can you forge cast iron?

[gypsy]

I was wondering, can you forge cast iron or will it just smush into a mess? I got some really neat old machine blades off some type of mower/mulcher/harvester circa 1900ish & they are riveted to some cool little cast iron arms that would make awesome fantasy knives if I can hammer them flat but I've never actually tried to hammer cast iron and I don't want to ruin one trying to figure it out. I realize they will always be brittle cast iron & all that but hey they were tough enough to go on whatever type machine they came off of & their going to be fantasy knives not survival knives right? :)

[BIGGUNDOCTOR]

Nope. It will just splatter all over the place. Best to find another use, or just use them as a pattern to make new ones out of steel.

[ThomasPowers]

cast iron "splashes" at high forging heat.

[Sam Thompson]

Perhaps you could fantasy forge it.

[gypsy]

THX! guys, I didn't think ya could but I couldn't remember :)

[pkrankow]

You can crayon CI onto lower carbon steel to "hardface" with at a welding heat. Cheap trade knives were made this way.

Phil

[Dragons lair]

I was wondering, can you forge cast iron or will it just smush into a mess? I got some really neat old machine blades off some type of mower/mulcher/harvester circa 1900ish & they are riveted to some cool little cast iron arms that would make awesome fantasy knives if I can hammer them flat but I've never actually tried to hammer cast iron and I don't want to ruin one trying to figure it out. I realize they will always be brittle cast iron & all that but hey they were tough enough to go on whatever type machine they came off of & their going to be fantasy knives not survival knives right?

Are ya sure their cast iron? Just sounds strange to have a "cutter blade" rivited
to a "little CI arm" Seems like any impact on the cutter would snap a little cast arm.
Ken.

[pkrankow]

Are ya sure their cast iron? Just sounds strange to have a "cutter blade" rivited
to a "little CI arm" Seems like any impact on the cutter would snap a little cast arm.
Ken.

Good point. A lot of hard working parts are drop forgings, and they look similar to castings. Maybe a test heat is worth the effort, taking precautions against splashy metal.

Phil

[Crunch]

Could they be cast steel?

[ThomasPowers]

Much less likely than dropforged with a flash along the seam. Casting steel is *expensive* not to mention that cast steel is not the best grain structure for items that need steel over iron. (old time stuff some of the new cast steels are quite good).

[infinityblacksmithing]

Although I have been told and read many many times that cast iron will just break if you try and forge it, I recently read in an old school book that was a high school teachers guide to blacksmithing that you can forge cast iron at a blood red heat. It mentions that at any higher heat it will break. I have not tested this yet, but it would be interesting to see if it works.

[Eric Farrar]

I have wondered about many of the low to moderate quality/duty tools that still boast their cast iron bases - grinders, drill presses, saws, etc.....

Anyone got some pointers about where I can do some reading about cast steel vs cast iron in modern production?

I had kind of figured that cast iron was pretty much replaced by steel for most modern applications.

[lordcaradoc]

I was wondering, can you forge cast iron or will it just smush into a mess? I got some really neat old machine blades off some type of mower/mulcher/harvester circa 1900ish & they are riveted to some cool little cast iron arms that would make awesome fantasy knives if I can hammer them flat but I've never actually tried to hammer cast iron and I don't want to ruin one trying to figure it out. I realize they will always be brittle cast iron & all that but hey they were tough enough to go on whatever type machine they came off of & their going to be fantasy knives not survival knives right?

Well, nobody else commented on this, so I will.

Got any pics?

Regards,
Tim

[peacock]

do a spark test on the cast. it will tell you if it is cast or steel.

[Max Mulholland - Tetnum]

you can forge cast at a dull red but it is slow and prone to failure i have done this but the end result is not worth while very little work can be done in a heat

cast iron can be forged when laminated in an iron or steel billet like low layer Damascus old safes were made this way out of many alternating layers of CI and Wrought

additionally Wootz steel is an insanely high carbon content metal that is forged (it has to be homogenized first)

[JNewman]

I have wondered about many of the low to moderate quality/duty tools that still boast their cast iron bases - grinders, drill presses, saws, etc.....

Anyone got some pointers about where I can do some reading about cast steel vs cast iron in modern production?

I had kind of figured that cast iron was pretty much replaced by steel for most modern applications.

Cast iron is still used for many high quality tools. Cast iron does have some advantages over steel. Cast iron has excellent vibration dampening properties, far better than steel. Vibration is obviously bad in machine tools. Surface finish on cast iron is typically better on cast iron than cast steel and much finer details can be cast in iron because it is much more fluid. Cast iron shrinks much less during solidification than cast steel so it needs much smaller risers, heavy risers can be difficult to remove and the removal can destroy casting details. Yes cast iron is much cheaper to cast but for some applications the more expensive option is not always the best.

Not useful for the original post but I have been told by an experienced foundryman that large iron castings can be bent or straightened cold with shotblasting. That is in effect forging them cold by use of thousands of tiny blows.

[ThomasPowers]

In general my experience is that in modern manufacturing they will use the absolute cheapest methods and materials that will be marginally acceptable in the marketplace. Cast steel would thus lag cast iron save for where it was absolutely necessary! Much more common is to replace iron castings with lighter fabbed steel items to evade the casting costs. Talk with tool users; many of them will extol the old massive cast iron beasts over modern "flimsey" versions.

[pkrankow]

In general my experience is that in modern manufacturing they will use the absolute cheapest methods and materials that will be marginally acceptable in the marketplace. Cast steel would thus lag cast iron save for where it was absolutely necessary! Much more common is to replace iron castings with lighter fabbed steel items to evade the casting costs. Talk with tool users; many of them will extol the old massive cast iron beasts over modern "flimsey" versions.

My Dad's table saw took 4 men and a boy to carry the base down the stairs into the basement. It has been re-motored, re-bearing-ed, rewired, etc.

It is an old Craftsman, unlike what can be had anymore. It requires a little more fiddling to set the fence, but it stays set the first time.

The base is a iron casting that may be an inch thick box.

The machine was used heavily in a commercial shop before my dad got it.

My table saw is a worn out old Skill bench saw. Gets the job done, but is unpleasant to use. It was free, and needed a $0.10 E clip because it was "broken" and "couldn't be fixed"

Phil

[Dragons lair]

My Dad's table saw took 4 men and a boy to carry the base down the stairs into the basement. It has been re-motored, re-bearing-ed, rewired, etc.

It is an old Craftsman, unlike what can be had anymore. It requires a little more fiddling to set the fence, but it stays set the first time.

The base is a iron casting that may be an inch thick box.

The machine was used heavily in a commercial shop before my dad got it.

My table saw is a worn out old Skill bench saw. Gets the job done, but is unpleasant to use. It was free, and needed a $0.10 E clip because it was "broken" and "couldn't be fixed"

Phil

Phil, Better than mine. Bought a 36" shear old guy said 1200-1500 lbs
Arrived 700miles later is 3400lbs no castors just 6X6 rubber pads. Had to move that one by myself by hand. Moved it 12 feet across a brushed concrete floor
Then found out it was a 16ga not a 10ga. Cost for a wrecker to get it outside and to the scrap yard would be a loss.
Ken.