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Hard spot in (cast iron) machine base?

Breescyclust

Plastic
Joined
May 1, 2021
I have a Grizzly mill, and have been installing a DRO on it. I've drilled and tapped (5mm) about a dozen holes on various cast iron parts, and have suddenly been unable to make any progress on a hole. No, I'm not running the drill backwards! I've replaced the HSS drill bit, and have tried the Dremel with carbide, and now (2mm) diamond drills to pilot, and have barely made 1/4" progress. I started the hole the same way as all the others, and it just ain't the same. I drilled & tapped another part of the base (about 2' away) without issue.

Any suggestions?

Thanks,
Brian
 
Suggestion #1 read the rules
Suggestion #2 sell that turd and buy a real mill.

This machine is banned here, it’s probably a piece of moon rock in that garbage metal casting from China
 
Chill cast, there was a heat shunt in the mould, usually deliberate but I’ve seen odd things, where the metal contacts the mould chill crystals form, fine grained cementite
Carbide through it is all I have
Mark
 
I had a problem with my Clausing when putting the dro on.

I broke a drill bit...
broke a carbide drill bit.

I wound up trying a masonry bit, It did the job... its a few years ago, and I don't remember the details, too much water under the bridge, but I do remember being surprised that a masonry bit worked where a normal carbide wouldn't.
 
Suggestion #1 read the rules
Suggestion #2 sell that turd and buy a real mill.

This machine is banned here, it’s probably a piece of moon rock in that garbage metal casting from China

Wow Blob..you're a real friendly sort, ain't ya! Being brand new to the forum it's understandable that you overlooked rule #1 in the sticky "Place location in profile"..have someone read it to you.:rolleyes5:

Stuart
 
Wow Blob..you're a real friendly sort, ain't ya! Being brand new to the forum it's understandable that you overlooked rule #1 in the sticky "Place location in profile"..have someone read it to you.:rolleyes5:

Stuart

No I didn’t bud, I had that info in there but I use mobile so when I edited it, it went away. I followed the rules it was a tech issue.

Leave your emotions at the door.
Hate the game not the player.
Don’t shoot the messenger.

Rules are rules Padre
 
If you plan to tap forget it. Either through hole with a nut or drill bigger and fill with jb weld or something and tap that material.
Bill D
 
Suggestion #1 read the rules
Suggestion #2 sell that turd and buy a real mill.

This machine is banned here, it’s probably a piece of moon rock in that garbage metal casting from China

Perhaps the machine best not named here.
So should we think this problem does not exist on 1/2 to two or three million dollar machine tools?
That seems a bit weird. One runs into many things at times. Add a cheap name/brand and that becomes the answer.
Bob
 
Perhaps machine best not named.
So should we think this problem does not exist on 1/2 to two million dollar machine tools?
That seems a bit weird.
Bob

Less likely to be a problem with a company using quality metal and a proper casting Techniques.

Message milacron if you want the rules changed. Don’t come at me over it
 
I was milling some cast iron I thought was Durabar but hit a hard spot and burned up an endmill and blew out the inserts on a face mill. Would Durabar also have spots that hard or did i get a substitute? I ended up using a surface grinder to get through the area. Worked but slow. Dave
 
Just my two cents, but I would doubt that Durabar would be anything else than perfect, metallurgically speaking. If you drill or machine cast iron improperly, you can bring out carbon and create your own hard spot. Don't linger in one spot for too long.

Stuart
 
You're the one enforcing the rules. This is a public forum. People ask questions looking for answers. And yeah some of the questions are obvious or silly. So what. Who cares what kind of machine tool it is. No reason to jump on the guy.

I’m not enforcing anything, I’m not a moderator. Rules are rules. Stop trying to shoehorn these machines into a forum that Explicitly forbids them.

The machine tool is very import in the grand Scheme of diagnosing problems. Maybe less important in this situation but that’s beside the fact.

Drop the emotions, if you have a problem with me then report me, if you have a problem with the rules you know where to find the creator, he’s still alive after all.

I think you guys should check out the other forum where there’s no end to these China machines you guys seem to have such an affinity for.

Example 1
https://www.practicalmachinist.com/vb/general/mini-mill-question-258988/?highlight=Mini+mill

Example 2
https://www.practicalmachinist.com/vb/general/small-knee-mill-questions-346654/?highlight=Mini+mill

Example 3
https://www.practicalmachinist.com/...ll-cnc-conversion-276638/?highlight=Mini+mill

Notice a trend boys?

