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Thinking about CNC
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Author:  Melvin Tucker [ Sat Mar 22, 2008 11:25 am ]
Post subject:  Thinking about CNC

Im thinking about getting a cnc machine. IMservice and Romaxx has a small machinge for around 2500-3000 and Shopbot has one a little bigger for around 4500.00. I wish I could build one like some of the guys on here but I have no knowledge about the machines so I don't know what to get much less how to set it up so I guess I need to go the package deal route. Ive had 3 different machines recommed which are the ones above. The Imservice and Romaxx size might work for mandolin work but not for anything on guitars and the Shopbot Buddy is big enough for both. I don't know if I would use it enough to justify the cost.

Author:  Parser [ Sat Mar 22, 2008 12:19 pm ]
Post subject:  Re: Thinking about CNC

I'd recommend getting into cad first...Rhino is a great package at a reasonable cost (http://www.rhino3d.com)

If you find that you enjoy doing the cad work, then cnc would be a good next step.

Author:  Melvin Tucker [ Sat Mar 22, 2008 2:13 pm ]
Post subject:  Re: Thinking about CNC

Someone who is into cad software and cnc machines is suppose to give me some cad software but I don't know what it is yet. He said he had used it to design his own airplane.

Author:  Jim Watts [ Sat Mar 22, 2008 2:16 pm ]
Post subject:  Re: Thinking about CNC

I agree with Parser, learn CAD first, then a machine might make sense.
I have a cheap router and it's very frustrating at times, not the programming the machine itself. I've had to rebuild quite a bit of it due primarily to backlash issues. I think you pretty much get what you pay for in these cheap machines.
I think the biggest bang for your buck is building a machine. Don Williams machine is going to ROCK compared to mine. The Shopbot is at least a usable machine from what I've seen.
Just my thoughts.

Author:  Bob Garrish [ Sat Mar 22, 2008 2:58 pm ]
Post subject:  Re: Thinking about CNC

CAD first is a good idea. If you can get your CAD down, then get some basic CAM software. Actually, if you can do the CAD then the machining software is quite easy to use at a basic level (easy to use, hard to master :) )

The other way to go is to just get the CNC machine and outsource your programming, though you need pretty specific reasons for that one. It's not a money saver, generally, to buy a machine and outsource programming (compared to just buying the parts you need), unless you've got need of a lot of parts. Still, in some cases that's the way to go. I do contract programming for some router manufacturers who offer 'turnkey' solutions to customers. The customers send me all their parts, and then the company delivers a machine already programmed to cut their stuff.

And, finally, as a general rule router manufacturers lie through their teeth about the capabilities of their machines. Either find someone using the machine you're looking at for the purpose you're looking to use it for, or find someone who really understands machines, and get a second opinion before you set your expectations based on what the sales people say. (or do a lot of reading on CNCZone, though I find there's a huge gap between guys on there for hobby stuff and the professionals. You can find loads on really accurate and fast machines, and loads on really inaccurate slow machines...but there's little talk about the stuff in the middle, relatively speaking)

Author:  Parser [ Sat Mar 22, 2008 3:46 pm ]
Post subject:  Re: Thinking about CNC

I have a k2 3925 machine and am very happy with it. It is a good machine for hom/light duty use with good enough accuracy for fret slotting & inlay.

I got the machine & all the software for about $9k (i'm using rhino & rhino cam).

Author:  Melvin Tucker [ Sat Mar 22, 2008 6:44 pm ]
Post subject:  Re: Thinking about CNC

well, I may have a leg up. My son is a flight paramedic and works with a pilot who is very well versed in the cad and cam software. So I think I could get some help in building the models I need to do the mandolins, etc

Author:  Don Williams [ Sat Mar 22, 2008 8:30 pm ]
Post subject:  Re: Thinking about CNC

I have to agree with all the guys who say that you should learn cad first before diving in to cnc. I have a cad background, so it was pretty easy for me, but I think there's going to be a learning curve with the cam stuff. That's all new to me.
I will say this...a LOT of mandolin guys are using cnc, because it helps them with all the difficult curves and the bindings for them. I was talking to a very well-known mando guy who was getting into cnc a number of years ago. When I asked why, he said "because all my competition is using it". Seemed like a logical move to me. For me, although selling wood has puled me away from building for awhile, I thing the main reason I'm getting into cnc (besides my backgammon board) is because my time is so limited for working in the shop. For me it is a major time saver, and it will also allow me to do things that I couldn't do in the past. I might even tackle a mando one of these days...

Author:  Marty M. [ Sun Mar 23, 2008 1:11 pm ]
Post subject:  Re: Thinking about CNC

Hi Melvin,
Here is what my approach was. I sent for plans to make a desktop cnc. It was from http://www.crankorgan.com. John's plans are designed to be built with a minimum amount of tools. He only has a drill press,belt sander, and assorted hand tools. He uses plastics, MDF, and aluminum for most of his designs. I bought a kit of motors and controllers and software from Maxnc. I built the CNC machine and learned how to make basic shapes by generating simple Gcode. After a while I decided to build a bigger version of my own design, big enough to work on necks and bodies.
Simple 2D CAD isn't all that difficult to learn for basic shapes. You can download a free version of CADdraw and get started there. It's not the greatest program but the price is right and you can save as a DXF file. Between all of these things you start simple and work you way up to complex shapes. If and when you get to the point where you want a commercial machine, you will probably want to go 3d..like Rhino with a bigger learning curve, but this way you can see results pretty rapidly and it may motivate you to really get into it. As always your mileage may vary.

