Yet another 4x4 hybrid cost question

[theminor]

Greetings all! I wonder if anyone can answer some questions about the cost of the 4x4 hybrid for me. I know this has been discussed in multiple threads before, but the answer remains elusive. I've looked through the forums but it looks like I'll need access to Joe's forum to view the detailed BOM and determine my actual costs. But I'd like to get an idea of what the big-ticket items are so I can get an idea of costs. Here is my situation:

I recently built my first cnc machine, following pretty closely the plans from buildyourcnc.com and the new book they are selling. So I'm now up and running with a basic 2' x 4' machine. The problem is that there is a fair amount of flex and accuracy is not ideal for me. More importantly, though, and I now have the CNC bug and I'm strongly considering building a 4x4 hybrid, since it looks like the best design for a home/hobby setup. What I'm trying to figure out is what I can reuse from the buildyourcnc machine in the 4x4 and what additional big-ticket items I'll need to buy. I assume I can re-use my electronics: I opted to go with a Gecko g540 drive, 48 v power supply, and three Keling 387 oz steppers. So I have a good setup with my motors. I also have some 10 TPI leadscrew which is probably too short for any of the 4x4 axes (except the Z I guess), but I have 3 leadscrew nuts from dumpstercnc and acme 10 TPI is quite cheap. But I'll probably want to build the rack and pinion version anyway, since that seems to be simpler and cheaper to build, from what I've read. I also have some other various parts that I might be able to re-use. I have a Hitachi router too.

I would also like to try to mill the mdf and plastic parts for the 4x4 using my existing machine, which will hopefully save some money (wouldn't have to order Joe's kit).

So I'm really looking at the cost of the mechanical parts of the 4x4, I assume. Can anyone help me determine what the big expenses here are? I assume the aluminum extrusions are a big part of it, but I'm not sure what type of extrusions are used. How much is needed? Also, steel angle, bearings, etc. Like many, I just don't want to have to pay $100 to access the BOM just to find out I can't afford to build the 4x4! Any help/advice would be appreciated.

[ger21]

I haven't built one or seen the plans, but I'd guess $2000-$2500. Yes you can reuse the G540 and the motors, but I think you'll need an additional motor. I would not consider using 1/2-10 acme, unless it's at least 2 start or 5 start. Sounds like you have single start, though, which is not a good choice at all, unless you want a really slow machine. If you go R & P, you'll need 3 of these, plus the racks. That and the 8020 are probably the biggest cost items.
http://www.cncrouterparts.com/produc...products_id=50

[curtis]

You are asking something that is hard to pin down. I built the 4x4 myself for a very low cost after some astute shopping and some recycling of parts and other careful collecting of stuff.

However, be prepared to spend at about $2 grand more with yoru present controllers just to get started.

[rfeatherhawk]

See my post here for a little more on the cost,


http://www.cnczone.com/forums/showth...405#post787405