Technical Drilling Nickel Rod Welded Cast Iron, Whats the best way?

My Uncle snapped an ear of his exhaust manifold for his 49 Hudson. The repair was done with nickel rod which has now made it nearly impossible to drill thru. Luckily it doe not require and anything more than a hole for a bolt. Any tips on getting the 5/8ths hole back to where it belongs? I tried a drill press today without much luck. I'm thinking the bridgeport is the next step. Any suggestions on bits? Tungsten Carbide?

 

A solid Carbide drill will do it.
They are hard enough to drill a tap.

Distant second choice is a carbide tipped concrete drill.
Probably need more than one.

 

Start out small and work your way up. use lots of coolent/oil. Ni rod is as hard as a brick bat but it can be drilled with a little patience.

 

Thats the purpose of using nickle rod to weld cast iron, I dosen't get harder than a bulls ass...My guess is regular steel rod was used and that adsorbs the carbon in the cast iron and does get harder than a bulls ass..Clamp in position and use c"bide end mills; sure you need a 7/8 hole?

 

I have had a lot of good luck with annular cutters. They are designed for mag drills but if you have access to a mill you should be able to hold it. The cutters will cut threw anything, just turn them slow.

 

Question? Is this a place that a plasma cutter would work?

 

I was under the impression that cast iron doesn't require coolant when being machined.

It was def nickel rod used in the repair.

 

If the nickel weld deposit is hard it is because of carbon dilution from the cast iron when it was welded.
Nickel weld deposits are not hard as a brick bat as one previous poster put it.
They are usually soft and machinable.
The brick analogy is a poor one, most bricks are easy to drill and in the scheme of things relatively soft.
The carbide cutters should have no trouble making the hole.
Coolant is not usually needed on cast iron, however on a hardened weld deposit it will be needed.

 

Whatever you do, the piece should be held down in a vise or be bolted to the table. Loosely-held parts will shatter carbide drills.

 

clamp solid,air blast to remove chips,step feed with thumb dial on drill press to control depth of cut,peck cycle works best.

 

Nickel rod is not cast iron. Yes tooling cast iron you use no coolant but you say that you are drilling Ni Rod it is not cast iron.

 

There are 2 types of rod available for stick welding cast iron. one is mostly nickel and easily machinable, easier than cast iron in my past experiences.
The other? I forget the name, but it is termed as "non machinable" and a brick can't even compare with it for hardness. Always avoided that rod and paid the premium price for a quality Ni Rod, so I dunno what to tell you about how to machine it, except you may have to do it with a die grinder and carbide burrs' maybe even abrasive mounted stones.
Good luck.

 

I'd use a carbide burr on a die grinder! You are going to destroy the burr, but it is cheaper than a carbide endmill, or drill.
Dirty old man is right about nickel and non-machinable rods

 

I used Carbide Burs to drill a hole in a bearing race once.
Double row bearing, boss wanted pressurized oil
in between the rows of balls, on a Hewland transaxle.
Took a couple minutes in a milling machine.

 

A 7/8 carbide burr is going to be as high as a cats back, I think that you could almost buy a diamond drill bit for the same price and be using a tool made for the job.

A trick I seldom tall anyone because it is pretty shade tree and I just don't need the heart ach that much is sugar. I wanted to lighten a set of timing gears once, they were hardened gears and nothing in our shop would touch 'em. I was going to have them annealed then re-hardened after I drilled them. This old guy said try making a past from table sugar and using it for a drilling compound. it worked.

But like I said its pretty shade tree.

 

I didn't say use a 7/8 burr, I've never seen a precise hole in an exhaust manifold yet!

 

Anyone ever see a 7/8" bolt hole in a manifold ?
That would take a 13/16" bolt.

OBVIOUSLY a typo.

 

I've also been wondering about that 7/8" hole, but it's beena long long time since I put a wrench on a Hudson.
What I'm saying is you may have to take a smaller cardide burr or maybe evn a mounted stone and "doodle" that hole out to size and location.
If the guy did use those non machinable rods to weld that unobtanium manifold, then he sure as hell didn, do yall any favor.

 

Well dunno bout that but I've drilled allen screws to make restrictor orfices. Heated them cherry red then drilled probably could anneal the Hudson "ear" and drill. You could hold an entire exhaust system on a Peterbuilt with a 7/8 hole and a 13/16" fastener...just sayin!

 

The problem isnt the Ni rod, it is the weld are which gets diluted with cast iron, which then become exceedingly hard. If you just need to drill a hole, a completed hole not bore out half a hole, then carbide masonry bit will work fine. If you need to open up a hole then the carbide burrs will work, and it will thrash the burr. Another option is stone for a die grinder, but you need to be sure your stone is rated for the rpm you are going to spin it. Stay away from the plasma cutter, it will just make the problem bigger.
Next time insert a carbon rod into the hole before welding to preserve the hole.

 

See post #8

 

[QUOTE="bobss396, post: 10861089, member: 62491"
Loosely-held parts will shatter carbide drills.[/QUOTE]
As well as break your arm!!!!!!!!

 

Whoops meant to write 7/16ths not 7/8ths. Its actually more like 29/64ths but I doubt Ill be able to find tooling easily

 

KBC has Carbide drills, in 29/64.
Not inexpensive though.