Author:  Guest [ Sun Mar 23, 2008 3:50 pm ]
Post subject:  Re: Thinking about CNC

That should have been Cadstd not caddraw in the above post.
Marty

Author:  Melvin Tucker [ Sun Mar 23, 2008 7:56 pm ]
Post subject:  Re: Thinking about CNC

well I guess after reading all this I better stick to the old fashion of doing it all by hand.
I probably can't master all this Cad stuff. I can still remember when farmers were still using horses, mules an wagons.

Author:  Don Williams [ Sun Mar 23, 2008 8:11 pm ]
Post subject:  Re: Thinking about CNC

Melvin, I have no doubts that if you can build an instrument as well as you do, that you can learn cad. It's not that hard. Pretty much it's just using a computer to do drafting instead of a pencil and triangles and compass etc. It's very logical, and a lot of software out there is very intuitive to learn.

Author:  KenH [ Sun Mar 23, 2008 9:30 pm ]
Post subject:  Re: Thinking about CNC

I'll jump in with another vote for the CAD first. I went the other route and am paying for it. I now have a good CAD/CAM software package and am learning how to do things on my own. This is a slow process, but it can be done.

Don's machine is going to rock! Mine is made from MDF instead of aluminum, and is one of those "in between" routers that Bob mentioned above. I think it is fine for the tolerances needed for most rough cutting that I do, but there is no way I would want to try any extreme precise work with it.

CNC machines can be built much cheaper than bought. Go look at one someone else has and you will see how to build one. You can expect for the software to cost as much or more than the machine.

Author:  Jim Watts [ Sun Mar 23, 2008 10:37 pm ]
Post subject:  Re: Thinking about CNC

Melvin, Don't be discouraged yet. You can down load a free trial of rhino and play with it. You might like it. I'd bet you can figure it out.

Author:  Melvin Tucker [ Mon Mar 24, 2008 9:31 am ]
Post subject:  Re: Thinking about CNC

Thanks fellows I had such visions of becoming a "High tech Redneck". A guy on another forum sent me some info and a picture of the machine that he made. It was a very, very nice machine. The problem with me building one is not knowing what I need to buy to build it.

Author:  Melvin Tucker [ Mon Mar 24, 2008 9:44 am ]
Post subject:  Re: Thinking about CNC

How hard would it be for one of you guys who knows all about these things and how to build them to come up with a list of parts, parts name and numbers and where to get them. Include everything even the software cad and cam. One guy sent me a pic of his cnc and it looked fantastic better looking than factory made. He said he got most of his parts off ebay. However he works in cad and cam everyday and know exactly what he needs.

Author:  Don Williams [ Mon Mar 24, 2008 10:26 am ]
Post subject:  Re: Thinking about CNC

Melvin Tucker wrote:
How hard would it be for one of you guys who knows all about these things and how to build them to come up with a list of parts, parts name and numbers and where to get them. Include everything even the software cad and cam. One guy sent me a pic of his cnc and it looked fantastic better looking than factory made. He said he got most of his parts off ebay. However he works in cad and cam everyday and know exactly what he needs.


I'm working on a *similar* concept as we speak.... a "DIY" cnc, everything included, but with assembly required. All parts cut, drilled, tapped, and ready to assemble and plug in. Gives you the DIY experience without having to chase down everything. All the tools you need for assembly are allen wrenches - for the most part.

Author:  Melvin Tucker [ Mon Mar 24, 2008 12:58 pm ]
Post subject:  Re: Thinking about CNC

Don since you are building one I thought you might like to see this. This guy has been really trying to help me. He built this from parts off of ebay. I think he said he has about 2 K in it and that he is going to enlarge it some.

Author:  Don Williams [ Mon Mar 24, 2008 1:47 pm ]
Post subject:  Re: Thinking about CNC

Interesting design. Looks like he's using ballscrews and 8020 linear motion glides and rails. Not a bad design. Small, but for mandolins, not bad at all. Looks pretty solid. Motors looks like NEMA 23's, perhaps a bit small, but they'll suffice.
He did a pretty good job if all it cost him was $2K...

Author:  Jim Watts [ Mon Mar 24, 2008 11:35 pm ]
Post subject:  Re: Thinking about CNC

I like the way the Y axis isn't cantilevered way above the X axis. This should be a more rigid design.

Author:  Don Williams [ Tue Mar 25, 2008 9:37 am ]
Post subject:  Re: Thinking about CNC

This is true, it will be relatively stable, but it also severly limits the usage of the cnc. His Z height is limited to about 4.5" or so. Mine is 8.25", which can allow me to do a lot of things with it. Then again, for all I know it may be overkill.
:)

Author:  Jeremy Vonk [ Tue Mar 25, 2008 9:44 am ]
Post subject:  Re: Thinking about CNC

Can't ever have too much Z! :D

Author:  npalen [ Tue Mar 25, 2008 9:52 am ]
Post subject:  Re: Thinking about CNC

Speaking of "Z", what is the origin of the Canadian "Zed"?

Author:  Don Williams [ Tue Mar 25, 2008 10:59 am ]
Post subject:  Re: Thinking about CNC

As in "Zed PM"? aka Zero Point Module....or ZPM?

Author:  Bob Garrish [ Tue Mar 25, 2008 11:08 am ]
Post subject:  Re: Thinking about CNC

Short answer is that the origin of 'zee' is the outlier. The US is the only English-speaking country that says 'zee'.

Slightly longer answer is that the pronunciation wasn't set in stone in England when them misfits took off to the West over the sea, and the ones who landed South of the border happened to be the small set of zeesayers.

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