I’m not the first and won’t be the last. Respond with your gray matter, not your emotions. This guy is in the wrong place
 
The machine tool is very import in the grand Scheme of diagnosing problems. Maybe less important in this situation but that’s beside the fact.


so my machine was an older American made machine and had the problem. For this issue, machine make is less important.

As far as Grizzly, I know of a few shops that employ quite a few machines because they are a good value and can get parts.

I realize that may not fit everyones view of a shop that they want to work at, but that's what these owners have bought for their needs. Are they less of a shop? I can't answer that.. I don't have an opinion..

It depends on the work they do, and their budget I guess.
 
so my machine was an older American made machine and had the problem. For this issue, machine make is less important.

As far as Grizzly, I know of a few shops that employ quite a few machines because they are a good value and can get parts.

I realize that may not fit everyones view of a shop that they want to work at, but that's what these owners have bought for their needs. Are they less of a shop? I can't answer that.. I don't have an opinion..

It depends on the work they do, and their budget I guess.

The rules don’t discriminate. In fact they are kinda black & white. Your barking up the wrong tree
 
The guy used one machine brand name and that makes all such hard spots in other brands go away? That's a ridiculous standpoint, why not adjust your mind to address the problem which you and everyone else knows can happen in any cast iron mass from any nation.
Thinking over the original question it seems to me that a thin section would best be treated by drilling a hole through and placing a nut behind it as some have noted.
In a larger section for a small hole I'd drill it oversized and use a diamond V dremel tool to give the sides of the hole plenty of roughness and set the nut flush with JB weld, you could even file additional roughness on the nut exterior so that it is even less likely to pull out.
 
The guy used one machine brand name and that makes all such hard spots in other brands go away? That's a ridiculous standpoint, why not adjust your mind to address the problem which you and everyone else knows can happen in any cast iron mass from any nation.

Jesus Christ. It’s like some of you can’t read, I’m amazed you guys can write a response at all with your heads so far up your rear.

It’s a BANNED machine, your EMOTIONS mean nothing. Get over yourself.

IF YOU GUYS HAVE A PROBLEM THEN MESSAGE MILACRON.

But I know you guys won’t because he’s got a reputation that Imitates you girls.

Please God lock this garbage thread full of those who can’t seem to comprehend RULES.

next do you guys want to bring geology and astronautics threads in here too?

What’s Brazil’s soil Composition?

What’s Pluto’s official Designation again?

What did you guys have for dinner today?

Read and follow the rules, that’s what makes this place different from hobby machinist.

Or should we just combine them? How about that guys, We just combine them so we can talk about that grizzly mini mill sitting next to your HAAS VMC.

GROW UP KIDS and leave your emotional baggage at the door
 
I have seen this problem in steel stock that I purchased right here in the good old US. It is called an "inclusion" and they can seemingly be as hard as a diamond. Diamond tooling is probably the only thing that can touch some of them and you may need to replace even that once or twice before finishing one hole.

Metals are melted in furnaces. Alloying agents are added. The melt is mixed in various ways, but not by someone standing there with a spoon. The process is not perfect. Is it something in the original ore? Or in one of the alloying additions? Or something that is created by a mixture of things? I don't know but I bet the steel and iron smelters do.

Then the melt is poured into some kind of a form and allowed to cool. They do not use a filter (just what could you use for melted iron) so any hard lumps are in that pour. And they will be in the billet. Or in a later mold for a specific part casting. And they will go through the rolling mill and still be there unless the finished size is thinner than the inclusion.

The point is, they EXIST. You can brag all you want about US or European quality vs. Chinese junk, but most of the metal sold in the US is made in China. I suspect that the same is true across the pond. So even your high quality, US or European made machines can have these inclusions in your high quality machines. And you, yes, YOU can also encounter one if you need to drill a hole in your high quality US or European made machines.

If you haven't encountered this, count yourself lucky.

As for what the OP should do, I would suggest that he consider what I did when I encountered that inclusion: MOVE the hole to another location. In my part, which was symmetrical, that was easy but he may have to make some kind of extension bracket. It is hard to know the exact size of the inclusion, but a one inch displacement would probably be enough so that bracket can be fairly small.
 








 
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