Newbie- Small mill for making alu parts

[Alex.G]

Hi Guys,
i was looking at rockcliff plans and thn was thinking about more rigid construction. I wonna (i plan) build someday a small mill for my rc needs, to make some holders, motor mounts and stuff like that. So it should be small enought and rigid to mill alu alloys.

Please could you suggest some plans or ideas?
Thank you

[will gilmore]

this forum is a great resource. start reading
start thinking about what you need: work envelope, tool size (rpm), accuracy, speed, budget?

[hesham morsy]

hi Alex any mdf plan well be good for a start it well gave u good Experian's
One More thing to ad to Mr. will Gilmore u should have enough space to host the mill

[veteq]

Hee Alex,
been designing and reading for over 4 years now, that mill you want isn`t the most easy, you need precision!!!

To make real nice rc parts for cars you should look at the minitech.com concept.

The machine will need 20000+ spindle, preloaded ballscrews, preloaded linear bearings etc.

A dovetail china mill will be a waste off money for the project.

Maybe you cann read older threads and post of me to get some more info.

Look at the mills of arie kabaalstra and jason (zealcnc.com)

[wildwestpat]

Hi Alex

I guess this is to be as a hobby and that expenditure has to be low. If you are wanting to make parts for another hobby then I suggest you fix by answering these questions:-

1. Fix how much you can (want to ) spend on the Mill and halve that sum to give some cash for tooling?

2. Decide how big the machining envelope needs to be. X,Y and Z axis

3. Decide on the accuracy and dimensional repeatability you need.

I would not be too hasty to pass over the far east drill mills. These are low cost and there is a wealth of CNC conversion information and parts available. Used with care and understanding accurate parts are with in the capability of these drill mills. A lot of the comments on poor quality relate to early examples and the quality has increased a lot from the early 2000's. Since you are in Europe you will find a number of different sources for these far east mills in addition to those of the Seig factory. Some of these are better in that they have not only greater machining envelope (X,Y and Z dimensions) but also have more ridgidity in their castings, slide widths etc. These start at arround the 350 euro mark for a basic manual up to 4,000 euro for the latest CNC ready to go.

I suggest going with a far east drill mill unless you have access to some machinery on which to make your first machine. You can then convert the base drill mill to CNC and make other mills and RC bits as the fancy takes you.

Hope this helps narrow the choice.

Regards

Pat

[Alex.G]

Thanks
you are right with precision, but not for that price
I was rather thinking about what is better? buy a sherline 5100 mill or some cross table as a base.
Or some all-custom-made mill from alu profiles.

[veteq]

Originally Posted by wildwestpat I suggest going with a far east drill mill unless you have access to some machinery on which to make your first machine. You can then convert the base drill mill to CNC and make other mills and RC bits as the fancy takes you.

You hit the nail right there Pat, maybe my conclusion was to fast, i was thinking in my own situation. I`ve you have CAD and know how to use it things get better, the ballscrews, linear bearings and spindle can be bought in ebay for around 1250 euro, then the machine controler with motors etc. will be another 750 euro.

The problem is lets say the 20 parts you need machined to bold it all together,
been trying to find a nice shop overhere in europe to do the job, all between 3 and 4000 euro. Now i`m talking with China, quotes between 4 and 600 dollar are here with shipping, all machined on expensive nice precision machines.

So a minitech one off cann be done for around 2500 euro, but a lot off patience and reading is needed. The China mills are nice but another leaque then the minitech, its a different machine concept....

I would advice you to read a lot overhere and dont make the decision to fast.

Regards,

Roy

[wildwestpat]

Hi Alex

I still think you need to work out how you are going to make the initial machine. The way many people start is with a far east mill drill or a combo lathe/mill/drill either new or second hand.

The Sherline 5100 as a starter pack is arround the 1,000 euro mark with no CNC. CNC conversions are available and will double that price and more.

