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Home built CNC Mill - Gonna make a 1911


StraightUp_OG

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3d-printing has it's place in manufacturing, but like Jared said, the materials used aren't that strong, and in my experience, get brittle with time.

His plastic parts would cost about $0.10 a piece if made on an injection molding machine, but that's AFTER you pay several thousand dollars for the mold. CNC manufacturing ends up being the default process for low volume runs (and in the world of injection molding, they want tens if not hundreds of thousands of parts to justify the expense of the molds.)

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I make prototypes like that for a full time job. That one is very well done. I bet it would sell like crazy. I normally use Delrin (homopolymer) or Acetal (copolymer). These are very similar. I prefer the copolymer because it has greater resistance to weak acids and chlorine. They are both very tough and machine beautifully.

The only suggestion I have is to make the top tabs on the black part and the sides next to it on the white part beefier. You could just make the black tabs go further down in the white part. It will take more abuse that way.

I have been keeping track of the 3D printing stuff, thinking about adding that to the shop. Right now there is no good way to print that part for production short of spending $400,000 to $700,000 for the printer. A couiple of injection molds would be way cheaper at around $50,000 to $100,000.

Edited by Toolguy
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It is hard to make a ELS replacement product without going injection and make it profitable at any scale. You need to be able to sell the unit to distribution for about $8.50, so your base cost needs to be in the $2-3 range.

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I've just spent most of the day reading this entire thread, and I must say it's a good one. I've been doing some research on buying a used Bridgeport or clone for a while now and found this thread. This will not be used for production but for personal pistol smithing and other small hobby work. Until now I had thought and was being told to buy the biggest heaviest mil that I can afford (hence the reason I was looking at Bridgeports). I do not plan to go the CNC route for a long time and would just like to perform manual operations for now. I guess I was under the impression that I would not be able to perform the milling operations without investing in a much larger machine, but you guys have pretty much changed that outlook for me.

So my question is what can I not do with these smaller machines that I would be able to do with the larger? Pros and cons I guess?

Edited by Abunchahicks
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You can work on just about any material relative to the mill size. I have been able to make chips out of everything I wanted that would fit the travel of my little mill.

The larger machines allow you to increase your speeds & feeds to a point and make some setups easier. Do I wish I had a slightly bigger machine, yes. Is it preventing me from doing anything I want, no.

It is a great place to start and learn on the cheap and it gives you the possibility of CNC conversion. Also, understand that converting to CNC does not mean you MUST learn GCode. It only means that you can now control the machine with the computer rather than crank the handle, not that there is anything wrong with that.

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I also thought a bridgeport was my only option until I discovered these square column benchtop type machine.I always wanted cnc, but didnt have bridgeport sized room in my garage, so what I did was ideal.

If you never plan to go cnc a bridgeport will be a better manual machine for the money if you can score a decent used one for under $3k or something. If you plan to do a cnc conversion a bridgeport is a bad choice as knee mills are poor cnc machines from a basic system layout.

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It is possible to have as accurate of cuts with a grizzly 704 or 759 as a Bridgeport ? That new 759 with dro does look sweet. Mill deflection would just be a function of feed speed an depth of cut? I have been looking for an old Bridgeport , but all I have found are ones that are beat.

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I just bought the G0759 myself. After using different machines at work I knew I'd regret it if I didn't get the DRO's.

How do you like it? Does the DRO have a lot of bells and whistles? Does it do calculations for finding center, and bolt spacing on a hub?

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With the LMS Mini mil is there enough room to use a rotary table or 4th axis setup if I ever go CNC to do front strap checkering?

So yes and no. There is a 4th axis setup but it would be very hard to setup to do a front strap.

You guys with all this talk of the BF20 have me thinking about an upgrade.

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