Depending on size, I’d consider some “durabar” or similar continuously cast 
iron bar. I made a compound for my atlas lathe and several other items from it. 
A bit hard on tools but the parts have come out great. I prefer to use a face 
mill to machine the flat surfaces and then carbide tooling to finish it. If you 
have a three axis CNC mill it might not be much more time and maybe less money 
than a casting. I usually buy it from speedymetals.com. 

I recently did the foundry route for a large (300) batch of aluminum parts and 
the price was right but it took a long time and required I make up a pattern 
board with 10 printed patterns per mold. Still haven’t finished machining all 
300 … but the castings came out nicely. I used cattail foundry near me in PA. I 
think it depends on the size and complexity of the part whether it’s worth 
getting it cast. 

Matt

> On Jan 23, 2022, at 1:59 PM, Chris Albertson <albertson.ch...@gmail.com> 
> wrote:
> 
> What you give a foundry is typically the part you want, a pattern.  They
> can advise on the limits of what they can do.  For example there is a
> minimum and maxim thickness and overall size.
> 
> They can also tell you how much the iron will shrink so you can adjust the
> pattern
> 
> Then for you own good you would want to make the pattern so as to minimize
> the amount of machine work.  This also saves you money as you pay the
> foundry by the pound.   So make the parrn have all the curves and shape you
> need.
> 
> Wrapping is another issue.  if you make it too thin or thick the result
> will not match the pattern.
> 
> Tranditionally, patterns where made of wood or maybe wood with bondo over
> it and sanded and finished sooth.  But today you would 3D print the pattern
> and give them a plastic copy of the part you want.  They pack it in sand
> and make a mold from your pattern.
> 
> Some can do a process that is like "lost wax" so then you print using a
> kind of plastic that the melted metal burns up
> 
> But this is for a "*mini*-mill"  you do NOT need cast iron parts.  The
> cutting force is very small.  Why not make your adaptor out of plastic?
> Platic seems like the wrong material because "real mills" are made of
> steel.   I have a CNC converted Mini mill and the conversion parts are
> printed plastic.    It you design, knowing the strength of that material
> you can do well.  I can not measure flex with a dial indcator
> Plastic is like designing a part with glass.  It is very strong and rigid
> until it shatters.  But look at the size of the spindle motor and drive
> gears on a mini mill.   You would shear the teeth off the drive gears
> before generating enough force to break a plastic adaptor shim.
> 
> In any case, then after AFTER you know the plastic part works, then you
> give the foundry the known-to-work part to use as a pattern and they make
> you one in metal.
> 
> I've dealt with some manufacturers and while you used to have to ship a
> pattern, now days you can email them the design file and they can print the
> pattern and do the design check that looks for violation of thier min and
> max thickness.
> 
> There are also places that can do a 3D print in metals like aluminum of
> even stainless steel.  But this is not yet cheap.
> 
> On Sat, Jan 22, 2022 at 6:26 PM fxkl47BF--- via Emc-users <
> emc-users@lists.sourceforge.net> wrote:
> 
>>> Yes, if you are near Windy Hill, then I understand that they do a lot
>>> of one-offs for vehicle restorers etc.
>>> 
>>> It's certainly worth considering.
>> 
>> OK
>> So from the photos in the ad what would I want to have made?
>> A big rectangle?
>> The only "true" surfaces on the back are the dovetails.
>> I think that's a bit of a wimpy mount.
>> If I disassemble it I can tell if the unfinished surfaces beside the
>> dovetails are thick enough to drill for additional supports.
>> Or is that a lot of overkill.
>> Just attach to the dovetails and be done with it.
>> I have a 3D printer.
>> This is go'n to to be fun :)
>> 
>> 
>> 
>> 
>> _______________________________________________
>> Emc-users mailing list
>> Emc-users@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/emc-users
>> 
> 
> 
> -- 
> 
> Chris Albertson
> Redondo Beach, California
> 
> _______________________________________________
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