What max spindle speed should a mill have ?

[nashtm]

Hi All

I am totally new to machining and wonder if you could give me some guidence.

I have located a mill that is on special in my area and it looks good to me except that the max spindle speed is 1600.

I want it for general use and small stuff (I fly rc planes) - I am wondering if that low speed will not be a problem with small cutters for modelling applications ?

This is a link to the type of mill (not from these people though)

http://www.allproducts.com/manufactu.../product5.html

Any other comments will be graetly appreciated.

regards
Tim

[Al_The_Man]

I imagine that is because it is a 1:1 with a 4 pole motor on 50hz. That is a bit restrictive, as many knee mills will go up to around 3000.
Some put a 3ph motor on with VFD, 1phase fed, and run the motor at 2x normal rpm.
Al.

[wizard]

May I be so bold as to suggest stepping bakc a minute or two before making an investment in such a mill. The mill in question is certainly a nice unit but may not it your needs well. Thus it may pay to research and learn a bit about machining before plunging in.

As to yoru question, like all things in life it depends. The dependancy here are the materials you will machine, the diameter of the tools and your skill with the machine. For example this mill might not be very usefull at all for machining balsa or even aluminum.

As to other comments, for a mill this big I'd certainly would suggest an R8 taper over the morse if you are based in the USA. For making parts for a flying model you might want to consdier a gantry machine with CNC controls. Very doable at reasonable expense on a do it yourself deal. Using a router these are very versatile machines for flying models. That is assuming you are interested in the plane and not the engine only. Here again you have to define where your interests are. If you interest are plane wide it may pay to have a smaller mill and a gantry machine together. Throw a lathe in there someplace to. A lathe should be considered a basic component of your shop.

Now if mony isn't a problem you certianly could make the mill in question do what you want done. Just realize that the mill is just a small part of equiping a shop. A lathe could very well be required. Tooling for all your machines is going to be pretty expensive, in fact it might outstrip the cost of the machines themselves.


Dave

Originally Posted by nashtm Hi All I am totally new to machining and wonder if you could give me some guidence. I have located a mill that is on special in my area and it looks good to me except that the max spindle speed is 1600. I want it for general use and small stuff (I fly rc planes) - I am wondering if that low speed will not be a problem with small cutters for modelling applications ? This is a link to the type of mill (not from these people though) http://www.allproducts.com/manufactu.../product5.html Any other comments will be graetly appreciated. regards Tim

[nashtm]

Thanks for the replies

Wizard: thanks for the input - I think you are right

Athough I would probably use the mill more for general use than rc and I am looking at buying a smallish chinese BV120b lathe and in my heart I know that I should gain more experience before getting a mill - I think I am getting drawn in by the "opening special" and the chance of saving a few hundred $$$ (rands in my case)

Thanks once again.
Tim

[wizard]

Well you are likely to learn that you need a whole shop full of tools. I just recently picked up a 9x20 lathe for home my self.

A lot of things figured into the purchase with cost being a big factor. That and movability. It comes down to getting the biggest lathe I could easily move into my cellar. How you expect to use the machine is certainly a factor in your decision to buy a lathe. Just remember a lath will end up being a primary component of you shop and the activities that take place there.

As to the mill and its usage with respect to general purpose and RC, it is certianly possible to get a mill that will handle both. Depending on how big your RC's are though that could imply a big mill, possibly larger than would be needed otherwise. Here I'm thinking about being able to cut or shape the components of a wing or fuselage out of sheet material. If you are into that, you should look at some of the home built gantry mills/routers that can befound here and elsewhere on line.

None of the above should be taken to indicate that you should not think about a mill. Obviously a mill is very important in the development of a shop. Just that acknowledging the need to make some components on a machine better suited to the task might change how you look at the mill purchase.

As to gaining experience that maybe isn't exactly what I had in mind. It is very hard to get experience without the hardware there to practice on. What I was trying to get at is that you should have a good idea of what you want to accomplish and the types of machines needed to accomplish that. This does require developing a bit of a background in machining and asking a few questions. Hopefully this will avoid poor investments in machines that won't do what you want easily.

Lastly; not to embarass myslef here but do try to avoid being drawn in by "SPECIALS" of any kind. It is the quickest way to loose money from ones wallet and gian a poor investment at the same time. Don't ask how I know this, just a bit of experience to pass along. Better to think like a cold calculating business man and look at what investments are required to produce you product (RC & hobbie) at the lowest costs. Then agian some business man are to cheap for their own good. The idea though is to buy to fullfill ones needs and to research what is required for production, just done on a much smaller scale for a home shop.

The other reality is that no matter what you buy you have to be carefull about not draining your cash flow to actually support the machine. That is machines of all sorts need tooling and fixturing. Don't forget about this our your machine will sit there and do nothing.

Dave

Originally Posted by nashtm Thanks for the replies Wizard: thanks for the input - I think you are right Athough I would probably use the mill more for general use than rc and I am looking at buying a smallish chinese BV120b lathe and in my heart I know that I should gain more experience before getting a mill - I think I am getting drawn in by the "opening special" and the chance of saving a few hundred $$$ (rands in my case) Thanks once again. Tim