 

A cobalt drill might be a better choice. It's harder than tool steel and even though some say it's not as hard as tungsten, it won't shatter like tungsten. I've used them to drill through chrome to keep it from peeling up and it's certainly hard enough and stays sharp enough to do that. How about having someone with a water jet cut it out? I once snapped a tap off in an engine I was building and found a place that used a beam that blasted it out ; and I don't think it was a laser, because the machine filled most of a large building. And, no, the people who worked there didn't have blue-green skin. Last suggestion: How come you don't just build a set of headers for it? This is, after all, a site that is about hot rods, right?

 

I would suggest using a Bridgeport mill, clamp it down tight, and start with a 7/16 carbide center drill.
Then use a 2 flute,7/16 carbide end mill.( 4 flute does not cut in the center) Run the end mill at about 1200 rpm. Keep the quill locked and go up with the knee (table) about .010" and then back down. Do this in .010" increments. It will take awhile, but don't let it heat up. If anything starts to turn blue, stop and let it cool. If you start with a smaller hole and work your way up, you will burn up your end mills, because you will only be cutting with the edges, and they will get dull quickly. It's all about patience, and if you rush, you will get frustrated quickly. Don't try to go up and down with the quill like a drill press,
because you won't get a steady feed, and you will chip carbide quickly.
PM me if you decide to take my advice, I'm in Ct. and we have mutual friends.

 

EDM

 

I have to agree with indyjps that EDM (electric discharge machining) is the best way to go if you have access to a machine, but unless you do, you will have to take it to a job shop and it could get pricey quick.
I have run them for the past 32 yrs., but currently do not have access. Sorry!

 

CLASS IS IN SESSION

i just read some of the responses from folks that have given their knowledge on the proper procedures for welding CAST IRON.
to start off with here is a bit of information on how cast iron is created. first if you go to a large foundry you will see huge piles of old bath tubs along with engine heads and blocks and anything and everything that was originally produced. there will also be huge piles of steel there as well. cast iron is derived from the oar that is extracted from the ground. the rock and other parts of mother earth is dug up and run through a crushing machine that pulverizes everything to a fine powder like substance. from there it goes through a separation process and the raw iron is extracted. it is then sent to a foundry where it is melted down and the material that floats to the surface is called slag. what is left in the furnace in a molten state is raw iron. there is no carbon in it or anything else. from there depending on what has to be produced depends on how much carbon is added to the batch when a required amount is poured into a ladle. typically the amount of carbon is about .025 percent by volume. the more carbon that is added the harder the grade will become depending if it needs a degree of wear resistance or impact resistance. the only time another alloy is added is if the pieces are going to be subjected to a high of corrosion like boat engines that will be in salt water. all marine applications are built for salt water. the alloy that is added is NICKEL. this not only gives the cast iron a higher degree of corrosion resistance but it also provides more elasticity. when cast iron is used in high heat conditions a bit more carbon is added to make the base material more resistant to heat. the carbon in cast iron is refereed to as free carbon. the carbon is suspended in the molecular structure because cast iron is a granular structure rather than a sty-rated structure like what is found in hot rolled steel. the granular structure of cast iron is also porous which allows for expansion and contraction.

now cast iron exhaust are produced for a high degree of expansion and contraction. over time and especially in the the use of exhaust manifolds there is a possibility of the engine over heating especially if for some reason the engine leans out and the cast iron manifolds start to glow red or worst cast they should start getting white then the free carbon is being burned away and when that happens the item is no longer usable.

the welding of cast iron is a rather tedious procedure. rebuilding a surface or repairing something that has broken off something requires the following procedure. if the item is a large piece it is best to take the item to a shop that has a heating table. what is done there the item is put under the heat resistance pads and there are rows of burners that are fed by natural gas. the item is brought to a temperature of about 1100 degrees which is just below the melting point. from there the welders use a gas welding torch that is fueled by acetylene and oxygen with a flame temperature of about 12,000 degrees at the center of the flame. the filler material is a high carbon that is flowed on to the base material and then the item is covered and the heat is reduced so the piece will not crack or fracture from cooling too fast. when the item reached about 500 degrees the burners are shut off and left to cool to ambient room temperature. now the part is ready to be reworked and cleaned up and is ready to put back in service.

the proper filler material to use if someone wants to try doing the repair themselves is as follows. there is a shielded metallic welding rod that can be used and it is called NiRod. this is a high nickel alloy rod that is used to repair cast iron with a stick welding machine. it is an ac/dc compatable material. the flux on the outside of the rod is black. it has to be run in a low heat range because it is a very fluid material when the arc is struck. it is a hot burning, low amperage combination. then there is a high nickel wire available for T.I.G. welding also. now when using stick rod after the flux is removed from the weld there will be a high amount of pin holing in and around the heat effected zone. that means the arc was too hot and the free carbon was being burned out of the base material.

do your homework and practice on some cast iron that is something that is going to scrap.

any questions contact me.
​

 

Wow, class in session indeed Bernie Your information on how cast iron is produced is so wrong it will get you a failing grade.
Back to school for you. You need to brush up on the carbon content of cast iron for one thing it is not .025
Cast iron is typically 1.5 percent carbon and higher.
Guys do yourselves a favor and ignore Bernie's long winded and misleading information and look it up where you can find real facts, possibly on the AWS website.
All of what he posted is wrong in so many ways.
Bernie, go back to your buddies on the rat rod forum and spend some more time admiring your original mold of Dan Woods Milk truck