy a manufactured crusher. Crushing one rock with the plates set up like a long handled nutcracker could give you the forces to size the bearings and drive, with one handle end on a bathroom scale and you and your gang on the other. It might even crush enough to test your stemming concept.

The price of scales to measure large forces is decreasing. The 2000 Kg crane scale cost me $89.99.

My first thought for a work hardening heavy load steel was railroad track. Didn't bother to look it up though.

My first thought for a work hardening heavy load steel was railroad track. Didn't bother to look it up though.

I have no knowledge of the history of the two sections of rail in my posession other than the fact that one came to our house with my maternal grandfather - a blacksmith, who once worked for Henry Ford - when he came to live with us in 1945; shortly thereafter he used a hand hacksaw to cut it in half to gift a piece to a neighbour. The other section came from a co-worker in 1972. this piece was taken to work by second son where he used the band saw to slice off a couple of paper weights for one of the office staff. Over the years I have subjected both pieces to severe beatings with hammers up to six pounds without noticeable dammage other than some cold chisel marks on the older piece from cutting a section of expanded metal sheet.

Rails for railroads are simply hard. Something like 0.6%C

Odd niche - last use of Bessemer converter in the UK was making rail steels - the nitrogen introduced from blowing with air (20%Oxygen

80%Nitrogen) - which gives a for-free hardening increase without its generally unacceptable deleterious effects being a problem in the specific application of railroad rails.

In UK there was the realisation that with computer control you could spray water on the head of the rail as it came off the mill, giving a quench-hardening. Which presumably self-tempers as the heat from the rest of the rail conducts up to the head of the rail.

Unforeseen problem - always be careful what you do and check it's all for-real...

The rails didn't wear. Great... Then we had a train crash where the rail shattered into many pieces on a corner on a mainline out of London heading North. Then it's found the entire network is riddled with cracks. Had to have a national "go-slow" to keep stress off the rails and make any further accidents low / survivable consequence. Tawdry story emerges. Railways have been "privatised". "Board" / Directors of private company all financial types. No engineering representation. The Ultrasonic Testing trains were picking up squillions of big cracks - and there was a pause while they worked out what the problem was with the U/T trains. With no-one technical at the top of the company, no-one thought to take a manual U/T set and a bucket of "goo" (couplant) to a few indicated sites and see what / if anything is really there - as any technical person would. "Schoolperson level" thought process. The cracks were real and everywhere - the U/T trains were correct.

New phenomenon no-one had ever seen before or thought of - previously the rails wore faster than they fatigued. No fatigue cracks. New hardened rails - rate they fatigue is faster than they wear - fatigue cracks. Now we have to have rail-grinding trains - periodically grind the top of the rails so any embyonic fatigue cracks are lost in the ginding swarf.

Orthodoxy says... That's way in the absence of anyone technical there we inexorably went straight into a disaster despite indications something was amiss.

Hope you enjoy the response.

Rails for railroads are simply hard. Something like 0.6%C

Odd niche - last use of Bessemer converter in the UK was making rail steels - the nitrogen introduced from blowing with air (20%Oxygen

80%Nitrogen) - which gives a for-free hardening increase without its generally unacceptable deleterious effects being a problem in the specific application of railroad rails.

In UK there was the realisation that with computer control you could spray water on the head of the rail as it came off the mill, giving a quench-hardening. Which presumably self-tempers as the heat from the rest of the rail conducts up to the head of the rail.

Unforeseen problem - always be careful what you do and check it's all for-real...

The rails didn't wear. Great... Then we had a train crash where the rail shattered into many pieces on a corner on a mainline out of London heading North. Then it's found the entire network is riddled with cracks. Had to have a national "go-slow" to keep stress off the rails and make any further accidents low / survivable consequence. Tawdry story emerges. Railways have been "privatised". "Board" / Directors of private company all financial types. No engineering representation. The Ultrasonic Testing trains were picking up squillions of big cracks - and there was a pause while they worked out what the problem was with the U/T trains. With no-one technical at the top of the company, no-one thought to take a manual U/T set and a bucket of "goo" (couplant) to a few indicated sites and see what / if anything is really there - as any technical person would. "Schoolperson level" thought process. The cracks were real and everywhere - the U/T trains were correct.

New phenomenon no-one had ever seen before or thought of - previously the rails wore faster than they fatigued. No fatigue cracks. New hardened rails - rate they fatigue is faster than they wear - fatigue cracks. Now we have to have rail-grinding trains - periodically grind the top of the rails so any embyonic fatigue cracks are lost in the ginding swarf.

Orthodoxy says... That's way in the absence of anyone technical there we inexorably went straight into a disaster despite indications something was amiss.

Hope you enjoy the response.

------------------------------------ At least your trains won't hit icebergs or launch into space.

I mustn't tell tales of those I worked for, but engineers running a business they created can be troublesome too. Almost every high tech company I worked for dissolved somehow.

The problems remain hidden until they cause a disaster and public inquiry, some of which I've studied to explore the decision process that allowed them and the methods and instrumentation of failure analysis. Part of my career was building custom instruments to measure something.

We also meander between private and public management of utilities. Both have their inherent problems which I divide into efficiency vs fairness. Here a citizens' cooperative is due to take over shopping for lowest electric rates, though we can opt out. Initially they are $0.0018 below the corporation's rate.