Bootstrapping? (the long road)

[eisman]

I have always been interested in CNC. I have been reading posts on cnczone and doing serious research for about two weeks now. I think I am ready to begin.

My background is computer science and construction. I am decently skilled at utlity type woodworking (ie. Garage cabinets, tool bases, shaker/mission style furniture, workbenches etc..) but I am by no means a cabinet maker. I do have a creative side and an above average warchest of tools for wood and metal working. I am just short of learning to weld, but I do have a 2 post lift in my garage. I also have been doing electronics as a hobby lately, which lead me back to CNC.

Enough about me, my purpose for posting is to get feedback from anyone who has bult their "next" machine with their current rig. I have seen many plans for mini mills made from scanner/printer parts with a dremel doing the cutting. I was thinking about starting out with a small setup like this and using it to drill MDF/pine for the next rig, then using that rig to cut aluminium parts to reinforce itself enough to cut thicker aluminium to make an even stronger mill... I think you get the idea.

My goal here isn't to get to milling asap, it is more education/hobby driven. I don't even know how big I want to go. I may stop at thin aluminum or just build a bigger rig and stay with wood. I'd like to ultimately at least make cabinet doors from glued together 2" pine stock.

I appreciate your time reading this and your replies. I won't be discouraged if the advice is "You are out of your gourd, buy a mini mill and CNC it". I want to know how realistic this course of action is.

Thanks
eisman

[jsheerin]

Mini mill + cnc would be more for small metal working projects. There is another forum for that if that's what you're interested in. Most people here are building wood routers. You can do aluminum work with these, but you typically don't get quite as good a surface finish as with a mill due to lower stiffness of the machine's frame. I don't think there's any reason to build a small machine and then a large one to get a wood router going. Just build what you want to start with using 80/20 extrusions which you can bolt together, and use cnc router parts components for the linear motion. The main tool beyond wrenches and sockets I needed to get this type of machine put together was a drill press for drilling holes in the cold rolled steel you use for linear rails and a few measuring instruments (calipers, dial test indicator mostly) to get things lined up. Having said that, I am planning on using this machine to make some parts to upgrade itself (water cooled spindle mount) and possibly some parts for a large vertical milling machine since these parts are not readily available.

So my advice would be establish what you want to cut to get a machine size and then look at what option gets you there in the way that makes the most sense to you (quickest, cheapest, most fun, etc.).

[Fastest1]

Yeah, what he said. However if deciding that cutting or milling metal is the way you want to go, go as big as you think you can afford and then some. Have you seen anyone post, I wish my mill wasnt so big? The size is so limiting!

[Fastest1]

Btw, the latest use of the term "bootstrapping" that I know of pertains to using a reprap extruder head on an existing cnc machine. I am interested in doing that next and adpating my Sherline to do such things. Shouldnt be any real load on the machine. If you arent familiar with reprap, look it up on youtube. It is cool.

[RomanLini]

I think it mainly comes down to money. The things that make a machine "good" are mainly things like linear rails/bearings, ballscrews, large motors, good motor drivers, and one of the least expensive is probably the structure itself. So if your first, smaller, budget goes on a small machine with limited capabilities then you still need to shell out the cash for all the bits for a good large machine later. And then what are you going to do with your wobbly little first machine?

I would work out the budget for all the main expensive parts first, to just build the machine you actually want to use. There's enough build logs etc on the forum to learn from so you are unlikely to blow it.

On the other hand if you just want the fun of learning, or want a small play machine to do things like route and drill PCBs then just nail something together from bits of wood and printer parts, lots of people have functional little machines like that.

But if your primary goal is to have the end result, the good working machine then start on that from the start. As far as cutting out all the wood structure parts you can just budget that and farm it out to any kitchen shop, there are kitchen shops all over that will cut all your flat wood parts to size for less money than you will probably pay for your linear bearings.