Well, I've been lurking for a few days, checking out the board. Now I'd like to be able to build my own gantry-style mill that I would convert over to CNC later down the road.

The motor I'll be using is a dremel, and I picked up a few endmills for it.

I'd like to use 8020 aluminum extrusions but I'm not sure how long.

The materials that i'll be cutting would be aluminum and plastic. The aluminum pieces would most likely be no larger than a foot long. the plastic, same deal.

Most of the designs would be transcribed on the aluminum/plastic itself.


Other than that, I'm pretty well clueless as to what parts I need to build the mill with.

Well how wide are the parts...you may be better off buying a mill/drill (table top mill).

I'm not sure what you mean. are you saying how wide is the aluminum profile?

How wide is the aluminum you'll be cutting. You said about a foot long. How wide?

Yes, how wide....it under 7 inches a mill/drill will handle it....

ah ok. well the aluminum would be about six inches wide at most.

reason I want to build my own is for the challenge of doing it.

Unfortunately your poor dremel will bend, twist, scream and smoke if you try to cut aluminum with it. You may be able to engrave with it, but not much more than that.
There is a huge difference between a mill and a router. A mill spindle runs at low RPM's (1500-4000) with very high torque, a router runs at high RPM's (15000-30000) with very low torque. Typically a mill is very solid, ie. made from cast iron, and a router is significantly less solid. Usually, you would use a mill to cut metals and a router to cut wood. Plastics can usually be cut on either. I am not saying that you cant cut metal on a router or wood on a mill, each has their application, just make certain you choose the right machine for the job.

Colin

Okay, maybe the word 'mill' wasn't the right choice. I guess it would be considered a three-axes manual router now.

There are a couple of things t consider beyound the use of a Dremel tool.

First charactristics that make a good manual machine may not apply to a CNC machine. Building for two different uses will result in compromise. One issue here is the leadscrews. For a manual machine they need to hold postion by them selves, ideally on a CNC implementation they would be ball screws or low backlash screws.

Location of the handles, indeed the very nature of the router will be dictated by the need to keep handles close together. It would be less than ideal for example to place a handle on a moving gantry. CNC is far more flexible in this respect.

I see nothing truely wrong with your idea, just realize that coordinating the movement of the axis will be a chore. Also iff the future revision is to go CNC then you need to consder that in your design today.

dave

Well, I've planned on the Z axis being able to hold itself as you mentioned, so I can set the cutting depth (which will probably be no deeper than 1/16" per pass) and let the bit do the work.

X and Y axes will have a little less hold, but enough to prevent the dremel from bouncing around like a superball.


I've also figured that when it's time to convert to CNC, I'll be able to remove the self-holding screws and replace them with ballscrews in a way that's simple to do.

Because if i'm going to build this thing, I may as well make it easy to perform maintenance and conversions to it.


On an off note, I tried cutting aluminum with the dremel on a scrap heatsink, and as long as I took it easy, it worked great.

Well you could always CNC a manual desktop Mill and end up with a much better machine...

wouldn't that negate the whole DIY process?

If you have access to a full size mill, and don't mind going straight to CNC, jgro's router plan can be easily modified for what I *think* you want to do.
Build it out of aluminum, instead of MDF, and use linear rails and bearings instead of the roller bearings and pipe, and build a gear reduced spindle. (You can put manual handles on it, but it will probably be awkward to use.)

Been there, done that, worked pretty well on non ferrous materials, and even though it is not the best way to get the end result, it turned out better than I thought it was going to. Approx. $200 CDN for the machine, less electronics, and I scrounged the linears.


HTH,
Iain

wouldn't that negate the whole DIY process?

there are lots of things that you should not DIY, either because they are so far beyond your ability, or they are so mucher cheaper to buy out. Nobody would make their own ball bearings or wire, right?

making a small metal working mill is both of the above - its a poor choice for a beginner project from a complexity point of view and will likely cost you more than some of the small bench top mills.

think about what you want - you suggest a decent work envelope, but you want to use a dremel? You will go mental with it. Consider learning a little bit about machining before you embark upon making your own machine tools.

what sort of things do you see yourself making?

There is nothing stopping anybody from building their own small metal mill.
It could be done as a project to simply prove you can, or to build a useful piece of machinery. Either way, no bigee, go to it. :cheers:

I have copies of articles from 1920's magazines that show you how to build various equipment and all of the equipment I built from them worked well, and got the job done if you understood their limits. A small benchtop horizontal mill is reasonably easy to do, and a vertical slightly harder, but you will need either a lathe, or someone to rework your spindle for you.

Using an 8 or 10 inch drill press, and an X-Y table from almost anywhere, you are mostly there. Then replacing the bearings in the drill spindle, making a quill lock, and an adapter to hold the endmill. DO NOT USE THE CHUCK TO HOLD THE ENDMILLS!!! Very bad things can happen!

Been there, done it, cost breaks done to about $40 for the (used) drill press, $60 for the XY table, $20 for the bearings and various bits from the scrap box.
Please note that the above prices are CDN $ and for most of the world, your cost will probably be less.
The idea came from an article I read on either the Colorado Model Engineering Society, or the Bay Area MES webpage, about an adventursome fellow who builds museum scale engines with an offshore 7x14 lathe and his 16" drill press converted to a mill.
Having said all that, if you are looking to save money, then unless your time is free, forget about it. I spent alot of time polishing the ways on the table and making the POS work, and if you want a knee mill, you will still have to come up a way of making that work. I did, but in the end I went with a floor model drill press and I still wound up with a miller that maxes out at a .100 pass in aluminum with a 1/4" end mill.

