CNC Noob Fixture Plate Question

Jonathans

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I'm still waiting on delivery of my mill. The use of a fixture plate looks very appealing.
My question is this: Why do folks who own a decent mill purchase ready made fixture plates?
Aren't their own mills more than capable to make an acurate one themselves?
Are commercially made ones more precise?
Is the choice of steel or aluminum significantly different when choosing an appropriate material?
 
Of course you can make your own fixture plate. Some people would just rather buy than to take the time make their own. Aluminum is easier to work and less durable than steel, but should give years of service in a hobby environment. For a commercial application, tool steel would be a better choice.

On the other hand, in 50 years of making chips I have never used one. But if I needed one, I would just build it.
 
If I were to guess the reasons others would buy instead of make them:
Time. You could be talking 100 holes that need to be spot drilled, drilled, reamed, then tapped. If your mill doesn't do rigid tapping, that would sure take a while.
Uncertainties about precision. Can't quite get that tram right to flycut perfectly flat? A little too much runout in your drill chuck to drill holes within the tolerance?
Lack of travel. A lot of the plates I have seen are a good bit larger than the mills travels. Sure its possible to machine precisely while pausing to refixture a part, but that adds time, complexity, and regardless of how careful you are, error.
Factory bought ones are relatively inexpensive. When compared to the time to design, fixture, and machine, a lot of the time it is "cheaper" to just buy one.
Not everyone's cup of tea. Some people want to make parts and see the tools/fixtures they need as inconveniences to get around. There's nothing wrong with that, and to those people it might make the most sense to buy it.

Personally, I love building the tools and fixtures I need to make the parts I want. It all just depends on what parts of the hobby bring you the most satisfaction and what means you have to get there. For me, designing the plate and machining it would be as satisfying as making the part I need the fixture for. I could probably afford to buy the tools I need, but that would take money away from buying the things I can't make.
 
I think Shooter's summary is right on. I will only offer that I am at the other end of the spectrum where I would rather purchase the tooling that I need and use my time to make parts. It is a trade off between price to purchase and time and skill to make. Occasionally I will made a tool because the cost/time trade off is just so lopsided even I can't ignore it. Of course when you need a custom fixture, there is no choice. I have a ton of respect for those that make a lot of what they use, often starting with the machine. It is just not my thing. I am not retired so I have and income and limited hobby time. Once I retire, the equation may work out much different with more time than money. In the end, if it is hobby then the choice to build or buy is personal so do what makes you happy.

- a different perspective -
 
Good perspectives, all.
If using aluminum, whether manufactured, or self made, is there a risk of electolosys between the plate and the table?
 
Good perspectives, all.
If using aluminum, whether manufactured, or self made, is there a risk of electolosys between the plate and the table?

I suppose that if you were using a water based coolant, and left the plate permanently mounted, there could be a problem, but rust would be more likely. Oiled paper between the table and the plate would pretty much eliminate the possibility of either.
 
Here is what I did for a tooling plate fixture...
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Am I the only one who can't see Cheeseking's photos?
 
Here is what I did for a tooling plate fixture...
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Sorry guys. Every so often my phone settings get change and I inadvertently post the dreaded x boxes. Funny I never use my pc much anymore I'd be dead without tapatalk. Works very nice for me and soooo much easier to post pics and read forums. Anyhoo lets see if these post

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ImageUploadedByTapatalk1498084320.881405.jpg
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