Any chance anyone knows the bolt hole pattern of this PM ER40 chuck?

LVLAaron

LVLAaron

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I'm building a backplate for my rotary table and curious if anyone magically already knows the bolt hole pattern for this.


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I've got that chuck but I'd have to measure it. Since you have one in hand, measuring with a edge finder on the mill, shouldn't be a big deal. Once you have the center of the chuck identified, you can determine the radius to a bolt hole again using edge finder or even a gauge pin. With radius in hand and having 3 holes, 120 degrees apart. With your DRO it has a bolt pattern function. You locate center of your backplate, give it diameter of bolt pattern and how many holes, then start angle and just move and drill.

You could get really close to center by placing a collet in chuck with a gauge pin and place pin in chuck and lower the assembly into your mill vise.

 
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I made a back plate for mine and now I am questioning why, I am planning to build a D1-4 adapter to accept any of my lathe chucks. The things that I find troublesome is that I have to break my chuck apart after centering it for concentricity on its D1-4 backing plate then once done recenter it, then there is the limit on sizes it holds which is the max the ER40 collet holds. I have plenty of work envelope vertically so D1-4 adapter here I come, as soon as I find a set of drawings for it.
 
@verbotenwhisky - check out "Inheritance Machining" on the youtubes. He build a D1-x mount for his rotary table. It's pretty cool that he can just move his chuck from lathe to rotary table without upsetting the part in the chuck. I'm that project is a little more than I'm willing to invest time/skills wise right now.

I rarely use the ER40 chuck.. but have a full set of imperial/metric collets. I also had a botched backplate from something else I could make fit this.. so I'll get centered up and pretty much live full time on the rotary. I use it as an indexer more than anything.

Ultimately I'd like to get a Shars "set-tru" type 6 inch 3 jaw, and build a back plate that indexes in the rotary table's MT2 mount. This was just something I tossed together with stuff I had until the chuck is in stock.

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LVLAaron said:
@verbotenwhisky - check out "Inheritance Machining" on the youtubes. He build a D1-x mount for his rotary table. It's pretty cool that he can just move his chuck from lathe to rotary table without upsetting the part in the chuck. I'm that project is a little more than I'm willing to invest time/skills wise right now.

I rarely use the ER40 chuck.. but have a full set of imperial/metric collets. I also had a botched backplate from something else I could make fit this.. so I'll get centered up and pretty much live full time on the rotary. I use it as an indexer more than anything.

Ultimately I'd like to get a Shars "set-tru" type 6 inch 3 jaw, and build a back plate that indexes in the rotary table's MT2 mount. This was just something I tossed together with stuff I had until the chuck is in stock.

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That looks very good, mine isn't pretty, it was built to serve a purpose then I saved it which exactly why I should have taken more time with it.....

I actually subscribe to Inheritance Machining and am a supporter on patrion. I have intended to ask him if he would share his design for a couple different projects he has done, the D1-4 being one of them and the vise rotary tool he recently built for radius work without the rotary table being the other.
 
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