Yes you could build an X-Y trolley arrangement using precision slides and screws but don't expect to have any change and you still have no mast for the Z axis and you will need to get the mounts for the screws machined some where or try and find a suitable kit of parts. This option is going to be expensive as the precision trolleys and ground rail are aimed at the production tool market and this is not known for its cost sensitivity as making rejects due to poor performance is the major design driver not cost.

There are some very cheap X Y vices that may have caught your eye. These are available for arround 30 euros but are not precision tools. The ridgidity might just about be OK for a bit of very light milling in plastic or alloy using a drill press for the Z. BUT and it is a very big but the accuracy will be poor and the chances of getting a satisfactory finish will be difficult as neither the drill press or the cross feed vice are adequate for milling. This set up would be suited to drilling holes in a pattern within the accuracy of the lead screws of the X Y vice traverses - think 0.1 mm tolerance at best. You could do as well by eye after a little practice.

The alloy sections that are available are certainly capable of building good machines provided the sections are heavy duty and of adequate cross section. However this will turn out to be expensive particularly if you have to buy bearing mounts and other parts. There are a number of good build threads for such machines on CNCZone.

Suggest you think long and hard about the three requirements I outlined in my pervious response. If you have no machining experience or local help the Sherline is a no risk route as there is a strong following for these mills in the various on line forums. The same comment applies to the X1 - X2 and X3 machines which cost a lot less.

Think twice and buy once.

Regards

Pat

[Alex.G]

have no exp at all and that is why i'm here, you guys opening my eyes widely, and it is better to get direct feedback rather than just reading and thinking about it with no exp behind.

Wonna buy lather as first machine, i think C0 is enought for me, price is good, rigidity is ok for my needs. Before that i was looking at TheCoolTool/Xendoll kit, but realized it is not good enough (http://cnczone.com/forums/showthread...158#post688158)

So maybe SX1 (coz X1 has no tilt) or SX2/X2 (SX2 just more powerful motor) is for me, just need to get some quotes here in EU.

[wildwestpat]

Hi Alex

The C0 lathe is a little on the small size and its bigger cousins C2 and C3 represent better value and would permit you to do some lathe type milling with the appropriate vice. The tilting of the head or mast is a little used feature for most operations where the three axis are needed to be as exactly at 90 degrees as possible. If you need to machine angles then holding the work on the table at the appropriate angle will get you out of most situations. X1 & X2 have a tilting masts and X3 a tilting head. However X3 has a quill and this has issues about play but can be worked around by clamping the quill when required. If you have the cash there are also the lathe / mill combos which whilst not as ridgid as individual machines are capable of machining alloy and steel if the feed rate is kept low.

Suggest you view the MIT workshop videos that have been prepared for students taking degree courses in robotics as these cover most of the basic machining operations and give a very good feel of what is involved. Look at all the videos as I have only posted a link to one of the set. All are worth a quick view.

http://techtv.mit.edu/genres/24-how-...machine-shop-5

Hope this helps

Pat

[Alex.G]

so you are saying c2 with x2 is best i can get for that money?
Thank you very much for vide links, will download them and look at.

P.S. off topic, is it possible to install brushless motor and esc from rc world into those?

[veteq]

Originally Posted by Alex.G P.S. off topic, is it possible to install brushless motor and esc from rc world into those?

No, that in`t possible, if you begin with cnc machines i think it is smart to look at control throough stepper motors.

You make a design in a CAD program, than you open that part in a CAM program, here you make a strategie how to mill youre part out off stock.
This CAM program makes a code in a Wordpad file (code is called G-code)

This G-code is loaded in a machinecontroller software (MACH3 by Artsoft)
This machinecontroller software gives a signal called a pulsetrain (With direction) through the parallelport of youre PC.
This pulsetrain goes through a wire to the drive that will turn the steppermotor, this steppermotor turn the screw that makes the table move.

RC motors aren`t suited for this.