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Alan H.
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My PM935TV mill is equipped with an Easson 12B DRO that Matt/OMT installed as part of the package I bought.
In the past several months there have been discussions on the Easson 12B DRO but not too many specifics on their capabilities. I thought I would post a specific glimpse into its bolt circle function. It makes child’s play out of drill and tapping holes on a part.
I am skinning a casting down making a die filer. It will have a small seal cover plate that surrounds the vertical shaft that drives the file. This casting is clamped in my PM935 and referenced. It is getting several operations while in this position in the mill including drilling these six holes for 4-40 screws.
The DRO has a function called “PCD” (Pitch Circle Diameter) or what I might call a bolt circle function. You invoke the function using the menu on the DRO and then simply scroll through the PCD's menu adding the center reference, bolt circle diameter, no. of holes, starting hole angle, and ending hole angle. This input of the parameters is quite intuitive. To drill them, you then toggle through each of the holes, zero x and y on the screen, and punch your hole. There’s a very nice graphical display on the DRO that shows you which hole you are working on. I also scrolled back through the coordinates to support the tap with a tap guide. This makes this sort of work unbelievably quick and accurate.
Thought this might help folks who wonder about the Easson 12B by showing a specific function that I have found very useful. No searching for a bolt circle calculator on the web, ciphering and capturing it on paper. The DRO does the ciphering and the process is quick as lightning.
The whole casting for context:
DRO with PCD Function up and running:
Drilled and tapped:
By the way, these 4-40's are on a 9/16" radius.
In the past several months there have been discussions on the Easson 12B DRO but not too many specifics on their capabilities. I thought I would post a specific glimpse into its bolt circle function. It makes child’s play out of drill and tapping holes on a part.
I am skinning a casting down making a die filer. It will have a small seal cover plate that surrounds the vertical shaft that drives the file. This casting is clamped in my PM935 and referenced. It is getting several operations while in this position in the mill including drilling these six holes for 4-40 screws.
The DRO has a function called “PCD” (Pitch Circle Diameter) or what I might call a bolt circle function. You invoke the function using the menu on the DRO and then simply scroll through the PCD's menu adding the center reference, bolt circle diameter, no. of holes, starting hole angle, and ending hole angle. This input of the parameters is quite intuitive. To drill them, you then toggle through each of the holes, zero x and y on the screen, and punch your hole. There’s a very nice graphical display on the DRO that shows you which hole you are working on. I also scrolled back through the coordinates to support the tap with a tap guide. This makes this sort of work unbelievably quick and accurate.
Thought this might help folks who wonder about the Easson 12B by showing a specific function that I have found very useful. No searching for a bolt circle calculator on the web, ciphering and capturing it on paper. The DRO does the ciphering and the process is quick as lightning.
The whole casting for context:
DRO with PCD Function up and running:
Drilled and tapped:
By the way, these 4-40's are on a 9/16" radius.