Why did I do it? Because I can not buy a small bench top mill for the less than $150 I spent on this, I had alot of extra time on my hands that month, and for what I need, this will do the job

As far as using a dremel for the spindle, not really worth it. They are too light, burn out fast, and too pricey to keep abusing. For the cost of 1 Dremel, you can make a decent spindle that will easily handle the cut passes you described.

Check out this, for a more detailed version:

http://www.pathcom.com/~vhchan/cnc/cnc.html

HTH,
Iain

interesting. I'll keep that in mind.

Now onto the part about Linear Bearings. I had a look around the board for these type of bearings, but I'm still in the dark about them. Also, what's a good source for Linear Bearings?

and yea, when I used the word 'mill', I did mean 'router'

Unless you know of a local company that surpluses linear rails and bearing blocks, in Canada, Ebay is your best bet for buying these components. As an example I bought 12 bearing blocks and 16ft of 17mm rail for about $300 thru Ebay, and buying the IDENTICAL branded components new was $110 per block(Bosch), and $10/ft for the rail (Star brand).

Have a look at these guys to see what is available for linears:
http://www.leecontrols.com/OLCAT~1.HTM

I've never dealt with them so have no ideas on costing.

If a router is what you are looking for, personal experience says forget about a wood frame for what you want to do. A system similar to JGRO's router, made from aluminum, will work decently if you have a solidly built rail system and forget about the Dremel.

HTH

Iain

there are lots of things that you should not DIY, either because they are so far beyond your ability, or they are so mucher cheaper to buy out. Nobody would make their own ball bearings or wire, right?

You would be very surprised to find out what some companies build for themselves. Sure they would like to get the vendor to supply the specialty stuff, but not all vendors or suppliers are willing to step up to the plate.

As to hobbie market well the only person you have to satisfy and justify things to is yourself. So if you have an itch why not go for it?

Using your thinking yahoo groups like the casting and Gingery groups would nte even exists. Sure some people would have a hard time justifying casting iron to make a door stop that can be purchased just about anywhere, but that is not the person the caster needs to worry about.

Cheap is another thing all together. I was just at the Iron Fever auction and saw some hardware go for prices I thought where way to high. But the effort to generate a functional machine froma heap is something I didn't want to deal with. That perspective could certianly change if I ended up with time on my hands suddenly.


making a small metal working mill is both of the above - its a poor choice for a beginner project from a complexity point of view and will likely cost you more than some of the small bench top mills.

Actually I think a router type machine is very good for a beginner. You can produce a full CNC machine for very low costs if you really want to. In the process you can learn a lot. A vertical mill is another story partly because of the differences in expectations, but somebody with machine shop experience could certainly pull it off as a first machine.


think about what you want - you suggest a decent work envelope, but you want to use a dremel? You will go mental with it. Consider learning a little bit about machining before you embark upon making your own machine tools.

Thinking before hand is always a good idea. A dremel has its place, probally wouldn't cut it for the original poster though. Where I would disagree though is that in my mind building a gantry type machine is a good place to build skills and learn machinery/machining. These sorts of machines can be done as cheaply as one wants or as elaborate as one wants. The good thing is gianing experience to apply to other tasks.


what sort of things do you see yourself making?

A good question to ask. The projects can dictate the optimal tool.

Dave

Not wanting to be taken as raining on Murdoch’s parade, let me add …

As to hobbie market well the only person you have to satisfy and justify things to is yourself. So if you have an itch why not go for it? .
Stretch is great but if the goal is so disparate from the resources at hand, you’re not helping him by cheering him on. I’m generally very can-do, but a rank beginner with no machine knowledge and no machining capacity or machine design knowledge would frustrate himself out of the hobby by starting with a manual mill build. Apologies to Murdoch if I’m wrong.

Using your thinking yahoo groups like the casting and Gingery groups would nte even exists.
Not fair, my post was to Murdoch’s situation.....I can’t imagine there any many good Gingery builds by people with no machining experience, no machine shop capacity etc. I’m a big fan of wacky new ideas (presented some of my own here) and encouraging people to go for it – but in his situation I thought there were better approaches like get a small mil/learn/start to convert to cnc etc.

Where I would disagree though is that in my mind building a gantry type machine is a good place to build skills and learn machinery/machining.
its semantics imo mill? router?, his primary thing is cutting AL so without more input and wanting to cut metal I think of it as a mill. That’s why more info on what Murdoch wants to make would help people to give him good advice.

Murdoch I wish you all the success and stand by my advice, making a manual metal mill is a tough go for a beginner without experience or a shop. It’s a project probably not considered worth while by an experience metal workers, although that’s more intangible – i.e. how you want to spend your time.

doh! I seem to have a few people confused here. When I said I wanted to cut Al, what I meant was I wanted to trim it. I know the dremel will die, screaming evil chants and curse words if I try and and plunge it into anything harder than Lexan, or thicker than 1/4".

One of the uses will be to trim a heatsink to fit a computer graphic card. So it will be very light-duty work. I've tried it before, freehand style. Not only did the dremel make short work of a scrap heatsink I had, I actually was able to achieve a relatively smooth surface by having it set one setting below high speed.

The depth was 1/64" and I went extremely slow. I would have no idea of the ipm (ipm means 'inches per second', correct?), but from what I saw from trying it out, I really liked.


On a secondary note, I've made accomodations to swap out the dremel for a much stronger motor when the time comes, which would fall into about the same timeframe as going to full CNC.

I've also worked in a machine shop (i get giddy when I see a new CNC machine :) ) a long time ago, and my favourite toy was the erector set. So putting together this type of project would be familiar ground for me.

So in a sense, this gantry-style manual router could be considered a prototype.

sorry if I underestimated your ability or overestimated the project. The way you've described it, I was wrong and it could well be something the beginner takes on. Nevertheless, you might be better off on a path where you ended up with a cnc mini mill. good luck with it and take lots of pictures!