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Tool Block Material?

Sam L

Cast Iron
Joined
Oct 12, 2007
Location
NJ
Hey guys,

We made a bunch of tool blocks for our lathes out of A36.
Over time they key-ways in the blocks have deformed to the point that the block will go out of square by a as much as .008", not the end of the world for turning, but for drilling it becomes an issue.
We are going to make new ones, im just deciding on material.
I was considering 4140 HT but i'm afraid the hardness would transmit vibration.
1045 while stronger than A36, might still deform.

Any thoughts?

Thanks
Sam
 
How did they manage to deform that badly in the first place? Operators not cleaning the turret before installing?

Sent from my SM-G930V using Tapatalk
 
I probably would go to 1018 or 1045, A36 is pretty gummy. It is surprising that they could deform like that though. I know OEM Haas blocks seem to be made from some soft cast junk, ones purchased from Global CNC are plain steel.
 
Why not have screw in keys? Mill a channel for them to locate into and then the keys can be a harder material if need be/ replaced occasionally.
 
The tool blocks are probably getting abused, slammed into place, maybe with a mallet. Contamination is a possibility as well, as @chip_maker mentioned.

I think using harder material is just going to encourage the behavior until the turret starts getting damaged.

Why not have screw in keys? Mill a channel for them to locate into and then the keys can be a harder material if need be/ replaced occasionally.

The keys are screwed into the turret. The blocks have keyways (female).

Photo courtesy of Hurco. Mill-Turn Turret Shootout: VDI vs. BMT

bmtvsvdi_2.jpg
 
Here's a side track - the link Orange Vise pointed to claims that it is normal to "indicate in" VDI tooling. Really? Mine fits over a pin, I doubt it could move - of course I'll have to check. But I've never seen this suggested anywhere else. Is this an outlier idea, or a sign of my overly sheltered life?
 
Here's a side track - the link Orange Vise pointed to claims that it is normal to "indicate in" VDI tooling. Really? Mine fits over a pin, I doubt it could move - of course I'll have to check. But I've never seen this suggested anywhere else. Is this an outlier idea, or a sign of my overly sheltered life?

My VDI tooling is a bit different. I have the base VDI that fits the pin snug but I have some higher quality stuff the has about .010 slop and 2 set screws on each side of the pin to dial them in dead nuts.
 
Here's a side track - the link Orange Vise pointed to claims that it is normal to "indicate in" VDI tooling. Really? Mine fits over a pin, I doubt it could move - of course I'll have to check. But I've never seen this suggested anywhere else. Is this an outlier idea, or a sign of my overly sheltered life?

Our VDI Live tools dont use the pin. They have a block on the front face of the turret to square it up.

The keys are in the turret. the slots are in the tool block. the slots have distorted.
Im trying to figure out how and why.View attachment 264862
 

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4140 normalized. Rc 30 not gummy. If that is not hard enough then heat-treat.
8620 somewhat gummy but case about 40 deep and quench in oil and they should last forever. ;-)
 








 
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